From nienhuis at stream.csis.gvsu.edu  Sat Aug  1 00:46:48 1998
From: nienhuis at stream.csis.gvsu.edu (Dogma)
Date: Fri, 31 Jul 1998 18:46:48 -0400 (EDT)
Subject: VCO idea
In-Reply-To: <35C1FB60.1CEBC55F@silver.sdsmt.edu>
Message-ID: <Pine.HPP.3.95.980731184445.9739B-100000@wiggler.csis.gvsu.edu>

On Fri, 31 Jul 1998, Jay wrote:

> I want to use my laptop computer as a midi sequencer, but it lacks a
> gameport.  Does anybody know of a PCMCA card that does midi?
> 

Why not just get a cheap soundcard like a SoundBlaster PCMCA.  It should
have a gameport/midi port on it.
						-R Nienhuis





From nc0839 at corp.netcom.com  Sat Aug  1 01:41:27 1998
From: nc0839 at corp.netcom.com (David Lee)
Date: Fri, 31 Jul 1998 18:41:27 -0500
Subject: VCO idea
Message-ID: <199807312340.QAA11494@k9gw.corp.netcom.com>

Try a midiquest parallel midi adaptor. It is 4 port!

David Lee

----------
From: Dogma <nienhuis at stream.csis.gvsu.edu>
To: Jay <jpc2125 at silver.sdsmt.edu>
Cc: Synth DIY <synth-diy at mailhost.bpa.nl>
Subject: Re: VCO idea
Date: Friday, July 31, 1998 5:46 PM

On Fri, 31 Jul 1998, Jay wrote:

> I want to use my laptop computer as a midi sequencer, but it lacks a
> gameport.  Does anybody know of a PCMCA card that does midi?
> 

Why not just get a cheap soundcard like a SoundBlaster PCMCA.  It should
have a gameport/midi port on it.
						-R Nienhuis





From 9705146x at lux.levels.unisa.edu.au  Sat Aug  1 06:38:59 1998
From: 9705146x at lux.levels.unisa.edu.au (9705146x)
Date: Sat, 1 Aug 1998 14:08:59 +0930 (CST)
Subject: VCO idea
In-Reply-To: <35C1FB60.1CEBC55F@silver.sdsmt.edu>
Message-ID: <Pine.SOL.3.91.980801140826.24414A-100000@lux.levels.unisa.edu.au>



On Fri, 31 Jul 1998, Jay wrote:

> I turned 20 on June 23rd.  Have I got you beat?
> 

Nope,,,,, i just turned 20 today, 1st of Augist :)

<bUd>



From merlin at ion.com.au  Sat Aug  1 06:45:41 1998
From: merlin at ion.com.au (Merlin Zener)
Date: Sat, 01 Aug 1998 14:45:41 +1000
Subject: VCO idea
References: <Pine.SOL.3.91.980801000011.8479A-100000@lux.levels.unisa.edu.au> <35C1FB60.1CEBC55F@silver.sdsmt.edu>
Message-ID: <35C29D75.9A60BEC9@ion.com.au>

Jay wrote:
> 
> [...snip]
> I want to use my laptop computer as a midi sequencer, but it lacks a
> gameport.  Does anybody know of a PCMCA card that does midi?
> 

IMHO you're better off getting an external MIDI interface that
plugs into either the serial or parallel port. There's a MOTU
parallel port unit that does two independant ins and outs; I own
a serial port one from Key Electronics that has one input and
four independant ouputs, for a total of 64 MIDI channels...

-- 
Merlin Zener                            mailto:merlin at ion.com.au
Piano and Synthesizer               voice: (+61) (0) 418 779 594
Gold Coast, Australia              http://www.ion.com.au/~merlin

"No-one ever went blind from looking on the bright side of life"




From urekar.m at EUnet.yu  Sat Aug  1 10:23:18 1998
From: urekar.m at EUnet.yu (<<marjan>>)
Date: Sat, 01 Aug 1998 10:23:18 +0200
Subject: please help with PSU  :-((
References: <35BF5010.2DBB2094@vossnet.de>
Message-ID: <35C2D076.7B23@eunet.yu>

tim0 (Timo Christ) wrote:
> 
> Hi,
> 
> i?m a bloody beginner and started working on my little synth last week.
> the first thing i built was /is the PSU, after lots of trial and error
> and i have learned from mistakes :) it still doesn?t work.
> to be precise, the -15 V regualted output doesn?t work.

Hey,it's my lab experience time :)

(assuming that you made everything right )
It seems that 7915 (and 79xx) need some output load to work ,so
when you test it it doesn't work but when connected to rest
of the circuit it works.Try connecting some 1k resistor from
regulator output to gnd when testing it .I had the same problem
some time ago...

sorry for late response



marjan



From bnillson at hotmail.com  Sat Aug  1 22:37:36 1998
From: bnillson at hotmail.com (Bjarne Nillson)
Date: Sat, 01 Aug 1998 13:37:36 PDT
Subject: VCO idea??
Message-ID: <19980801203736.24049.qmail@hotmail.com>

>On Fri, 31 Jul 1998, Jay wrote:
>
>> I want to use my laptop computer as a midi sequencer, but it lacks a
>> gameport.  Does anybody know of a PCMCA card that does midi?
>> 
>>Why not just get a cheap soundcard like a SoundBlaster PCMCA.  It 
should
>have a gameport/midi port on it.

Oh dear o dear, using a PC for Midi just hopes that
its not ""runnig"" under WIN311....

I hawe only problems whit my PC...:-(

BJ


______________________________________________________
Get Your Private, Free Email at http://www.hotmail.com



From bnillson at hotmail.com  Sat Aug  1 22:43:31 1998
From: bnillson at hotmail.com (Bjarne Nillson)
Date: Sat, 01 Aug 1998 13:43:31 PDT
Subject: Buchla
Message-ID: <19980801204331.18026.qmail@hotmail.com>

Hiiiii.

Does anyone have the email adress/odinary adress to
MR Don Buchla??

Is he still alive?

Nisse

______________________________________________________
Get Your Private, Free Email at http://www.hotmail.com



From eduni at ucsd.edu  Sat Aug  1 23:10:40 1998
From: eduni at ucsd.edu (Ethan Duni)
Date: Sat, 1 Aug 1998 14:10:40 -0700 (PDT)
Subject: VCO idea
Message-ID: <199808012110.OAA10228@smtp.ucsd.edu>


>Nope, I just turned six last week.

-well, i'm 19 but i don't know how to read.  does that count as young?

Ethan




From sky36919 at skynet.be  Sun Aug  2 05:29:09 1998
From: sky36919 at skynet.be (Hugo Haesaert)
Date: Sun, 2 Aug 1998 05:29:09 +0200
Subject: VCO idea
In-Reply-To: <199807311026.MAA29436@window.intermetall.de>
Message-ID: <199808020329.FAA08858@papagena.skynet.be>

Hi Martin and List !

Have a look at the digisound VCDO for anti aliasing at :

http://www.synthfool.com/vcdoschm.jpg

Uses low slew rate of 741 to do the job :)

Keep 'em oscillating :)

Hugo
=



From terrymbowman at rica.net  Sun Aug  2 05:45:23 1998
From: terrymbowman at rica.net (KA4HJH)
Date: Sat, 1 Aug 1998 23:45:23 -0400
Subject: Another Buchla question
Message-ID: <v04011700b1e990dc7cf7@[208.1.108.63]>

Does anybody know how Don's name is pronounced? It's not as tricky as Moog
but it's more ambiguous. I hate getting names wrong. I've been wondering
for years.
Terry Bowman, KA4HJH
"The Mac Doctor"



From cmacdon at ix.netcom.com  Sun Aug  2 10:21:52 1998
From: cmacdon at ix.netcom.com (cmacdon at ix.netcom.com)
Date: Sun, 02 Aug 1998 01:21:52 -0700
Subject: First module done
Message-ID: <35C421A0.60AE@ix.netcom.com>

Greetings,

I have completed my first diy module, a "Triple Sine to Pulse
Converter".  There are pictures of it along with the previously
mentioned schematic if anyone is interested:

http://www.evenfall.com/diy/pwm.html

-Chris



From dfulton at kopb2.opb.org  Sun Aug  2 11:27:49 1998
From: dfulton at kopb2.opb.org (Dave Fulton)
Date: Sun, 2 Aug 1998 02:27:49 -0700 (PDT)
Subject: PAIA Shepard Function Generator
Message-ID: <Pine.BSF.3.96.980802013346.6769A-100000@kopb2.opb.org>

This is strange but true...

A little history.

I lost this PAIA kit years ago, unbuilt & waiting for me to complete. 

I have built, given away, sold,& begged people to take away many a PAIA
modular, proteus etc.. But I kept the EK-9 shepard function generator. I
just never had the time to complete (or even start) building it. It was
allways put aside for somthing more exciting at the time. 

Over the last couple of years or so I thought about it & started to look
for it (I mean really look for it!) but was never able to find it. I
finally gave up figuring I gave it, or threw it away.

And now the strange part... 

I was cleaning the cat box...And I was by the sink in our basement laundry
room, I looked upon the ironing board my wife had set up, and just sitting
there was my missing kit. All parts & the PCB, I could not believe this. I
called up to her and asked "where did you find this? I have been looking
for this years!". 

Her response was "That thing?... It just was allways in my way, I kept
moving it and no matter where it put it, it was still in my way. I was
down in the basement looking for the lantern for our camping trip and it
was in my way again. This time I left it out to ask you about it &
possibly throw it out"!

Why is this going out on the list? 

I cannot find the wiring diagram,schematics or anything else about it. Can
anyone supply any info about this item. Will it finally be worth my time
to build it or should I loose it again? 

Is it as cool as I remember?

The moral? Clean the cat box often & talk to your wife about your
EM projects. She may not be interested, but you might find out about
your missing shit.


Dave





From chrisc at zetnet.co.uk  Sun Aug  2 12:33:44 1998
From: chrisc at zetnet.co.uk (Chris Crosskey)
Date: Sun, 2 Aug 1998 11:33:44 +0100
Subject: chorus pedal IC's
Message-ID: <199808021033.LAA05727@irwell.zetnet.co.uk>

Hi Folks, 
While on the subject of MN3xxx series stuff I'm still trying to find a data 
sheet for the MN3005, and/or service sheets for the Melos Analog Delay and the 
Echorder analog delay, both of which used this. I have two disfunctional delays 
here, but AFAICT the MN chips are OK, but the circuits are a bit confusing.

I believe Maplin still sell a kit based on the MN3004, and it's possible they 
still do a kit for the MN3011 analog reverb (actually it's a multitap delay, but 
they call it a reverb)..

chrisc



From terrymbowman at rica.net  Sun Aug  2 20:28:38 1998
From: terrymbowman at rica.net (KA4HJH)
Date: Sun, 2 Aug 1998 14:28:38 -0400
Subject: PAIA Shepard Function Generator
In-Reply-To: <Pine.BSF.3.96.980802013346.6769A-100000@kopb2.opb.org>
Message-ID: <v04011700b1ea5f6576c6@[208.1.108.44]>

>I cannot find the wiring diagram,schematics or anything else about it. Can
>anyone supply any info about this item. Will it finally be worth my time
>to build it or should I loose it again?

I think the schematic etc. is at the PAiA website. If you have some analog
modules around it's definitely worth playing with.

BTW, if you want to hear the Shepard tones I have a 1MB wav file I can
e-mail you. Sorry, no web site of my own.

Terry Bowman, KA4HJH
"The Mac Doctor"



From cmacdon at ix.netcom.com  Sun Aug  2 21:39:37 1998
From: cmacdon at ix.netcom.com (cmacdon at ix.netcom.com)
Date: Sun, 02 Aug 1998 12:39:37 -0700
Subject: Capacitor questions
Message-ID: <35C4C079.6A1A@ix.netcom.com>

I apologize if this is a worn-out retread of an old topic, I'm a bit new
at this.

I am breadboarding a diode ladder filter and have bought polystyrene and
polypropylene capacitors for the project based on what I have been
reading on various diy web sites (thanks a million to those of you who
put those up BTW!).

I erroneously assumed that all low-value capacitors are small and paid
no attention to the dimensions listed for the polypropylene caps in the
Mouser catalog.  Well the .22uf items are about as big as my thumb!

So my questions are, am I making a silly error here?  Do others use
these giant caps in their filters?  The dimensions for metallized
polypropylene caps are somewhat smaller, are those okay instead?  Does
the capacitor type affect the audio qualities of a filter circuit or is
it mainly for stability or some other reason?


Thanks,

Chris



From robh at biols.susx.ac.uk  Sun Aug  2 23:14:48 1998
From: robh at biols.susx.ac.uk (Rob Hukin)
Date: Sun, 2 Aug 1998 22:14:48 +0100
Subject: Bell Electrolabs phaser
Message-ID: <l03010d00b1ea86487110@[139.184.162.110]>

Hi all,

I'm trying to fix an old Bell Electrolabs phaser, but somehow I fear it's
going to be difficult to find schematics (although AnalogMike *may* have
them...).

It seems to be a six-stage device with the variable elements being 6 LDR's
encapsulated with a single LED. Question is, does anyone know of a similar
design?

thanks,
rob.





From magnus at analogue.org  Mon Aug  3 00:43:43 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Mon, 03 Aug 1998 00:43:43 +0200
Subject: Capacitor questions
In-Reply-To: Your message of "Sun, 02 Aug 1998 12:39:37 -0700"
References: <35C4C079.6A1A@ix.netcom.com>
Message-ID: <199808022243.AAA21413@piraya.electrum.kth.se>

>>>>> "c" == cmacdon  <cmacdon at ix.netcom.com> writes:

Hi!

 c> I apologize if this is a worn-out retread of an old topic, I'm a bit new
 c> at this.

Well, capacitors MAY seem trivial but that is not really the case with
it's real life function.

 c> I am breadboarding a diode ladder filter and have bought polystyrene and
 c> polypropylene capacitors for the project based on what I have been
 c> reading on various diy web sites (thanks a million to those of you who
 c> put those up BTW!).

 c> I erroneously assumed that all low-value capacitors are small and paid
 c> no attention to the dimensions listed for the polypropylene caps in the
 c> Mouser catalog.  Well the .22uf items are about as big as my thumb!

 c> So my questions are, am I making a silly error here?  Do others use
 c> these giant caps in their filters?  The dimensions for metallized
 c> polypropylene caps are somewhat smaller, are those okay instead?  Does
 c> the capacitor type affect the audio qualities of a filter circuit or is
 c> it mainly for stability or some other reason?

Well, there is many reasons for capacitors being of this and that
size.

For instance, one of the parameters of the dielectrum, the relative
dielectric constant may vary over a range of 1 to 1000. A large value
means you can get smaller physical dimension for the same capacitance
(so you where not totally out in the blue). The downside with most of
the higher values is that they have bad properties in other fields,
such as high leackage and bad linearity. If you want really good
leackage you would turn to Teflon/PTFE which is the best material in
that respect. Many materials tend to absorb water and this will alter
their conductivity/leakage. The trouble is that Teflon has a
dielectric constant of about 2.1 so a capacitor made out of Teflon
will not be very small. If you pick Polystyrene which is about 2.55
then the size would go down somewhat. If you would go with Barium
titane (BaTiO3) you could see the constant to go up to 3600 in one of
the directions and given that you do not put physical strain on it.
The directionallity and strain/preassure sensitivity is certainly an
issue for some applications and you would not like your filters to be
microphonic since you usually have good dynamics in a system.
The temperature stability is another. Since the inner mechanics of the
dielectric comes into play it is not very supprising that temperature
can affect the dielectric constant. On the other side you can see how
the physical properties of a capacitor comes into play. A larger
capacitor will have larger series resistance and also larger series
inductance, both of which are parasitic properties which may be
considered as part of a design. Most of the materials with high
dielectric constant has high internal losses and leakage. Poor
temperature stability on top of that and you know that they don't fit
in audio.

One factor which will control the size is the breakthrough voltage,
which will be linear with the dielectrum thickness and thus requireing
an dielectrum area increase which is also linear.

So, the caps that you have is not at all very of scale, there is
several reasons for caps being picked for audio but sadly is the full
knowledge not very well known. Personally I would go with
polypropylene.

Cheers,
Magnus



From chordman at flash.net  Mon Aug  3 01:54:21 1998
From: chordman at flash.net (Scott Gravenhorst)
Date: Sun, 02 Aug 1998 23:54:21 GMT
Subject: Natural Resonant Systems
Message-ID: <35cff9d1.107358402@mail.lan>

A friend showed me  a video taping of the Leno show in which he had
"The Blue Men Band" as guests.  They had, what I would characterize
as, a "Drumbone".  It was several pieces of drainage size PVC pipe
(like 5 or 6 inches in diameter) that they connected in a telescoping
manner so that the length of the tubing could be changed just like a
slide trombone.  One of the Blue Men (It looked like they all wore
skin tight electric blue latex which covered their faces) struck one
end of the tube system with mallets and the other was responsible for
changing the length of the tubing in proper time.  Very well done.
The drumming was actually the bass part.

Perhaps this could be used in a synth system.  The "drummer" could be
replaced by noise pulses injected at one end by a speaker.  The
musician could then play tunes by adjusting the length of the tubing.

Needless to say, I remain intrigued and fascinated.


-- Scott Gravenhorst
-- FatMan Site: www.teklab.com/~chordman



From pfperry at melbpc.org.au  Mon Aug  3 07:04:26 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Mon, 3 Aug 1998 15:04:26 +1000 (EST)
Subject: Natural Resonant Systems
Message-ID: <1.5.4.16.19961225213940.0e87043e@popa.melbpc.org.au>

At 11:54 PM 2/08/98 GMT,Scott chordman wrote:
>A friend showed me  a video taping of the Leno show in which he had
>"The Blue Men Band" as guests.  They had, what I would characterize
>as, a "Drumbone".  It was several pieces of drainage size PVC pipe

there are 'xylophone' like devices made from 3 inch plastic spouting, 
played by whacking with a thong on the end.
Any physical system can be excited by a speaker etc and then picked up again,
like in a guitar spring reverb box.
An amusing thing is to amplify the output from a semiacoustic as a radio etc
plays.
No reason why more interesting resonant systems should be incorporated in a 
modular, even sharpened up by judicious feedback.

paul perry melb aust




From brun at bart.nl  Mon Aug  3 10:32:00 1998
From: brun at bart.nl (Jeroen Bruintjes)
Date: Mon, 3 Aug 1998 10:32:00 +0200
Subject: Cleaning those rubber thingies
Message-ID: <199808030832.KAA15210@smtp1.xs4all.nl>

Hello,

Has anyone come up with *the* solution to clean those rubber pads under a 
synth-keyboard? My Roland SH-101 keeps getting dirty key contacts. And 
since I have a TV remote controller that has the same kind of rubber contacts 
and suffers from the same problem, it would be nice if someone had found a 
way to keep these darn things clean.

Jeroen



From martin.czech at intermetall.de  Mon Aug  3 11:50:12 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Mon, 3 Aug 1998 11:50:12 +0200 (MET DST)
Subject: Cleaning those rubber thingies
Message-ID: <199808030950.LAA21492@window.intermetall.de>

> Has anyone come up with *the* solution to clean those rubber pads under a 
> synth-keyboard? My Roland SH-101 keeps getting dirty key contacts. And 
> since I have a TV remote controller that has the same kind of rubber contacts 
> and suffers from the same problem, it would be nice if someone had found a 
> way to keep these darn things clean.
> 
> Jeroen
>
This seems to be the Roland Desease. My D70 also suffers from
malfunctioning contacts, midi messages come out, but velocity is 0.
The system is as follows: grey rubber cussions contain black resistive
rubber contacts, the cussions are attached to a pcb (clamped, not
glued). A pressed key squeezes the cussion and the first contact
closes, then the second (velocity). I asked the Roland official at the
Frankfurt music fair, they know the problem. First: little particles
can stick to the rubber surface and interrupt contact. Try to get rid
of them with air pistol (also compressed canned air). Be shure to use
clean air, many workshops have dirty oil aerosol air, this will make
things worse. If this doesn't help, try alcohol or mild "tuner" cleaner
and q-tips. Replacing the contact set won't help, because the whole
contact thing works like a vacuum pump. It sucks (yes, you allready
know ;->) all kind of dust into the mechanism during operation. Remedy:
try to seal the ventilation openings with some kind of
non-particle-emitting foam or tissue. Try to glue the grey contact
rubber to the pcb, this interface is where the dust gets mostly in. But
the air must still be able to flow.  Otherwise key action will be
strange (farthzz, farthzzz , hae , hae).

A unhappy D70 user.

m.c.





From chris.crosskey at metrics.co.uk  Mon Aug  3 12:49:52 1998
From: chris.crosskey at metrics.co.uk (Chris Crosskey)
Date: Mon, 3 Aug 1998 11:49:52 +0100
Subject: Maplin Echo Chamber...
Message-ID: <c=GB%a=_%p=Oxford_Metrics_L%l=FILESERV-980803104952Z-3780@fileserv.metrics.co.uk>


Hi Folks....



Does anyone have a contact at Maplin technical or Maplin Service who can
get me the service notes or a circuit diagram of this thing please. It's
the same as the Echorder (it even says Echorder on it) and Melos units
I've got that need fixing. I tried to get some info out of their main
lines but they blanked me......BTW they also do a fixed 200mS Stereo
Analogue (BBD) delay for around 40 UKP if anyones interested


chrisc



From robh at biols.susx.ac.uk  Mon Aug  3 13:03:22 1998
From: robh at biols.susx.ac.uk (Rob Hukin)
Date: Mon, 3 Aug 1998 12:03:22 +0100
Subject: Cleaning those rubber thingies
In-Reply-To: <199808030832.KAA15210@smtp1.xs4all.nl>
Message-ID: <l03130300b1eb47abf3fe@[139.184.162.16]>

>Hello,
>
>Has anyone come up with *the* solution to clean those rubber pads under a
>synth-keyboard? My Roland SH-101 keeps getting dirty key contacts. And
>since I have a TV remote controller that has the same kind of rubber contacts
>and suffers from the same problem, it would be nice if someone had found a
>way to keep these darn things clean.

Hi Jeroen,

Your problem may not be that the contacts keep getting dirty as much as the
conductive layer on the rubber is gradually deteriorating. I find that
cleaning only really works the first couple of times.

The best thing i've found for refurbishing keyboard rubber contact strips
is some stuff called Circuit Works Rubber Keypad Repair kit. It's a 'two
part carbon/silver coating that cures to form a tough, flexible, wear
resistant surface which provides excellent adhesion and
electrical conductivity...Tesing has shown repairs can withstand over 500
000 simulated keystrokes' (from the literature that comes with it). It's
quite expensive (about 20ukp for a kit) and rather irritatingly comes in
two sets of two-part mixtures that have to be mixed all in one go, and will
only stay usable for 72 hours (less in my experience), so make sure you
have plenty to do to make it economical. It's made by a company called
Chemtronics Inc, Kennesaw, GA 30152-4370 USA, 800-645-5244. I've used it on
an HR-16, MMT-8 and my OB8 and it seems to work pretty well.

rob.






From Per.Mattsson at mkv.mh.se  Mon Aug  3 13:36:24 1998
From: Per.Mattsson at mkv.mh.se (Per.Mattsson at mkv.mh.se)
Date: Mon, 03 Aug 1998 12:36:24 +0100
Subject: Cleaning those rubber thingies
In-Reply-To: <199808030832.KAA15210@smtp1.xs4all.nl>
References: <199808030832.KAA15210@smtp1.xs4all.nl>
Message-ID: <2277568478.467535@mkv.mh.se>

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From moxie at idonex.se  Mon Aug  3 13:56:02 1998
From: moxie at idonex.se (Johan Gustavsson)
Date: Mon, 3 Aug 1998 13:56:02 +0200 (MET DST)
Subject: Cleaning those rubber thingies
In-Reply-To: <l03130300b1eb47abf3fe@[139.184.162.16]> (message from Rob Hukin
	on Mon, 3 Aug 1998 12:03:22 +0100)
Message-ID: <199808031156.NAA08648@jolt.idonex.se>

> Your problem may not be that the contacts keep getting dirty as much as the
> conductive layer on the rubber is gradually deteriorating. I find that
> cleaning only really works the first couple of times.

Yep...I've found a somewhat cheaper way to go than that two-component
thingy, though. Electrolube silver conductive paint, for repairing
PCBs. I've sucessfully fixed a HR-16 with it, using only a small part
of the 3 gram contents, and it is still liquid some months
later. Don't know if it is as tough, though. It isn't cheap, either,
but you don't have to throw away what you don't use.
/Moxie (Quick commenting)




From Juergen.Haible at nbgm.siemens.de  Mon Aug  3 14:22:20 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Mon, 3 Aug 1998 14:22:20 +0200 
Subject: Uranus phaser
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D58291AA4A@nbgm336a.nbgm.siemens.de>

Hi,

just a few words about my latest project.
Six cheap surplus LDR's soldered to 12 pins
of a 14-pin DIL socket, sensitive side of each
pointing inwards. A red LED soldered to the
remaining 2 pins, the LED's wires bent so that
LED lies horizontally in the "corridor" made
of the 6 LDR's.
The spaces between these components are
filled with heat glue (sp ?), transparent enough
to distibute a diffused light.
The whole thing wrapped in black heat shrink tube,
remaining gaps closed with black paint.
Very compact hex "Vactrol" device ...

The circuit: 
Discrete all pass stages similar to the 
Univibe. NPN darlingtons as phase splitters, with
positive feedback to increase input impedance,
and capacitive coupling between each stage.
For details, see the univibe schemos. Just six
stages instead of four, and the 1st stage is like
the other ones (not a preamp like the Univibe).

Found a very interesting "Colour" (or resonance)
mode. First, I have variable mix of original
and phase shifted signal by wiring a potentiometer
from the emitter of the first stage to the emitter
of the last stage. Nothing special, if I use a high
resistance value (50 ... 100k). But with a 10k Pot,
things become more complicated. First, there is
some amount of feedback (10k / 4.7k) from the last
to the first stage, and second, the first stage will
not act as a unity gain phase splitter anymore,
because it sees a lower impedance at the emitter
than on the collector !
This is very unlike the Resonance on other phasers.
On other phasers, feedback would affect all peaks 
and notches in a similar way. With my method,
the 3rd (highest frequency) peak is much more
enhanced than the others, so the whole thing sounds
like a mix of phaser and band pass filter.
It's hard to describe, but the old overused word "warm"
hits the point, IMO.
As soon as I found this, I decided to use a 50k pot,
and a "color" switch that connects a fixed 12k resistor
across this pot. A single resistor, but very impressive ...

Capacitors:
As I could not expect the LDRs to match very well,
I included sockets for the all pass capacitors. I selected
them by ear, and ended up with 10nF x4 and 100nF x2.
No idea if the poles are similar or wide apart. Don't
care too much about that, as long as it sounds good.

Modulation:
The LDRs are slooow. Especially because they don't get
much light thru the glue. But that's just right for me.
It adds to the smooth and warm character.
Expo converter: Two LEDs in series. One is in the "Vactrol",
and one is on the front panel. (So you see directly what's
going on.) These LEDs are directly driven by an opamp
output, so the LEDs will convert a linear voltage to an
exponential current all by themselves. Why do it complicated
when things can be so easy (;->).
LFOs: Two of them. Triangle LFOs, 0.012Hz ... 10Hz each.
I like deep slow sweeps with a little bit of fast vibration on
top of it. Each LFO can be switched off by a footswitch jack.
A FET is shorting the integration cap then.

External "Colour" jack:
The 12k resistor (see above) is used as normal connection of
a stereo 1/4" jack. You can plug external passive networks
in here ... 

Name:
First I wanted to name it "JH-HV1 Hexa Vibe Optoelectronic 6 
stage phaser" - obviously not a good name. (;->)
Working title is "Uranus" now. But I want to make sure that this
name wasn't already used for electronic music devices, before I start
engraving a front panel. So, is there an "Uranus" already (other than
in the solar system) ??

Schemos comming soon on my site at Synthfool. A few weeks I
think.

JH.





From 104065.2340 at compuserve.com  Mon Aug  3 15:25:48 1998
From: 104065.2340 at compuserve.com (Terry Michaels)
Date: Mon, 3 Aug 1998 09:25:48 -0400
Subject: electronotes
Message-ID: <199808030926_MC2-54FA-579C@compuserve.com>

Hello:
I joined the group yesterday, and I read through some of the archived
messages from the 1996 time period (that seemed to be all that I could
access) and I found numerous references to Electronotes.  At that time
there was a debate as to the ethics of distributing Electronotes circuits
on the net.  I was wondering if someone can tell me how this was finally
resolved.

I did synth design in the early 70's, and I contributed a number of designs
to Electronotes.  I still have issues 1 thru 160, and most of the app
notes.

I'm currently redoing all of my 70's analog synth designs, taking advantage
of current components, and 25 years experence in circuit design.  I'd be
grateful to know the latest on what's been done recently.
Terry Michaels



From Chris.List at sc.siemens.com  Mon Aug  3 15:43:57 1998
From: Chris.List at sc.siemens.com (List, Christopher)
Date: Mon, 3 Aug 1998 09:43:57 -0400
Subject: Capacitor questions
Message-ID: <81A062BC5305D111A9D700805F065968CE949D@maildepo.sc.siemens.com>

On Sunday, August 02, 1998 3:40 PM, cmacdon at ix.netcom.com
[SMTP:cmacdon at ix.netcom.com] wrote:
> I apologize if this is a worn-out retread of an old topic, I'm a bit
new
> at this.
> 
> I am breadboarding a diode ladder filter and have bought polystyrene
and
> polypropylene capacitors for the project based on what I have been
> reading on various diy web sites (thanks a million to those of you who
> put those up BTW!).

My understanding is that Polystyrenes are generally the best - and the
radial lead ones come in a relatively small package from 560pF through
10nF (.01uF). Above that you start needing polypropylene. You will
notice that the "Metalized" polypro's in the Mouser catalog (the Xicons,
not the Vishay "Orange Drop") tend to be a "size" or two smaller than
the non-metallized, so I generally go for these.Also, if you can find
polypros with a voltage rating of 100VDC, they tend to be smaller in
size than the 400VDC models - so keep an eye out for that. The metalized
polypros are fairly usable - size wise - up to about .47uF - these are a
little bigger than .5" lead spacing (15mm). For anything bigger than
that in terms of capacitance, I usually struggle between what I want for
performance and what I need for size. I've tried different types in a
couple of applications and haven't noticed any difference.

My real point is that you can often find a good balance between size and
the type of cap you want just by diligently searching through all of
your catalogs.

::CList 





From keen at austin.ibm.com  Mon Aug  3 15:55:22 1998
From: keen at austin.ibm.com (R.G. Keen)
Date: Mon, 03 Aug 98 08:55:22 -0500
Subject: Uranus phaser 
In-Reply-To: (Your message of Mon, 03 Aug 98 14:22:20 +0200.)
             <1BF5E20E0C4DD111BBAB00805FE2D58291AA4A@nbgm336a.nbgm.siemens.de>
Message-ID: <199808031355.IAA25564@keen.austin.ibm.com>

Re your six stage - 

Good work on the phaser. A few suggestions from my tinkering with 
vibe clones (I probably drew up the schematics you refer to). These are 
all in the spirit of gilding the lily... 

- The six-LDR module is a good idea. Since it is a replaceable module,
you might try using just enough heat-set glue to hold the LDR's in
place, then putting a shiny-inside cover over the top of the whole
mess. The reflections inside the "light cavity" do a good job of mixing
and leveling the light amplitude. This is why the original has a
shiny-inside cover, I think.

- You can get MUCH faster LDR's. Your slow-sweep applications may not
need them, but faster ones won't hurt you, either. You can test the
LRD's for speed by rigging up a light-tight tube with an LED inside and
a hole to press the LDR into. Drive the LED from a pulse source at
about 1- 10 Hz, and use a resistor in series with the LDR to a voltage
source. Monitor the drive to the LED and the voltage across the LDR.

This gives you the turn-on and turn-off slopes directly on an
oscilloscope. You can also sort them by resistance per unit light this
way, as the LED light does not vary much from one LDR to the next, and
so the voltage across the LDR is a direct measure of the relative LDR 
resistance. Again, this may not matter in your application, but does
for people who want to place the phase notches exactly.

- Typical CdS LDR's are most sensitive to green light, just like the
human eye. Using a green LED, especially an ultra-bright green LED,
will make the current used to drive the LED much lower. 

By the way, I did finally hear a reasonable suggestion for why the
univibe has the phasing capacitor values staggered like it does, which
had always mystified me. The original 'vibe also had a "Vibrato"
setting. If you set the caps to all the same value, the phase shift is
all concentrated in one spot. With the large staggering of phase shift
values, there is some phase shift at the top and bottom end of the
audio spectrum to provide vibrato even at the extremes of the swing.
That made far more sense than any other explanation that I had heard or
could come up with.



From aschrock at cs.brandeis.edu  Mon Aug  3 16:30:08 1998
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Mon, 3 Aug 1998 10:30:08 -0400 (EDT)
Subject: Cleaning those rubber thingies
In-Reply-To: <199808030832.KAA15210@smtp1.xs4all.nl>
Message-ID: <Pine.SGI.3.95.980803101835.8830B-100000@pearl.cs.brandeis.edu>

On Mon, 3 Aug 1998, Jeroen Bruintjes wrote:
> Has anyone come up with *the* solution to clean those rubber pads under a 
> synth-keyboard? My Roland SH-101 keeps getting dirty key contacts. And 
> since I have a TV remote controller that has the same kind of rubber contacts 
> and suffers from the same problem, it would be nice if someone had found a 
> way to keep these darn things clean.

Eww! Ditch those pads ASAP. The problem is just oxidation of the metal pad 
and dust getting trapped on or between the surface and the rubber pads. 

On my mmt-8, I replaced _all_ the buttons (something like 50 of them) with
low-profile tact switches. It works great now, and isn't "mushy" anymore.
If you check hyperreal in the music machines section (under Alesis) I seem
to remember sending something over to them with the appropriate mouser
part numbers in it. It was around $20 for the switches, and I got the
mmt-8 used for $50... so that's an 8 track sequencer with tactile switches
and mute/unmutes for each track for $70. Not too bad. It is somewhat of a
pain to solder all the switches, but trust me, it's worth it not to have
the frustration of trying to mute something (esp. LIVE!) and have the
button "bounce" so it doesn't actually mute... or have the play button
"bounce"... 

If you're really set on not replacing the switches, I've heard the
following works well, and gives a minimal amount of abrasion: Use fine
sandpaper to powder some graphite (rub a pencil against sandpaper).
Carefully collect the powder on the tip of a pencil eraser and _gently_
rub it against the metal contact. I would think that this method is a
little less severe than the razor blade method. 

Andrew

| Andrew Schrock							|
| Network Programmer, Synthesizer and electronic music enthusiast	|
| aschrock at cs.brandeis.edu						|







From Juergen.Haible at nbgm.siemens.de  Mon Aug  3 16:44:08 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Mon, 3 Aug 1998 16:44:08 +0200 
Subject: AW: Uranus phaser 
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D58291F5AE@nbgm336a.nbgm.siemens.de>

	>A few suggestions from my tinkering with 
	>vibe clones (I probably drew up the schematics you refer to).

Most probably. Building synthesizer modules for quite some time,
I'm pretty new to small "stomp box" devices. The more I look at it,
the more I like the topic ...

	>- You can get MUCH faster LDR's.

It's strange how much they vary in their response time. My friend
at MAM has selected dual types from Vactrol for his Resonator,
and he has thrown out a lot of the slow ones.

	>By the way, I did finally hear a reasonable suggestion for why the
	>univibe has the phasing capacitor values staggered like it does,
which
	>had always mystified me. The original 'vibe also had a "Vibrato"
	>setting. If you set the caps to all the same value, the phase shift
is
	>all concentrated in one spot. With the large staggering of phase
shift
	>values, there is some phase shift at the top and bottom end of the
	>audio spectrum to provide vibrato even at the extremes of the
swing.
	>That made far more sense than any other explanation that I had
heard or
	>could come up with.

Interesting explanation. I'll have to try this. I have an OTA-based
phaser that can continuously spread its 6 poles with an extra 
control voltage, so it should be easy to check ...

BTW, do you know of any good books about vintage (guitar) effect
boxes ?

JH.



From niklas.lindberg at enator.se  Mon Aug  3 17:19:22 1998
From: niklas.lindberg at enator.se (niklas.lindberg at enator.se)
Date: Mon, 3 Aug 1998 16:19:22 +0100
Subject: FW: Buchla
Message-ID: <C1505206D8BFD0118E130060970AD7BA0AC4B7@ees1>



> -----Original Message-----
> From:	Lindberg, Niklas 
> Sent:	Monday, August 03, 1998 3:37 PM
> To:	'diylist'
> Subject:	RE: Buchla
> 
> Well, I suggest you have a look at Don's company site:
> 
> http:/www.buchla.com/
> 
> There you will find their present products (Thunder and Lightning)
> as well as adresses and a real nice history page...
> 
> / Niklas
> 
> <~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~<
>  >  Niklas Lindberg                                   >
> <   Analogue Synths & Electronics Freak              <
>  >                                                    >
> <     "The availability of a certain patchcord       <
>  >	    is inversely proportional to its need"         >
> <                                                    <
>  >       _                              Anonymus      >
> <_______/ \   _______________________________________<
>            \_/
> 
> 
> -----Original Message-----
> From:	Bjarne Nillson [SMTP:bnillson at hotmail.com]
> Sent:	Saturday, August 01, 1998 10:44 PM
> To:	synth-diy at mailhost.bpa.nl
> Subject:	Buchla
> 
> Hiiiii.
> 
> Does anyone have the email adress/odinary adress to
> MR Don Buchla??
> 
> Is he still alive?
> 
> Nisse
> 
> ______________________________________________________
> Get Your Private, Free Email at http://www.hotmail.com



From keen at austin.ibm.com  Mon Aug  3 17:32:19 1998
From: keen at austin.ibm.com (R.G. Keen)
Date: Mon, 03 Aug 98 10:32:19 -0500
Subject: AW: Uranus phaser 
In-Reply-To: (Your message of Mon, 03 Aug 98 16:44:08 +0200.)
             <1BF5E20E0C4DD111BBAB00805FE2D58291F5AE@nbgm336a.nbgm.siemens.de>
Message-ID: <199808031532.KAA26684@keen.austin.ibm.com>


>BTW, do you know of any good books about vintage (guitar) effect
>boxes ?

No books on the topic that I know of with technical content. There 
are some overviews of the history, notably "Stompbox" by one of the
writers for Guitar Player. I'm writing one on the technologies, 
although it's only an introduction and part of one chapter at the 
moment.

You might take a look at my web page, http://www.eden.com/~keen/
for the Guitar Effects FAQ and for the articles on the technologies
of the Univibe, Fuzz Face, and Tube Screamer stompboxes. There 
are some other places, but the technical content is spread pretty 
thinly.




From aschrock at cs.brandeis.edu  Mon Aug  3 17:39:51 1998
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Mon, 3 Aug 1998 11:39:51 -0400 (EDT)
Subject: resonance in
In-Reply-To: <35cff9d1.107358402@mail.lan>
Message-ID: <Pine.SGI.3.95.980803110331.8830E-100000@pearl.cs.brandeis.edu>

Hi all,

I would like to have a VCF I'm building have a resonance input, since I
think it would lead to some versatile sounds. The res. feedback loop in
most VCFs is basically just a volume knob to control feedback, so I was
thinking I could replace the res. knob with a VCA, so that the "gain" knob
on the VCA would control the intitial resonance, _and_ you'd be able to
have a modulation signal in to control the res. I was thinking of using an
asm-1 VCA for this purpose since it's a simple design... maybe (hopefully)
it will overdrive the res. a bit at max res. and lead to an interesting
overdriven sound.. Hopefully not _too_ noisy at low resonance, though.. 

Has anybody done this using the method I described? Is there an easier
way? 

Andrew

| Andrew Schrock							|
| Network Programmer, Synthesizer and electronic music enthusiast	|
| aschrock at cs.brandeis.edu						|





From jfoster at lucasdigital.com  Mon Aug  3 17:49:01 1998
From: jfoster at lucasdigital.com (Jeff Foster)
Date: Mon, 03 Aug 1998 08:49:01 -0700
Subject: Another Buchla question
References: <v04011700b1e990dc7cf7@[208.1.108.63]>
Message-ID: <35C5DBED.50FA8DFB@lucasdigital.com>

I went to school with one of his daughters.
I always here is as "bookla", but it
has been many years ...

JEff

KA4HJH wrote:

> Does anybody know how Don's name is pronounced? It's not as tricky as Moog
> but it's more ambiguous. I hate getting names wrong. I've been wondering
> for years.
> Terry Bowman, KA4HJH
> "The Mac Doctor"



--
Jeff Foster 415-662-1254
Unix Systems/Networks
Skywalkersound, LucasDigital Ltd.





From b.layer at vikingelectronics.com  Mon Aug  3 17:51:36 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Mon, 03 Aug 1998 10:51:36 -0500
Subject: Little rubber thingies, rubber switches, etc.
Message-ID: <3.0.5.32.19980803105136.007a26b0@192.168.210.18>

Hi All,

A bit of useful info from the world of telecom.

Conductive rubber switches are a major business in the telco industry;
several small companies stay busy doing nothing but repairing and replacing
these failure prone little devices. The ones that rely on conductive paint
are the worst, and can be quite prone to shorts.

A mail order company in Chicago IL, called Telecom Products has several
professional 'board-level' repair systems for these types of switches, as
well as cleaners, conditioners and plastic restorers. They also stock
obsolete parts, which could come in handy.

Telecom Products / Mike Sandman
804 Nerge Road
Roselle, IL 60172	
630.980.7710


Bill Layer
"Heavy old junk wanted"



From johns at oei.com  Mon Aug  3 17:53:52 1998
From: johns at oei.com (John Speth)
Date: Mon, 3 Aug 1998 08:53:52 -0700
Subject: Uranus phaser
In-Reply-To: <1BF5E20E0C4DD111BBAB00805FE2D58291AA4A@nbgm336a.nbgm.siemens.de>
Message-ID: <000101bdbef6$e9d31900$2c15d7d0@johns.oei.com>

The name sounds good but (as my sick mind always does) it reminds me of
"Brown-25, that all purpose substance from Uranus".  Anybody who remembers
the cult classic movie "Groove Tube" spoof about television will know what
I'm talking about.  It had a really descriptive scene that always make me
chuckle when I hear the word Uranus.

John Speth
Object Engineering, Inc
mailto:johns at oei.com


> Name:
> First I wanted to name it "JH-HV1 Hexa Vibe Optoelectronic 6
> stage phaser" - obviously not a good name. (;->)
> Working title is "Uranus" now. But I want to make sure that this
> name wasn't already used for electronic music devices, before I start
> engraving a front panel. So, is there an "Uranus" already (other than
> in the solar system) ??





From eli at gs160.sp.cs.cmu.edu  Mon Aug  3 18:19:09 1998
From: eli at gs160.sp.cs.cmu.edu (Eli Brandt)
Date: Mon, 3 Aug 1998 12:19:09 -0400 (EDT)
Subject: Another Buchla question
In-Reply-To: <v04011700b1e990dc7cf7@[208.1.108.63]> from "KA4HJH" at Aug 1, 98 11:45:23 pm
Message-ID: <199808031619.SAA25730@mailhost.bpa.nl>

KA4HJH wrote:
> Does anybody know how Don's name is pronounced?

I think it's "byoo-klah", since
1) he was called that by somebody who knows him pretty well, and
2) he did not visibly cringe or anything.

-- 
     Eli Brandt  |  eli+ at cs.cmu.edu  |  http://www.cs.cmu.edu/~eli/



From b.layer at vikingelectronics.com  Mon Aug  3 18:34:05 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Mon, 03 Aug 1998 11:34:05 -0500
Subject: Capacitor questions
In-Reply-To: <81A062BC5305D111A9D700805F065968CE949D@maildepo.sc.siemens
 .com>
Message-ID: <3.0.5.32.19980803113405.007a7bb0@192.168.210.18>

 Hi Chris, here's two cents worth:

I am breadboarding a diode ladder filter and have bought polystyrene
>and
>> polypropylene capacitors for the project based on what I have been
>> reading on various diy web sites (thanks a million to those of you who
>> put those up BTW!).

>From my experience in high-end audio, I can make a recomendation. I have
used polystyrene caps frequently in circuit locations requiring stable,
critical value. One example of this is the RIAA eq. circuit in a
preamplifer. It is mandatory to maintain <.5% total error, if your curve is
to be correct, and polystyrenes are found almost exclusively in this
application. If I was constructing a high-precision filter, this would be
my choice. The only real detractors here are the fragility of the parts, so
dont over solder them.

Also, a word on metallized polypropylines. Great performance, small
package, self-healing properties (you can drill a hole through one, and it
will self heal most of the time) but boy do they sound bad in high-end
systems. Probably fine  for guitar amps (especially for their ruggedness)
but in the music signal path, they sound well, like grinding metal. Regular
polyprops are a little more neutral. BTW, don't get 'sold' on Sprague
Orange Drops, they are FINE but nothing AMAZING...

Some really fine poly pro/sty caps come from Reliable Capacitor in
California. Call for their catalog! PSST Eric Barbour; do you have that
number handy? Perhaps from a GA.

Hope I've not muddied the waters for you.>
Bill Layer
Sales Technician
<b.layer at vikingelectronics.com>

----------------------------------
Viking Electronics, Inc.
Hudson, WI. U.S.A
715.386.8861 (ext. 210)
<http://www.vikingelectronics.com>
----------------------------------

"Telecommunications Solutions for the 21st Century"



From b.layer at vikingelectronics.com  Mon Aug  3 18:44:16 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Mon, 03 Aug 1998 11:44:16 -0500
Subject: Vacuum Tube Circuit Books
In-Reply-To: <09DB74475204D1119C8200805F19D0032D12A2@aeromsg1.ball.com>
Message-ID: <3.0.5.32.19980803114416.007b21c0@192.168.210.18>

Hi Malcom,

>"Vacuum-Tube Circuits and Transistors", by: Lawrence Baker Arguimbau and
>Richard Brooks Adler (1956)
>"Reference Data for Radio Engineers", published by: Federal Telephone
>and Radio Corporation (1944)
>"Pulse Techniques", by: Sidney Moskowitz and Joseph Racker (1951)

These sound like interesting titles. Some others include:

"Waveforms" - MIT Radiation Labs series
"Electronic Tubes And Circuits" - Cruft Electronics Staff/ Mc Graw Hill
"Radiotron Designers Handbook 4th ed" - Langford Smith / RCA press

And one good little laymans guide

"Practical Radio Construction and Repairing" - MCGraw Hill

Good luck with the tube stuff!

"
Bill Layer
Sales Technician
<b.layer at vikingelectronics.com>

----------------------------------
Viking Electronics, Inc.
Hudson, WI. U.S.A
715.386.8861 (ext. 210)
<http://www.vikingelectronics.com>
----------------------------------

"Telecommunications Solutions for the 21st Century"



From walters at digidesign.com  Mon Aug  3 19:09:34 1998
From: walters at digidesign.com (Tim Walters)
Date: Mon, 3 Aug 1998 10:09:34 -0700
Subject: Another Buchla question
Message-ID: <v01530500b1eb9eaae415@[204.31.105.81]>

At 12:19 PM 8/3/98, Eli Brandt wrote:
>I think it's "byoo-klah", since
>1) he was called that by somebody who knows him pretty well, and
>2) he did not visibly cringe or anything.

A friend of mine who is a Buchla employee and one-time tenant omits the "y"
sound.  The first syllable rhymes with "kook" (no doubt just a
coincidence).


-----------------------------
Tim Walters  --  walters at digidesign.com  --  http://www.slip.net/~coredump





From b.layer at vikingelectronics.com  Mon Aug  3 19:53:33 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Mon, 03 Aug 1998 12:53:33 -0500
Subject: Uranus phaser
In-Reply-To: <000101bdbef6$e9d31900$2c15d7d0@johns.oei.com>
References: <1BF5E20E0C4DD111BBAB00805FE2D58291AA4A@nbgm336a.nbgm.siemens.de>
Message-ID: <3.0.5.32.19980803125333.007b47d0@192.168.210.18>

At 08:53 AM 8/3/98 -0700, you wrote:
>The name sounds good but (as my sick mind always does) it reminds me of
>"Brown-25, that all purpose substance from Uranus".  Anybody who remembers
>the cult classic movie "Groove Tube" spoof about television will know what
>I'm talking about.  It had a really descriptive scene that always make me
>chuckle when I hear the word Uranus.

Yeah, the potenital humor content of anything called Uranus cannot be
overstated. Inasmuch as I like the way it sounds, this probably wouldn't be
the best choice for the name... Hard to take seriously, at the best. 

Which reminds me of a serious marketing flub by CBM back in the 80's. Seems
they wanted to sell the VIC-20 in Germany, but there was a conflict with
another manufacturer who used the VIC name. So in their infinite wisdom,
the marketing guys at Commodore renamed it the "Vixen-20". Remember this
Juergen?

'Vixen' is word meaning a prostitute in German.

Also, in Mandarin Chinese "Coca-Cola" (co-ca-co-la) means "Bite the wax
tadpole" and Coke's campaign "Coke adds life" got translated into Mandarin
meaning "Coke brings back your ancient ancestors from the dead".

Thats all.
Bill Layer
Sales Technician
<b.layer at vikingelectronics.com>

----------------------------------
Viking Electronics, Inc.
Hudson, WI. U.S.A
715.386.8861 (ext. 210)
<http://www.vikingelectronics.com>
----------------------------------

"Telecommunications Solutions for the 21st Century"



From terrymbowman at rica.net  Mon Aug  3 20:05:32 1998
From: terrymbowman at rica.net (KA4HJH)
Date: Mon, 3 Aug 1998 14:05:32 -0400
Subject: Uranus phaser
In-Reply-To: <000101bdbef6$e9d31900$2c15d7d0@johns.oei.com>
References:  <1BF5E20E0C4DD111BBAB00805FE2D58291AA4A@nbgm336a.nbgm.siemens.de>
Message-ID: <v04011700b1ebac0fc9f4@[208.1.108.63]>

>The name sounds good but (as my sick mind always does) it reminds me of
>"Brown-25, that all purpose substance from Uranus".  Anybody who remembers
>the cult classic movie "Groove Tube" spoof about television will know what
>I'm talking about.  It had a really descriptive scene that always make me
>chuckle when I hear the word Uranus.

Did you know that there's a ring around Uranus? I think NASA found it with
one of those deep probes.
Terry Bowman, KA4HJH
"The Mac Doctor"



From terrymbowman at rica.net  Mon Aug  3 20:09:16 1998
From: terrymbowman at rica.net (KA4HJH)
Date: Mon, 3 Aug 1998 14:09:16 -0400
Subject: Uranus phaser
In-Reply-To: <199808031355.IAA25564@keen.austin.ibm.com>
References: (Your message of Mon, 03 Aug 98 14:22:20 +0200.)            
 <1BF5E20E0C4DD111BBAB00805FE2D58291AA4A@nbgm336a.nbgm.siemens.de>
Message-ID: <v04011702b1ebac80e48b@[208.1.108.63]>

>By the way, I did finally hear a reasonable suggestion for why the
>univibe has the phasing capacitor values staggered like it does, which
>had always mystified me. The original 'vibe also had a "Vibrato"
>setting. If you set the caps to all the same value, the phase shift is
>all concentrated in one spot. With the large staggering of phase shift
>values, there is some phase shift at the top and bottom end of the
>audio spectrum to provide vibrato even at the extremes of the swing.
>That made far more sense than any other explanation that I had heard or
>could come up with.

This is a long shot, but do the values make the spacing intervalic instead
of linear (or a some rough approximation thereof)? That would definitely
make it sound more like real vibrato (or tremelo, as Leo Fender called
it--groan).

Terry Bowman, KA4HJH
"The Mac Doctor"



From b.layer at vikingelectronics.com  Mon Aug  3 22:17:54 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Mon, 03 Aug 1998 15:17:54 -0500
Subject: Identify unknown MIDI devices
Message-ID: <3.0.5.32.19980803151754.007be740@192.168.210.18>

Hi All,

I got some MIDI stuff this weekend at a Garage sale, but I dont know quite
what it is, or if it's of any use in this era.

Item 1: A 'MIDIMAN" pc sequencer setup, made by MIDIMAN of California.
Dated 1991, this set includes a circuit card for an IBM compatible, a cable
which when connected to the card provides a MIDI in and MIDI out
connection, a set of softwares including CuBase, CakeWalk etc. and a
software manual. The box is labeled "The worlds fastest MIDI interface: The
MIDIMAN-400" or something.

Is it worth messing with, or too slow and outdated?

Item 2: A Roland unit with some generic designation (like) MDI-TPU or
something. It is a metal box 8 inches long with some MIDI in & out ports, a
metronome port and such. The box has a cable attached, which terminates in
what appears to be a male printer port plug.

What is it, and does it require an additonal interface card or something?
If the designation is important, I can get it when I'm home tonight.

Thanks in advance!

Bill Layer
Sales Technician
<b.layer at vikingelectronics.com>

----------------------------------
Viking Electronics, Inc.
Hudson, WI. U.S.A
715.386.8861 (ext. 210)
<http://www.vikingelectronics.com>
----------------------------------

"Telecommunications Solutions for the 21st Century"



From keen at austin.ibm.com  Mon Aug  3 22:23:09 1998
From: keen at austin.ibm.com (R.G. Keen)
Date: Mon, 03 Aug 98 15:23:09 -0500
Subject: Uranus phaser 
In-Reply-To: (Your message of Mon, 03 Aug 98 14:09:16 -0400.)
             <v04011702b1ebac80e48b@[208.1.108.63]>
Message-ID: <199808032023.PAA23862@keen.austin.ibm.com>

>>By the way, I did finally hear a reasonable suggestion for why the
>>univibe has the phasing capacitor values staggered like it does, which
>>had always mystified me. The original 'vibe also had a "Vibrato"
>>setting. If you set the caps to all the same value, the phase shift is
>>all concentrated in one spot. With the large staggering of phase shift
>>values, there is some phase shift at the top and bottom end of the
>>audio spectrum to provide vibrato even at the extremes of the swing.
>>That made far more sense than any other explanation that I had heard or
>>could come up with.
>
>This is a long shot, but do the values make the spacing intervalic instead
>of linear (or a some rough approximation thereof)? That would definitely
>make it sound more like real vibrato 

The phase capacitor values are 0.22uF, 0.015uf, 470pF, 4700pF. For
continuous coverage of frequency, you probably need caps on decade
boundaries, which one set does have, but the others are not related 
by decades, octaves, musical intervals, arithmetic or geometric
progression, or phase of the moon that I can see. 




From moxie at idonex.se  Mon Aug  3 23:20:51 1998
From: moxie at idonex.se (Johan Gustavsson)
Date: Mon, 3 Aug 1998 23:20:51 +0200 (MET DST)
Subject: Identify unknown MIDI devices
In-Reply-To: <3.0.5.32.19980803151754.007be740@192.168.210.18>
	(b.layer@vikingelectronics.com)
Message-ID: <199808032120.XAA24040@jolt.idonex.se>

> Item 2: A Roland unit with some generic designation (like) MDI-TPU or
> something. It is a metal box 8 inches long with some MIDI in & out
> ports, a metronome port and such. The box has a cable attached, which
> terminates in what appears to be a male printer port plug.

My quick guess on this is a MIDI->DCB converter to MIDIfy old Junos
and Jupiters. The DCB connector on the synt is a 14-pin
Centronics-style jack, and it makes sense that it should have MIDI
ports, an arpeggiator clock out and maybe even a filter control
jack. Then again, it might be something completely different - Go get
that designation! If it is cheap, I'd want it, but *waves to rest of
list* I guess they go for more than I could pay these days,
really. Seem to remember that the Roland MIDI->DCB usually fetch
around $150ish at least.
/Moxie (Takes a wild guess)




From ebarbour at svetlana.com  Tue Aug  4 00:52:04 1998
From: ebarbour at svetlana.com (Eric Barbour)
Date: Mon, 3 Aug 1998 15:52:04 -0700
Subject: poly caps
Message-ID: <01BDBEF6.A9F85B60.ebarbour@svetlana.com>

>Some really fine poly pro/sty caps come from Reliable Capacitor in
>California. Call for their catalog! PSST Eric Barbour; do you have that
>number handy?

(310) 946-8577, fax (310) 944-7494.

Eric Barbour
Svetlana Electron Devices
Portola Valley CA USA




From francois at hyperreal.org  Tue Aug  4 01:21:51 1998
From: francois at hyperreal.org (Francois Dion)
Date: Mon, 3 Aug 1998 19:21:51 -0400
Subject: Identify unknown MIDI devices
Message-ID: <199808032318.BAA01854@mailhost.bpa.nl>

> > Item 2: A Roland unit with some generic designation (like) MDI-TPU or
> > something. It is a metal box 8 inches long with some MIDI in & out
> > ports, a metronome port and such. The box has a cable attached, which
> > terminates in what appears to be a male printer port plug.
> My quick guess on this is a MIDI->DCB converter to MIDIfy old Junos
> and Jupiters. The DCB connector on the synt is a 14-pin
> Centronics-style jack, and it makes sense that it should have MIDI
> ports, an arpeggiator clock out and maybe even a filter control
> jack. Then again, it might be something completely different

Could be an MPU 401 external (brain) box. It requires an MDI IPC
card for the PC or MDI APL card for the Apple 2. Was also available
for the commodore 64 and probably other computers.

Ciao,
Francois Dion (francois at hyperreal.org)

--
Member: FLU #1722, PCNA
http://www.fortunecity.com/silverstone/zagato/101/launch.html
Alfa Romeo, Fiat, Lancia, Peugeot, Volvo, Solex

----------
> De : Johan Gustavsson <moxie at idonex.se>
> A : b.layer at vikingelectronics.com
> Cc?: synth-diy at mailhost.bpa.nl
> Objet : Re: Identify unknown MIDI devices
> Date?: Monday, August 03, 1998 5:20 PM
> 
> 
> My quick guess on this is a MIDI->DCB converter to MIDIfy old Junos
> and Jupiters. The DCB connector on the synt is a 14-pin
> Centronics-style jack, and it makes sense that it should have MIDI
> ports, an arpeggiator clock out and maybe even a filter control
> jack. Then again, it might be something completely different - Go get
> that designation! If it is cheap, I'd want it, but *waves to rest of
> list* I guess they go for more than I could pay these days,
> really. Seem to remember that the Roland MIDI->DCB usually fetch
> around $150ish at least.
> /Moxie (Takes a wild guess)
> 



From mwmjr at ix.netcom.com  Tue Aug  4 01:22:06 1998
From: mwmjr at ix.netcom.com (Michael Maloney)
Date: Mon, 03 Aug 1998 19:22:06 -0400
Subject: Identify unknown MIDI devices
In-Reply-To: <3.0.5.32.19980803151754.007be740@192.168.210.18>
Message-ID: <3.0.5.32.19980803192206.007a34e0@popd.ix.netcom.com>

At 03:17 PM 8/3/98 -0500, Bill Layer wrote:
>
>Item 2: A Roland unit with some generic designation (like) MDI-TPU or
>something. It is a metal box 8 inches long with some MIDI in & out ports, a
>metronome port and such. The box has a cable attached, which terminates in
>what appears to be a male printer port plug.
>

May be either an MPU-IPC or MPU-IMC:
the IPC is a midi interface for standard PC's, the IMC is an IBM
MicroChannel variation of the same. However, there is a computer card which
is doing all the work - you apparently have just the breakout box.

Mike Maloney

PS - have just signed on to this mailing list.  Is it customary to "reply
to all" (original sender AND synth-diy), or just reply to the list?  While
it is redundant to do so, is there some threading mechanism for a mailing
list in the same way as a USENET newsgroup? Just curious.



From mwmjr at ix.netcom.com  Tue Aug  4 02:04:26 1998
From: mwmjr at ix.netcom.com (Michael Maloney)
Date: Mon, 03 Aug 1998 20:04:26 -0400
Subject: Linear response VCA's
Message-ID: <3.0.5.32.19980803200426.007a6cc0@popd.ix.netcom.com>

I've finally gotten my life in order to attack the modular synth project
I've been promising myself for years. However, I am stumbling over a few
questions that I hope can be answered here:

Are there situations in which purely linear response is desirable in a VCA?

My envelope generators and LFOs are digital - using an embedded
microcontroller, I can easily allow for both linear and exponential
response in the software of the envelope generator. And I can see
situations in which this may be a desirable feature.

The VCA is another matter.  While I like the "universality" of having
separate expo and linear cv inputs, I'm planning on having a lot of these
things (probably starting with six), so I don't want to give up a lot of
board space or panel space on functions that I wouldn't use. 

So if someone has any opinions on the matter, I look forward to hearing them.

TIA


Mike Maloney





From robh at biols.susx.ac.uk  Tue Aug  4 03:05:39 1998
From: robh at biols.susx.ac.uk (Rob Hukin)
Date: Tue, 4 Aug 1998 02:05:39 +0100
Subject: Cyclosonic...?
Message-ID: <l03010d02b1ec0eaba1d5@[139.184.162.110]>

Hi all,

Anyone heard of a fancy panning device called a Cyclosonic...?

rob.





From mamundso at mr.net  Tue Aug  4 03:43:21 1998
From: mamundso at mr.net (Mark Amundson)
Date: Mon, 03 Aug 1998 18:43:21 -0700
Subject: IEEE cover article
References: <01BDBEF6.A9F85B60.ebarbour@svetlana.com>
Message-ID: <35C66739.23F7@mr.net>

Thanks Eric for the great vacuum tube article on the front cover of the
August issue of IEEE Spectrum Magazine. I am surprised they gave you
that much word count to go into that amount of depth.

Mark Amundson,



From martin.czech at intermetall.de  Tue Aug  4 07:13:20 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Tue, 4 Aug 1998 07:13:20 +0200 (MET DST)
Subject: Uranus phaser
Message-ID: <199808040513.HAA28053@window.intermetall.de>


> - Typical CdS LDR's are most sensitive to green light, just like the
> human eye. Using a green LED, especially an ultra-bright green LED,
> will make the current used to drive the LED much lower. 
> 
??
I have seen sensitivity measurement diagrams that show two peaks of
equal hights for CdS:  at green 540nm AND orange/red 640nm. So these
very bright orange/red diodes should be sufficient, they are much
brighter then any green led I've ever seen, indeed one should not
directly look into the light source, danger of eye damage !


m.c.

------------------------------------------------------------------------
m.c. has made it finally:  3 CDs out now; 72 min. minimum; "1"
(1994-1995),"2" (95-96),"three" (96-97); experimental stuff; mostly
Eimert/Stockhausen style; but also modern popular style





From martin.czech at intermetall.de  Tue Aug  4 07:18:51 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Tue, 4 Aug 1998 07:18:51 +0200 (MET DST)
Subject: resonance in
Message-ID: <199808040518.HAA28067@window.intermetall.de>

> Hi all,
> 
> I would like to have a VCF I'm building have a resonance input, since I
> think it would lead to some versatile sounds. The res. feedback loop in
> most VCFs is basically just a volume knob to control feedback, so I was
> thinking I could replace the res. knob with a VCA, so that the "gain" knob
> on the VCA would control the intitial resonance, _and_ you'd be able to
> have a modulation signal in to control the res. I was thinking of using an
> asm-1 VCA for this purpose since it's a simple design... maybe (hopefully)
> it will overdrive the res. a bit at max res. and lead to an interesting
> overdriven sound.. Hopefully not _too_ noisy at low resonance, though.. 
> 
> Has anybody done this using the method I described? Is there an easier
> way? 
> 
When I toyed arround with my state variable filter, I used a N-JFET
voltage divider.  Of course the "feedback" in a state variable works
different from a cascade, but that should be no problem. I added a
little diode network in order to have an equal control scale, without
this most of the resonance happens in only 10 degrees of the pot angle.
So no need for fancy reverse log pots, just a linear. You'll need an
control voltage summing op-amp anyway.

m.c.

------------------------------------------------------------------------
m.c. (alias mad scientist) has made it finally: 3 CDs ? 72 minimum ready.
Visit my homepage at http://www.geocities.com/SoHo/Museum/4459/index.html




From martin.czech at intermetall.de  Tue Aug  4 07:48:14 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Tue, 4 Aug 1998 07:48:14 +0200 (MET DST)
Subject: Linear response VCA's
Message-ID: <199808040548.HAA28338@window.intermetall.de>

> I've finally gotten my life in order to attack the modular synth project
> I've been promising myself for years.

I wish I could.

> Are there situations in which purely linear response is desirable in a VCA?

Yes, you can use a vca also for controling other modulations, e.g. an
automatic vibrato that comes on softly. In this case a linear response
sounds quite nice.  If you want to have some (deep) tremolo on audio
signals, it sounded better to me to use the linear input. Otherwise the
sine tremolo sounded uneven or strange.

Some time ago there was a discussion of envelope waveform, linear,
exponential etc. This makes a difference. If you want to hear it,
you'll also have to use the linear input.

In fact, the only application of expo control is slow fading with
linear control voltages, that's why devices like mixer vca have only
expo inputs.

I used SSM2018, this means you have to add a log circuit.  The expo
voltage and logged voltage are added Ve+log(Vl) and then feed to the
expo input exp{k(Ve+log(Vl))}= exp{k*Ve} * Vl^k.  There is some kind of
multiplication taking place between both inputs, this is a feature if
you use both at the same time, but it is also a bit confusing, if you
want full control scale of one input you have to turn the other to
100%. If you turn it to 0% instead, well this is even more complicated,
you need some rectifier to prevent the log cicuit going mad, etc.

Many people say that expo vcas sound punchier, well if you have a very
fast attack, the expo as well as the linear input look like a step,
maybe the difference is more in the medium attack range. The expo
control scale is a natural porperty of simple discrete multipliers, if
such are used, there may be audible control feedthrough, this can also
sound punchy.

If I where to have only one control input, I'd make them all linear.
An expo module can be added afterwards, if needed.

m.c.

------------------------------------------------------------------------
m.c. has made it finally:  3 CDs out now; 72 min. minimum; "1"
(1994-1995),"2" (95-96),"three" (96-97); experimental stuff; mostly
Eimert/Stockhausen style; but also modern popular style





From tomg at vivid.net  Tue Aug  4 08:11:35 1998
From: tomg at vivid.net (tomg)
Date: Tue, 04 Aug 1998 01:11:35 -0500
Subject: Uranus phaser
In-Reply-To: <1BF5E20E0C4DD111BBAB00805FE2D58291AA4A@nbgm336a.nbgm.siemens.de>
Message-ID: <yam7520.1769.119249456@mail.vivid.net>

On 03-Aug-98, Haible Juergen wrote:
>Hi,

>just a few words about my latest project.
>Six cheap surplus LDR's soldered to 12 pins
>of a 14-pin DIL socket, sensitive side of each
>pointing inwards. A red LED soldered to the
>remaining 2 pins, the LED's wires bent so that
>LED lies horizontally in the "corridor" made
>of the 6 LDR's.
>The spaces between these components are
>filled with heat glue (sp ?), transparent enough
>to distibute a diffused light.
>The whole thing wrapped in black heat shrink tube,
>remaining gaps closed with black paint.
>Very compact hex "Vactrol" device ...

I did the same thing a few years ago, inspired by Craig Anderton's CLM-6000
phaser (a clm-6000 is a LED & LDR in the same package)  and found the 1 led
muilt LDR arrangement ok but the sweep range was very limited, just not enough
light on the LDR. I didn't want to buy CLM's I think they were $3.50 each.
Anyway to make a long story shorter a standard sized LED fits perfectly in a
standard rubber grommet then with a little effort you can cover the assembly
with 1/2" heat shrink. Makes a nice full range CLM sub. The down side is you
have to make 6 the up side is a huge sweep range.

-tg






From cmacdon at ix.netcom.com  Tue Aug  4 08:26:47 1998
From: cmacdon at ix.netcom.com (cmacdon at ix.netcom.com)
Date: Mon, 03 Aug 1998 23:26:47 -0700
Subject: Capacitor questions answered
Message-ID: <35C6A9A7.1D89@ix.netcom.com>

Thanks to everyone who responded to my questions about capacitors, I
learned a lot!  Also, my apologies to Mr. List and any other "Chris'" in
the group for signing only my first name on the original mail!

-Chris MacDonald



From tomg at vivid.net  Tue Aug  4 08:36:28 1998
From: tomg at vivid.net (tomg)
Date: Tue, 04 Aug 1998 01:36:28 -0500
Subject: Cleaning those rubber thingies
In-Reply-To: <199808030832.KAA15210@smtp1.xs4all.nl>
Message-ID: <yam7520.1425.119249456@mail.vivid.net>

On 03-Aug-98, Jeroen Bruintjes wrote:
>Hello,

>Has anyone come up with *the* solution to clean those rubber pads under a 
>synth-keyboard?

I have done a lot of Rolands others (Korg & Kurzweil come to mind) have the
same problem but Rolands seem to be the worst. I don't know about "THE"
solution but a pencil eraser is my tool for carbon contacts. Just enough
rubbing to remove the gunk on the pad and contact. Then blow the debre away
with clean air. It works most of the time and when it works I never get a
return. If not Roland is usually very reasonable for replacements. Most pads
running in the $20 range and contacts costing arround $15. (exceptions the JPX
the costing about $90 for the pair and if your RD-5000 is sick the whole kbd
has to be replacd $400) I have ordered jpx sets, juno and rhodes 660 contacts
in the past two years.

-tg




From jorgen.bergfors at idg.se  Tue Aug  4 09:06:24 1998
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Tue, 4 Aug 1998 8:06:24 +0100
Subject: resonance in
Message-ID: <TFSGKNKI@idg.se>

Yes, that's how you normally do it. I added voltage controlled resonance to my 
Formant 24 dB/oct VCF this way. I made a simple VCA from a CA3080 and a few 
other components. It was a simplified version of the Formant VCA. 

/Jorgen





MIME:aschrock at cs.brandeis.edu on 98-08-03 19.21.14
To:  synth-diy at mailhost.bpa.nl @ SMTP 
cc:  (bcc: Jorgen Bergfors/IDGSE)
Subject: resonance in 

Hi all,

I would like to have a VCF I'm building have a resonance input, since I
think it would lead to some versatile sounds. The res. feedback loop in
most VCFs is basically just a volume knob to control feedback, so I was
thinking I could replace the res. knob with a VCA, so that the "gain" 
knob
on the VCA would control the intitial resonance, _and_ you'd be able to
have a modulation signal in to control the res. I was thinking of using 
an
asm-1 VCA for this purpose since it's a simple design... maybe 
(hopefully)
it will overdrive the res. a bit at max res. and lead to an interesting
overdriven sound.. Hopefully not _too_ noisy at low resonance, though.. 

Has anybody done this using the method I described? Is there an easier
way? 

Andrew

| Andrew Schrock       |
| Network Programmer, Synthesizer and electronic music enthusiast |
| aschrock at cs.brandeis.edu      |











From jorgen.bergfors at idg.se  Tue Aug  4 09:35:03 1998
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Tue, 4 Aug 1998 8:35:03 +0100
Subject: AN749?
Message-ID: <TFSGTVLS@idg.se>

Hi transistor gurus.

My Doepfer PMS VCOs use a transistor marked AN749 to discharge the timing cap. 
This works fine, but if I try any other transistor the sawthooth wave vill not 
be linear at medium to lower frequencies. Increasing the base resistor (to 1M 
from 680k) improves linearity somewhat, but not enough. Even the AN749 gives 
reduced linearity at very low frequencies, but it is still much better. 
Anyone know what's so special about the AN749? I have a couple of VCO boards 
that are unpopulated, so I need the components, but the AN749 is nowhere to be 
found. Well, at least Farnell and a couple of others don't stock it.

/Jorgen




From martin.czech at intermetall.de  Tue Aug  4 10:10:19 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Tue, 4 Aug 1998 10:10:19 +0200 (MET DST)
Subject: AN749?
Message-ID: <199808040810.KAA28970@window.intermetall.de>

> Hi transistor gurus.
> 
> My Doepfer PMS VCOs use a transistor marked AN749 to discharge the timing cap. 
> This works fine, but if I try any other transistor the sawthooth wave vill not 
> be linear at medium to lower frequencies. Increasing the base resistor (to 1M 
> from 680k) improves linearity somewhat, but not enough. Even the AN749 gives 
> reduced linearity at very low frequencies, but it is still much better. 
> Anyone know what's so special about the AN749? I have a couple of VCO boards 
> that are unpopulated, so I need the components, but the AN749 is nowhere to be 
> found. Well, at least Farnell and a couple of others don't stock it.
> 
I'm no guru. 

This looks like a leakage problem. AN... a germanium tranny or a kind
of scr ?  If it is the normal type of sawtooth vco with comparator, any
Si small signal transistor should do. Formant uses BC107 (from my head,
check !), but : leakage varies very much, you have too measure it. For
this purpose you could use a low leakage integrator (polystyrene cap,
CA3140, tranny socket), load cap resistor to some voltage (expected
voltage in application) and then switch resistor off. (check first
without tranny, to see the cap and buffer leakage), and see how long it
takes for the tranny leakage to discharge the cap (obviously a grounded cap
integrator, do not use a integrator with cap in feedback path, this
won't work). This way you can measure very small currents with cheap
equipment.

m.c.

------------------------------------------------------------------------
m.c. (alias mad scientist) has made it finally: 3 CDs ? 72 minimum ready.
Visit my homepage at http://www.geocities.com/SoHo/Museum/4459/index.html





From jorgen.bergfors at idg.se  Tue Aug  4 10:21:20 1998
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Tue, 4 Aug 1998 9:21:20 +0100
Subject: Maxx BRM-1A and CA3946
Message-ID: <TFSHKWEN@idg.se>

Looking at the schematics for this ring modulator (
http://www2.vivid.net/~tomg/maxx/page_026.html), I notice that pin 7 of the 
CA3046 is at the lowest potential. I have got the impression that pin 13 is 
connected to the substrate and must be at the lowest potential. Is this 
correct? What happens if you violate this? Will the chip self-destruct or just 
malfunction? Does the Maxx BRM-1A really work?

/Jorgen




From tomg at vivid.net  Tue Aug  4 10:52:15 1998
From: tomg at vivid.net (tomg)
Date: Tue, 04 Aug 1998 03:52:15 -0500
Subject: Uranus phaser
In-Reply-To: <1BF5E20E0C4DD111BBAB00805FE2D58291AA4A@nbgm336a.nbgm.siemens.de>
Message-ID: <yam7520.794.119235216@mail.vivid.net>

On 03-Aug-98, Haible Juergen wrote:
>Hi,

>just a few words about my latest project.
>Six cheap surplus LDR's soldered to 12 pins
>of a 14-pin DIL socket, sensitive side of each
>pointing inwards. A red LED soldered to the
>remaining 2 pins, the LED's wires bent so that
>LED lies horizontally in the "corridor" made
>of the 6 LDR's.

You know you may have inspired me again. I get mail from time to time from
people asking where my intermediate projects are. It now goes from the TherMan
to the Mini4cv. Thats a pretty big leap. So I've been working on a three chip
15 transistor synth (inspired by the paia Gnome) something about $3O, what I
would call a dead simple synth. The rules are keep it under $35 no OTAs, less
than 4 chips, under 12 controls switches and pots. CV interface pitch, pitch
bend, mod and trigger. specs so far 1 unj VCO w/sub oct, BP VCF, VCA, 1
LFO/MOD, 2 EGs w/attack & decay. Parts so far LM324,CD4O11,CD4O13,UNJ several
FETS, NPNs and PNPs. I was having a problem getting the LFO to perform the MOD
function using a FET and I think the solution may involve a LDR/LED. I might
even be able to change the BP VCF to a LP VCF. The no OTA less than 4 chip
rule is proving tough to follow, but If I really want to build it for less
that $35 I need to follow it. We'll see how it turns out. I think I'll call it
the Mad-Mouse  after that awful ride I loved so much.

BTW I went looking for a couple of 3 space rack panels for a pair of Mini1cv's
But they were out so I bought a 6 space panel. Every time I look at it, it
changes. There is a pic of what it looked like last time on my site under
UMaxx. Sort of a contained modular thing. It's safe to say the mini1 will not
get built any time soon so I have moved it into the new project archive area.
I am making a lot of changes. I have a lot of information there but it's not
arranged very well so I'm working at it. Some links may break. 

1 cv interface - glide / pitch bend range / 3 attenuators...ect
2 3374 VCOs - CV / PWM / FM / Sync Inputs & Saw / Pulse / Tri / Sine
1 VCO-4A - CV / PWM / FM / Sync Inputs & Saw / Pulse / Tri / Sine 
2 LFOS LFO-1A - Tri / Square Waves CV range.
1 S&H noise LFO-2A type with internal 555 clock
2 TGS w/cyle and CV range
2 EGS w/ CV range
1 Ring Modulator
1 Sub Octave
3 CV or Audio mixers
1 Moog type VCF w/FM
1 MS50 type VCF w/FM <- New addition ;-) Where am I gona put this?
1 3372 VCF w/FM
1 Dual VCA w/pan

Cya

-tg




From tomg at vivid.net  Tue Aug  4 11:07:51 1998
From: tomg at vivid.net (tomg)
Date: Tue, 04 Aug 1998 04:07:51 -0500
Subject: Maxx BRM-1A and CA3946
In-Reply-To: <TFSHKWEN@idg.se>
Message-ID: <yam7520.2590.119235216@mail.vivid.net>

On 04-Aug-98, jorgen.bergfors at idg.se wrote:
>Looking at the schematics for this ring modulator (
>http://www2.vivid.net/~tomg/maxx/page_026.html), I notice that pin 7 of the 
>CA3046 is at the lowest potential. I have got the impression that pin 13 is 
>connected to the substrate and must be at the lowest potential. Is this 
>correct? What happens if you violate this? Will the chip self-destruct or
just

>malfunction? Does the Maxx BRM-1A really work?

>/Jorgen

Yes it the Maxx BRM-1A really works. The 3046 will not blow up! The NS app
notes does mention the pin 13 thing, so I guess I should rearrange it  but no
explosions so far. It says "to maintain proper isolation and normal
transistior action" nothing about self destruction. If it adds crosstalk it
may even help in a balance-modulator.

-tg






From tomg at vivid.net  Tue Aug  4 11:25:26 1998
From: tomg at vivid.net (tomg)
Date: Tue, 04 Aug 1998 04:25:26 -0500
Subject: EFM R&D
Message-ID: <yam7520.1326.119239784@mail.vivid.net>

Lately there has been some interest here and in my personal mail
concerning the amount of work I am getting done and how I'm doing it.
Thanks for all of your comments, congratulations and criticisms. Let me assure
all of you it has not always been this way. I don't have any special talent.
It's hard work paying off. EFM is the product of two years of hard core r&d.
It has been almost exactly two years since I decided to build my first synth
and five synthesizers later I am just starting to get the hang of it. Most of
you guys are professionals so my equipment list and procedures will seem
elementary to you. I'm just a guitar player who learned to fix things and
decided to build a synthesizer. BTW I'm just getting started good. I only have
so much cash for parts. And I wish I could work faster...:-) 

As to why I'm doing this. I just want to build myself a few really good
synths. I really don't have to, I have a ton of cool gear, I just want to.
Hanging out with you guys helps a lot. Thanks to all of you for being here.
Finding SynthTech was the answer to a prayer.

Development Environment.

) Lots of free, quite time. I have the wife most men dream of. 
) I am a very, very lucky man.

) My office/studio.
) My beloved Amiga 3OOO (I have Macs and PCs too. No Flames Please.)
) A huge collection of reference books, manuals and magazine articals.

Equipment List (Just the synth r&d stuff.)

) Homemade +-12V at 1A/+-5V at 1A/+-O to 28V at 1.5A/+-35V at 5A power supply 
) internal 1 watt monitor amp on a separate +12V PS .

) Homemade Synth r&d box internal VCO VCF VCA EG.
) Homemade 6OW current limiter with internal variac.
) Homemade 8O38 based function generator.
) Micronta 22-195 digital meter
) Micronta 22-188 digital meter
) Micronta 22-2O2U multi meter
) Micronta 22-2O9A fet-vom
) BK 1803 1OOMHZ frequency counter
) Hitachi V-212 2OMHZ dual scope
) Eico 1120 cap box
) Eico 11OO resistance box
) Weller TC-2O2 power unit 24V 42W iron 
) Wish Board 2O6 prototype board 26OO+ tie points 18 ic capacity

) It helps to have a large supply of parts. I have been collecting
) stuff for 1O years. I have one of most things. That's what
) happens if you always buy two. BTW I found those top octive chips. If
) you are the one who needed it mail me. I can do better than $40.

Research Procedure.

) Have a idea, or borrow one. If I borrow, I borrow from the best and
) give them credit. That means I'm always giving credit to someone
) else. Who said "I stand on the shoulders of giants."? I need to borrow 
) that too...:-)

Development Procedure.

) Hand draw the circuit. (This is an important step)
) Proto-board the circuit note voltages at critical points. Note changes.

) I understand not everyone likes the proto-board part. But you test the
) design and the parts together. Saves me tons of time.

) NEW ADDITION-> Make parts list. It must be harder to read values online
) than I thought. Everybody wants parts lists.

) Cad the schematic diagram and pc-board layout. Note changes.
) Build a perf-board version. Note changes.
) Correct Cad drawings. Note changes.

Do you get the idea I take a lot of notes?

I have not preceded to the next step in a long time. At this point I'm
ready to mount whatever it is it on a piece of aluminum angle and put knobs on
it. It's also at this point I usually post it on my site and
wait for people to ask if it works or not.

) Print final board transparency.
) Expose, etch, drill, clean and mount parts on the pc-board.
) Final assembly.

) About every six months I take my drawings and printouts to the
) local copy center and have them bound. They become referance books.

I hope this helps the interested and doesn't bore everyone else.

-Tom





From tomg at vivid.net  Tue Aug  4 12:09:11 1998
From: tomg at vivid.net (tomg)
Date: Tue, 04 Aug 1998 05:09:11 -0500
Subject: No subject
Message-ID: <yam7520.565.119124040@mail.vivid.net>

This is my last post to this group. Thanks for the good times.

cya

-tg




From sidlar at loon.norlink.net  Tue Aug  4 12:29:43 1998
From: sidlar at loon.norlink.net (Frank Lemieux)
Date: Tue, 04 Aug 1998 06:29:43 -0400
Subject: mysterious delay lines
In-Reply-To: <199808021033.LAA05727@irwell.zetnet.co.uk>
Message-ID: <3.0.2.32.19980804062943.00807680@mail.norlink.net>

Looking through my bin of mysterious surplus parts, I've found these
oddities: little plastic rectangles marked "delay line".  

The symbol upon these is a diamond, with "KSS" inside.  They model numbers
at MS-15 and MS-19.  There are 4 leads coming out the bottom.

Anyone have any data on these things?  If they are what I think they are,
they have a million uses...

-/9\-




From Juergen.Haible at nbgm.siemens.de  Tue Aug  4 13:08:50 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Tue, 4 Aug 1998 13:08:50 +0200 
Subject: Neptune (was: AW: Uranus phaser)
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D58292A981@nbgm336a.nbgm.siemens.de>

	>I did the same thing a few years ago, inspired by Craig Anderton's
CLM-6000
	>phaser (a clm-6000 is a LED & LDR in the same package)  and found
the 1 led
	>muilt LDR arrangement ok but the sweep range was very limited, just
not enough
	>light on the LDR. 

I can confirm that. Not very large range on my new phaser.
(I've prototyped one with VTL5C4/2 dual devices, and the range
was much larger. Unfortunately, you can only use these dual 
Vactrols in the opamp circuit (where one leg is at GND).

BTW, my new device is called Neptune now. Some of you
pointed out that uranus was a little ambiguous.

JH.



From Juergen.Haible at nbgm.siemens.de  Tue Aug  4 13:15:07 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Tue, 4 Aug 1998 13:15:07 +0200 
Subject: nanometers (was: AW: Uranus phaser)
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D58292A99B@nbgm336a.nbgm.siemens.de>


	>> - Typical CdS LDR's are most sensitive to green light, just like
the
	>> human eye. Using a green LED, especially an ultra-bright green
LED,
	>> will make the current used to drive the LED much lower. 
	>> 
	>??
	>I have seen sensitivity measurement diagrams that show two peaks of
	>equal hights for CdS:  at green 540nm AND orange/red 640nm. 

I think CdS is only one of several materials for LDRs.
There's CdSe (sp?), and probably mixtures of both.
I have no idea what these surplus parts are made of.

	>So these
	>very bright orange/red diodes should be sufficient, they are much
	>brighter then any green led I've ever seen, indeed one should not
	>directly look into the light source, danger of eye damage !

Is this really true? I think that even if there would be danger
when you look at it with an optical device (telescope ...),
it would have to be labelled so. (At least in Germany)
Just wondering.

JH.




From Juergen.Haible at nbgm.siemens.de  Tue Aug  4 13:25:34 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Tue, 4 Aug 1998 13:25:34 +0200 
Subject: AW: Uranus phaser
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D58292CED3@nbgm336a.nbgm.siemens.de>

	>So in their infinite wisdom,
	>the marketing guys at Commodore renamed it the "Vixen-20". Remember
this
	>Juergen?
	>
	>'Vixen' is word meaning a prostitute in German.

Well, almost. It actually means consuming drugs with the needle,
but the other will often result from the first.

	>Also, in Mandarin Chinese "Coca-Cola" (co-ca-co-la) means "Bite the
wax
	>tadpole" and Coke's campaign "Coke adds life" got translated into
Mandarin
	>meaning "Coke brings back your ancient ancestors from the dead".

That's a good one !

JH.




From martin.czech at intermetall.de  Tue Aug  4 13:36:34 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Tue, 4 Aug 1998 13:36:34 +0200 (MET DST)
Subject: nanometers (was: AW: Uranus phaser)
Message-ID: <199808041136.NAA29921@window.intermetall.de>

> 
> 	>> - Typical CdS LDR's are most sensitive to green light, just like
> the
> 	>> human eye. Using a green LED, especially an ultra-bright green
> LED,
> 	>> will make the current used to drive the LED much lower. 
> 	>> 
> 	>??
> 	>I have seen sensitivity measurement diagrams that show two peaks of
> 	>equal hights for CdS:  at green 540nm AND orange/red 640nm. 
> 
> I think CdS is only one of several materials for LDRs.
> There's CdSe (sp?), and probably mixtures of both.
> I have no idea what these surplus parts are made of.

There are (according to book):
CdS  operate in visible light
CdSe     ""

PbS   operate in infra red
PbSe            "
InSb            "
Hg(n)Cd(m)Te    "

The text says further, that allmost all photoresitive devices for
visible light use CdS.

> 
> 	>So these
> 	>very bright orange/red diodes should be sufficient, they are much
> 	>brighter then any green led I've ever seen, indeed one should not
> 	>directly look into the light source, danger of eye damage !
> 
> Is this really true? I think that even if there would be danger
> when you look at it with an optical device (telescope ...),
> it would have to be labelled so. (At least in Germany)
> Just wondering.
> 
>
I read this in a catalogue text, these diodes already have some kind of
optical lens, the radiation angle is quite narrow. Very, very bright
indeed, make a visible spot on your hand at 30 cm distance even in
daylight. Never looked directly into the beam thogh, I already have bad
eyes 8->.




From Hcabnivek at aol.com  Tue Aug  4 14:09:34 1998
From: Hcabnivek at aol.com (Hcabnivek at aol.com)
Date: Tue, 4 Aug 1998 08:09:34 EDT
Subject: mysterious delay lines
Message-ID: <7e2333fa.35c6f9ff@aol.com>

In a message dated 98-08-04 06:31:20 EDT, you write:

> Looking through my bin of mysterious surplus parts, I've found these
>  oddities: little plastic rectangles marked "delay line".  
>  
>  The symbol upon these is a diamond, with "KSS" inside.  They model numbers
>  at MS-15 and MS-19.  There are 4 leads coming out the bottom.

Yeah, I have a few of these things too, and I'd like to know as well.  The
ones I have are tear-outs from several video cassette recorders.  If you
extract the guts from the plastic case you will find a (I guess) quartz waffer
with the wire leads fused to the edges.  Each pair of leads is attached to
opposite sides of the waffer, which on the ones that I have, is about  2cm x
3cm.  I find it hard to believe that these are "delay lines" in the sense that
we in the synth world think of them.  Any of the electro-Gurus out there know
what these things are for?
Kevin



From jorgen.bergfors at idg.se  Tue Aug  4 14:37:28 1998
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Tue, 4 Aug 1998 13:37:28 +0100
Subject: mysterious delay lines
Message-ID: <TFSKTNWI@idg.se>

They are probably made for delaying one scan line in PAL television sets. If I 
remember correctly, it is a plexiglass block where the signal from a transducer 
bounces a couple of times and then is picked up at the other end. It was 20 
years ago since school, where I learned this stuff. As the line frequency is 
15625 hz, the delay time should be 64 microseconds. Or am I doing the math 
wrong?

/Jorgen





MIME:sidlar at loon.norlink.net on 98-08-04 14.20.16
To:  synth-diy at mailhost.bpa.nl @ SMTP 
cc:  (bcc: Jorgen Bergfors/IDGSE)
Subject: mysterious delay lines 

Looking through my bin of mysterious surplus parts, I've found these
oddities: little plastic rectangles marked "delay line".  

The symbol upon these is a diamond, with "KSS" inside.  They model 
numbers
at MS-15 and MS-19.  There are 4 leads coming out the bottom.

Anyone have any data on these things?  If they are what I think they 
are,
they have a million uses...

-/9\-










From ryckebu at subasehp.san.mrms.navy.mil  Tue Aug  4 14:44:05 1998
From: ryckebu at subasehp.san.mrms.navy.mil (Jules Ryckebusch)
Date: Tue, 4 Aug 1998 12:44:05 +0000
Subject: SPDIF coax cables
In-Reply-To: <3F68DD840B4@fs2.cp.umist.ac.uk>
References: <TFSKTNWI@idg.se>
Message-ID: <199808041946.MAA26306@subasehp.san.mrms.navy.mil>



> Does anyone know how SPDIF cables should be made up? I know there's 
> a requirement of 90ohm (?) impedance, but not how that is supposed to 
> be achieved...?
> 
> It seems noone around here actually stocks premade SPDIF cables...
  You can actually use regular RCA to RCA cables. I have made ones 
using thin 75 ohm coax with no problem running 20 feet. If anyone 
knows where to get 90ohm cable, I would like to know!

Jules



From Hcabnivek at aol.com  Tue Aug  4 15:04:56 1998
From: Hcabnivek at aol.com (Hcabnivek at aol.com)
Date: Tue, 4 Aug 1998 09:04:56 EDT
Subject: Another capacitor question
Message-ID: <9a0ffc63.35c706f9@aol.com>

I can tell that my polyproplene capactiors are, in fact, polyproplene caps
only because Digikey says that is what they are.  This is fine, I trust them
to be right.  My question is; How does one identify a cap of unknown origin as
to it's material type i.e. polypro, polyeth, polysty, mylar etc.  Obviously
electrolytics and ceramics are easy, and all the polystyrene caps I've seen
have the same look to them, but how do I tell what type cap I have if I don't
know it's origin?  Most of the rest of these cap types are in epoxy dipped
cases and are visually similar, correct?.  Is there a secret code that
identifies the material type.  A lot of the stuff I use to build modules is
"surplus". On occation I'll tear out a cap or pot from a piece of expensive
(and often times fairly modern) scientific equipment that our physics lab has
junked. Lots and lots of physically large, small value epoxy dipped caps in
this stuff.  How does one figure out what is inside these plastic blobs?
Thanks in advance,
Kevin

Kevin Bach
Hcabnivek at aol.com



From ijfritz at earthlink.net  Tue Aug  4 16:21:09 1998
From: ijfritz at earthlink.net (Ian Fritz)
Date: Tue, 04 Aug 1998 08:21:09 -0600
Subject: mysterious delay lines
References: <7e2333fa.35c6f9ff@aol.com>
Message-ID: <35C718D5.A7F1E652@earthlink.net>

Surface acoustic wave (SAW) delay lines , maybe? -- Ian

Hcabnivek at aol.com wrote:
> 
> In a message dated 98-08-04 06:31:20 EDT, you write:
> 
> > Looking through my bin of mysterious surplus parts, I've found these
> >  oddities: little plastic rectangles marked "delay line".
> >
> >  The symbol upon these is a diamond, with "KSS" inside.  They model numbers
> >  at MS-15 and MS-19.  There are 4 leads coming out the bottom.
> 
> Yeah, I have a few of these things too, and I'd like to know as well.  The
> ones I have are tear-outs from several video cassette recorders.  If you
> extract the guts from the plastic case you will find a (I guess) quartz waffer
> with the wire leads fused to the edges.  Each pair of leads is attached to
> opposite sides of the waffer, which on the ones that I have, is about  2cm x
> 3cm.  I find it hard to believe that these are "delay lines" in the sense that
> we in the synth world think of them.  Any of the electro-Gurus out there know
> what these things are for?
> Kevin



From pfperry at melbpc.org.au  Tue Aug  4 16:26:51 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Wed, 5 Aug 1998 00:26:51 +1000 (EST)
Subject: Another capacitor question
Message-ID: <1.5.4.16.19961227070202.38678d30@popa.melbpc.org.au>

At 09:04 AM 4/08/98 EDT, Kevin Bach wrote:

>this stuff.  How does one figure out what is inside these plastic blobs?

well the best thing, really, is to buy some of each type & get a feel for it.
Size is a useful indicator too. The best intro to capacitors is in
"Troubleshooting
Analog Circuits" by R.A. Pease. Not a synth book as such, but FULL of wisdom.
One good thing I saw here was that there are 2 types of 'ceramic' capacitor, one
fairly precise, the other much physically smaller for the same value but with
unbelievably bad temp coefficients, no precision, and wacky volt/cap variance.

paul perry melb aust




From pfperry at melbpc.org.au  Tue Aug  4 17:01:05 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Wed, 5 Aug 1998 01:01:05 +1000 (EST)
Subject: theremin antenna design
Message-ID: <1.5.4.16.19961227073617.0e3f4b3e@popa.melbpc.org.au>

well RF is not my thing.....
so I wonder has anyone any idea for multiple theremin antennas?
I wondered if I had a horizontal plate say 10 cm diameter on the 
end of a pole with the outside of the pole earthed and the wire 
going up the pole, would this give reasonable isolation from 
another say 50cm away?
Does it matter at all what freq I am using, bearing in mind the
structure will be several orders of magnitude smaler than a wavelength?
Woulkd it be better to make some kind of balanced quadropoke structure
so it has a shaped near field but the signal dies away rapidly as you
move away from the unit?
Is the original 'classical' theremin structure optimal in some way?

So many questions, and only the ham radio handbook to guide me..
opinions anyone?

paul perry melbourne australia




From jmar at intface.com  Tue Aug  4 17:23:54 1998
From: jmar at intface.com (Jay Martin)
Date: Tue, 4 Aug 1998 11:23:54 -0400 
Subject: mysterious delay lines
Message-ID: <3ED7C23D1CA6D01183370060B01A842E221656@lp1>

If I remember correctly they are used to delay the audio path slightly to
keep it in sync with the video.  There is no control over the amount of
delay.  This is done because the audio path of a composite signal is shorter
and requires less filtering and processing than the video signal.  The extra
time it takes for the processing is compensated for by the device. The delay
is usually extremely short, but I can't for the life of me remember how
short.  They used to use a delay coil in the older tube-type TV's for the
same purpose.  See, I got to mention TUBE's in there somewhere!

Jay Martin

> -----Original Message-----
> From:	Ian Fritz [SMTP:ijfritz at earthlink.net]
> Sent:	Tuesday, August 04, 1998 9:21 AM
> To:	Hcabnivek at aol.com
> Cc:	sidlar at loon.norlink.net; synth-diy at mailhost.bpa.nl
> Subject:	Re: mysterious delay lines
> 
> Surface acoustic wave (SAW) delay lines , maybe? -- Ian
> 
> Hcabnivek at aol.com wrote:
> > 
> > In a message dated 98-08-04 06:31:20 EDT, you write:
> > 
> > > Looking through my bin of mysterious surplus parts, I've found these
> > >  oddities: little plastic rectangles marked "delay line".
> > >
> > >  The symbol upon these is a diamond, with "KSS" inside.  They model
> numbers
> > >  at MS-15 and MS-19.  There are 4 leads coming out the bottom.
> > 
> > Yeah, I have a few of these things too, and I'd like to know as well.
> The
> > ones I have are tear-outs from several video cassette recorders.  If you
> > extract the guts from the plastic case you will find a (I guess) quartz
> waffer
> > with the wire leads fused to the edges.  Each pair of leads is attached
> to
> > opposite sides of the waffer, which on the ones that I have, is about
> 2cm x
> > 3cm.  I find it hard to believe that these are "delay lines" in the
> sense that
> > we in the synth world think of them.  Any of the electro-Gurus out there
> know
> > what these things are for?
> > Kevin



From Chris.List at sc.siemens.com  Tue Aug  4 17:46:27 1998
From: Chris.List at sc.siemens.com (List, Christopher)
Date: Tue, 4 Aug 1998 11:46:27 -0400
Subject: Linear response VCA's
Message-ID: <81A062BC5305D111A9D700805F065968CE94A4@maildepo.sc.siemens.com>

> -----Original Message-----
> From:	Michael Maloney [SMTP:mwmjr at ix.netcom.com]
> Sent:	Monday, August 03, 1998 8:04 PM
> To:	synth-diy at mailhost.bpa.nl
> Subject:	Linear response VCA's
> 
> I've finally gotten my life in order to attack the modular synth
> project
> I've been promising myself for years. However, I am stumbling over a
> few
> questions that I hope can be answered here:
> 
> Are there situations in which purely linear response is desirable in a
> VCA?
> 
	Yes. When your ADSR has an exponential curve.



From Hcabnivek at aol.com  Tue Aug  4 17:57:06 1998
From: Hcabnivek at aol.com (Hcabnivek at aol.com)
Date: Tue, 4 Aug 1998 11:57:06 EDT
Subject: Hammond delay thingie (was: mysterious delay lines)
Message-ID: <19670293.35c72f53@aol.com>

Speaking of delay like devices  (though I'm not sure this real is one) can
someone explain how the small motor driven drum inside a Hammond organ that
has all the wires connected to it works to generate tremolo/varabrato.  I'm
not talking about a Leslie here, this thing has a wire from each of the draw
bars connected to it I guess a single output wire, and some rotating part
inside that's turned by a belt running off the same motor that turns the tone
wheels.
Anyone?
Kevin



From mfay at fs2.cp.umist.ac.uk  Tue Aug  4 16:03:59 1998
From: mfay at fs2.cp.umist.ac.uk (Martin Fay)
Date: Tue, 4 Aug 1998 16:03:59 BST
Subject: SPDIF coax cables
In-Reply-To: <TFSKTNWI@idg.se>
Message-ID: <3F68DD840B4@fs2.cp.umist.ac.uk>

Does anyone know how SPDIF cables should be made up? I know there's 
a requirement of 90ohm (?) impedance, but not how that is supposed to 
be achieved...?

It seems noone around here actually stocks premade SPDIF cables...



Martin

 man(i)kin / Demos 1 & 2 available (6 mp3 tracks)
+------------------------------------------------+
| Email: martin.fay at umist.ac.uk                  |
| Web: http://www.cp.umist.ac.uk/users/martin/   |
+------------------------------------------------+
| See web site for:                              |
| VAZ: Vurtual Analogue Synth Emulator           |
| man(i)kin: demos, info, pictures               |
+------------------------------------------------+



From b.layer at vikingelectronics.com  Tue Aug  4 18:06:02 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Tue, 04 Aug 1998 11:06:02 -0500
Subject: Another capacitor question
In-Reply-To: <9a0ffc63.35c706f9@aol.com>
Message-ID: <3.0.5.32.19980804110602.007b6810@192.168.210.18>

Hi Kevin,

  How does one figure out what is inside these plastic blobs?
>Thanks in advance,

 Fun question. This requires some messing around, but it's not so difficult
really. The process is one of dissection, and indentification. We will
require samples of both the dilectric and the conductor. So cut up a sample
with your X-acto!

Conductors are either metal foil, or metallized film. The foil may
frequently be identified by color (copper, aluminum) or other basic
physical means, such as stimulating corrosion with acid. The films may be
identified as below.

Insulators are generally paper or plastic films. Mylar can be idntified by
the fact that it is a) metallized and b) very strong in terms of TSI. Other
films (polypro/sty) are much more fragile, and must be differentiated by a
burn test.

Note: burning plastic can give off potentially lethal fumes, so do this
outside and AT YOUR OWN RISK. Polyethyline smells much like candle wax,
polystyrene smells like styrofoam etc. If you don't know how to identify
plastics by smell, get some parts of known composition, then use them as
samples to compare against. When you have determined the compositon, note
whether or not the film is metallized on side or not.

In ceratin metallized film caps (such as the Xicon) my recall is that the
dilectric and conductor are one in the same, since the material can both
conduct and insulate, thus giving greater capacity in a smaller package. 

As for the specifics of this, and also the case types, are there any cap
construction experts out there?


Bill Layer
Sales Technician
<b.layer at vikingelectronics.com>

----------------------------------
Viking Electronics, Inc.
Hudson, WI. U.S.A
715.386.8861 (ext. 210)
<http://www.vikingelectronics.com>
----------------------------------

"Telecommunications Solutions for the 21st Century"



From b.layer at vikingelectronics.com  Tue Aug  4 18:14:38 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Tue, 04 Aug 1998 11:14:38 -0500
Subject: Unknown MIDI devices
Message-ID: <3.0.5.32.19980804111438.007b5960@192.168.210.18>

Hi All, and thanks for the good info,

The Roland part in question is a 'MPU-IPC' MIDI processing unit. Has one
MIDI in two MIDI outs, a sync out, tape in/out and metronome out.

Terminates in a 26 pin D-style connector. Seems to be a breakout box for an
internal PC card. But there is some low-level logic inside the box; not
just wires and jax.

If the PC card is required, missing and unavailible, I'll offer the MPU box
up to whoever wants it for a spare or something. 

As always, thanks for your advice(s).


Bill Layer
"Heavy old junk wanted"



From keen at austin.ibm.com  Tue Aug  4 18:38:53 1998
From: keen at austin.ibm.com (R.G. Keen)
Date: Tue, 04 Aug 98 11:38:53 -0500
Subject: Hammond delay thingie (was: mysterious delay lines) 
In-Reply-To: (Your message of Tue, 04 Aug 98 11:57:06 -0500.)
             <19670293.35c72f53@aol.com>
Message-ID: <199808041638.LAA26178@keen.austin.ibm.com>

>Speaking of delay like devices  (though I'm not sure this real is one) can
>someone explain how the small motor driven drum inside a Hammond organ that
>has all the wires connected to it works to generate tremolo/varabrato.  I'm
>not talking about a Leslie here, this thing has a wire from each of the draw
>bars connected to it I guess a single output wire, and some rotating part
>inside that's turned by a belt running off the same motor that turns the tone
>wheels.
Sounds like an oil can delay. These work by having an insulating layer
inside the rotating can and a high voltage signal source which deposits
charge on the inside of the insulating surface, somewhat like the
charge depositer in a Van de Graff generator. The charge then rotates
with the can and is picked off some rotational delay later by a (very!)
high impedance input. The oil inside is to keep the charge from
bleeding off into the air inside the can.





From ajnelson at scf-fs.usc.edu  Tue Aug  4 18:47:58 1998
From: ajnelson at scf-fs.usc.edu (+monkeypuzzle+)
Date: Tue, 4 Aug 1998 09:47:58 -0700 (PDT)
Subject: SPDIF coax cables
In-Reply-To: <3F68DD840B4@fs2.cp.umist.ac.uk>
Message-ID: <Pine.SV4.3.94.980804094617.21035A-100000@aludra.usc.edu>

Just use the 75 ohm rated video cable that terminates with an RCA plug at
each end.  better than 90 ohm impedence and you can buy them virtually
anywhere (camera shop, electronics store).

--Andrew

On Tue, 4 Aug 1998, Martin Fay wrote:

> Does anyone know how SPDIF cables should be made up? I know there's 
> a requirement of 90ohm (?) impedance, but not how that is supposed to 
> be achieved...?
> 
> It seems noone around here actually stocks premade SPDIF cables...
> 
> 
> 
> Martin
> 
>  man(i)kin / Demos 1 & 2 available (6 mp3 tracks)
> +------------------------------------------------+
> | Email: martin.fay at umist.ac.uk                  |
> | Web: http://www.cp.umist.ac.uk/users/martin/   |
> +------------------------------------------------+
> | See web site for:                              |
> | VAZ: Vurtual Analogue Synth Emulator           |
> | man(i)kin: demos, info, pictures               |
> +------------------------------------------------+
> 




From ebarbour at svetlana.com  Tue Aug  4 19:15:58 1998
From: ebarbour at svetlana.com (Eric Barbour)
Date: Tue, 4 Aug 1998 10:15:58 -0700
Subject: Reliable Capacitors
Message-ID: <01BDBF90.E06122A0.ebarbour@svetlana.com>

>Some really fine poly pro/sty caps come from Reliable Capacitor in
>California. 

>Tried calling them and got a nastygram from the phone
>company saying that
>the call could not be completed as dialed...

Sorry---they apparently do NOT do direct sales business anymore.
This change just appeared in their latest ads.
You have to go thru their reps at (530) 885-6809, fax (530) 823-0156.
They have a web site www.capacitors.com.

Eric Barbour
Svetlana Electron Devices
Portola Valley CA USA




From don at till.com  Tue Aug  4 19:30:54 1998
From: don at till.com (Don Tillman)
Date: Tue, 4 Aug 1998 10:30:54 -0700 (PDT)
Subject: Hammond delay thingie (was: mysterious delay lines)
In-Reply-To: <19670293.35c72f53@aol.com> (Hcabnivek@aol.com)
Message-ID: <199808041730.KAA02045@shell9.ba.best.com>

   From: Hcabnivek at aol.com
   Date: Tue, 4 Aug 1998 11:57:06 EDT

   Speaking of delay like devices (though I'm not sure this real is
   one) can someone explain how the small motor driven drum inside a
   Hammond organ that has all the wires connected to it works to
   generate tremolo/varabrato.

The Hammond service manual is readily available online (gotta love
the internet!) and has the complete explanation.

http://theatreorgans.com/hammond/faq/a-100/a-100.html

It's a tapped LC delay line, a 3-position range switch to select eight
of the taps, and a rotating mechanical scanner to fade between the taps.

   Date: Tue, 04 Aug 98 11:38:53 -0500
   From: "R.G. Keen" <keen at austin.ibm.com>

   Sounds like an oil can delay. 

That's a different beast.

Oil delays are used only on those Moreley and Gibson echos, as far
as I know.

  -- Don







From Robert.Schrum at harpercollins.com  Tue Aug  4 19:49:00 1998
From: Robert.Schrum at harpercollins.com (Robert Schrum)
Date: Tue, 4 Aug 1998 13:49:00 -0400
Subject: Hammond delay thingie (was: mysterious delay lines)
Message-ID: <00064B75.CE21411@harpercollins.com>

Interesting theory, but...

Look at http://theatreorgans.com/hammond/faq/hammond-faq.html#SEC6 for a quick
explanation of the vibrato scanner,
http://theatreorgans.com/hammond/faq/files/schematics/b3sch-a.pdf for the
schematic of the whole B3 with particular detail on the scanner.


-----Original Message-----
From: "R.G. Keen" <keen at austin.ibm.com> at hcinternet-server
Sent: Tuesday, August 04, 1998 12:38 PM
To: Hcabnivek at aol.com at HCINTERNET-SERVER
Cc: synth-diy at mailhost.bpa.nl at HCINTERNET-SERVER;
keen at keen.austin.ibm.com at HCINTERNET-SERVER
Subject: RE: Hammond delay thingie (was: mysterious delay lines)


>Speaking of delay like devices  (though I'm not sure this real is one) can
>someone explain how the small motor driven drum inside a Hammond organ that
>has all the wires connected to it works to generate tremolo/varabrato.  I'm
>not talking about a Leslie here, this thing has a wire from each of the draw
>bars connected to it I guess a single output wire, and some rotating part
>inside that's turned by a belt running off the same motor that turns the tone
>wheels.
Sounds like an oil can delay. These work by having an insulating layer
inside the rotating can and a high voltage signal source which deposits
charge on the inside of the insulating surface, somewhat like the
charge depositer in a Van de Graff generator. The charge then rotates
with the can and is picked off some rotational delay later by a (very!)
high impedance input. The oil inside is to keep the charge from
bleeding off into the air inside the can.



From mgranger at greenville.infi.net  Tue Aug  4 21:04:04 1998
From: mgranger at greenville.infi.net (Mike)
Date: Tue, 04 Aug 1998 15:04:04 -0400
Subject: Hammond delay thingie (was: mysterious delay lines)
References: <19670293.35c72f53@aol.com>
Message-ID: <35C75B24.3AB9@greenville.infi.net>

Hcabnivek at aol.com wrote:
> 
> Speaking of delay like devices  (though I'm not sure this real is one) can
> someone explain how the small motor driven drum inside a Hammond organ that
> has all the wires connected to it works to generate tremolo/varabrato.  I'm
> not talking about a Leslie here, this thing has a wire from each of the draw
> bars connected to it I guess a single output wire, and some rotating part
> inside that's turned by a belt running off the same motor that turns the tone
> wheels.
> Anyone?
> Kevin
Kevin,The Hammond device you are referring to is called a vibrato
scanner. It works something like the distributor in your automobile
engine. There are multiple fixed capacitor poles arranged in a circle
that are connected to different points on an inductor/capacitor delay
line that the organ signal is run through. There is a scanning pole that
rotates inside this assembly that capacitively couples the various
delayed signals to the scanner output. Since the delays are different as
the scanner rotates, the scanner output signal consists of a variable
time delayed version of the organ tone that shifts its pitch alternately
up and down thus giving a true vibrato sound.

Mike Granger



From costello at seanet.com  Tue Aug  4 21:10:43 1998
From: costello at seanet.com (Sean Costello)
Date: Tue, 04 Aug 1998 12:10:43 -0700
Subject: Tom G.'s site down - anyone know why?
Message-ID: <35C75CB3.7B897E74@seanet.com>

Hi folks:

I went to Tom G.'s pretty amazing site just a few minutes ago
(http://www.tomg.vivid.net/) to download his instructions on how he
constructs perfboard circuits, and...the site is gone.  Just a note
saying "THIS SITE IS CLOSED."

Anyone know what happened?  It was a great site.  I was going to print
out the info on how to construct things on perfboard.

Sean Costello



From b.layer at vikingelectronics.com  Tue Aug  4 21:52:05 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Tue, 04 Aug 1998 14:52:05 -0500
Subject: Hammond delay thingie (was: mysterious delay lines)
In-Reply-To: <199808041730.KAA02045@shell9.ba.best.com>
References: <19670293.35c72f53@aol.com>
Message-ID: <3.0.5.32.19980804145205.007c4d30@192.168.210.18>

>The Hammond service manual is readily available online (gotta love
>the internet!) and has the complete explanation.
>
>http://theatreorgans.com/hammond/faq/a-100/a-100.html
>
>It's a tapped LC delay line, a 3-position range switch to select eight
>of the taps, and a rotating mechanical scanner to fade between the taps.

I've got one of the LC delay lines sitting in a pile in my attic, along
with the rest of my M-2. It's got about fifteen inductors in it. I've been
trying to think what to do with it; wonder if it could be employed in some
sort of delay device. One would have to duplicate the scanner, though.
Or... digital scanner?

What you think?
		
Bill Layer
Sales Technician
<b.layer at vikingelectronics.com>

----------------------------------
Viking Electronics, Inc.
Hudson, WI. U.S.A
715.386.8861 (ext. 210)
<http://www.vikingelectronics.com>
----------------------------------

"Telecommunications Solutions for the 21st Century"



From digiboy at erols.com  Tue Aug  4 21:58:22 1998
From: digiboy at erols.com (mike(digiboy))
Date: Tue, 4 Aug 1998 14:58:22 -0500
Subject: WTB:EML 400/401 sequencer
Message-ID: <l03130303b1ed1828ab9a@[207.172.114.112]>

Searching for an EML 400/401/416  32 stage sequencer....yeah I know it's a
tough one. I have
cash ready.
OR: Will trade or offer cash for a working EML 32 stage sequencer panel.
This is the left panel of the 400/401. Referred to as the 400 panel or the
dual 400 panel or the 400/416 panel.
Please Email me privately on this.

Thanks

Mike B.

--
digiboy at erols.com

digiboy at erols.com (Mike)

"Ahh rock on, George, for Ringo one time!"
	-Ringo





From johns at oei.com  Tue Aug  4 22:13:42 1998
From: johns at oei.com (John Speth)
Date: Tue, 4 Aug 1998 13:13:42 -0700
Subject: 19 inch rack source
Message-ID: <000801bdbfe4$6033d420$2c15d7d0@johns.oei.com>

Hi folks,

I'm looking for a nice 19 inch rack home for my MOTM modules and have had
little luck finding a source of cabinets.  Can anyone point me to a source
of 19 inch rack cabinets that are not priced at horrendous industrial
levels?

John Speth
Object Engineering, Inc
mailto:johns at oei.com





From magnus at analogue.org  Tue Aug  4 22:43:08 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Tue, 04 Aug 1998 22:43:08 +0200
Subject: nanometers (was: AW: Uranus phaser)
In-Reply-To: Your message of "Tue, 4 Aug 1998 13:15:07 +0200 "
References: <1BF5E20E0C4DD111BBAB00805FE2D58292A99B@nbgm336a.nbgm.siemens.de>
Message-ID: <199808042043.WAA22446@piraya.electrum.kth.se>

>>>>> "HJ" == Haible Juergen <Juergen.Haible at nbgm.siemens.de> writes:

Hi!

In my habbit of talking about subjects I know too little of...

 >>> - Typical CdS LDR's are most sensitive to green light, just like
 HJ> the
 >>> human eye. Using a green LED, especially an ultra-bright green
 HJ> LED,
 >>> will make the current used to drive the LED much lower. 
 >>> 
 >> ??
 >> I have seen sensitivity measurement diagrams that show two peaks of
 >> equal hights for CdS:  at green 540nm AND orange/red 640nm. 

 HJ> I think CdS is only one of several materials for LDRs.
 HJ> There's CdSe (sp?), and probably mixtures of both.
 HJ> I have no idea what these surplus parts are made of.

There are many semiconductors with diffrent properties to use for this
purpose, and surely is CdS and CdSe just a few of them.

 >> So these
 >> very bright orange/red diodes should be sufficient, they are much
 >> brighter then any green led I've ever seen, indeed one should not
 >> directly look into the light source, danger of eye damage !

 HJ> Is this really true? I think that even if there would be danger
 HJ> when you look at it with an optical device (telescope ...),
 HJ> it would have to be labelled so. (At least in Germany)
 HJ> Just wondering.

Eh... I can understand that my 35 mW laserdiode might hurt my eyes
since the light is in phase and all that, but a 35 mW LED? No...
In that case would a glimp at the clock in the morning be disasterous.

I think it is a matter of confusing laser diodes and normal diodes.

Cheers,
Magnus



From mgranger at greenville.infi.net  Tue Aug  4 22:45:53 1998
From: mgranger at greenville.infi.net (Mike)
Date: Tue, 04 Aug 1998 16:45:53 -0400
Subject: Tom G.'s site down - anyone know why?
References: <35C75CB3.7B897E74@seanet.com>
Message-ID: <35C77301.22A8@greenville.infi.net>

Sean Costello wrote:
> 
> Hi folks:
> 
> I went to Tom G.'s pretty amazing site just a few minutes ago
> (http://www.tomg.vivid.net/) to download his instructions on how he
> constructs perfboard circuits, and...the site is gone.  Just a note
> saying "THIS SITE IS CLOSED."
> 
> Anyone know what happened?  It was a great site.  I was going to print
> out the info on how to construct things on perfboard.
> 
> Sean Costello
Tom sent a message to the list saying that it was his last post to the
group, and said "cya". Anybody know what happened? His site was really
great....

Mike G



From magnus at analogue.org  Tue Aug  4 22:58:08 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Tue, 04 Aug 1998 22:58:08 +0200
Subject: mysterious delay lines
In-Reply-To: Your message of "Tue, 4 Aug 1998 13:37:28 +0100"
References: <TFSKTNWI@idg.se>
Message-ID: <199808042058.WAA22543@piraya.electrum.kth.se>

>>>>> "jb" == jorgen bergfors <jorgen.bergfors at idg.se> writes:

 jb> They are probably made for delaying one scan line in PAL television sets. If I 
 jb> remember correctly, it is a plexiglass block where the signal from a transducer 
 jb> bounces a couple of times and then is picked up at the other end. It was 20 
 jb> years ago since school, where I learned this stuff. As the line frequency is 
 jb> 15625 hz, the delay time should be 64 microseconds. Or am I doing the math 
 jb> wrong?

64 us is the right delay for the PAL once's. They are used as a part
of a interesting piece of signal processing that will (for PAL but not
NTSC) among other things compensate away phase distorsions due to
ground reflections of the signals. The phase is used for color (it is
actually the angle of the color circle!). The lack of phase
compensation in NTSC is the reason that it earned it's nick-name Never
Twice Same Color sine the phase error keeps changing and banging the
poor TV set woun't help since it is not it's fault. PAL got set just a
little later than NTSC out of basically the same work and the
phasecompensation got into PAL.

Nowdays they got this funny idea of squeeze things into bits and spend
a lot more power in that compression than an PAL or NTSC encoder ever
did... in digital.

64us might not be that usefull, but maybe a couple in series and
feedback to get some sort of diffusion effect, maybe even one will do.

Cheers,
Magnus



From LEG at btinternet.com  Tue Aug  4 23:26:51 1998
From: LEG at btinternet.com (george & lorraine)
Date: Tue, 4 Aug 1998 22:26:51 +0100
Subject: Tom G.'s site down - anyone know why?
Message-ID: <01bdbfee$9827aaa0$LocalHost@windows95>


-----Original Message-----
From: Sean Costello <costello at seanet.com>
To: synth-diy at mailhost.bpa.nl <synth-diy at mailhost.bpa.nl>
Date: 04 August 1998 21:30
Subject: Tom G.'s site down - anyone know why?


>Hi folks:
>
>I went to Tom G.'s pretty amazing site just a few minutes ago
>(http://www.tomg.vivid.net/) to download his instructions on how he
>constructs perfboard circuits, and...the site is gone.  Just a note
>saying "THIS SITE IS CLOSED."
>
>Anyone know what happened?  It was a great site.  I was going to print
>out the info on how to construct things on perfboard.
>
>Sean Costello



HI SEAN
I too have just checked out tom's site for some more ace info: which has
helped this mere starter  get fired up a little!!.Have you seen
"THIS IS MY LAST POST TO THIS GROUP.THANKS FOR THE GOOD TIMES  04/08/98
11.37

UUUUMMMM?

live long and prosper

george  8track man BATH.UK




From scott.bernardi at fritz.com  Tue Aug  4 23:47:27 1998
From: scott.bernardi at fritz.com (Scott Bernardi)
Date: Tue, 04 Aug 1998 14:47:27 -0700
Subject: Tom G.'s site down - anyone know why?
In-Reply-To: <35C75CB3.7B897E74@seanet.com>
Message-ID: <3.0.1.32.19980804144727.009fac10@uxsfo4.fritz.com>

He also posted a message to synth-diy saying that it would be his last
post. ???


At 12:10 PM 8/4/98 -0700, you wrote:
>Hi folks:
>
>I went to Tom G.'s pretty amazing site just a few minutes ago
>(http://www.tomg.vivid.net/) to download his instructions on how he
>constructs perfboard circuits, and...the site is gone.  Just a note
>saying "THIS SITE IS CLOSED."
>
>Anyone know what happened?  It was a great site.  I was going to print
>out the info on how to construct things on perfboard.
>
>Sean Costello
>
>
--------------------------------------
Scott Bernardi
voice: 415-538-0439 
fax:   415-904-8375
scott.bernardi at fritz.com



From jamos at technotoys.com  Tue Aug  4 23:54:12 1998
From: jamos at technotoys.com (Jim Johnson)
Date: Tue, 04 Aug 1998 14:54:12 -0700
Subject: Tom G.'s site down - anyone know why?
In-Reply-To: <35C75CB3.7B897E74@seanet.com>
References: <35C75CB3.7B897E74@seanet.com>
Message-ID: <199808041454120260.0637EB24@mail.proaxis.com>

I don't know - but you're right, it's gone. I was also wondering about his
mysterious "goodbye" note from a few hours ago.

Anyone know why he flew the coop?

Jim Johnson 
Metaphoric Software
-------------------
Makers of Techno Toys
Software for Electronic Music
http://www.technotoys.com
info at technotoys.com


*********** REPLY SEPARATOR ***********

On 8/4/98, at 4:13 PM, Sean Costello  wrote: 

>Hi folks:
>
>I went to Tom G.'s pretty amazing site just a few minutes ago
>(http://www.tomg.vivid.net/) to download his instructions on how he
>constructs perfboard circuits, and...the site is gone.  Just a note
>saying "THIS SITE IS CLOSED."
>
>Anyone know what happened?  It was a great site.  I was going to print
>out the info on how to construct things on perfboard.
>
>Sean Costello



From urekar.m at EUnet.yu  Wed Aug  5 00:28:23 1998
From: urekar.m at EUnet.yu (<<marjan>>)
Date: Wed, 05 Aug 1998 00:28:23 +0200
Subject: Tom G.'s site down - anyone know why?
References: <01bdbfee$9827aaa0$LocalHost@windows95>
Message-ID: <35C78B07.7B25@eunet.yu>

> >I went to Tom G.'s pretty amazing site just a few minutes ago
> >(http://www.tomg.vivid.net/) to download his instructions on how he
> >constructs perfboard circuits, and...the site is gone.  Just a note
> >saying "THIS SITE IS CLOSED."
> >
> >Anyone know what happened?  It was a great site.  I was going to print
> >out the info on how to construct things on perfboard.
> >
> >Sean Costello
> 
> HI SEAN
> I too have just checked out tom's site for some more ace info: which has
> helped this mere starter  get fired up a little!!.Have you seen
> "THIS IS MY LAST POST TO THIS GROUP.THANKS FOR THE GOOD TIMES  04/08/98



From don at till.com  Wed Aug  5 00:31:19 1998
From: don at till.com (Don Tillman)
Date: Tue, 4 Aug 1998 15:31:19 -0700 (PDT)
Subject: Tom G.'s site down - anyone know why?
In-Reply-To: <199808041454120260.0637EB24@mail.proaxis.com>
	(jamos@technotoys.com)
Message-ID: <199808042231.PAA23987@shell9.ba.best.com>

   Date: Tue, 04 Aug 1998 14:54:12 -0700
   From: "Jim Johnson" <jamos at technotoys.com>

   I don't know - but you're right, it's gone. I was also wondering about his
   mysterious "goodbye" note from a few hours ago.

   Anyone know why he flew the coop?

I'm guessing either:

  He discovered some top-secret information about UFO landings and
  government agents just showed up at his door to take him away.  He
  only had time to send off a quick goodbye note.

or 

  He didn't pay his internet service provider bill.

  -- Don








From urekar.m at EUnet.yu  Wed Aug  5 00:34:58 1998
From: urekar.m at EUnet.yu (<<marjan>>)
Date: Wed, 05 Aug 1998 00:34:58 +0200
Subject: Tom G.'s site down - anyone know why?
References: <01bdbfee$9827aaa0$LocalHost@windows95> <35C78B07.7B25@eunet.yu>
Message-ID: <35C78BF1.10C9@eunet.yu>

What happened ?
He posted some detailed post about his R&D
and now going off ?
Went on a holiday or something ?

too bad ...


marjan



From thelab at sprint.ca  Wed Aug  5 00:39:22 1998
From: thelab at sprint.ca (Philip)
Date: Tue, 04 Aug 1998 20:39:22 -0200
Subject: Tom G.'s site down - anyone know why?
References: <35C75CB3.7B897E74@seanet.com> <199808041454120260.0637EB24@mail.proaxis.com>
Message-ID: <35C78D9A.7236@sprint.ca>

Does anyone have a copy of the schematic for his souped up Moog Prodigy
Osc...I was just about to build it?

It's a shame to see his excellent site and interesting comments
dissappear. 

It's only been a short while however it has been quite an impact. He is
certainly missed by all.

Philip
-- 
Philip Pilgrim                  The Lab Audio Works
5 Evan's Drive                  - Analog/Digital Recording/Processing
Hammonds Plains                 - Computer/Synth Interfacing
Nova Scotia, Canada             - Hardware/Software Development
B4B 1M8

Phone     +1.902.835.7844
Email      mailto:thelab at sprint.ca

Web Page: http://www.robotnik.com/the_lab



From sasami at blaze.net.au  Wed Aug  5 00:56:18 1998
From: sasami at blaze.net.au (Ken Stone)
Date: Wed, 5 Aug 1998 00:56:18 +0200 (MET DST)
Subject: Tom G.'s site down - anyone know why?
Message-ID: <199808042256.AAA26052@mailhost.bpa.nl>

>I don't know - but you're right, it's gone. I was also wondering about his
>mysterious "goodbye" note from a few hours ago.
>
>Anyone know why he flew the coop?

The message PRIOR to that may hold the answer. 
In it he suggests that he was bombarded by emails asking if his designs
really worked, especially at the rate at which he was producing them.

Perhaps he took this as a vote of no confidence and decided enough was enough.

Ken
_____________________________________________________________

                Ken Stone  sasami at blaze.net.au
                   ** Catgirl Paradise **
               <http://www.anime.net/~kens/>
         ** Australian Miniature Horses and ponies **
             <http://www.blaze.net.au/~sasami/>
_____________________________________________________________





From sebsi23 at hooked.net  Wed Aug  5 01:07:24 1998
From: sebsi23 at hooked.net (matt wilson)
Date: Tue, 04 Aug 1998 16:07:24 -0700
Subject: fuel to the tomg fire
Message-ID: <199808042305.QAA04516@mom.hooked.net>

i received a post from tom just last night (included below) in response to
a post to him a week or so ago...so as of last night he's still around.




>From: tomg <tomg at vivid.net>
>Reply-To: tomg at vivid.net
>To: matt wilson <sebsi23 at hooked.net>
>Date: Mon, 03 Aug 1998 22:16:25 -0500
>Subject: Re: hi tom
>
>On 26-Jul-98, matt wilson wrote:
>>first of all thanks for all your great help and input on synth diy, and
>>your pages
>>are excellent.
>
>>second, i've got some rather naive questions about building the vca-1a.
>>i've
>>built a few devices, but i'm perplexed about the schem's and the pcb
>>layout.
>
>Sorry for the slow reply kinda on vacation. What can I help you with?
>
>-tg


Matt Wilson, Odyssey Studios
               on the web: www.wenet.net/~sebsi23
                          on the phone: 415 675-4886
                                    on the email: sebsi23 at hooked.net				
                            




From dave at mail.kc.net  Wed Aug  5 01:36:34 1998
From: dave at mail.kc.net (Dave)
Date: Tue, 04 Aug 1998 18:36:34 -0500
Subject: Tom G.'s site down - anyone know why?
In-Reply-To: <35C75CB3.7B897E74@seanet.com>
Message-ID: <3.0.1.32.19980804183634.00739e88@mail.kc.net>

At 12:10 PM 8/4/98 -0700, Sean Costello wrote:
>
>Anyone know what happened?  It was a great site.  I was going to print
>out the info on how to construct things on perfboard.

Perhaps more to the point: did anyone archive this site?  I think I have a
couple of pages, but not enough to rebuild it.  I'd be happy to 'mirror' it
if someone has the files.

Dave in KCMO USA
dave at o2.net
http://www.o2.net/~dave/




From chordman at flash.net  Wed Aug  5 02:16:00 1998
From: chordman at flash.net (Scott Gravenhorst)
Date: Wed, 05 Aug 1998 00:16:00 GMT
Subject: Tom G.'s site down - anyone know why?
In-Reply-To: <3.0.1.32.19980804183634.00739e88@mail.kc.net>
References: <3.0.1.32.19980804183634.00739e88@mail.kc.net>
Message-ID: <35c9a2ad.3105476@mail.lan>

On Tue, 04 Aug 1998 18:36:34 -0500, Dave <dave at mail.kc.net> wrote:

>did anyone archive this site?  I think I have a
>couple of pages, but not enough to rebuild it.  I'd be happy to 'mirror' it
>if someone has the files.

I was very interested in his FatMan section (obviously).  But due to
the fact that people change things on their sites, I am reluctant to
archive, but rather I had a link on my FatMan site to his FatMan
pages.  Occasionally, I will download certain schematics for
private/personal use, but I have nothing from tomg.  Further, even if
I did, I would (for my own ethics) require his permission to post
anything.

If anyone is in contact with him, let him know that I have room for at
least the FatMan stuff he had.

BTW, I emailed him almost an hour ago and still haven't seen a bounce
message.  Maybe just slow email.

-- Scott Gravenhorst
-- FatMan Site: www.teklab.com/~chordman



From eleckie at cochlear.com.au  Wed Aug  5 02:58:59 1998
From: eleckie at cochlear.com.au (Edward Leckie)
Date: Wed, 05 Aug 98 10:58:59 +1000
Subject: PCBs and front panels
Message-ID: <9808059022.AA902279000@ccgate.cochlear.com.au>


I was wondering of those who make their own PCBs for their modulars, do you
prefer to make all sockets and pots PCB mounting to avoid the mucky-muck of
wires or to have the flexibility of being able to position controls on the front
panel anywhere you wish. 

Ed.  Sydney, Australia.







From girard at enel.ucalgary.ca  Wed Aug  5 03:26:23 1998
From: girard at enel.ucalgary.ca (Arno)
Date: Tue, 04 Aug 1998 19:26:23 -0600
Subject: everything is not lost ...
Message-ID: <199808041926230810.0005F925@mailhost.ucalgary.ca>


I have a printed archive of the Maxx modular (complete)
II was about to archive the whole site for an off-line browsing ! And I didn't have time enough ...

Arno



From pfperry at melbpc.org.au  Wed Aug  5 03:38:11 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Wed, 5 Aug 1998 11:38:11 +1000 (EST)
Subject: archive archive archive (was: Tom G.'s site down - anyone know
  why?)
Message-ID: <1.5.4.16.19961227181322.2c971040@popa.melbpc.org.au>

At 12:16 AM 5/08/98 GMT, Scott Gravenhorst wrote:
  But due to
>the fact that people change things on their sites, I am reluctant to
>archive, but rather I had a link on my FatMan site to his FatMan
>pages. 

Mate! this is crazy......
the fact that people change their sites (including the rather radical
step of closing them) means that you HAVE to archive anything you might want in
the future.

People say the internet is the worlds biggest library.
Well, I think it's more like a periodicals stack, and half the
fucker burns down every week.

paul perry, library of alexandria, melbourne australia




From sasami at blaze.net.au  Wed Aug  5 04:50:46 1998
From: sasami at blaze.net.au (Ken Stone)
Date: Wed, 5 Aug 1998 04:50:46 +0200 (MET DST)
Subject: Tom G.'s site down - anyone know why?
Message-ID: <199808050250.EAA29028@mailhost.bpa.nl>

Tom's site is back up!
_____________________________________________________________

                Ken Stone  sasami at blaze.net.au
                   ** Catgirl Paradise **
               <http://www.anime.net/~kens/>
         ** Australian Miniature Horses and ponies **
             <http://www.blaze.net.au/~sasami/>
_____________________________________________________________





From Dr_Forrester at webtv.net  Wed Aug  5 04:57:13 1998
From: Dr_Forrester at webtv.net (R. Hess)
Date: Tue, 4 Aug 1998 22:57:13 -0400 (EDT)
Subject: Tom G.'s Site Is Back!
Message-ID: <2155-35C7CA09-398@mailtod-121.bryant.webtv.net>

 I just went to http://www.tomg.vivid.net/ , 
and to my surprise and delight, I found
a revised version of the Electronics For
Music page. Some things have been 
moved around, but thankfully, it all seems
to be there. Guess you never appreciate
what you have until it's gone.

 Richard Hess
 dr_forrester at webtv.net




From tomg at vivid.net  Wed Aug  5 05:55:47 1998
From: tomg at vivid.net (tomg)
Date: Tue, 04 Aug 1998 22:55:47 -0500
Subject: Snapping on-line
Message-ID: <yam7520.2365.119033760@mail.vivid.net>

Sorry guys, I just snapped. It's kinda like reading a book out loud
with dozens of people looking over your shoulder asking questions about
every sentence. It was the one, one more "DOES THIS REALLY WORK?"
question (it had nothing to do about who asked. it was the question)
that caused me to slam the book shut and stomp away in disgust. Not realizing
the many people who were digging the story so far would be very, VERY
disappointed not hearing the end.

I may continue to react badly to "DOES THIS REALLY WORK?". Like I went to all
the trouble to design this huge elaborate hoax to trick a few people into
spending $20 building something that does not work. Putting it up implies it
works.

Anyway the site is back on line and I'll re-subscribe to the list. Thanks
for ALL! the mail and genuine concern. I feel like I should say I'm
sorry to each of you and I realize you guys really are the best.

Please respond by personal email or not, the mail I have recieved is
more than enough. My subscription won't take effect until tomorrow.
 
-tg




From girard at enel.ucalgary.ca  Wed Aug  5 06:21:58 1998
From: girard at enel.ucalgary.ca (Arno)
Date: Tue, 04 Aug 1998 22:21:58 -0600
Subject: tomg .. archive
Message-ID: <199808042221580520.001AA669@mailhost.ucalgary.ca>


Scott have room for the fatman pages
and I can have room for the Maxx modular, but like scott, I need tomg permission ....
Arno



From girard at enel.ucalgary.ca  Wed Aug  5 06:24:48 1998
From: girard at enel.ucalgary.ca (Arno)
Date: Tue, 04 Aug 1998 22:24:48 -0600
Subject: tomg maxx
Message-ID: <199808042224480290.001D3D96@mailhost.ucalgary.ca>


Since i am planning to work on the maxx modular (my first project so I need to have a few modules before doing my own design) 
Thus I could maintain a site .. all the more that I plan to provide pcb files and I will redraw  the schematics  ...





From girard at enel.ucalgary.ca  Wed Aug  5 06:43:33 1998
From: girard at enel.ucalgary.ca (Arno)
Date: Tue, 04 Aug 1998 22:43:33 -0600
Subject: tomg
Message-ID: <199808042243330220.002E6898@mailhost.ucalgary.ca>


Thank you to be still with us ....



From ka4hjh at gte.net  Wed Aug  5 08:06:31 1998
From: ka4hjh at gte.net (KA4HJH)
Date: Wed, 5 Aug 1998 02:06:31 -0400
Subject: nanometers (was: AW: Uranus phaser)
In-Reply-To: <199808042043.WAA22446@piraya.electrum.kth.se>
References: Your message of "Tue, 4 Aug 1998 13:15:07 +0200 "
 <1BF5E20E0C4DD111BBAB00805FE2D58292A99B@nbgm336a.nbgm.siemens.de>
Message-ID: <v04011700b1eda45c41eb@[208.255.152.22]>

> >> So these
> >> very bright orange/red diodes should be sufficient, they are much
> >> brighter then any green led I've ever seen, indeed one should not
> >> directly look into the light source, danger of eye damage !
>
> HJ> Is this really true? I think that even if there would be danger
> HJ> when you look at it with an optical device (telescope ...),
> HJ> it would have to be labelled so. (At least in Germany)
> HJ> Just wondering.
>
>Eh... I can understand that my 35 mW laserdiode might hurt my eyes
>since the light is in phase and all that, but a 35 mW LED? No...
>In that case would a glimp at the clock in the morning be disasterous.
>
>I think it is a matter of confusing laser diodes and normal diodes.

I'll say (although there are some REALLY bright LED's that might leave you
seeing spots for a while).

I think we can agree that a 35mW laser diode is definitely a hazard to
vision ( we can also assume that it's infrared, which is even more
dangerous because you can't tell when it's on).

I personally wouldn't stare directly into a 2mW laser. Definitely be seeing
spots for a while. I do have a .2mW green HeNe laser that's so weak you can
actually stare into it with no ill effect, but most visible lasers are
significantly higher in output and infrared lasers even higher.

Lasers aren't toys, but they are a lot of fun to play with. Besides, they
look good next to analog equipment, old 'scopes, etc. Can't get enough of
that mad scientist look.
Terry Bowman, KA4HJH
"The Mac Doctor"



From Luke at unsw.edu.au  Wed Aug  5 08:33:16 1998
From: Luke at unsw.edu.au (Dearnley, Luke)
Date: Wed, 5 Aug 1998 16:33:16 +1000 
Subject: NewBie Question:  Trigger-To-MIDI DIY?
Message-ID: <35BA3E1E6E91D111A2CC00A0C98E32F608D922@central01-eng.eng.unsw.EDU.AU>


You can use a couple of already existing things to do this. Often they
can be picked up quite cheaply second hand. Casio made a 9 input trigger
to MIDI box which a friend of mine got for like $70 off a friend. Cheap
looking gray plastic thing with sliders on the front for sensitivity. It
has four scenes where you can program in which notes it sends per input.
Also the Alesis D4 drum module will do the same (and has some sounds
too) but is more expensive.
As for DIY I dunno - there was an e510 keyboard chip around once but I
never knew where to get it.....

anyway good luck.

:L uke, out.
Sub Bass Snarl Sound System
AUSTRALIA
www.cia.com.au/peril





From martin.czech at intermetall.de  Wed Aug  5 09:04:24 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Wed, 5 Aug 1998 09:04:24 +0200 (MET DST)
Subject: SPDIF coax cables
Message-ID: <199808050704.JAA06504@window.intermetall.de>

> Does anyone know how SPDIF cables should be made up? I know there's 
> a requirement of 90ohm (?) impedance, but not how that is supposed to 
> be achieved...?
> 
> It seems noone around here actually stocks premade SPDIF cables...
> 
> 
> 
I simply use 0.5 m audio chinch cable, right from the shelf.  No
problems so far. The frequency should be about 1 MHz, this gives a
wavelength of about 300m (just order of magnitude approximation). So,
this cable is very short compared to lambda/4. No need for impedance
matching.


m.c.




From jorgen.bergfors at idg.se  Wed Aug  5 09:48:38 1998
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Wed, 5 Aug 1998 8:48:38 +0100
Subject: Signal level standards
Message-ID: <TFSGYMAI@idg.se>

I'm sure this has been discussed before, so I hope you don't mind that I bring 
it up again.
I need to set the standard for the signal levels in my synth.
Barry Klein's book suggests that audio signals are +/-5 volts peak to peak and 
control signals are 0 - 10 volts. But what about LFOs? They are control 
signals, but isn't it more practical to have them swing symmetrically (no DC 
offset)? Maybe it would be better to standardise on +/- 5V for all control 
signals? But then a VCA would be half on if you don't connect an EG to it. 
Maybe that isn't a bad thing? Then you could plug in an LFO and make tremolo 
without problems. But on the other hand it would mean that things start to make 
noise as soon as you unplug things. Not good, I suppose.
Another thing I'm pondering is how much headroom to provide. If the audio 
signals are +/- 5V p-p, I assume that the inputs ought to take some more than 
that before clipping. Is clipping at +/- 7,5 volts a good margin? I want to 
minimise noise, so I don't want more headroom than necessary.
Some synths (the Format for instance) seem to use 0 - 5 V for contol signals 
and +/- 2,5 V for audio. An advantage with this is that you can run 4066s on 
+/- 5 volts.
What do you say? What do the ASM-1 people use? Others?

/Jorgen




From fa_diy at fa.camelot.de  Wed Aug  5 10:21:00 1998
From: fa_diy at fa.camelot.de (Florian Anwander)
Date: 05 Aug 1998 10:21:00 +0200
Subject: Linear response VCA's
In-Reply-To: <3.0.5.32.19980803200426.007a6cc0@popd.ix.netcom.com>
Message-ID: <6zJFj2N4HFB@fa.camelot.de>

Hallo Mike

>Are there situations in which purely linear response is desirable in
>a VCA?
Also for audio I use seldom(!) the log. VCAs. Especially with short decay and  
long release the sound of a linear VCA comes closer to my expectation of  
sound than an logarithmic.

>My envelope generators and LFOs are digital - using an embedded
So you should use linear VCAs al the way, because you can realize the log  
characteritics more easy (without trimming!) on the digital side.

btw.: are your digital envelopes and LFOs as fast as analogue ones?


Gruss,
 Florian Anwander
-------------------------------------------------------------------------
Maus-Netz: Florian Anwander at M4
Internet:  fa at fa.camelot.de           http://www.camelot.de/~fa/
## CrossPoint v3.11 R ##



From moxie at idonex.se  Wed Aug  5 10:34:52 1998
From: moxie at idonex.se (Johan Gustavsson)
Date: Wed, 5 Aug 1998 10:34:52 +0200 (MET DST)
Subject: Tom G.'s site down - anyone know why?
In-Reply-To: <35C75CB3.7B897E74@seanet.com> (message from Sean Costello on
	Tue, 04 Aug 1998 12:10:43 -0700)
Message-ID: <199808050834.KAA14690@jolt.idonex.se>

Yes, Iwas a bit worried yesterday...But I can get to it today *Whee!*.

For a while, I thought my Maxx dream had gone down the drain because
of some silly flamer or something...Is there anybody out there who has
built any Maxx modules, or who has any particular opinions about them?
I'm leaning heavily towards building the Maxx, starting something like
the next week, so...Anyone got any last-minute advice for me?

Why Maxx? Well...Not as expensive as the MOTM (Which I would go for,
where I not a skint student), not V/Hz, not old components (Like old
PAIA stuff), somewhat more serious feeling than the Penfold
stuff...Any options I've missed for the poor DIYer? :-)
/Moxie (Happy to see EFM up)





From jorgen.bergfors at idg.se  Wed Aug  5 11:03:44 1998
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Wed, 5 Aug 1998 10:03:44 +0100
Subject: The MC3340 VCA
Message-ID: <TFSHYCPC@idg.se>

I recently did some experiments with the MC3340, to find out if it is of any 
use to us synth DIY types.
It is a complete logarithmic VCA in an 8 pin mini-DIP package. All external 
components are two or threee capacitors. Price is around $2 to $3.
The chip is designed for single power supply, but with an input capacitor, you 
can feed it any audio signal. It won't work for DC or very low frequency signal 
though. IE not for control voltages.
The control voltage range is from 5,65 to 2,8 volts. The response is -30 
dB/volt. This means it will get louder if you reduce the voltage. By adding an 
op-amp connected as an inverting amplifier with offset, you can get a contol 
range of 0 - 10 volts or whatever you like.
Maximum audio input signal is 1,6 volts peak to peak. This will give 8 volts 
p-p out at maximum gain. The output will have a DC offset of 8,7 volts. All 
these figures are for a supply voltage of 15 volts.
Noise and signal bleedthrough at maximum attenuation is around 0,3 mV p-p on my 
scope. There is a control voltage bleedthrough of 0,5 volts. That is, if you 
change the control voltage between max and min with no signal in, the DC level 
on the output will change 0,5 volts.
I suppose the control bleedthrough is what rules it out for synth use. That it 
can't be used for control voltages is also a bit daft. Anyway, I thoght you 
might like to know.

/Jorgen





From Ullrich at kapsch.net  Wed Aug  5 12:31:44 1998
From: Ullrich at kapsch.net (Ullrich at kapsch.net)
Date: Wed, 5 Aug 1998 12:31:44 +0200
Subject: AW: Tom G.'s site down - anyone know why?
Message-ID: <06E83B40290BD111B41B08002BB769DAE3C16A@balu.kapsch.co.at>

Hi Dave!

>Perhaps more to the point: did anyone archive this site?  I think I have a
>couple of pages, but not enough to rebuild it.  I'd be happy to 'mirror' it
>if someone has the files.

I archieved the site about one month ago and updated the newer parts last
week.
I will have a look for my archieve Zip-Disks.

Ciao
Peter

        \|/
       (o o)
--oOOO--(_)--OOOo------------------------------------------------------
                   Ing. Peter Ullrich         mailto:ullrich at kapsch.net
                   Homepage: http://come.to/ullrich    or the full link
                   http://www.geocities.com/SiliconValley/Heights/3586/
                   Hardware & Software Developer /  Electronic Musician
   .oooO           KAPSCH AG / SGB2                    Vienna / Austria
   (   )   Oooo.            Traffic Control and Transmission Technology
----\ (----(   )-------------------------------------------------------
     \_)    ) /
           (_/





From jorgen.bergfors at idg.se  Wed Aug  5 13:24:22 1998
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Wed, 5 Aug 1998 12:24:22 +0100
Subject: Tom G.'s site down - anyone know why?
Message-ID: <TFSJUCUY@idg.se>

Well, I suppose he got some of us a bit suspicious by hyping his circuits a bit 
too much. Like saying "WOW it's nice" about the sinewave output on the Maxx 
VCO-4A. The sinewave converter employed is the same as in the Formant. It is 
widely known that this circuit give a fairly crude approximation if a sine 
wave. Several better circuits exist.
Also that he omits temperature compensation without mentioning it (like in the 
VCF-5A) raises some skepticism. There also are some bad design practices, like 
in the BRM-1A where pin 13 on the CA3046 is not at the lowest potential, which 
the National Semiconductor datasheet points out is important for proper 
operation. I don't doubt that he has actually bulit the circuits and that they 
do work, but things like that raise questions.
I think if he had said up front that these are simple circuits suitable for 
beginners and less critical applications, but have some limitations, he would 
have got more understanding and support.
I'm thinking of building his VCO-4A as an VCLFO, by changing the timing cap. In 
that case the lack of temperature compensation and crude sine wave is not a 
problem. But on the other hand, I might as well adapt the VCO from the ASM-1 
for LFO use instead. If I omit the tempco (which I don't think is needed in an 
LFO) it is about as simple to build. Then of course I have to add triangle and 
sine converters, but I have already cloned those from the Moog 921.
 
/Jorgen





PC:moxie at idonex.se on 98-08-05 12.17.46
To:  costello at seanet.com @ SMTP 
cc:  synth-diy at mailhost.bpa.nl @ SMTP  (bcc: Jorgen Bergfors/IDGSE)
Subject: Re: Tom G.'s site down - anyone know why? 

Yes, Iwas a bit worried yesterday...But I can get to it today *Whee!*.

For a while, I thought my Maxx dream had gone down the drain because
of some silly flamer or something...Is there anybody out there who has
built any Maxx modules, or who has any particular opinions about them?
I'm leaning heavily towards building the Maxx, starting something like
the next week, so...Anyone got any last-minute advice for me?

Why Maxx? Well...Not as expensive as the MOTM (Which I would go for,
where I not a skint student), not V/Hz, not old components (Like old
PAIA stuff), somewhat more serious feeling than the Penfold
stuff...Any options I've missed for the poor DIYer? :-)
/Moxie (Happy to see EFM up)











From merlin at ion.com.au  Wed Aug  5 13:47:23 1998
From: merlin at ion.com.au (Merlin Zener)
Date: Wed, 05 Aug 1998 21:47:23 +1000
Subject: Identify unknown MIDI devices
References: <3.0.5.32.19980803192206.007a34e0@popd.ix.netcom.com>
Message-ID: <35C8464B.EFF3A83E@ion.com.au>

Michael Maloney wrote:
> 
> [...snip]
> is there some threading mechanism for a mailing
> list in the same way as a USENET newsgroup? Just curious.

If you're using Netscape to read your mail, you can easily
sort by thread (or date, or sender, or whatever) - it's under
the "view" pulldown menu. You can also automatically sort
mail from different mailing lists into different folders:
it's under "Edit/Mail Filters"...

Hope this is of some help.

-- 
Merlin Zener                            mailto:merlin at ion.com.au
Piano and Synthesizer               voice: (+61) (0) 418 779 594
Gold Coast, Australia              http://www.ion.com.au/~merlin

"No-one ever went blind from looking on the bright side of life"




From pfperry at melbpc.org.au  Wed Aug  5 14:15:42 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Wed, 5 Aug 1998 22:15:42 +1000 (EST)
Subject: The MC3340 VCA
Message-ID: <1.5.4.16.19961228045052.3997fb30@popa.melbpc.org.au>

At 10:03 AM 5/08/98 +0100, jorgen.bergfors wrote:
>I recently did some experiments with the MC3340, to find out if it is of any 
>use to us synth DIY types.
....all this is true.....
dang near broke my heart trying to use one as a tremolo unit, the bleedthru
is too high for this even.
Whether you might be able to balance out the bleedthru I dont know, but i 
doubt it, bound to be nonlinear.
The units themselves have a 50% output variation so no point balancing 2.
A real disappointment, this chip. Anyone want to swap anything for some? ;-)

paul perry melb aust




From graham at dashdash.demon.co.uk  Wed Aug  5 15:27:12 1998
From: graham at dashdash.demon.co.uk (Graham Wignall)
Date: Wed, 05 Aug 1998 14:27:12 +0100
Subject: Tom G.'s site down - anyone know why?
References: <yam7521.2480.119321760@mail.vivid.net>
Message-ID: <35C85DB0.520722BB@dashdash.demon.co.uk>

tomg wrote:

> 
> How Nice.
> 
> -tg
Tom,

Welcome back! I don't want to start a flame war here, but what are we
actually trying to achieve here anyway? I have a sample based synth
which will produce the purest sine, square, saw and triangles you ever
saw. Rock steady, perfect pitch, no drift.

I'm starting to homebrew mods to a FatMan (including a couple of extra
VCOs and LFOs) because I want something that *is* slightly dodgy - a
rough waveform, non-linearities across the keyboard range and all that
stuff add character to the instrument I'm building - in fact, IMHO, they
define it - otherwise I'd stick with the digital sample thing.

As to temperature drift, well I'll have to wait and see. I don't take it
out gigging, so it won't see massive changes in ambient temperature, and
if it drifts as it warms itself up, then I may have to go back and
revise the design.

Isn't that what it's all about? Otherwise, someone will come up with the
'perfect' VCO/VCF/VCA/whatever and we'll all be reduced to kit
builders...

I was looking forward to taking some of Tom's stuff and using it in my
own system - adapting it if it didn't work for me. To my mind, it's far
better to start with something that *mostly* works and adapt rather than
start from scratch or clone something outright - it's been too many
years out of electronics school for the former and the latter's
downright dull.

Hopefully I should be contributing my own VCO/LFO designs shortly, based
on the much maligned 8038. So the purists may hate it and scoff, but if
it sounds good in my system, I don't care. 

Keep it up, Tom

Graham



From chordman at flash.net  Wed Aug  5 15:29:35 1998
From: chordman at flash.net (Scott Gravenhorst)
Date: Wed, 05 Aug 1998 13:29:35 GMT
Subject: Warning:  I'm not an EE
Message-ID: <35ca5c5c.33031728@mail.lan>

I propose a rating system, similar to geek code:

+EE  EE degree
-EE  No EE degree
+KE  Knows Everything
-KE  Doesn't know everything
+P   Purist
-P   Not a purist
+CD  Conventional Designer
-CD  Non conventional Designer

Eh, ME?  -EE -KE -P -CD.  Maybe that's why my stuff sounds a little
different.  Is it wrong?  Not to me.

<sigh>  I guess DIY needs some temperature compensation...

-- Scott Gravenhorst
-- FatMan Site: www.teklab.com/~chordman



From clark at andrews.edu  Wed Aug  5 15:35:48 1998
From: clark at andrews.edu (Tony Clark)
Date: Wed, 5 Aug 1998 09:35:48 -0400 (EDT)
Subject: In Tom's defense.  :)
In-Reply-To: <TFSJUCUY@idg.se>
Message-ID: <Pine.SOL.3.91.980805090809.29736A-100000@edmund.cs.andrews.edu>

> Well, I suppose he got some of us a bit suspicious by hyping his 
> circuits a bit 
> too much. Like saying "WOW it's nice" about the sinewave output on the Maxx 
> VCO-4A. The sinewave converter employed is the same as in the Formant. It is 
> widely known that this circuit give a fairly crude approximation if a sine 
> wave. Several better circuits exist.

   It's no wonder that Tom was frustrated.  He's obviously not getting 
much praise from this person!  The main problem is that there are people 
that are wanting too much perfection out of the circuits they build.  
Hey, I'm one of those people!  But I do realize that there was a reason 
circuits like Tom's exist.
   It is because "better" circuits are typically 2 to 3 times harder to 
build!  I build a very good tri-sine converter, but it has a great deal 
more circuitry than "crude" approximators.  Will mine sound better?  
Probably not.  That is why if you go back and take a look at MANY of the 
Moog, Arp, Korg, etc. schematics, you will find many "cheap" circuits.

> Also that he omits temperature compensation without mentioning it 
> (like in the VCF-5A) raises some skepticism.

   Why?  There are many on this list that are running ASM-1 VCO's without 
temperature compensation _and they run fine_.  You don't have to 
temperature compensate "everything".

> There also are some bad design practices, like 
> in the BRM-1A where pin 13 on the CA3046 is not at the lowest 
> potential, which the National Semiconductor datasheet points out is 
> important for proper operation.

   Some of the best advances in circuit design is using stuff in ways 
they weren't meant to be used.  A case in point, using that CMOS chip for 
8 matched MOSFETs by not tying the Vee (or some such thing).  Whoever 
came up with that trick is a genious in my book.

> I don't doubt that he has actually bulit the circuits and that they 
> do work, but things like that raise questions.
> I think if he had said up front that these are simple circuits suitable for 
> beginners and less critical applications, but have some limitations, he would 
> have got more understanding and support.

   I think it is clear that there was obviously too much expectation on 
the part of certain individuals for mind blowing advances in circuit 
design.
   The best part about the DIY list is that we can have a wide range of 
expertise in the field of electronics, but also have a large membership 
of people who really don't know much about electronics whatsoever.  I'm 
sure had Tom gone through and given all of the theoretical data for his 
circuits prior to putting circuits up on his site, it would have 
eliminated the need for certain individuals to fuss. 
   However if anyone on this list has any knowledge of engineering worth 
a salt, his circuits should be fairly easy to deconstruct.
   Anyway, I certainly appreciate the amount of time and work Tom has put 
into his site.  Keep it up, Tom!  And don't ever let any non-believers 
get you down!

   Tony

P.S.  Always ask "WHY" it works, not "DOES" it work.

------------------------------------,----------------------------------
I can't drive (my Moog) 55!         |     The E-Music DIY Archive
------------------------------------|  
Tony Clark -- clark at andrews.edu     | aupe.phys.andrews.edu/diy_archive
http://aupe.phys.andrews.edu/~clark |     Contributions welcomed!
------------------------------------'----------------------------------




From tomg at vivid.net  Wed Aug  5 15:40:49 1998
From: tomg at vivid.net (tomg)
Date: Wed, 05 Aug 1998 08:40:49 -0500
Subject: Tom G.'s site down - anyone know why?
In-Reply-To: <TFSJUCUY@idg.se>
Message-ID: <yam7521.2480.119321760@mail.vivid.net>

On 05-Aug-98, jorgen.bergfors at idg.se wrote:
>Well, I suppose he got some of us a bit suspicious by hyping his circuits a
>bit 
>too much. Like saying "WOW it's nice" about the sinewave output on the Maxx 
>VCO-4A. The sinewave converter employed is the same as in the Formant. It is 
>widely known that this circuit give a fairly crude approximation if a sine 
>wave. Several better circuits exist.
>Also that he omits temperature compensation without mentioning it (like in
the

>VCF-5A) raises some skepticism. There also are some bad design practices,
like

>in the BRM-1A where pin 13 on the CA3046 is not at the lowest potential,
which

>the National Semiconductor datasheet points out is important for proper 
>operation. I don't doubt that he has actually bulit the circuits and that
they

>do work, but things like that raise questions.
>I think if he had said up front that these are simple circuits suitable for 
>beginners and less critical applications, but have some limitations, he would

>have got more understanding and support.
>I'm thinking of building his VCO-4A as an VCLFO, by changing the timing cap.
>In 
>that case the lack of temperature compensation and crude sine wave is not a 
>problem. But on the other hand, I might as well adapt the VCO from the ASM-1 
>for LFO use instead. If I omit the tempco (which I don't think is needed in
an

>LFO) it is about as simple to build. Then of course I have to add triangle
and

>sine converters, but I have already cloned those from the Moog 921.
> 
>/Jorgen




How Nice.

-tg




From Colin.Fraser at scottishpower.plc.uk  Wed Aug  5 15:51:29 1998
From: Colin.Fraser at scottishpower.plc.uk (Fraser, Colin J)
Date: Wed, 5 Aug 1998 14:51:29 +0100 
Subject: Tom G.'s site down - anyone know why?
Message-ID: <81880CC73125D211BC6800805F0D83070C0F@spresource.cat.scottishpower.plc.uk>

Anybody know the url for Jorgen's site ?
I'd like to see how it should be done properly.

Colin f


> -----Original Message-----
> From: tomg [mailto:tomg at vivid.net]
> Sent: 05 August 1998 14:41
> To: synth-diy at mailhost.bpa.nl
> Subject: Re: Tom G.'s site down - anyone know why?
> 
> 
> On 05-Aug-98, jorgen.bergfors at idg.se wrote:
> >Well, I suppose he got some of us a bit suspicious by hyping 
> his circuits a
> >bit 
> >too much. Like saying "WOW it's nice" about the sinewave 
> output on the Maxx 

<snip>

> > 
> >/Jorgen
> 
> 
> 
> 
> How Nice.
> 
> -tg
> 



From b.layer at vikingelectronics.com  Wed Aug  5 16:35:16 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Wed, 05 Aug 1998 09:35:16 -0500
Subject: Analog Speech Synthesis
Message-ID: <3.0.5.32.19980805093516.007ad810@192.168.210.18>

Hi All, 

I came across something curious recently, an analog speech synthesis
experiment kit. It was produced in about 1964 by Bell Labs as a part of
their education program for computer and electronics students.

It includes a rather in depth book which discusses the fundamental theories
of speech synthesis, all in purley analog terms. When this kit was sold,
the Votrax SC-01 was still over a decade away. The kit allows you to
construct an analog vowel synthesizer, comprised of a rectangle wave
generator, three L-C formant stages (ferrie bobbin type) and an audio
stage. By tweaking the cap values in the formant stages, the unit can
(rougly) produce all english vowel sounds, and lots of other strange noises
in between.

Has anyone encountered anything else related to analog speech production?
Frankly, I've never seen anything else like it.




Bill Layer
"Heavy old junk wanted"



From martin.czech at intermetall.de  Wed Aug  5 16:36:27 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Wed, 5 Aug 1998 16:36:27 +0200 (MET DST)
Subject: Tom G.'s site down - anyone know why?
Message-ID: <199808051436.QAA08125@window.intermetall.de>

Ok, I think that's enough now.

Please all come back to topic.

This was a friendly low noise list without flame wars etc, please let's
keep it that way.

m.c.

p.s.:

On one hand: If sombody thinks that something must be harshly
critisized, he should write it down, wait to the next day and read it
again, throw it away and write again. Try to be friendly and polite.
E-mail is so damned fast, sometimes it would be better if you have to
walk 5 km to the next postbox, because you can think it over what you
are going to do.

On the other:  If one publishes things, it may bring some criticism.
There might be strange responses. One has to take thisrisk. That's life.

Ohh, I should have thought more about this posting, but then I touched
DELIVER ;-> ;-> ;-> ;-> ;-> ;->






From Neil.Johnson at camcon.co.uk  Wed Aug  5 16:44:37 1998
From: Neil.Johnson at camcon.co.uk (Neil Johnson)
Date: Wed, 5 Aug 1998 15:44:37 +0100
Subject: In Tom's defence - another view
Message-ID: <5c870480@camcon.co.uk>

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Reply-To: tomg <tomg at vivid.net>
To: synth-diy at mailhost.bpa.nl
Date: Wed, 05 Aug 1998 08:40:49 -0500
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-------------- next part --------------
     tomg wrote:
     
     >On 05-Aug-98, jorgen.bergfors at idg.se wrote:
     >> <snip> whinge, moan, gripe....
     
     >How Nice.
     
     >-tg
     
     
     Mmmmmm <takes long pause while contemplating reply....>
     
     Most of the time I'm quite happy just cruisin' the waves, but now and 
     again I feel the urge to open my literal mouth (yeh, I know, "a closed 
     mouth gathers no feet" etc etc) and ponder in public.
     
     To Tom, I would look upon this sort of "discussion" in the same way 
     that I view people who "discuss" how fast their souped-up ordinary 
     cars are: "I've re-bored mine", "I've put a flared exhaust on mine", 
     etc etc.  Me, I drive a Lotus Esprit S3.  See what I mean?  My advice 
     - ignore them.
     
     As for those who have been seen to criticise Tom's work, my 2 pence 
     worth (we don't have any cents in the UK...) is to refrain from 
     publicly criticising such work.  Please bear in mind that this work is 
     all voluntary - no-one gets paid to design these circuits and put them 
     on websites for all to enjoy.  It usually takes a lot of effort to do, 
     and getting kicked in the ankles for your efforts is usually not 
     considered encouraging.
     
     True, Tom's circuits may not stand up in court in front of such 
     marvels as the Moog, but so what.  What matters is that they produce 
     something that you find useful, pure sine or not-so-pure sine.  
     Whatever turns you on.
     
     Remember, the art of circuit design is to design a circuit that meets 
     your requirements and NO MORE!  How do you know that Toms' 
     requirements are the same as yours?  Probably not.  So, read and 
     enjoy.
     
     Here endeth the sermon.
     
     Me, I tinker about with odds and ends.  Anyone want a discussion on 
     additive synthesis using Walsh functions...? I thought not - oh well, 
     back to sleep.........
     
     Neil
     ----
     
     
     +---------------------------+-----------------------------+
      Neil Johnson               * All thoughts and opinions
      Cambridge Consultants Ltd  * expressed here are my own.
      email: nej at camcon.co.uk    * Heck, even _I_ don't believe
      http://www.camcon.co.uk    * what I say at times.....
     +---------------------------+-----------------------------+ 
     

     

From Juergen.Haible at nbgm.siemens.de  Wed Aug  5 17:06:22 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Wed, 5 Aug 1998 17:06:22 +0200 
Subject: AW: Snapping on-line
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5829436F5@nbgm336a.nbgm.siemens.de>

	>I may continue to react badly to "DOES THIS REALLY WORK?". Like I
went to all
	>the trouble to design this huge elaborate hoax to trick a few
people into
	>spending $20 building something that does not work. Putting it up
implies it
	>works.

Hmm, I think I know what you mean.

But anyway, I'm sure that critical questions about the circuits we present
to the list are a good thing. I can't think of any of my own circuits that 
could not be improoved at one end or the other, and so I am thankful for
any critical voice. "Does this really work" is either a chance to expand my
knowledge (looking at the limits of my circuit), or to boast with a good
explanation *why* it actually works, even if it's not obvious at first
glance.

Well, this refers to the posts I have seen on the list. I don't know what
private
mails you have received, and about their politeness. And after you left,
and speculations started - seems that people are the same all over the
world,
talking about you when you have (aparently) left the room. Not exactly nice,
but quite human. And more embarrassing for whom who speaks than whom 
who listens, IMO.

Keep up the good work, and get used to our critical comments, if you can.
Receiving a critical comment is a compliment of sort; really stupid things
are likely to rather be *ignored*.

Just my thoughts frankly spoken - no intention to hurt anybody.

JH.




From keen at austin.ibm.com  Wed Aug  5 17:22:17 1998
From: keen at austin.ibm.com (R.G. Keen)
Date: Wed, 05 Aug 98 10:22:17 -0500
Subject: Analog Speech Synthesis 
In-Reply-To: (Your message of Wed, 05 Aug 98 09:35:16 -0500.)
             <3.0.5.32.19980805093516.007ad810@192.168.210.18>
Message-ID: <199808051522.KAA27224@keen.austin.ibm.com>


>I came across something curious recently, an analog speech synthesis
>experiment kit. It was produced in about 1964 by Bell Labs as a part of
>their education program for computer and electronics students.
Yeah, I ran into the book for that. Neat, succinct description of voice
synthesis.

>It includes a rather in depth book which discusses the fundamental theories
>of speech synthesis, all in purley analog terms. When this kit was sold,
>the Votrax SC-01 was still over a decade away. The kit allows you to
>construct an analog vowel synthesizer, comprised of a rectangle wave
>generator, three L-C formant stages (ferrie bobbin type) and an audio
>stage. By tweaking the cap values in the formant stages, the unit can
>(rougly) produce all english vowel sounds, and lots of other strange noises
>in between.

>Has anyone encountered anything else related to analog speech production?
>Frankly, I've never seen anything else like it.
I still have a couple of SC-01's somewhere. Of course, the
text-to-speech that comes with some soundblasters makes the hardware
kind of unneeded now. The other speech-related item that comes to mind
is the Electro-Harmonix "Talking Pedal", which was a guitar stompbox; a
variant of the wah pedal, it used two bandpass filters and a dual
center control on a rocker pedal that were optimized for faking the
first two formants of speech - at least as well as they can be faked
with so simple a setup.



From Juergen.Haible at nbgm.siemens.de  Wed Aug  5 17:27:27 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Wed, 5 Aug 1998 17:27:27 +0200 
Subject: AW: Linear response VCA's
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D582943745@nbgm336a.nbgm.siemens.de>


	> Also for audio I use seldom(!) the log. 

I agree. 90% of my VCAs are linear, and 90% of my envelope
generators have (exponential) RC shapes. Perfect match.
BTW, the remaining 10% of my VCA's are *not* "exponential"
either. I rather use them to "bend" the response of some
potentiometer into the right shape, like "reverse log" for
resonance potentiometers, for example. 

> >My envelope generators and LFOs are digital - using an embedded
> So you should use linear VCAs al the way, because you can realize the log
> 
> characteritics more easy (without trimming!) on the digital side.
> 
I don't think so. You're right about trimming, but resolution
might be a problem. Linear steps at the DAC output will
cause equally spaced *level* (dB) steps with an exponential
VCA, which is a good thing to avoid zipper noise at one
end of the control range.
Unless you have a lot of bits of resolution  in your digital 
envelopes, of course ...

JH.




From tomg at vivid.net  Wed Aug  5 17:28:57 1998
From: tomg at vivid.net (tomg)
Date: Wed, 05 Aug 1998 10:28:57 -0500
Subject: To Snap or not to Snap?
Message-ID: <yam7521.2890.119059592@mail.vivid.net>

I'm feeling volatile, close to snapping again, maybe somebody
should mirror my site while it's sill on line... Is anyone still
confused over my exit?

Relax...I'm back and I'm not going anywhere. Despite the fact some
people would take the fun out of everything. As long as this is
DIY not NASA I will feel free to post what I like when I like, help
who I want, ignore assholes, and express as much enthusiasm as I want
over the fact I got something cool to work. If there is any body
on this list who does not like this, tough!

The overwhelming support expressed yesterday has had a major positive
effect on my attitude. I will continue to have fun! And continue to
enjoy DIY.

(He's not quite so crabby today - Mrs tg)

-tg




From jmcmahon at prometric.com  Wed Aug  5 17:33:26 1998
From: jmcmahon at prometric.com (jmcmahon at prometric.com)
Date: Wed, 5 Aug 1998 11:33:26 -0400
Subject: To snap or not to snap?
Message-ID: <85256657.0054F46D.00@Albatross.educate.com>

>>As long as this is
DIY not NASA I will feel free to post what I like when I like

I worked at NASA...trust me, they're not doing anything better than we are
right now :-)  Don't be discouraged by criticism and don't let a few ruin
the fun for the rest of us.

Jason McMahon
experimental/noise musician
i break things on purpose





From eli at gs160.sp.cs.cmu.edu  Wed Aug  5 17:40:59 1998
From: eli at gs160.sp.cs.cmu.edu (Eli Brandt)
Date: Wed, 5 Aug 1998 11:40:59 -0400 (EDT)
Subject: Walsh functions
In-Reply-To: <5c870480@camcon.co.uk> from "Neil Johnson" at Aug 5, 98 03:44:37 pm
Message-ID: <199808051541.RAA14404@mailhost.bpa.nl>

Neil Johnson wrote:
>      Me, I tinker about with odds and ends.  Anyone want a discussion on 
>      additive synthesis using Walsh functions...?

Actually, yeah.  You wrote an interesting tutorial on Walsh functions
a while back, but I haven't gotten around to playing with them.  Have
you made any interesting noises?

If you'd care to spoon-feed a bit further, I'm curious how you do
analysis into this basis set.  Like, I can take a sound, FFT it, and
resynthesize from sinusoids, which gives me a starting point for
manipulation.  Is there an equivalent here?  (For example, how did you
get that decomposition of a sine into W_i's?  I know there's a thing
called a "Hadamard transform", which is a promising _name_, but...)

btw, there are a couple of references from the 80s in:
http://www.astro.virginia.edu/~eww6n/math/WalshFunction.html

-- 
     Eli Brandt  |  eli+ at cs.cmu.edu  |  http://www.cs.cmu.edu/~eli/



From martin.czech at intermetall.de  Wed Aug  5 17:57:22 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Wed, 5 Aug 1998 17:57:22 +0200 (MET DST)
Subject: off topic !: CDD2600 Question
Message-ID: <199808051557.RAA08600@window.intermetall.de>

This is off topic.

This is the most intelligent bunch of people I found so far on the
internet, maybe a friendly soul can help me.

I'm offered a used CDD2600, good condition.  I tested it, ok, but no
Disc at Once Mode.  This DAO doesn't work somehow. I use Gear4.0
software and was able to burn DAO with a Yamaha CDR100.  The software
says, the drive version is 1.07, I suppose this is the firmware
version, or ias it the internal software driver version?

I tryed to find this out everywhere, but e.g. the Philips homepage
is a hoax. Just advertising, no answers.

Does somebody know if a CDD2600 with supposed version 1.07 supports
Disc at Once mode.

Any help will be appreciated.

m.c.




From b.layer at vikingelectronics.com  Wed Aug  5 17:58:22 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Wed, 05 Aug 1998 10:58:22 -0500
Subject: Gift horses
Message-ID: <3.0.5.32.19980805105822.007c8220@192.168.210.18>

Hi all (and a specific few as well),

I like Scott's 'truth-in-design' rating system (I'm a firm -EE, -CD), but
how would one indictate that they both a) knew it all and b) frequently
looked gift horses in the mouth? If you really know better, then just do
your own thing, right?. What do you need synth-diy for?

While DIY means do it youself, I'm openly glad that I DONT have to do this
all myself; I'd never get half as far re-inventing someone else's wheel.  

Hard to believe that someone would shoot down 'freeware' designs, for no
purpose other than the exposition of rightous attitudes, and opinions.
Finding weaknesses or outright problems in even the best and most famous
designs is not impossible.

Especially if that is what you are looking for to begin with.



 
Bill Layer
Sales Technician
<b.layer at vikingelectronics.com>

----------------------------------
Viking Electronics, Inc.
Hudson, WI. U.S.A
715.386.8861 (ext. 210)
<http://www.vikingelectronics.com>
----------------------------------

"Telecommunications Solutions for the 21st Century"



From Barry.L.Klein at wdc.com  Wed Aug  5 17:59:00 1998
From: Barry.L.Klein at wdc.com (Barry L Klein)
Date: Wed, 5 Aug 1998 08:59:00 -0700 (Pacific Daylight Time)
Subject: Analog Speech Synthesis
Message-ID: <ISSMTP.1.3(1).19980805085900.4294800215E@Corp.wdc.com>

That is the kit that got me interested in electronic music!  It was in my
electronics class in 10th grade.  I tried making a keyboard for it so you
could play a tune....  Any extras?  Love to put it up on the wall!

Barry

----------
From: 	B.LAYER at VIKINGELECTRONICS.COM
Sent: 	Wednesday, August 05, 1998 7:35 AM
To: 	SYNTH-DIY at MAILHOST.BPA.NL
Subject: 	Analog Speech Synthesis

<<File: IST822383_2.txt>><<File: IST822583_3.txt>>
Hi All, 

I came across something curious recently, an analog speech synthesis
experiment kit. It was produced in about 1964 by Bell Labs as a part of
their education program for computer and electronics students.

It includes a rather in depth book which discusses the fundamental
theories
of speech synthesis, all in purley analog terms. When this kit was sold,
the Votrax SC-01 was still over a decade away. The kit allows you to
construct an analog vowel synthesizer, comprised of a rectangle wave
generator, three L-C formant stages (ferrie bobbin type) and an audio
stage. By tweaking the cap values in the formant stages, the unit can
(rougly) produce all english vowel sounds, and lots of other strange
noises
in between.

Has anyone encountered anything else related to analog speech production?
Frankly, I've never seen anything else like it.




Bill Layer
"Heavy old junk wanted"





From lkirn at mich.com  Wed Aug  5 18:02:42 1998
From: lkirn at mich.com (Larry Kirn)
Date: Wed, 5 Aug 1998 12:02:42 -0400
Subject: Analog Speech Synthesis
References: <3.0.5.32.19980805093516.007ad810@192.168.210.18>
Message-ID: <98Aug5.115750edt.43009@brickwall.ceddec.com>



Bill Layer wrote:
...

I came across something curious recently, an analog speech synthesis experiment
kit. It was produced in about 1964 by Bell Labs as a part of their education
program for computer and electronics students.
...

Wow, I built and mod'd that kit when in jr. high!  Later, I had a lot of fun
with voltage-controlled parallel BP filters driven by an analog sequencer for
dynamic output, using their formant frequencies as a baseline.  Sadly, I lost
the book.  Have you tried web searches on any of the research cited there?

Larry





From Ullrich at kapsch.net  Wed Aug  5 18:12:49 1998
From: Ullrich at kapsch.net (Ullrich at kapsch.net)
Date: Wed, 5 Aug 1998 18:12:49 +0200
Subject: AW: Analog Speech Synthesis
Message-ID: <06E83B40290BD111B41B08002BB769DAE3C16C@balu.kapsch.co.at>

I also have a PCB that has the SC01-A on board and is controlable via a
serial interface.
I also have two other chips that should be speech synthesizers but I have no
datasheet
for these chips. If anyone has datasheet please let me know.

The chips are: HKA5003M and ITT UAA1003-1

Ciao
Peter

        \|/
       (o o)
--oOOO--(_)--OOOo------------------------------------------------------
                   Ing. Peter Ullrich         mailto:ullrich at kapsch.net
                   Homepage: http://come.to/ullrich    or the full link
                   http://www.geocities.com/SiliconValley/Heights/3586/
                   Hardware & Software Developer /  Electronic Musician
   .oooO           KAPSCH AG / SGB2                    Vienna / Austria
   (   )   Oooo.            Traffic Control and Transmission Technology
----\ (----(   )-------------------------------------------------------
     \_)    ) /
           (_/





From jamos at technotoys.com  Wed Aug  5 18:21:36 1998
From: jamos at technotoys.com (Jim Johnson)
Date: Wed, 05 Aug 1998 09:21:36 -0700
Subject: To Snap or not to Snap?
In-Reply-To: <yam7521.2890.119059592@mail.vivid.net>
References: <yam7521.2890.119059592@mail.vivid.net>
Message-ID: <199808050921360290.009F7108@mail.proaxis.com>

Tom, I'm confused.. nobody has attacked you, just a couple questions about
your design practices. If a person can't question you, than there must be a
problem somewhere.

I think the amount of stuff that you've created, and the quality, speaks
for itself. At times I did wonder if you found time to actually build it
all - but you answered that. After somebody asked.

Tolerance goes both ways - people should not ridicule your designs (again,
I haven't seen anyone do that - maybe I missed it), but at the same time,
we should not have to worry about a major contributor quitting the group
and shutting down his web site if someone says something negative about his
work.

I hope you stick around.

Jim Johnson 
Metaphoric Software
-------------------
Makers of Techno Toys
Software for Electronic Music
http://www.technotoys.com
info at technotoys.com


*********** REPLY SEPARATOR ***********

On 8/5/98, at 10:28 AM, tomg  wrote: 

>I'm feeling volatile, close to snapping again, maybe somebody
>should mirror my site while it's sill on line... Is anyone still
>confused over my exit?
>
>Relax...I'm back and I'm not going anywhere. Despite the fact some
>people would take the fun out of everything. As long as this is
>DIY not NASA I will feel free to post what I like when I like, help
>who I want, ignore assholes, and express as much enthusiasm as I want
>over the fact I got something cool to work. If there is any body
>on this list who does not like this, tough!
>
>The overwhelming support expressed yesterday has had a major positive
>effect on my attitude. I will continue to have fun! And continue to
>enjoy DIY.
>
>(He's not quite so crabby today - Mrs tg)
>
>-tg



From jamos at technotoys.com  Wed Aug  5 18:21:37 1998
From: jamos at technotoys.com (Jim Johnson)
Date: Wed, 05 Aug 1998 09:21:37 -0700
Subject: Warning:  I'm not an EE
In-Reply-To: <35ca5c5c.33031728@mail.lan>
References: <35ca5c5c.33031728@mail.lan>
Message-ID: <199808050921370500.009F75C0@mail.proaxis.com>

We need another designation (for me, at least) 

?EE Has EE degree, but moved to software almost immediately and can barely
remember Ohm's Law, let alone transistor theory...

Jim Johnson 
Metaphoric Software
-------------------
Makers of Techno Toys
Software for Electronic Music
http://www.technotoys.com
info at technotoys.com


*********** REPLY SEPARATOR ***********

On 8/5/98, at 10:38 AM, chordman at flash.net wrote: 

>I propose a rating system, similar to geek code:
>
>+EE  EE degree
>-EE  No EE degree
>+KE  Knows Everything
>-KE  Doesn't know everything
>+P   Purist
>-P   Not a purist
>+CD  Conventional Designer
>-CD  Non conventional Designer
>
>Eh, ME?  -EE -KE -P -CD.  Maybe that's why my stuff sounds a little
>different.  Is it wrong?  Not to me.
>
><sigh>  I guess DIY needs some temperature compensation...
>
>-- Scott Gravenhorst
>-- FatMan Site: www.teklab.com/~chordman



From jorgen.bergfors at idg.se  Wed Aug  5 18:30:07 1998
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Wed, 5 Aug 1998 17:30:07 +0100
Subject: In Tom's defense. :)
Message-ID: <TFSNUYUU@idg.se>

Tony Clark writes:
>I think it is clear that there was obviously too much expectation on 
>the part of certain individuals for mind blowing advances in circuit 
>design.

Well the kicker here is that Tom created that expectation himself by writing 
such things as "I keep looking for the perfect VCO. The VCO-3B almost fits 
bill", "This is a GREAT VCO!", "This is worlds most dangerous VCF ".
It's fine to publish simpler circuits, that are easier and cheaper to build, as 
long as you clearly declare what they are and not pretend they are world class. 
I'm sure he has put a lot of effort into this, but think about how much time 
DIYers around the world might waste if they build the circuits in the belief 
that they really are the best you can find? 
There is definitely a place for simplified circuits too, as long as they are 
labeled as such.
I'm all for using cheap easy to get components and I think Tom's initiative is 
a very good one. It's just the prose on his web site that bothers me a bit. And 
I think suppliers of high quality kits like Paul Schreiber must be even more 
bothered. 
To build stable and reliable analog circuitry is not trivial. Even the pros 
like Moog had problems with that. Beginners deserve to know what the pitfalls 
are before they waste too much of their time.
I don't have all the answers myself but I listen to the other people on this 
list and try to avoid making the mistakes that they have done. I also think I 
should warn the others not to make the mistakes that I have done. 
I like to check with the other people on the list what their opinion on a 
circuit is, before I try to build it. Why waste time if somebody else already 
has found out that the circuit has problems? Or that a better one exists, that 
is just as simple to build?


/Jorgen




From ebarbour at svetlana.com  Wed Aug  5 18:35:16 1998
From: ebarbour at svetlana.com (Eric Barbour)
Date: Wed, 5 Aug 1998 09:35:16 -0700
Subject: rating system
Message-ID: <01BDC054.5B285E40.ebarbour@svetlana.com>

At 01:29 PM 8/5/98 GMT, Scott wrote:
>I propose a rating system, similar to geek code:
>Eh, ME?  -EE -KE -P -CD.  Maybe that's why my stuff sounds a little
>different.  Is it wrong?  Not to me.
><sigh>  I guess DIY needs some temperature compensation...=

This is NOTHING. You wanna see REALLY bizarre behaviour,
get on the SOUND PRACTICES mailing list (AKA  "Joenet").

Synth builders are polite and decorous compared to single-ended
triode audiophiles..........if anyone is interested I could post some
nice, ripe samples here............

Eric Barbour
Svetlana Electron Devices
Portola Valley CA USA





From torbjorn.hornfeldt at abc.se  Wed Aug  5 18:52:35 1998
From: torbjorn.hornfeldt at abc.se (=?iso-8859-1?Q?Torbj=F6rn?= =?iso-8859-1?Q?_H=F6rnfeldt?=)
Date: Wed, 05 Aug 1998 18:52:35 +0200
Subject: Walsh functions
In-Reply-To: <199808051541.RAA14404@mailhost.bpa.nl>
References: <5c870480@camcon.co.uk>
Message-ID: <3.0.3.32.19980805185235.0097b730@mail.abc.se>

Me too! :-)

I have circuit description (possibly from ETI?) somewhere in my archives
which looks interesting, but among other things I don?t understand the
graphics (that are supposed to explain/illustrate it). However, thats
probably only beacause I?m a -EE etc :-)

Any interesting noises available as sound bytes?

Torbjorn,
Solna, Sweden

At 11:40 1998-08-05 -0400, you wrote:
>Neil Johnson wrote:
>>      Me, I tinker about with odds and ends.  Anyone want a discussion on 
>>      additive synthesis using Walsh functions...?
>
>Actually, yeah.  You wrote an interesting tutorial on Walsh functions
>a while back, but I haven't gotten around to playing with them.  Have
>you made any interesting noises?
>
<snip>
>
>btw, there are a couple of references from the 80s in:
>http://www.astro.virginia.edu/~eww6n/math/WalshFunction.html
>
>-- 
>     Eli Brandt  |  eli+ at cs.cmu.edu  |  http://www.cs.cmu.edu/~eli/
>




From don at till.com  Wed Aug  5 19:12:14 1998
From: don at till.com (Don Tillman)
Date: Wed, 5 Aug 1998 10:12:14 -0700 (PDT)
Subject: Does this thing really work?
In-Reply-To: <1BF5E20E0C4DD111BBAB00805FE2D5829436F5@nbgm336a.nbgm.siemens.de>
	(message from Haible Juergen on Wed, 5 Aug 1998 17:06:22 +0200)
Message-ID: <199808051712.KAA11410@shell9.ba.best.com>

   From: Haible Juergen <Juergen.Haible at nbgm.siemens.de>
   Date: Wed, 5 Aug 1998 17:06:22 +0200 

   >I may continue to react badly to "DOES THIS REALLY WORK?". 

   I'm sure that critical questions about the circuits we present to
   the list are a good thing. I can't think of any of my own circuits
   that could not be improoved at one end or the other, and so I am
   thankful for any critical voice. "Does this really work" is either
   a chance to expand my knowledge (looking at the limits of my
   circuit), or to boast with a good explanation *why* it actually
   works, even if it's not obvious at first glance.

Absolutely agree.  Besides all the interesting stuff happens at the
edges of circuit operation, so that's the part that's really worth
discussing.

And "Does this thing really work?" might also be an abreviated way to
ask what problems you had to solve in the process of making it the
circuit operate in the real world and to share insights about it.
I'd treat it as a good thing.

  -- Don





From aschrock at cs.brandeis.edu  Wed Aug  5 19:15:31 1998
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Wed, 5 Aug 1998 13:15:31 -0400 (EDT)
Subject: In Tom's defense. :)
In-Reply-To: <TFSNUYUU@idg.se>
Message-ID: <Pine.SGI.3.95.980805124230.22591B-100000@peridot.cs.brandeis.edu>

On Wed, 5 Aug 1998 jorgen.bergfors at idg.se wrote:
> Tony Clark writes:
> >I think it is clear that there was obviously too much expectation on 
> >the part of certain individuals for mind blowing advances in circuit 
> >design.
> Well the kicker here is that Tom created that expectation himself by writing 
> such things as "I keep looking for the perfect VCO. The VCO-3B almost fits 
> bill", "This is a GREAT VCO!", "This is worlds most dangerous VCF ".
> It's fine to publish simpler circuits, that are easier and cheaper to build, as 
> long as you clearly declare what they are and not pretend they are world class. 
> I'm sure he has put a lot of effort into this, but think about how much time 
> DIYers around the world might waste if they build the circuits in the belief 
> that they really are the best you can find? 
> There is definitely a place for simplified circuits too, as long as they are 
> labeled as such.
> I'm all for using cheap easy to get components and I think Tom's initiative is 
> a very good one. It's just the prose on his web site that bothers me a bit. And 
> I think suppliers of high quality kits like Paul Schreiber must be even more 
> bothered. 
> To build stable and reliable analog circuitry is not trivial. Even the pros 
> like Moog had problems with that. Beginners deserve to know what the pitfalls 
> are before they waste too much of their time.
> I don't have all the answers myself but I listen to the other people on this 
> list and try to avoid making the mistakes that they have done. I also think I 
> should warn the others not to make the mistakes that I have done. 
> I like to check with the other people on the list what their opinion on a 
> circuit is, before I try to build it. Why waste time if somebody else already 
> has found out that the circuit has problems? Or that a better one exists, that 
> is just as simple to build?

This brings up some good points... I have tomg's designs right alongside
MOTM modules, and although I appreciate both, the difference between the
two is great. The noise on the MOTM units is literally nil. I've worked
with modular Buchla and Doepfer systems before, but the MOTM stuff really
does blow them away. I haven't done any in-depth A to B comparisons, but
the noise on the MOTM literally isn't audible. On the other stuff, eh, you
can pick up static, problems here and there.. some general noise here and
there; I also had to redo my power supply wiring scheme to accomodate one
of my maxx VCF's. Much of the noise I see is definitely from the manner in
which the design is constructed: ie on protoboard vs. a well-done PCB
with plated-through holes. I had lots of trouble with the same VCF just
since I was stupidly stealing a ground from a _very_ bad place. In this
case, there's nothing wrong with the design, just my construction. I can
see why tomg would get bugged by the same type of question over and over. 

If you consider the price difference we're talking about here, the quality
difference is warranted.. for an MOTM kit it's $125-130. For a maxx module
(specifically the VCF I'm mentioning here) it cost me around $15, mostly
for connectors, pots, and knobs. Much of the time I just don't WANT to
blow that much money on something I can throw together for peanuts, like a
VCA or LFO. Yes, the results may not be spectacular, but the results are
more useful than not! Bottom line, I simply couldn't afford (or patiently
enough way for ;) a completely MOTM system. 

Both tomg _and_ Paul Schreiber have been very forthcoming with helpful
info, even though neither of them (tomg ESPECIALLY) really _has_ to.
There's a place for both types of module, and I think both have a place
here on this list. (not that anybody's disputing that) 

With that said, I can see why some would be confused by tomg's claims. I
think his web site is, literally, indespensible to me personally for plans
and ideas, but I've really had to tweak things around a bit to get the
modules working properly. Please don't take this as a flame against
tomg.. I would much rather have tomg enthusiastically do his thing and put
up literally dozens of helpful schematics than go away forever. Perhaps we
could assemble some comments on tomg's designs to take some of the load
off him? (like has been done with the asm-1) There's no reason why he 
should have to handle it all by himself. 

Andrew

| Andrew Schrock							|
| Network Programmer, Synthesizer and electronic music enthusiast	|
| aschrock at cs.brandeis.edu						|








From cyborg0 at GlobalEyes.net  Wed Aug  5 19:26:51 1998
From: cyborg0 at GlobalEyes.net (cyborg0 at GlobalEyes.net)
Date: Wed, 05 Aug 1998 12:26:51 -0500
Subject: Warning:  I'm not an EE
References: <35ca5c5c.33031728@mail.lan>
Message-ID: <35C895DB.A65A118F@globaleyes.net>

yes, but, what about the many ETs and EETs ?.. A EET is almost a more of
a hands on EE: less theory but more breadboarding and practical
knowledge. ETs, EETs, and EEs work hand in hand in industry, and saying
that one is better than the other (at least in EE vs EET) is like saying
a tomato is red and a bell pepper is green. Apples and oranges, so to
speak.

Some of us didnt have the resources available to finish our EE, so, to
get into the job market sooner, went with ET and EET degrees..Its hard
to rank ppl with degrees.. I know EEs who can't change the oil on a car,
and I know ETs who can't figure out why a mux acts erratically. (me,
gotta put the inhibit line low, gotta put inhibit line low...) :)) 

Also, there are many places where they foregoe the EE altogether and get
an electro-physics major to do most of the design work. But, we also
cannot discredit electrophysics when it comes to design work.
rob

Scott Gravenhorst wrote:
> 
> I propose a rating system, similar to geek code:
> 
> +EE  EE degree
> -EE  No EE degree
> +KE  Knows Everything
> -KE  Doesn't know everything
> +P   Purist
> -P   Not a purist
> +CD  Conventional Designer
> -CD  Non conventional Designer
> 
> Eh, ME?  -EE -KE -P -CD.  Maybe that's why my stuff sounds a little
> different.  Is it wrong?  Not to me.
> 
> <sigh>  I guess DIY needs some temperature compensation...
> 
> -- Scott Gravenhorst
> -- FatMan Site: www.teklab.com/~chordman



From PATMAC at lglass.com  Wed Aug  5 19:27:55 1998
From: PATMAC at lglass.com (McElhatton, Pat)
Date: Wed, 05 Aug 1998 13:27:55 -0400
Subject: In Tom's defense. :)
Message-ID: <1998Aug05.132100.1654.360454@MAILGW.lglass.com>


Jorgen Bergfors writes:

Tony Clark writes:
>I think it is clear that there was obviously too much expectation on
>the part of certain individuals for mind blowing advances in circuit
>design.

Well the kicker here is that Tom created that expectation himself by   
writing
such things as "I keep looking for the perfect VCO. The VCO-3B almost   
fits
bill", "This is a GREAT VCO!", "This is worlds most dangerous VCF ".
It's fine to publish simpler circuits, that are easier and cheaper to   
build,
as

long as you clearly declare what they are and not pretend they are world
class.

The VCO-3B quote, IN CONTEXT, is:

  "The VCO-2A is a great oscillator but it uses a couple of hard to find   
parts
   and the layout, assembly and setup is more complicated than I would
  like it to be so, I keep looking for the perfect VCO.
  One that sounds as good as the 2A, it needs to be stable, easy to
  build and scale.

  The VCO-3B almost fits bill. If it just sounded as good as the 2A.   
Don't
  get me wrong it sounds very good and it's almost there... but not   
quite.
  You could compair it to the Octive Cat or Rogue oscillators sound wise.

  So what I have here with the VCO-3B is a really good sounding VCO
  that uses common parts, has a low parts count, is easy to build, it's
  very stable and setup is easy. But it's not a replacement. "

This doesn't sound like the blatant misrepresentation that you are
stating.  It explicitly points out that this is not as good sounding as
another design, but is easier to build.

The "worlds most dangerous filter" quote was (I think) referring to the
fact that the circuit went into resonance very easily, not that it is the
worlds best sounding filter.


I'm sure he has put a lot of effort into this, but think about how much   
time
DIYers around the world might waste if they build the circuits in the   
belief
that they really are the best you can find?
There is definitely a place for simplified circuits too, as long as they   
are
labeled as such.
I'm all for using cheap easy to get components and I think Tom's   
initiative
is
a very good one. It's just the prose on his web site that bothers me a   
bit.
And

I think suppliers of high quality kits like Paul Schreiber must be even   
more
bothered.
To build stable and reliable analog circuitry is not trivial. Even the   
pros
like Moog had problems with that. Beginners deserve to know what the   
pitfalls
are before they waste too much of their time.
I don't have all the answers myself but I listen to the other people on   
this
list and try to avoid making the mistakes that they have done. I also   
think I
should warn the others not to make the mistakes that I have done.
I like to check with the other people on the list what their opinion on a   

circuit is, before I try to build it. Why waste time if somebody else   
already
has found out that the circuit has problems? Or that a better one exists,
that
is just as simple to build?
Okay Jorgen, show me the VCO circuit that is "better", and as simple to   
build.

In your previous post you mentioned that he omitted temperature   
compensation
from the VCF-5A without mentioning it.  Wrong!  The circuit description
explicitly states that he left out the temperature compensation diodes.


/Jorgen

TomG: I appreciate your website.  I'm amazed at the amount of work you   
have put
  into collecting/designing and documenting these circuits.
Please keep up the good work.

Jorgen: I respectfully suggest you stuff a sock in your blow hole.

  Pat McElhatton







From tomg at vivid.net  Wed Aug  5 19:34:22 1998
From: tomg at vivid.net (tomg)
Date: Wed, 05 Aug 1998 12:34:22 -0500
Subject: Stop the Snap
Message-ID: <yam7521.1147.119335944@mail.vivid.net>

I really like this list and hate being at the center of something
this un-synth related. I really didn't think it made anny differance it I
Let's just drop it.

 




From thelab at sprint.ca  Wed Aug  5 20:03:04 1998
From: thelab at sprint.ca (|[| Philip Pilgrim |]|)
Date: Wed, 05 Aug 1998 15:03:04 -0300
Subject: Gift horses
References: <3.0.5.32.19980805105822.007c8220@192.168.210.18>
Message-ID: <35C89E58.2F49@sprint.ca>

Bill Layer wrote:

> I like Scott's 'truth-in-design' rating system (I'm a firm -EE, -CD)

How about: Hack, Trying hard to make the world sound better ,
Non-Commital and Snob as ratings?

Philip the hacker


-- 
Philip Pilgrim          	The Lab 
5 Evan's Drive          	- Analog/Digital Recording/Processing
Hammonds Plains       		- Computer/Synth Interfacing
Nova Scotia, Canada   		- Hardware/Software Development
B4B 1M8                   

   <<<<< Home of SH-101 NovaMod and UP Midi Programmer
>>>>>                     

Phone     +1.902.835.7844
Email     mailto:thelab at sprint.ca
Web Page: http://www.robotnik.com/the_lab/



From tomg at vivid.net  Wed Aug  5 20:09:48 1998
From: tomg at vivid.net (tomg)
Date: Wed, 05 Aug 1998 13:09:48 -0500
Subject: Stop the Snap!
Message-ID: <yam7521.2413.119335944@mail.vivid.net>

Let's let it go. Deep breath .....ahhhhh Back to synth stuff...

-tg




From mgranger at greenville.infi.net  Wed Aug  5 20:16:11 1998
From: mgranger at greenville.infi.net (Mike)
Date: Wed, 05 Aug 1998 14:16:11 -0400
Subject: Analog Speech Synthesis
References: <ISSMTP.1.3(1).19980805085900.4294800215E@Corp.wdc.com>
Message-ID: <35C8A16B.5864@greenville.infi.net>

Barry L Klein wrote:
> 
> That is the kit that got me interested in electronic music!  It was in my
> electronics class in 10th grade.  I tried making a keyboard for it so you
> could play a tune....  Any extras?  Love to put it up on the wall!
> 
> Barry
> 
> ----------
> From:   B.LAYER at VIKINGELECTRONICS.COM
> Sent:   Wednesday, August 05, 1998 7:35 AM
> To:     SYNTH-DIY at MAILHOST.BPA.NL
> Subject:        Analog Speech Synthesis
> 
> <<File: IST822383_2.txt>><<File: IST822583_3.txt>>
> Hi All,
> 
> I came across something curious recently, an analog speech synthesis
> experiment kit. It was produced in about 1964 by Bell Labs as a part of
> their education program for computer and electronics students.
> 
> It includes a rather in depth book which discusses the fundamental
> theories
> of speech synthesis, all in purley analog terms. When this kit was sold,
> the Votrax SC-01 was still over a decade away. The kit allows you to
> construct an analog vowel synthesizer, comprised of a rectangle wave
> generator, three L-C formant stages (ferrie bobbin type) and an audio
> stage. By tweaking the cap values in the formant stages, the unit can
> (rougly) produce all english vowel sounds, and lots of other strange
> noises
> in between.
> 
> Has anyone encountered anything else related to analog speech production?
> Frankly, I've never seen anything else like it.
> 
> Bill Layer
> "Heavy old junk wanted"
Barry L Klein wrote:
> 
> That is the kit that got me interested in electronic music!  It was in my
> electronics class in 10th grade.  I tried making a keyboard for it so you
> could play a tune....  Any extras?  Love to put it up on the wall!
> 
> Barry
> 
> ----------
> From:   B.LAYER at VIKINGELECTRONICS.COM
> Sent:   Wednesday, August 05, 1998 7:35 AM
> To:     SYNTH-DIY at MAILHOST.BPA.NL
> Subject:        Analog Speech Synthesis
> 
> <<File: IST822383_2.txt>><<File: IST822583_3.txt>>
> Hi All,
> 
> I came across something curious recently, an analog speech synthesis
> experiment kit. It was produced in about 1964 by Bell Labs as a part of
> their education program for computer and electronics students.
> 
> It includes a rather in depth book which discusses the fundamental
> theories
> of speech synthesis, all in purley analog terms. When this kit was sold,
> the Votrax SC-01 was still over a decade away. The kit allows you to
> construct an analog vowel synthesizer, comprised of a rectangle wave
> generator, three L-C formant stages (ferrie bobbin type) and an audio
> stage. By tweaking the cap values in the formant stages, the unit can
> (rougly) produce all english vowel sounds, and lots of other strange
> noises
> in between.
> 
> Has anyone encountered anything else related to analog speech production?
> Frankly, I've never seen anything else like it.
> 
> Bill Layer
> "Heavy old junk wanted"
Barry & Bill,

How interesting! I also built this kit in the 10th grade, as well as
one  where you create a silicon solar cell from a silicon wafer, and
another  where you grow and study various chemical crystals. I learned a
lot from these kits, but the speech synthesis kit was my favorite. I
made the kit on the cardboard layout on the box first, and then designed
and built a PC board for it. Wish I could remember what happened to all
my old projects. They are probably in my mom's attic somewhere... I
still have the manual though, and showed it to my teenage son recently.
He thought it was cool.


Thanks for sharing your experience with us.



From tomg at vivid.net  Wed Aug  5 20:39:33 1998
From: tomg at vivid.net (tomg)
Date: Wed, 05 Aug 1998 13:39:33 -0500
Subject: Does this thing really work?
In-Reply-To: <199808051712.KAA11410@shell9.ba.best.com>
Message-ID: <yam7521.1667.119366832@mail.vivid.net>

On 05-Aug-98, Don Tillman wrote:
>   From: Haible Juergen <Juergen.Haible at nbgm.siemens.de>
>   Date: Wed, 5 Aug 1998 17:06:22 +0200 

>   >I may continue to react badly to "DOES THIS REALLY WORK?". 

>   I'm sure that critical questions about the circuits we present to
>   the list are a good thing. I can't think of any of my own circuits
>   that could not be improoved at one end or the other, and so I am
>   thankful for any critical voice. "Does this really work" is either
>   a chance to expand my knowledge (looking at the limits of my
>   circuit), or to boast with a good explanation *why* it actually
>   works, even if it's not obvious at first glance.

>Absolutely agree.  Besides all the interesting stuff happens at the
>edges of circuit operation, so that's the part that's really worth
>discussing.

>And "Does this thing really work?" might also be an abreviated way to
>ask what problems you had to solve in the process of making it the
>circuit operate in the real world and to share insights about it.
>I'd treat it as a good thing.

>  -- Don

It's a trick Don. Don't fall for it. It never worked at all. 

If you don't like the way it looks don't build it. I'm too busy on 
the next to spoonfeed you the last. You never know though if you 
did take the chance it might work and if you had problems 
actually building it. Then we would have something to talk about.
 
-tg






From b.layer at vikingelectronics.com  Wed Aug  5 21:00:46 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Wed, 05 Aug 1998 14:00:46 -0500
Subject: AW: Analog Speech Synthesis
In-Reply-To: <06E83B40290BD111B41B08002BB769DAE3C16C@balu.kapsch.co.at>
Message-ID: <3.0.5.32.19980805140046.007eb610@192.168.210.18>

At 06:12 PM 8/5/98 +0200, you wrote:
>I also have a PCB that has the SC01-A on board and is controlable via a
>serial interface.
 
I've been looking for a SC-01 based speech module for a while now. Do you
know where I can get one? Back in the old times, I had a neat little SC-01
speech synth for my VIC-20 called (sorry) The SpeakEasy. Does anyone
remember this very limited production unit and it's tiny little icon-based
phoneme editor software? My version was supplied on CASSETTE!

My interest in the SC-01 was revived about 7 or 8 years ago, when I saw Dr.
Stephen Hawking address a group at the U of M. The speech production
mechanism in his chair was obviously a phoneme based editor with an SC-01
output. Totally freaked me out. And yes, he made several Dalek/Davros jokes.

 I'd also like to find a speech module based on the 'speak-and-spell'
chips. BTW: am I the only one who couldn't understand those s&s things for
a damn? Great voice o' the computer but intelligibility?? I'm glad Dr.
Hawking didn't sound like one of those...

 Thanks for all the replies. The details of the Bell Labs kit are now
destined for future website posting. The book is really great - does anyone
have a scannable (read: well-broken bindings) copy?


Bill Layer
Sales Technician
<b.layer at vikingelectronics.com>

----------------------------------
Viking Electronics, Inc.
Hudson, WI. U.S.A
715.386.8861 (ext. 210)
<http://www.vikingelectronics.com>
----------------------------------

"Telecommunications Solutions for the 21st Century"



From tomg at vivid.net  Wed Aug  5 21:10:25 1998
From: tomg at vivid.net (tomg)
Date: Wed, 05 Aug 1998 14:10:25 -0500
Subject: In Tom's defense. :)
In-Reply-To: <TFSNUYUU@idg.se>
Message-ID: <yam7521.1297.119321848@mail.vivid.net>

It's not going away is it?

>Well the kicker here is that Tom created that expectation himself by writing 
>such things as "I keep looking for the perfect VCO. The VCO-3B almost fits 
>bill", "This is a GREAT VCO!", "This is worlds most dangerous VCF ".

I did say almost.

>It's fine to publish simpler circuits, that are easier and cheaper to build,
>as 
>long as you clearly declare what they are and not pretend they are world
>class. 
>I'm sure he has put a lot of effort into this, but think about how much time 
>DIYers around the world might waste if they build the circuits in the belief 
>that they really are the best you can find? 

I did say almost.

>There is definitely a place for simplified circuits too, as long as they are 
>labeled as such.
>I'm all for using cheap easy to get components and I think Tom's initiative
is

>a very good one. It's just the prose on his web site that bothers me a bit.

I did say almost. Have I got the meaning of almost right?

>And 
>I think suppliers of high quality kits like Paul Schreiber must be even more 
>bothered. 

Paul seems to like them..

>To build stable and reliable analog circuitry is not trivial. Even the pros 
>like Moog had problems with that. Beginners deserve to know what the pitfalls

>are before they waste too much of their time.

Did Moog or anybody else ever build a drift proof synth? News to me.

>I don't have all the answers myself but I listen to the other people on this 
>list and try to avoid making the mistakes that they have done. I also think I

>should warn the others not to make the mistakes that I have done. 
>I like to check with the other people on the list what their opinion on a 
>circuit is, before I try to build it. Why waste time if somebody else already

>has found out that the circuit has problems? Or that a better one exists,
that

>is just as simple to build?

If you don't like the way it looks don't build it. But don't slam it
until you've built it yourself (this means YOU, no second/third hand
crap). Make sure if you have a problem it's not builder error.

-tg

  






From magnus at analogue.org  Wed Aug  5 21:31:48 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Wed, 05 Aug 1998 21:31:48 +0200
Subject: archive archive archive (was: Tom G.'s site down - anyone knowwhy?)
In-Reply-To: Your message of "Wed, 5 Aug 1998 11:38:11 +1000 (EST)"
References: <1.5.4.16.19961227181322.2c971040@popa.melbpc.org.au>
Message-ID: <199808051931.VAA10381@piraya.electrum.kth.se>

>>>>> "PP" == Paul Perry <pfperry at melbpc.org.au> writes:

Hi All!

First let me say that this tomg droping out of sigth isn't exactly
what I would like to see. He seems to be able to be a contributive
person. Has anyone tried to approach him and ask why it happend?
Hey Tom, come back!

 PP> At 12:16 AM 5/08/98 GMT, Scott Gravenhorst wrote:
 PP>   But due to
 >> the fact that people change things on their sites, I am reluctant to
 >> archive, but rather I had a link on my FatMan site to his FatMan
 >> pages. 

 PP> Mate! this is crazy......
 PP> the fact that people change their sites (including the rather radical
 PP> step of closing them) means that you HAVE to archive anything you might want in
 PP> the future.

 PP> People say the internet is the worlds biggest library.
 PP> Well, I think it's more like a periodicals stack, and half the
 PP> fucker burns down every week.

The lack of conservatism in the positive sence is a wide spread
deseace in the web world. When I was chief editor of a website back in
94-95 we spent a lot of effort building the site so that we could drop
in things as we went along without the need to move other things. As
long as the disc was not full just leave it or maybe update it. Also,
doing stuff for a longer lifetime than a couple of weeks makes one
care more about design. These things is a lost knowledge with most
websites, commercial, private or otherwise. To put it bluntly, it's a
mess all over... (sigh). Also, most webdesigners should be forced to
use the website over a 2400 baud mode in order to prioritice the right
things, in a diffrent part in the world (of their desk) will available
bandwidth appoach such numbers and many websites becomes totally
useless due to their bandwidth hunger. It has allways been easier to
make a flashy webdesign than make a usefull one. I hope people
understand why I chose not to proceed to a carieer in the webdesign
world... 

Sorry for this of topicness, but once the subject was on... can
someone get those schematics back online?

 PP> paul perry, library of alexandria, melbourne australia

Paul, Alexandria is in Egypt, not Melbourne Australia...  :) ?

Cheers,
Magnus



From mmcintos at ball.com  Wed Aug  5 21:41:37 1998
From: mmcintos at ball.com (McIntosh, Malcolm)
Date: Wed, 5 Aug 1998 13:41:37 -0600
Subject: rating system
Message-ID: <09DB74475204D1119C8200805F19D0032D12A6@aeromsg1.ball.com>

As an OE (Optical Engineer) and definitely a -EE -KE and a host of other
minuses, all I can say is:

I can't buy what I want, I must build it myself, I want to learn how
from all of you, so ALL of you PLEASE STAY ON THE LIST!  PLEASE SHARE
YOUR KNOWLEDGE!

PS,  I found "The Oscillator At Work" by John F. Rider (1940) which
gives more tube oscillator circuits in a local used book store.  One
interesting circuit (Pg 51- 52) uses a tetrode, is frequency stabilized
but has a "feedback" resistor which is used to minimize "harmonic
content".  Could the circuit be used to oscillate in the audio range and
what does "harmonic content" sound like?  Maybe its good, maybe its bad,
maybe it needs an ADSR!

PSS,  Thanks for the other titles Bill

Malcolm, (my 2 zorkmids - look it up)

> -----Original Message-----
> From:	Eric Barbour [SMTP:ebarbour at svetlana.com]
> Sent:	Wednesday, August 05, 1998 9:35 AM
> To:	'synth-diy at mailhost.bpa.nl'
> Subject:	Re: rating system
> 
> At 01:29 PM 8/5/98 GMT, Scott wrote:
> >I propose a rating system, similar to geek code:
> >Eh, ME?  -EE -KE -P -CD.  Maybe that's why my stuff sounds a little
> >different.  Is it wrong?  Not to me.
> ><sigh>  I guess DIY needs some temperature compensation...=
> 
> This is NOTHING. You wanna see REALLY bizarre behaviour,
> get on the SOUND PRACTICES mailing list (AKA  "Joenet").
> 
> Synth builders are polite and decorous compared to single-ended
> triode audiophiles..........if anyone is interested I could post some
> nice, ripe samples here............
> 
> Eric Barbour
> Svetlana Electron Devices
> Portola Valley CA USA
> 



From smart at nn.com  Wed Aug  5 22:22:53 1998
From: smart at nn.com (Mark Smart)
Date: Wed, 5 Aug 1998 15:22:53 -0500 (CDT)
Subject: VP-330 (analog speech synthesis)
Message-ID: <199808052022.PAA03541@medusa.nn.com>

This thread relates to what I have been curious about lately...the Roland
VP-330 Vocoder Plus. I just found out that this keyboard had, in addition
to a regular vocoder section, "choir" presets which were supposed to
represent choirs of male and female vocalists singing "Ahhh". This was
implemented totally in the analog domain using an organ-like divide-down
network going through a bunch of static analog filters. This sounds to me
like it could conceivably be really cool, but a have a lot of questions.

1. Did these presets sound any good? I've never heard or seen this keyboard
   in person.

2. Are there any recordings featuring the choir presets alone?

3. What waveforms are going into the filters to make the sounds? How are
   they derived from the square waves of the divide-down network?

It seems to me that a setup like this has the potential to sound better
than samples being played back at different speeds, since the formants
would not move. This could avoid the chipmunk and Jabba the Hutt sounds
which mulitple-speed sample playback create.

I would appreciate any information on this subject. Thanks!

************************************************
*     Mark Smart                               *
*     Electronics Engineer                     *
*     NovaNET Learning, Inc.                   *
*     smart at medusa.nn.com                      *
************************************************



From jdec at mindspring.com  Wed Aug  5 23:25:19 1998
From: jdec at mindspring.com (Bright Boy)
Date: Wed, 05 Aug 1998 14:25:19 -0700
Subject: In Tom's defense. :)
References: <1998Aug05.132100.1654.360454@MAILGW.lglass.com>
Message-ID: <35C8CDBF.3D21@mindspring.com>

Let's put this stupid issue to rest....

"USE AT YOUR OWN RISK!!!!"

That sums it up nicely....

Jeff R. Dec

P.S.  Tom, your Matrix 12 Filter module is brilliant and I haven't
      even built it!!!!  :)



From jim at base.demon.co.uk  Wed Aug  5 23:29:24 1998
From: jim at base.demon.co.uk (Jim Shearer)
Date: Wed, 5 Aug 1998 22:29:24 +0100
Subject: VP-330 (analog speech synthesis)
In-Reply-To: <199808052022.PAA03541@medusa.nn.com>
Message-ID: <VabE2EA06My1Ew$v@base.demon.co.uk>

In message <199808052022.PAA03541 at medusa.nn.com>, Mark Smart
<smart at nn.com> writes
>This thread relates to what I have been curious about lately...the Roland
>VP-330 Vocoder Plus. I just found out that this keyboard had, in addition
>to a regular vocoder section, "choir" presets which were supposed to
>represent choirs of male and female vocalists singing "Ahhh". This was
>implemented totally in the analog domain using an organ-like divide-down
>network going through a bunch of static analog filters. This sounds to me
>like it could conceivably be really cool, but a have a lot of questions.
>
>1. Did these presets sound any good? I've never heard or seen this keyboard
>   in person.
...I messed about with one of these in the early '80's, I thought it
sounded great! Nice "Tomita" like choirs and strings.
>
>2. Are there any recordings featuring the choir presets alone?
...Tomita actually credits it in his later albums (along with a
veritable wish-list of other analog machines).
>
>3. What waveforms are going into the filters to make the sounds? How are
>   they derived from the square waves of the divide-down network?
...The original signals are square-waves from the divider chips, these
are then integrated (simple R-C-Diode), then filtered, then chorused (To
liven up an otherwise static sound).
>
>It seems to me that a setup like this has the potential to sound better
>than samples being played back at different speeds, since the formants
>would not move. This could avoid the chipmunk and Jabba the Hutt sounds
>which mulitple-speed sample playback create.
...A way often used to avoid this in samplers, is to take multiple
samples at various pitches, so the 'chipmunk' effect never gets too
noticable before the next sample takes over. (Logical extension is to
have a unique sample for every key (I believe some sample-based piano's
do this)).
>
>I would appreciate any information on this subject. Thanks!
>
>************************************************
>*     Mark Smart                               *
>*     Electronics Engineer                     *
>*     NovaNET Learning, Inc.                   *
>*     smart at medusa.nn.com                      *
>************************************************

--Jim Shearer jim at base.demon.co.uk




From costello at seanet.com  Thu Aug  6 00:13:14 1998
From: costello at seanet.com (Sean Costello)
Date: Wed, 05 Aug 1998 15:13:14 -0700
Subject: A Serge Wave Multiplier Idea (Part 47)
Message-ID: <35C8D8FA.8D7FC148@seanet.com>

Hi everybody:

As I sit here, typing at my computer, working on the corporate web site,
listening to Harmonia and Klaus Schulze's "Irrlicht" (as well as the
inhuman yips of siamang monkeys - I live close to a zoo), my mind drifts
to the Serge Wave Multiplier, Module of Mystery.

Ok, so I ask about this damn module every few months.

This time, however, I have an idea.  I am pretty sure that the top
section of the module is something like an overdriven 3080 (differential
distortion).  The bottom section is probably four stages of an LM3900
cascaded together, where each stage is a voltage-controlled full wave
rectifier (adding voltage causes the module to morph from a voltage
follower to a full-wave rectifier).  

The middle section is a mystery. The best suggestion I have heard is
that it is a diode function generator, where different pairs of diodes
come into effect with louder signals (a VCA would need to be placed in
front of the circuit in order to add voltage control).  However, I
thought of a simpler solution last night: What if it is simply several
LM3900 voltage-controlled full-wave rectifier stages in series (as in
the bottom circuit), where each stage is followed by an op-amp inverter?
This would create foldover of the top and bottom of the waveform - each
stage would be creating foldover on a different side of the waveform.

The more I think about it, the more I suspect it isn't this simple. I
doubt that the above circuit would sweep through the odd harmonics
cleanly, as the Wave Multiplier is supposed to do with a triangle wave.
I think that it would work with 2 VC-FWR stages, but adding additional
stages would cause the circuit to depart from the behavior of the Serge
module. Intuitively, I think that the waveform would contain multiple
foldovers very quickly, instead of going from one triangle peak to 3 to
5 to 7 and so on.  However, the VC-FWR->inverting op amp->VC-FWR would
probably be a cool effect.

Any ideas, folks?

Sean Costello

P.S.  Just want to say again what a great list this is. You wouldn't
believe the flame wars going on over in Analogue Heaven right now. At
least people on this list are debating things like circuits and the
right way to offer advice and criticism, instead of some @#$%! bragging
about ripping off UPS on a COD delivery and getting bent out of shape
when people inform him that stealing is not a good thing to do.

P.P.S. Has anyone ever synthesized the sounds of a lemur?  Hearing two
lemurs talking to each other in close proximity gives you a better
understanding of beat frequencies.  Ring modulation that takes place
inside your head.  Man, I love heterodyning.



From sasami at blaze.net.au  Thu Aug  6 00:59:03 1998
From: sasami at blaze.net.au (Ken Stone)
Date: Thu, 6 Aug 1998 00:59:03 +0200 (MET DST)
Subject: VP-330 (analog speech synthesis)
Message-ID: <199808052259.AAA24349@mailhost.bpa.nl>

The VP-330 choir sounds did sound pretty good, and this ultimately led me to
building a synth module based on the circuit in question.

The filters are a bandpass, a common design found even in linear databooks,
and  from memory there are two stages per filter to get the Q up. There are
seven filters in total, and four of these are used for each of the three
vocal settings, the input signal being mixed at various levels by simple
resitor mixers.

I've been feeding mine with rectangular/square waves or three octaves mixed
at various levels, and find that some settings give much better vocal sounds
than others. The female filter so far has not produced anything decent, but
the other two are pretty good. Positive feedback also helps adding a pretty
substancial punch.

The design was done entirely with common value components.

Ken

>This thread relates to what I have been curious about lately...the Roland
>VP-330 Vocoder Plus. I just found out that this keyboard had, in addition
>to a regular vocoder section, "choir" presets which were supposed to
>represent choirs of male and female vocalists singing "Ahhh". This was
>implemented totally in the analog domain using an organ-like divide-down
>network going through a bunch of static analog filters. This sounds to me
>like it could conceivably be really cool, but a have a lot of questions.
>
>1. Did these presets sound any good? I've never heard or seen this keyboard
>   in person.
>
>2. Are there any recordings featuring the choir presets alone?
>
>3. What waveforms are going into the filters to make the sounds? How are
>   they derived from the square waves of the divide-down network?
>
>It seems to me that a setup like this has the potential to sound better
>than samples being played back at different speeds, since the formants
>would not move. This could avoid the chipmunk and Jabba the Hutt sounds
>which mulitple-speed sample playback create.
>
>I would appreciate any information on this subject. Thanks!
>
>************************************************
>*     Mark Smart                               *
>*     Electronics Engineer                     *
>*     NovaNET Learning, Inc.                   *
>*     smart at medusa.nn.com                      *
>************************************************
>
>
_____________________________________________________________

                Ken Stone  sasami at blaze.net.au
                   ** Catgirl Paradise **
               <http://www.anime.net/~kens/>
         ** Australian Miniature Horses and ponies **
             <http://www.blaze.net.au/~sasami/>
_____________________________________________________________





From 9705146x at lux.levels.unisa.edu.au  Thu Aug  6 02:58:42 1998
From: 9705146x at lux.levels.unisa.edu.au (BuDWeiSeR)
Date: Thu, 6 Aug 1998 10:28:42 +0930 (CST)
Subject: Tom G's efforts...
Message-ID: <Pine.SOL.3.91.980806102040.6236A-100000@lux.levels.unisa.edu.au>

I would just like to say that Tom's site is one of the best organised and 
fulfullingly useful archive son the web. The effort that he has put into 
his page just shows how much he loves what he is doing, and i'm sure many 
people (including myself) have benefitted from this. 

I have printed out all of the Maxx Modular articles and intend to start 
building modules soon. If i find something i don't like, or have trouble 
with something i will post my troubles... only so i can help others in 
their choices of what they do... Isn't what the net is all about : 
freedom of sharing information?

To those that critised Tom : stop complaining that your sine wave 
oscilator has better shape on the CRO than some1 elses.... let your ears 
be the judge!

just my input...

L8r


<bUd>



From lavaud at pratique.fr  Thu Aug  6 03:27:07 1998
From: lavaud at pratique.fr (Denis Lavaud)
Date: Thu, 06 Aug 1998 03:27:07 +0200
Subject: Newbie... first and common questions about CA3084 and uA726
Message-ID: <199808060128.DAA12615@absinthe.pratique.fr>

Hi,

I subscribed one week ago and as I plan to build
a fully (as most a possible) midified Formant, I
have these questions (asked many times, I suppose):

. Is there any replacement IC for the CA3084 and
uA726 ICs ?! If not, I would be very interested in
any datasheet about these ICs or replacement
solutions ! I read on Rick Jansen's page that he
would use the MAT02 and MAT03 but I do not have
any clue of what it is !


		Thanks a million !

		Denis Lavaud


To indroduce myself, I am an Electronical Engineer
but in digital IC design and digital signal
processing. I am supposed to have knowledges in
analog electronics but as I did not practice this
last years...

My project is to build a fully MIDIfied Formant
using microcontrollers (reading analog pot and
switches values and of course MIDI controls and
sending bulk dump and all of this classical stuff)
and controlling digital potentiometers and analog
switches. It seems easy to do, maybe easier than
finding replacement chip to build the analog parts !
This is still the beginning of the project and I
plan to start with the 12dB filter and then,
MIDIfying it. Any comments are welcome !




From ijfritz at earthlink.net  Thu Aug  6 05:06:41 1998
From: ijfritz at earthlink.net (Ian Fritz)
Date: Wed, 05 Aug 1998 21:06:41 -0600
Subject: Nonlinear circuit ideas needed
Message-ID: <35C91DC1.3669E106@earthlink.net>

Hi all --

I've been thinking in a somewhat vague way of trying to build an unusual
kind of analog sound source. It might be refered to as a
pseudo-physical-modeling synthesizer. It would be a nonlinear relaxation
oscillator operating in a manner similar to one-dimensional theoretical
behavior of musical instruments, but without the delay-line type
implementation used by the Yamaha-Stanford axis. My idea is to generate
the needed delay from a standard VCO, which would run in parallel with
and "guide" the relaxation circuit.

To start with I need a certain kind of nonlinear circuit, and I wonder
if any kind listers could point me in the right direction to find what I
need. The required circuit needs to have a transfer function with an
inverted "U" shape. To understand why this is needed think of a clarinet
mouthpiece. With a small blowing pressure the air velocity into the
mouthpiece increases monotonically with pressure, but beyond some point
the pressure closes the reed off to where the flow decreases with
increasing pressure. Eventually the velocity becomes zero at all
pressures beyond a cutoff point. The negative (mechanical) impedance
region is what makes the clarinet operate as a relaxation oscillator.
The circuit needed to simulate this behavior should have a way to adjust
the shape of the response curve (preferably under voltage control!) to
obtain different timbres and response characteristics. 

Any ideas? Anybody else interested in working on this? A good reference
for understanding physical modeling is "On the oscillations of musical
instruments", ME McIntyre, RT Schumaker and J Woodhouse, J. Acoust. Soc.
Am., v. 74, p. 1325 (1983), for anybody interested in digging into the
physics.

  Ian



From aschrock at cs.brandeis.edu  Thu Aug  6 05:07:27 1998
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Wed, 5 Aug 1998 23:07:27 -0400 (EDT)
Subject: Newbie... first and common questions about CA3084 and uA726
In-Reply-To: <199808060128.DAA12615@absinthe.pratique.fr>
Message-ID: <Pine.SGI.3.95.980805230327.25499B-100000@amber.cs.brandeis.edu>

Hi Denis! 

On Thu, 6 Aug 1998, Denis Lavaud wrote:
> . Is there any replacement IC for the CA3084 and
> uA726 ICs ?! If not, I would be very interested in
> any datasheet about these ICs or replacement
> solutions ! I read on Rick Jansen's page that he
> would use the MAT02 and MAT03 but I do not have
> any clue of what it is !

The uA726 is super-rare, used in the early moogs for scaling, I believe.
It would cost you at least $75 if you were to actually FIND one, so I
would _highly_ suggest working around it. The MAT02 is a matched
transistor pair, used for temperature-compensated stability. You can just
use a pair of 3096's (or whatever) easily enough. MAT02's are pricey (for 
a single part), around $5 or so. 3084 I'm not sure about.. I know 3046's
are transistor arrays, I think. 

> To indroduce myself, I am an Electronical Engineer
> but in digital IC design and digital signal
> processing. I am supposed to have knowledges in
> analog electronics but as I did not practice this
> last years...
> 
> My project is to build a fully MIDIfied Formant
> using microcontrollers (reading analog pot and
> switches values and of course MIDI controls and
> sending bulk dump and all of this classical stuff)
> and controlling digital potentiometers and analog
> switches. It seems easy to do, maybe easier than
> finding replacement chip to build the analog parts !
> This is still the beginning of the project and I
> plan to start with the 12dB filter and then,
> MIDIfying it. Any comments are welcome !

Wow! Sounds great.. keep us updated, good to have ya here among us without
any degree whatsoever... 

take care,
Andrew

| Andrew Schrock							|
| Network Programmer, Synthesizer and electronic music enthusiast	|
| aschrock at cs.brandeis.edu						|






From eleckie at cochlear.com.au  Thu Aug  6 06:47:24 1998
From: eleckie at cochlear.com.au (Edward Leckie)
Date: Thu, 06 Aug 98 14:47:24 +1000
Subject: Newbie... first and common questions about CA3084 and
Message-ID: <9808069023.AA902379112@ccgate.cochlear.com.au>


The uA726 is a supermatched pair of pnps with built-in temperature
compensation/control. They're also used in Roland SH-2. The 3094 is near
impossible to get pnp tranny array, similar to the 3086/46 npn array.

btw does anybody know of any decent mods for the SH-2

Ed Sydney, Australia.

____________________Reply Separator____________________
Subject:    Re: Newbie... first and common questions about CA3084 and uA
Author: Andrew Schrock <aschrock at cs.brandeis.edu>
Date:       5/08/98 23:07

Hi Denis! 

On Thu, 6 Aug 1998, Denis Lavaud wrote:
> . Is there any replacement IC for the CA3084 and
> uA726 ICs ?! If not, I would be very interested in
> any datasheet about these ICs or replacement
> solutions ! I read on Rick Jansen's page that he
> would use the MAT02 and MAT03 but I do not have
> any clue of what it is !

The uA726 is super-rare, used in the early moogs for scaling, I believe.
It would cost you at least $75 if you were to actually FIND one, so I
would _highly_ suggest working around it. The MAT02 is a matched
transistor pair, used for temperature-compensated stability. You can just
use a pair of 3096's (or whatever) easily enough. MAT02's are pricey (for 
a single part), around $5 or so. 3084 I'm not sure about.. I know 3046's
are transistor arrays, I think. 

> To indroduce myself, I am an Electronical Engineer
> but in digital IC design and digital signal
> processing. I am supposed to have knowledges in
> analog electronics but as I did not practice this
> last years...
> 
> My project is to build a fully MIDIfied Formant
> using microcontrollers (reading analog pot and
> switches values and of course MIDI controls and
> sending bulk dump and all of this classical stuff)
> and controlling digital potentiometers and analog
> switches. It seems easy to do, maybe easier than
> finding replacement chip to build the analog parts !
> This is still the beginning of the project and I
> plan to start with the 12dB filter and then,
> MIDIfying it. Any comments are welcome !

Wow! Sounds great.. keep us updated, good to have ya here among us without
any degree whatsoever... 

take care,
Andrew

| Andrew Schrock                                                        |
| Network Programmer, Synthesizer and electronic music enthusiast        |
| aschrock at cs.brandeis.edu                                                |









From cmacdon at ix.netcom.com  Thu Aug  6 08:03:22 1998
From: cmacdon at ix.netcom.com (Christopher MacDonald)
Date: Wed, 05 Aug 1998 23:03:22 -0700
Subject: AC Safety Questions
Message-ID: <35C9472A.2725@ix.netcom.com>

Hi all,

In the interest of avoiding electrocuting myself or, worse, someone
else, I would like to describe my intentions for routing the AC supply
into my synth enclosure.  I would appreciate it if those more
experienced than I  could offer advice or at least confirm that I have
made no safety-jeopardizing errors!

I have bought a receptacle for a standard US AC line cord.  This
receptacle is identical to that which one would find on a PC or a
factory synth.  This jack has three prongs, the center of which is earth
(it's marked with an "e" and the "ground" schematic symbol). I intend to
connect this center prong to the ground buss of my power supply and also
to connect the metal enclosure to the PS ground buss.

I'm a bit unsure about polarity on the other two prongs, one is marked
"L" and the other "N".  I intend to connect the prong marked "L" to a
fuse holder and then to my SPST power switch in series, and to connect
that to one lead of the primary power supply transformer coil.  The "N"
prong would connect directly to the other end of the PS primary coil. 
Does polarity matter here?

Bad ASCII diagram:

                             \
"L" prong                     \        transformer
<<<------------o^^^^o------o   \o---------o  o------
	    fuse holder    switch         )||(
                                          )||(------
"N" prong                                 )||(
<<<---------------------------------------o  o------

(Ground prong connection not shown)

Is this okay overall?  I was planning to use a 1 amp (not slow blow)
fuse. It all seems logical but that hasn't always worked for me in the
past...    :)

Thanks, sorry for more pesky newbie posts.

-Chris MacDonald



From martin.czech at intermetall.de  Thu Aug  6 09:24:35 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Thu, 6 Aug 1998 09:24:35 +0200 (MET DST)
Subject: Nonlinear circuit ideas needed
Message-ID: <199808060724.JAA14164@window.intermetall.de>

> To start with I need a certain kind of nonlinear circuit, and I wonder
> if any kind listers could point me in the right direction to find what I
> need. The required circuit needs to have a transfer function with an
> inverted "U" shape. To understand why this is needed think of a clarinet

A full wave rectifier has a V-shape, you can add offset and invert this
to get shifted/mirrored shapes from that. A diode network could
make the breakpoint a bit softer (like in a tri-sin shaper).
This comes close to the desired U-shape. A vca in front will
controll the steepnes of both branches.

Hope this helps.

m.c.




From brun at bart.nl  Thu Aug  6 10:25:13 1998
From: brun at bart.nl (Jeroen Bruintjes)
Date: Thu, 6 Aug 1998 10:25:13 +0200
Subject: snapping, downed sites and other events
Message-ID: <199808060825.KAA25683@smtp3.xs4all.nl>

Just wanted to say that all this arguing _did_ help me discover tg's site, which 
I'd never seen before. Definately a great website, with a lot of nice, lean and 
mean circuits. Would I be stepping out of line if I would thank you for snapping 
:-)

Jeroen



-> Brun, met een dakje op de u.



From Neil.Johnson at camcon.co.uk  Thu Aug  6 10:45:58 1998
From: Neil.Johnson at camcon.co.uk (Neil Johnson)
Date: Thu, 6 Aug 1998 09:45:58 +0100
Subject: Walsh functions
Message-ID: <5c96d7f0@camcon.co.uk>

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Subject: Walsh functions
To: smoking silicon <synth-diy at mailhost.bpa.nl>
Date: Wed, 5 Aug 1998 11:40:59 -0400 (EDT)
From: Eli Brandt <eli at gs160.sp.cs.cmu.edu>
In-Reply-To: <5c870480 at camcon.co.uk> from "Neil Johnson" at Aug 5, 98 03:44:37 pm

X-Portmanteau: pantryptaminergeticallysisterrainbowtie
Reply-To: eli+ at cs.cmu.edu
X-Mailer: ELM [version 2.4 PL25-40]
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-------------- next part --------------
     To all,
     
     Well, well, well, looks like I've just applied the opener to a can of 
     wriggly thingies....
     
     OK, there seems to be quite a bit of interest in Walsh functions.  So, 
     in the interests of educating the masses, I'll start a Walsh function 
     page on my website (no comments please...)
     
     Point your browser at:
     
        http://members.xoom.com/Neil_Johnson
     
     and go to the Interests section.  At this precise moment in time 
     (Thursday morning) there'll be nothing there about Walsh functions, 
     mainly 'cos I just thought about doing it!  So, give me time (and 
     maybe a _gentle_ prod or two) and there should be some useful 
     information.
     
     Of course, if any other list members have any useful tips or, 
     possibly, corrections, I'd be very happy to receive them.
     
     So, let the party begin ....
     
     Neil
     ----
     
     +======================================================+
     |     Neil Johnson  BEng(Hons) MSc CEng MIEE MIEEE     |
     |         http://members.xoom.com/Neil_Johnson         |
     |       "I speak for myself, not for my employer"      |
     +======================================================+

From tomg at vivid.net  Thu Aug  6 11:02:01 1998
From: tomg at vivid.net (tomg)
Date: Thu, 06 Aug 1998 04:02:01 -0500
Subject: EFM Mad Mouse (Preliminary)
Message-ID: <yam7522.53.119320488@mail.vivid.net>


WARNING! Do not look at this if simple clean designs 
torque your wrench. 

The Mad Mouse is a normalized analog synthesizer designed 
to work with the PAiA Midi2CV8 midi to control voltage converter.
It's designed with a nod to the old PAiA Gnome. Thanks John.
It can be used with any 1 volt per octave (1v/oct) controller 
keyboard ,midi interface or sequencer. It has not been built 
yet but the individual parts have been tested and work together. 
The weak point in the design is the BP VCF. I think I can 
swap a LED/LDR LP VCF without adding too much to the cost.

It sounds better than it looks. Even the VCF. Kinda like the
old bass envelope pedals. Pretty good really. The VCA
is very nice. So nice I may never use a 3O8O for a final 
VCA again.

I get mail from time to time asking where the intermediate 
projects are. So I decided to do the Mad Mouse the design 
rules were fairly loose but I wanted it to cost about $35 
use less than 4 ics and no OTAS. I think I made it but I'm 
not sure yet.

When I get it together I'll post scans & waves.

http://www.tomg.vivid.net/madm/title.html

-tg




From jorgen.bergfors at idg.se  Thu Aug  6 11:11:22 1998
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Thu, 6 Aug 1998 10:11:22 +0100
Subject: Nonlinear circuit ideas needed
Message-ID: <TFSIBEOU@idg.se>

Wouldn't Juergen Haible's Interpolating scanner fit the bill? Or at least be 
something to start with? http://www.synthfool.com/diy/hj.html

/Jorgen





MIME:ijfritz at earthlink.net on 98-08-06 06.49.56
To:  synth-diy at mailhost.bpa.nl @ SMTP 
cc:  (bcc: Jorgen Bergfors/IDGSE)
Subject: Nonlinear circuit ideas needed 

Hi all --

I've been thinking in a somewhat vague way of trying to build an unusual
kind of analog sound source. It might be refered to as a
pseudo-physical-modeling synthesizer. It would be a nonlinear relaxation
oscillator operating in a manner similar to one-dimensional theoretical
behavior of musical instruments, but without the delay-line type
implementation used by the Yamaha-Stanford axis. My idea is to generate
the needed delay from a standard VCO, which would run in parallel with
and "guide" the relaxation circuit.

To start with I need a certain kind of nonlinear circuit, and I wonder
if any kind listers could point me in the right direction to find what I
need. The required circuit needs to have a transfer function with an
inverted "U" shape. To understand why this is needed think of a clarinet
mouthpiece. With a small blowing pressure the air velocity into the
mouthpiece increases monotonically with pressure, but beyond some point
the pressure closes the reed off to where the flow decreases with
increasing pressure. Eventually the velocity becomes zero at all
pressures beyond a cutoff point. The negative (mechanical) impedance
region is what makes the clarinet operate as a relaxation oscillator.
The circuit needed to simulate this behavior should have a way to adjust
the shape of the response curve (preferably under voltage control!) to
obtain different timbres and response characteristics. 

Any ideas? Anybody else interested in working on this? A good reference
for understanding physical modeling is "On the oscillations of musical
instruments", ME McIntyre, RT Schumaker and J Woodhouse, J. Acoust. Soc.
Am., v. 74, p. 1325 (1983), for anybody interested in digging into the
physics.

  Ian









From chris at scp.de  Thu Aug  6 13:08:08 1998
From: chris at scp.de (Christian Hofmann)
Date: Thu, 6 Aug 1998 13:08:08 +0200
Subject: VP-330 (analog speech synthesis)
In-Reply-To: <199808052022.PAA03541@medusa.nn.com>
References: <199808052022.PAA03541@medusa.nn.com>
Message-ID: <199808061108.NAA30315@dilbert.scp.de>

On Wed, 5 Aug 1998 15:22:53 -0500 (CDT)
Mark Smart <smart at nn.com> wrote:

> This thread relates to what I have been curious about lately...the Roland
> VP-330 Vocoder Plus. I just found out that this keyboard had, in addition
> to a regular vocoder section, "choir" presets which were supposed to
> represent choirs of male and female vocalists singing "Ahhh". This was
> implemented totally in the analog domain using an organ-like divide-down
> network going through a bunch of static analog filters. This sounds to me
> like it could conceivably be really cool, but a have a lot of questions.
>  [...]
> 2. Are there any recordings featuring the choir presets alone?

Hi,
I took a listen last night.

Vangelis reportedly liked the VP-330, so I guess it is used for the
choir sounds on the Chariots of Fire Soundtrack album. Listen to the
beginning of "Eric's Theme", or the closing minutes of the title track
(and I mean "Chariots of Fire, not "Titles" :-), starting at about 17:10
up to the end.
And the "See you later" album has been mentioned in the VP-330 context,
but I don't have that one.

Another ocurrence can be found on Laurie Anderson's "Big Science' album,
on "Oh Superman" (though more vocoder-ish on that one), and on "Let X=X"
(VP vocal presets & lovely strings).

cu
Christian




From Hcabnivek at aol.com  Thu Aug  6 14:47:16 1998
From: Hcabnivek at aol.com (Hcabnivek at aol.com)
Date: Thu, 6 Aug 1998 08:47:16 EDT
Subject: MAT-02 and tempcos
Message-ID: <cc30ec0c.35c9a5d5@aol.com>

Could someone point me to a US source for the MAT-02 and for the tempco
resistor for the ASM-1

Also, could someone give me Gene Stopp's current Email address.
Thanks
Kevin



From Hcabnivek at aol.com  Thu Aug  6 14:53:24 1998
From: Hcabnivek at aol.com (Hcabnivek at aol.com)
Date: Thu, 6 Aug 1998 08:53:24 EDT
Subject: 2N3955A
Message-ID: <c02f8e0b.35c9a745@aol.com>

Could someone out there, with a better trany reference that I, please give me
basic info on the 2n3955.  There are 6 leads coming out of the thing, so I'm
assuming it's a matched pair?  Any chance it might work as MAT-02 replacement?
I've had 4 of these things in a plastic envalope for some time and figure I
should use them some year.
Thanks
Kevin



From Juergen.Haible at nbgm.siemens.de  Thu Aug  6 15:03:37 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Thu, 6 Aug 1998 15:03:37 +0200 
Subject: AW: VP-330 (analog speech synthesis)
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D582951CF7@nbgm336a.nbgm.siemens.de>

	>The VP-330 choir sounds did sound pretty good, and this ultimately
led me to
	>building a synth module based on the circuit in question.

	[...]

	>I've been feeding mine with rectangular/square waves or three
octaves mixed
	>at various levels, and find that some settings give much better
vocal sounds
	>than others.

Played one a few months ago, and I was really impressed.
Planned to build these filters, too, but all I've done so far are a few
Spice simulations.
What has kept me from building it so far is that in the original it's not
just feeding one input signal to a filter bank. Different partial filters
of a certain preset are fed by different footage signals from the
divider circuitry. But maybe I should build it nevertheless and 
experiment with different input signals.

>Vangelis reportedly liked the VP-330, so I guess it is used for the
>choir sounds on the Chariots of Fire Soundtrack album. Listen to the
>beginning of "Eric's Theme", or the closing minutes of the title track
>(and I mean "Chariots of Fire, not "Titles" :-), starting at about 17:10
>up to the end.
>And the "See you later" album has been mentioned in the VP-330 context,
>but I don't have that one.

Rumors go that Vangelis has changed to the 330 when he abandoned
the Mellotron.
See You Later is an excellent, much underrated album. Vocoder is
clearly audible on "I can't take it anymore", but the real gems are
the minimalistic "Memories of Green", and the whole second side.

Another speciality of the VP-330 is its bend slider. Very effective for
making vocal sounds more realistic. Different from other bender devices.

JH. 



From Robert.Schrum at harpercollins.com  Thu Aug  6 15:23:00 1998
From: Robert.Schrum at harpercollins.com (Robert Schrum)
Date: Thu, 6 Aug 1998 09:23:00 -0400
Subject: AC Safety Questions
Message-ID: <00066D46.CE21411@harpercollins.com>

The "L" and "N" are likely "Live" and "Neutral", respectively.  In this case,
you have the fuse/switch on the right side.  In ~117VAC systems in a perfect
world, the neutral wire (white in house wiring convention) is at zero volts or
ground potential.  I've never met a perfect AC outlet, though--there is always
some kind of voltage--sometimes surprisingly high in older homes--between
neutral and ground.  So, never equate neutral for ground, and especially never
tie them together!

The "live" or "hot" wire (black) carries the main ~117 volts.  Putting the fuse
and switch on that side leaves less lesser portion of the circuit at this
potential, should the fuse blow.  (But remember the corollary of Murphy's Law
that says that expensive components will fail in order to protect the fuse. :) )

-----Original Message-----
From: Christopher MacDonald <cmacdon at ix.netcom.com> at hcinternet-server

Sent: Thursday, August 06, 1998 2:03 AM
To: synth-diy at mailhost.bpa.nl at HCINTERNET-SERVER
Subject: AC Safety Questions


Hi all,

In the interest of avoiding electrocuting myself or, worse, someone
else, I would like to describe my intentions for routing the AC supply
into my synth enclosure.  I would appreciate it if those more
experienced than I  could offer advice or at least confirm that I have
made no safety-jeopardizing errors!

I have bought a receptacle for a standard US AC line cord.  This
receptacle is identical to that which one would find on a PC or a
factory synth.  This jack has three prongs, the center of which is earth
(it's marked with an "e" and the "ground" schematic symbol). I intend to
connect this center prong to the ground buss of my power supply and also
to connect the metal enclosure to the PS ground buss.

I'm a bit unsure about polarity on the other two prongs, one is marked
"L" and the other "N".  I intend to connect the prong marked "L" to a
fuse holder and then to my SPST power switch in series, and to connect
that to one lead of the primary power supply transformer coil.  The "N"
prong would connect directly to the other end of the PS primary coil.
Does polarity matter here?

Bad ASCII diagram:

                             \
"L" prong                     \        transformer
<<<------------o^^^^o------o   \o---------o  o------
            fuse holder    switch         )||(
                                          )||(------
"N" prong                                 )||(
<<<---------------------------------------o  o------

(Ground prong connection not shown)

Is this okay overall?  I was planning to use a 1 amp (not slow blow)
fuse. It all seems logical but that hasn't always worked for me in the
past...    :)

Thanks, sorry for more pesky newbie posts.

-Chris MacDonald



From Robert.Schrum at harpercollins.com  Thu Aug  6 15:39:00 1998
From: Robert.Schrum at harpercollins.com (Robert Schrum)
Date: Thu, 6 Aug 1998 09:39:00 -0400
Subject: AC Safety Questions
Message-ID: <00066DBB.CE21411@harpercollins.com>

(I hit send too quick before my last thought)

For best safety, make sure any soldered connections that are connected directly
to the "L" or "N" terminals are ridiculously insulated.  These would be the
terminals on your power connector and those on the fuse holder.  I usually use a
double-thick layer of heat-shrink, sometimes adding a glob of silicone sealant
too.  Those are the only points that are unprotected by the fuse in case a
wandering screw or tool ventures there.  (Actually, I insulate the hell out of
every point on the primary side of the power transformer--what can I say, I'm a
safety guy.)


-----Original Message-----
From: Christopher MacDonald <cmacdon at ix.netcom.com> at hcinternet-server

Sent: Thursday, August 06, 1998 2:03 AM
To: synth-diy at mailhost.bpa.nl at HCINTERNET-SERVER
Subject: AC Safety Questions


Hi all,

In the interest of avoiding electrocuting myself or, worse, someone
else, I would like to describe my intentions for routing the AC supply
into my synth enclosure.  I would appreciate it if those more
experienced than I  could offer advice or at least confirm that I have
made no safety-jeopardizing errors!

I have bought a receptacle for a standard US AC line cord.  This
receptacle is identical to that which one would find on a PC or a
factory synth.  This jack has three prongs, the center of which is earth
(it's marked with an "e" and the "ground" schematic symbol). I intend to
connect this center prong to the ground buss of my power supply and also
to connect the metal enclosure to the PS ground buss.

I'm a bit unsure about polarity on the other two prongs, one is marked
"L" and the other "N".  I intend to connect the prong marked "L" to a
fuse holder and then to my SPST power switch in series, and to connect
that to one lead of the primary power supply transformer coil.  The "N"
prong would connect directly to the other end of the PS primary coil.
Does polarity matter here?

Bad ASCII diagram:

                             \
"L" prong                     \        transformer
<<<------------o^^^^o------o   \o---------o  o------
            fuse holder    switch         )||(
                                          )||(------
"N" prong                                 )||(
<<<---------------------------------------o  o------

(Ground prong connection not shown)

Is this okay overall?  I was planning to use a 1 amp (not slow blow)
fuse. It all seems logical but that hasn't always worked for me in the
past...    :)

Thanks, sorry for more pesky newbie posts.

-Chris MacDonald



From pfperry at melbpc.org.au  Thu Aug  6 15:42:06 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Thu, 6 Aug 1998 23:42:06 +1000 (EST)
Subject: 2N3955A
Message-ID: <1.5.4.16.19961229061714.0dff2b7a@popa.melbpc.org.au>

At 08:53 AM 6/08/98 EDT, the retrograde  Hcabnivek wrote:
>Could someone out there, with a better trany reference that I, please give me
>basic info on the 2n3955.  
..dual N-channel fet for VHF applications

There are 6 leads coming out of the thing, so I'm
>assuming it's a matched pair? 
..well, if its for modulation/demod applics, it might be...

 Any chance it might work as MAT-02 replacement?
....no way....

>I've had 4 of these things in a plastic envalope for some time and figure I
>should use them some year.
....if you have to use them, and they are matched, perhaps a very simple 
stereo vca.

paul perry melbourne australia




From Juergen.Haible at nbgm.siemens.de  Thu Aug  6 15:50:26 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Thu, 6 Aug 1998 15:50:26 +0200 
Subject: My Wurlie drives me crazy !
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5829534D2@nbgm336a.nbgm.siemens.de>

My Wurlitzer is producing loud noises again.
HF oscillation / radio receiver noises - only that the electronic
part is *not* oscillating. I'll explain why I came to believe this.

Symptoms:

Switch it on, there are some "radio like" tones present, but rather
quiet.
Play a few notes, some are okay, some are terribly distorted, with
a tail of much louder "radio noises" behind the note.
This is, with the damper pedal *not* depressed.
When I do activate the damper pedal, hell breaks open. Noises
increase dramitically, being louder than the notes that I play.
This is remarkable, because the damper pedal does only remove
all the damper felts from the tines, and nothing else.

Why I don't think the electronics (amplifiers) are to blame:

Well, I've removed them completely, and the noises are still there.
I have made the following steps:
(1) removed the power amplifier (the speakers are broken anyway).
(2) powered the preamp with a battery (It's the model that has the
     preamp directly on top of the pickup.)
(3) Tried various capacitors across various transistors, like described
     in the service manual.

All this without any change. Then I tried something more radical:

(4) Removed the internal electronics completely. Instead I built a
simple source follower from one FET, with series resistor and tiny
ferrite ring on the gate connection to give oscillations no chance.
The Pickup was supplied by a 80V Laboratory supply, and the
source follower ran on 12V. I had 1m of shielded cable between the
pickup and the source follower, and I was aware of the damping
(approx. 12dB) and possible increase of hum in this configuration,
but well, I didn't intend to use this for playing, only for testing.
I monitored the output of the source follower with a Mic input of my
mixing desk.
The configuration did work as intended, hiss and hum increased as
expected, AND the whole radio noise the same as before.

So, I am quite sure that the HF desaster happens *before* the 
amplifier. At least it would be more than strange if this second
(test) amplifier would oscillate in the same way as the first one.

So, what could be the problem ?

My theory is that the Reed bar picks up HF waves, and the high DC
voltage helps to demodulate this HF directly inside the Pickup,
before the signal goes to the preamp.
It's hard to tell *where* this demodulation would take place (dirt
inside the pickup? dirst inside the GND connections ? ??), but
that's the only explanation that seems to be left.
BTW, looking for dirt I tried blowing compressed air into the pickup,
and the problem was immediately *increased*.

I haven't disassembled the reed bar so far - I'm a little shy to touch
something that is so carefully adjusted.

Now I think about trying the method that was once suggested by 
Don Tillman (Hi Don !), building a HF oscillator around the pickup
capacitance (approx. 250pF) with a few CMOS gates, and an
FM demodulator with a 4046.
But before I do this, I'd like to know:

(1) Has anybody run into a similar problem before ?

(2) Does the FM oscillator / Demodulator method really help?
     (I know that FM is rather insensitive if the *HF channel* is
      noisy, but in my case the noise would not affect the HF
     channel, but rather the voltage at the oscillator capacitor ...)
     Now high voltages anymore, though ...

(3) Just to be sure: I know early Wurlies had a second metal shield
     above the wooden damper action. Mine doesn't have this extra shield,
     and it looks like it never had one. (The serive manual isn't clear
     either)

Sorry for the long post, but I need help. The sound of a Wurlie is one
of the sweetest sounds ever, but at the moment it drives me crazy !

JH.






From b.layer at vikingelectronics.com  Thu Aug  6 15:54:13 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Thu, 06 Aug 1998 08:54:13 -0500
Subject: AC Safety Questions
In-Reply-To: <35C9472A.2725@ix.netcom.com>
Message-ID: <3.0.5.32.19980806085413.007c2d80@192.168.210.18>

Hi Chris.

The PC-type receptacle you are discussing is known as an IEC connector.
>
>I'm a bit unsure about polarity on the other two prongs, one is marked
>"L" and the other "N".  

L = Line (Black), N= Neutral (White). If the wiring in your house is
correct, Neutral is made common to Ground at the AC Mains breaker box.

I intend to connect the prong marked "L" to a
>fuse holder and then to my SPST power switch in series, and to connect
>that to one lead of the primary power supply transformer coil.  The "N"
>prong would connect directly to the other end of the PS primary coil. 
>Does polarity matter here?
>
You are right in fusing the Line side right off the bat; this is the best
method. The onto the switch and xfmr. Other side of xfmr primary is then
common to neutral. 

Polarity is only of (minor) concern with respect to ground leakage current.
Do this test:

Wire the arrangement temporarily, so that the polarity of the xfrm primary
may be changed. Using a CHEATER plug (blow off the ground...), connect the
AC cord to the mains socket. Using a VTVM or DVM, measure AC volts from the
chassis of your power supply to the AC Ground at the socket.

Record the reading, disconnect power, then reverse the xfmr primary and
perform the test again. Record the reading.

Whichever arrangement gave the lowest AC volts reading is more correct.
Wire it that way permanently.

Have fun!

 
Bill Layer
"Heavy old junk wanted"



From don at till.com  Thu Aug  6 17:30:50 1998
From: don at till.com (Don Tillman)
Date: Thu, 6 Aug 1998 08:30:50 -0700 (PDT)
Subject: My Wurlie drives me crazy !
In-Reply-To: <1BF5E20E0C4DD111BBAB00805FE2D5829534D2@nbgm336a.nbgm.siemens.de>
	(message from Haible Juergen on Thu, 6 Aug 1998 15:50:26 +0200)
Message-ID: <199808061530.IAA14816@shell9.ba.best.com>

Hi Juergen!

A few quick possible suggestions...
  Dirt, dust or a dead insect might be shorting the pickup's high
  voltage to something.

  Check the high voltage supply on a 'scope, before that large value
  resistor, to make sure it's clean.  (I can imagine an aging capacitor
  causing some problems there.)

  Check all ground connections.  The description really sounds like a
  grounding problem.

On my Wurlie, an older model than yours, the loudest noise is the hiss
of the preamp.

  -- Don



From ebarbour at svetlana.com  Thu Aug  6 18:54:29 1998
From: ebarbour at svetlana.com (Eric Barbour)
Date: Thu, 6 Aug 1998 09:54:29 -0700
Subject: The Mad Mouse
Message-ID: <01BDC120.349C1380.ebarbour@svetlana.com>

Nice work, Tom. Don't apologize for anything, this is exactly
what the world needs--implemented with common low-cost 
devices. Let me encourage you to consider making a commercial
product out of it, perhaps in rackmount form.

>The Mad Mouse is a normalized analog synthesizer designed 
>to work with the PAiA Midi2CV8 midi to control voltage converter.
>It's designed with a nod to the old PAiA Gnome. 
>I get mail from time to time asking where the intermediate 
>projects are. So I decided to do the Mad Mouse the design 
>rules were fairly loose but I wanted it to cost about $35 
>use less than 4 ics and no OTAS. I think I made it but I'm 
>not sure yet.
>When I get it together I'll post scans & waves.
>http://www.tomg.vivid.net/madm/title.html

Eric Barbour
Svetlana Electron Devices
Portola Valley CA USA




From iadunn at mcmail.com  Thu Aug  6 23:03:50 1998
From: iadunn at mcmail.com (Iain Dunn)
Date: Thu, 06 Aug 1998 22:03:50 +0100
Subject: snapping
Message-ID: <35CA1A36.5BB2@mcmail.com>

Hi

Ive been reading the mail about Tomg and the flaming he recieved with 
much interest.
Whats the problem?
Most of Tomgs' circuits are well Known designs with interesting
solutions eg the ladder filter with ca3080 as a differential amp-
elegant!
The maxx 4 vco is basicly the Moog prodigy and the later Minimoog
oscillator design; uhm I think thats a proven design. So it hasnt got
range switching or temperature compensation- well just add that its not
diificult eg heated 3046 and prodigy style range switching using the
referance current.Tomg has said he will add  heated compensation one day
but modern compnents are much better than they used to be and if you
keep the oscillators in one locale they wont drift too much-ask Gene
Stopp!
Tomg adsrs are also well proven Moog designs using the 555 timer so come
on everyone stop bitching at him build the bloody stuff and add your own
design improvement/customization where needed.

And finally yes I have built a lot of synths and learned an awful lot
just by hacking parts of circuits together from various designs and
improving commercial designs ie the Doepfer Moog Filter wher the
capacitor values are too small and the cutoff therefor too high.

I look forward to being flamed!

Many thanks to Gene Stopp,Juergen Haible and Tomg whose sites and ideas
are superb and brilliant food for thought.


Iain Dunn




From verbos at on-q.com  Thu Aug  6 23:05:53 1998
From: verbos at on-q.com (mark verbos)
Date: Thu, 06 Aug 1998 15:05:53 -0600
Subject: (G-TECH) smile
References: <35C9EDEC.BB2C704E@aldiscon.ie>
Message-ID: <35CA1AB1.66AFDAA3@on-q.com>



Brian Rooney wrote:

> ...though your heart is aching.....
>
> Can anyone tell me who is behind the 'Smile' label out of NYC? (its not
> Steve Stoll BTW)
>

It is owned by Profile.

As in Run DMC's label!

DJ DB used to run it, but he left them for Sony now, I dont know who is in
charge there now.

--
mark verbos

"I think the future of analog modulars is to build them yourself."

verbos at on-q.com
http://www.on-q.com/verbos
massive magazine... http://www.massivemag.com
current release...
 "Logic Circuits" as CMOS on Shokoy, Germany





From thelab at sprint.ca  Fri Aug  7 00:53:51 1998
From: thelab at sprint.ca (Philip)
Date: Thu, 06 Aug 1998 22:53:51 +0000
Subject: Sync 24 pinout
Message-ID: <35CA33FF.4D00@sprint.ca>

I'm away from my schematics and I need info on the Roland Sync 24 jack.
What are the signals?
Where are they located? (please give orientation because the female jack
I have has no numbers. Maybe this helps?)

       pin3
          0
pin 2  0     0  pin4
pin 1 0       0 pin5 
          _

Female socket "jack" as viewed looking at it mounted on a front panel.
       
-- 
Philip Pilgrim                  The Lab Audio Works
5 Evan's Drive                  - Analog/Digital Recording/Processing
Hammonds Plains                 - Computer/Synth Interfacing
Nova Scotia, Canada             - Hardware/Software Development
B4B 1M8

Phone     +1.902.835.7844
Email      mailto:thelab at sprint.ca

Web Page: http://www.robotnik.com/the_lab



From jkjelec at tiac.net  Fri Aug  7 01:26:30 1998
From: jkjelec at tiac.net (Kyle Jarger)
Date: Thu, 6 Aug 1998 23:26:30 +0000
Subject: snapping
Message-ID: <199808070307.XAA19097@mailnfs0.tiac.net>

iadunn at mcmail.com wrote:

> ...but modern compnents are much better than they used to be and if you
> keep the oscillators in one locale they wont drift too much...

No flame intended, but I always thought that temperature compensation 
of the type seen in VCOs and VCFs has nothing at all to with the 
quality of the components, but everything to do with the laws of physics!

Regards,
Kyle Jarger
jkjelec at tiac.net
JKJ Electronics
Visit our MIDI/CV converters website 
http://www.tiac.net/users/jkjelec



From smart at nn.com  Fri Aug  7 01:46:57 1998
From: smart at nn.com (Mark Smart)
Date: Thu, 6 Aug 1998 18:46:57 -0500 (CDT)
Subject: AW: VP-330 (analog speech synthesis)
In-Reply-To: <1BF5E20E0C4DD111BBAB00805FE2D582951CF7@nbgm336a.nbgm.siemens.de> from "Haible Juergen" at Aug 6, 98 03:03:37 pm
Message-ID: <199808062346.SAA17002@medusa.nn.com>

Thanks to everyone for the info and recording suggestions!

> Played one a few months ago, and I was really impressed.
> Planned to build these filters, too, but all I've done so far are a few
> Spice simulations.
> What has kept me from building it so far is that in the original it's not
> just feeding one input signal to a filter bank. Different partial filters
> of a certain preset are fed by different footage signals from the
> divider circuitry. But maybe I should build it nevertheless and 
> experiment with different input signals.
> 

Wow. Sounds like a really involved design! Makes me even more curious to
see it. Also a bit disappointed, since I was hoping to be able to run other
stuff through the same filters and have it sound as good. Maybe that's not
possible. I still want a VP-330, though! 

I can believe that the input waveform is vital.
I've spent some time recently trying to get vocal sounds like these
out of my JD-800, using three voices, each one going thru a bandpass filter
set at a different frequency. I got the frequency values out of a book on
speech synthesis. I was able to get something kinda VAGUELY vocal sounding
using a really narrow pulse wave as an input (I read somewhere that that's
how they do it in speech synthesis). But I found that by changing to a
different waveform, a "vocal" waveform on the JD-800, it became MUCH more
realistic. And the vocal waveform alone didn't sound nearly as good as it
did with the filters. The problem was that, since it was a sample playback
machine, and the recording had formants in it, I got a chipmunk/Jabba
effects playing up and down the keyboard.

It would be great to be able to combine the cool VP-330 filters with the trippy
"pitch random" feature on the JD-800 for making Ligeti sounds minus the
chipmunk/Jabba effects. I can already do good Ligeti sounds WITH
chipmunk/Jabba effects.

> Another speciality of the VP-330 is its bend slider. Very effective for
> making vocal sounds more realistic. Different from other bender devices.
> 
> JH. 

I just checked out the Laurie Anderson "Let x = x" that was suggested
earlier, and this pitch slider appears to be in use. Sounds like she's
using it to tranpose the whole thing up and down a fourth. Cool!



************************************************
*     Mark Smart                               *
*     Electronics Engineer                     *
*     NovaNET Learning, Inc.                   *
*     smart at medusa.nn.com                      *
************************************************



From rams0046 at tc.umn.edu  Fri Aug  7 02:58:19 1998
From: rams0046 at tc.umn.edu (rams0046)
Date: Thu, 06 Aug 1998 19:58:19 -0500
Subject: [Fwd: Majordomo results: (no subject)]
Message-ID: <35CA512B.3C240A1F@tc.umn.edu>

no, I dont know what to do.  please help me to get off this list.  please
forward this to the list admin    thanks   joseph ramstrom

Majordomo at mailhost.bpa.nl wrote:

> --
>
> >>>> unsubscribe synth-diy rams0046 at tc.umn.edu
> **** unsubscribe: 'rams0046 at tc.umn.edu' is not a member of list 'synth-diy'.
> **** contact "synth-diy-approval" if you need help.
> >>>>


-------------- next part --------------
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From mamundso at mr.net  Fri Aug  7 03:24:14 1998
From: mamundso at mr.net (Mark Amundson)
Date: Thu, 06 Aug 1998 18:24:14 -0700
Subject: AC Safety Questions
References: <35C9472A.2725@ix.netcom.com>
Message-ID: <35CA573E.D71@mr.net>

> In the interest of avoiding electrocuting myself...
> 
> I have bought a receptacle for a standard US AC line cord.  This
> receptacle is identical to that which one would find on a PC or a
> factory synth.  This jack has three prongs, the center of which is earth
> (it's marked with an "e" and the "ground" schematic symbol). I intend to
> connect this center prong to the ground buss of my power supply and also
> to connect the metal enclosure to the PS ground buss...
> 
> Is this okay overall?  I was planning to use a 1 amp (not slow blow)
> fuse. It all seems logical but that hasn't always worked for me in the
> past...  -Chris MacDonald

Your IEC connector scheme looks good. Bond the earth terminal to your
chassis first. Consider separating the power supply ground bus from the
chassis with a 100 ohm resistor to your IEC earth wire bond point. By
floating all control and audio connectors to signal (supply) ground
instead of chassis ground avoids all those nasty ground loop humming
problems. Star grounding your module supply ground returns helps too. I
am just scratching the surface on this topic.

Mark Amundson,



From sasami at blaze.net.au  Fri Aug  7 04:27:59 1998
From: sasami at blaze.net.au (Ken Stone)
Date: Fri, 7 Aug 1998 04:27:59 +0200 (MET DST)
Subject: AC Safety Questions
Message-ID: <199808070227.EAA22815@mailhost.bpa.nl>

And when bolting the earth to the chassis, use star washers between the lug
and the case, to make sure paint/oxide or whatever is pierced and you get a
good ground.

Ken
_____________________________________________________________

                Ken Stone  sasami at blaze.net.au
                   ** Catgirl Paradise **
               <http://www.anime.net/~kens/>
         ** Australian Miniature Horses and ponies **
             <http://www.blaze.net.au/~sasami/>
_____________________________________________________________





From cdjeris at math.uchicago.edu  Fri Aug  7 06:34:09 1998
From: cdjeris at math.uchicago.edu (Christopher Jeris)
Date: Thu, 6 Aug 1998 23:34:09 -0500 (CDT)
Subject: AC Safety Questions
Message-ID: <Pine.SUN.3.96.980806233311.24627E-100000@math.uchicago.edu>


An NSA securitybot masquerading as Ken Stone says:
> And when bolting the earth to the chassis, use star washers between the lug
> and the case, to make sure paint/oxide or whatever is pierced and you get a
> good ground.

I'll remember that next time I'm bolting the planet nice and tight ... <g>

(apologies to Commonwealth English speakers; `earth' always sounded
strange to this particular unwashed Yankee)

Obligatory sDIY content:  Can anyone point me to a tutorial or good set of
instructions on `How to make sturdy reliable low-noise patchcords' ?  I've
heard many modular owners attach their own plugs, and I have trouble
finding 1/8" patchcords anyway ... but I don't want to louse up the job.

thanks & peace,

Christopher Jeris	c-jeris at uchicago.edu	Chicago (soon MIT) Math!





From cmacdon at ix.netcom.com  Fri Aug  7 07:56:21 1998
From: cmacdon at ix.netcom.com (Christopher MacDonald)
Date: Thu, 06 Aug 1998 22:56:21 -0700
Subject: AC Safety Questions
Message-ID: <35CA9705.46C4@ix.netcom.com>

Thanks to everyone for helping me with the AC questions.  I feel much
more informed about what to do.  I hope to finish this part of my
project over the weekend (I've been drilling holes in the enclosure
lately), I'll post some pictures if I can.

-Chris MacDonald



From jungmann at citycom.fr  Fri Aug  7 10:48:26 1998
From: jungmann at citycom.fr (Renaud Jungmann)
Date: Fri, 7 Aug 1998 10:48:26 +0200
Subject: Sync 24 pinout
Message-ID: <01bdc1e0$2463d780$021410ac@pc-rj>

>I'm away from my schematics and I need info on the Roland Sync 24 jack.
>What are the signals?



                                
                       
                                pin 2                
                                  *
                        pin 5 *       *   pin 4

                       pin 3 *         *  pin 1



This is looking at the rear view of the connector.  The pins are
basically what has been posted:

pin #        tr-808          tr-606/tb-303         cr-1000
1            start/stop      start/stop            start/stop
2            ground          ground                ground
3            tempo clock     tempo clock           tempo clock
4            reset           tap                   not used
5            fill in         not used              not used


The control voltage is 0 to +5 volts DC.


(this is a copy of a previously posted message !)


                        --- Re/\/o ---


      o       o    o     o     o  <o     <o>    o>    o
     .|.     \|.  \|/   //     X    \     |    <|    <|>
      /\     >\   /<    >\    /<   >\    /<     >\   /<

                  LET THE GROOVE MOVE YOUR BODY




From Juergen.Haible at nbgm.siemens.de  Fri Aug  7 15:21:08 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Fri, 7 Aug 1998 15:21:08 +0200 
Subject: AW: 2N3955A
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5829663E4@nbgm336a.nbgm.siemens.de>

	> ..dual N-channel fet for VHF applications

	Good for discrete high impedance buffer stages. 
	Minmoog ?
	ARP Phaser ?
	I have recently bought a few dual FETs (forgot the number), but
	they were very expensive.

	JH.



From mglnsky at magicnet.net  Fri Aug  7 17:05:38 1998
From: mglnsky at magicnet.net (Mark Glinsky)
Date: Fri, 7 Aug 1998 11:05:38 -0400 (EDT)
Subject: snapping
Message-ID: <199808071505.LAA06730@magicnet.magicnet.net>

>Ive been reading the mail about Tomg and the flaming he recieved with 
>much interest.  Whats the problem?

I believe the problem is one more of perception and the vagaries of
communication
through the Internet.  A person sends what seems to him to be a normal, harmless
question.  The recipient (particularly if they're a bit new to the Net)
receives it and
interprets it to be questioning his ability.  Multiply that by however many
times he
receives the same question, and all of a sudden it seems that the world is
ganging
up on him.  I've seen this happen on several other lists.  I think one just
has to decide
that if they're going to be on the Net for the long term, and dealing with
people from
many countries and cultures, that you have to cultivate a bit of a thick
skin and not
take things too literally.


_______________________________________________________
 Mark Glinsky -   Orlando, Florida
 Email:                 mglnsky at magicnet.net
 Manual Manor:   http://www.magicnet.net/~mglnsky/msg4.html
 "Be seeing you...."  [ No. 6  -  The Prisoner ]
 "Don't Panic!"   [ HitchHiker's Guide ]
-------------------------------------------------------




From girard at enel.ucalgary.ca  Fri Aug  7 17:35:49 1998
From: girard at enel.ucalgary.ca (Arno)
Date: Fri, 07 Aug 1998 09:35:49 -0600
Subject: Maxx modular - to whom it may concern
Message-ID: <199808070935490500.000A01C5@mailhost.ucalgary.ca>


Hi,

I plan to build the maxx modular and i was talking to u about sharing some boring task ..
I HAVE LOST YOUR E-MAIL AND I DON'T REMEMBER YOUR NAME CAN YOU MAIL ME AGAIN

Arno
France



From debus at cityweb.de  Fri Aug  7 21:00:11 1998
From: debus at cityweb.de (Ingo Debus)
Date: Fri, 07 Aug 1998 21:00:11 +0200
Subject: AC Safety Questions
References: <Pine.SUN.3.96.980806233311.24627E-100000@math.uchicago.edu>
Message-ID: <35CB4EBA.7CB1@cityweb.de>

Christopher Jeris wrote:
> (apologies to Commonwealth English speakers; `earth' always sounded
> strange to this particular unwashed Yankee)

Isn't the term "PE" (for Protection Earth) used in the US too?

Ingo





From debus at cityweb.de  Fri Aug  7 21:04:00 1998
From: debus at cityweb.de (Ingo Debus)
Date: Fri, 07 Aug 1998 21:04:00 +0200
Subject: AC Safety Questions
References: <199808070227.EAA22815@mailhost.bpa.nl>
Message-ID: <35CB4FA0.3D18@cityweb.de>

Ken Stone wrote:
> 
> And when bolting the earth to the chassis, use star washers between the lug
> and the case, to make sure paint/oxide or whatever is pierced and you get a
> good ground.

And make sure the mains transformer gets good ground too (if it isn't an
insulated or toroidal one).

Ingo




From 8brain at spiritone.com  Sat Aug  8 01:12:22 1998
From: 8brain at spiritone.com (R.Fahl)
Date: Fri, 7 Aug 1998 16:12:22 -0700 (PDT)
Subject: AW: 2N3955A
Message-ID: <v02130500b1f0d8de851e@[205.139.109.61]>

I forget who made this original post, but check TEMIC's  webpage.  They
manufacture a line of dual, matched JFETs that are semi easy to get, not
too expensive.   I think 3955s were used in the ARP 4012 filter as well as
the Buchla 200 series bandpass vcf.

R>



>        > ..dual N-channel fet for VHF applications
>
>        Good for discrete high impedance buffer stages.
>        Minmoog ?
>        ARP Phaser ?
>        I have recently bought a few dual FETs (forgot the number), but
>        they were very expensive.
>
>        JH.





From bmouwen at stad.dsl.nl  Sat Aug  8 08:34:03 1998
From: bmouwen at stad.dsl.nl (bert mouwen)
Date: Fri, 07 Aug 1998 23:34:03 -0700
Subject: My Wurlie drives me crazy ! 
Message-ID: <35CBF15B.7CA4@stad.dsl.nl>

Don Tillman wrote to Haible Juergen: 

> .-..some things about Wurlies-


not very much an analog synthesizer I think,
but talking about this very analog piano-oldie:

does anyone know a supplier for spare parts nowadays?
especially new tongues of course, and in my case preferably in "the
neighbourhoud of the netherlands".

About the noise theme: I don't think i can add much to Don Tillman's 
advise:

>  Dirt, dust or a dead insect might be shorting the pickup's high
>  voltage to something.

dust or things like dead insects can cause terrifying noises at 
impredictable moments in my own experience. When you check for dust it 
might be useful to look at the distances between the tongues and the 
frame. If the tongues are not well centered, dirt has more chance. I 
never had the experience of radio-like sounds however caused by dirt.
Unwanted electromagnetic "input" should be be prevented sufficiently by 
the shield in the wurlitzer's cap. But i suppose this thing is correctly 
grounded. The fact that noises get worse by lifting the damper might be 
explained by the fact that every sound from the speaker gets a chance at 
any tone-tongue to get it it resonating, soon resulting i an avalange of 
sounds. (by the way -one of my favorite ways aof playing the wurlitzer: 
hitting the key not hard enough to get the hammer on the tong, amplifier 
just loud enough to prevent continuous feedback, resulting in a nice 
sustain = being very off-topic already? okay then. Anyone ever worked 
out the idea of a sort of "tuned resonator with strong enhancing 
characteristics" this way?)

grtz. bert mouwen.




From paul at darlow.powernet.co.uk  Sat Aug  8 11:01:02 1998
From: paul at darlow.powernet.co.uk (paul darlow)
Date: Sat, 08 Aug 1998 10:01:02 +0100
Subject: ring mod
Message-ID: <35CC13CE.7497@darlow.powernet.co.uk>

Hi this is my first post to the diy list 
Iv just finished building a ADSR with a ssm2056 and now my modular
project wants a ring mod could any one tell me of a nice one thats not
too hard to build (Im not a electrition this is a hobby)
any help would be most gratfully receved
paul



From synth1 at airmail.net  Sat Aug  8 13:16:16 1998
From: synth1 at airmail.net (Paul Schreiber)
Date: Sat, 8 Aug 1998 11:16:16 -0000
Subject: FW: from Sally
Message-ID: <01BDC2BE.3AAF8C80@dal16-03.ppp.iadfw.net>

This is a thank you note from Sally Tilson, CharlieT's wife. As many of you know,
Charlie was an active AH/DIY'er for many years. Just after Christmas, he
contracted cancer in his optic nerve, and since has spread. He is at home with
Sally and his parents.

In May, the response to my "CharlieT" sale was wonderful: as you raised over $2800
towards his staggering medical bills.

Thanks again to everyone out there!

Paul Schreiber
Synthesis Technology


----------
From: 	Charlie T[SMTP:charliet at flash.net]
Sent: 	Saturday, August 08, 1998 5:20 AM
To: 	Paul Schreiber
Subject: 	from Sally


Dear Paul,

It's about ten 'til midnight, and I just listened to your message on the machine, and I am afraid to call so late...

Let this suffice as a  heartfelt thank you from both of us.  I know this may sound pretty strange, but in the face of all this suffering and tragedy, you have to try to find something to restore your faith or you crumble.... Something to give you serenity, hope, and acceptance.  

Cancer teaches you to enjoy each moment.  Sometimes it's a great day if we see a red cardinal in the birdfeeder, or a enjoy a beautiful stormy night, sometimes  it's a gesture from a friend  (pretty corny and Hallmark, huh? but true, nonetheless)...the "everyday" things we take for granted until they become the most important and meaningful. 

Finally we know what is important - the affirmation of the simple joys  - in recognizing goodness in the mist of the incomprehensible "badness".  The outreach of friends, and in particular you, Paul, and the way you rallied the Synth-DIY'ers -  our virtual friends who were caring enough to give us not only a very practical obvious financial assistance, but to make us aware that no matter what happens in this sometimes short life, there are those that reach  out in love, compassion and fellowship, making cancer or other hardships seem very small and powerless in comparison.

Please count on me to be part of the family that could in the future, offer support to someone else in the group that faces a similar challenge.

If this is not too "off topic", would you forward all or part of it to the group for me??

With much admiration , appreciation, and love to all,

Sally Tilson






From steve at babcom.u-net.com  Sat Aug  8 17:10:16 1998
From: steve at babcom.u-net.com (Steven Cook)
Date: Sat, 08 Aug 1998 16:10:16 +0100
Subject: A Serge Wave Multiplier Idea (Part 47)
References: <35C8D8FA.8D7FC148@seanet.com>
Message-ID: <35CC6A58.F1A970D0@babcom.u-net.com>

Hi,

Here's my idea - I don't know if it would duplicate the effect of the Serge
Wave Multiplier, but anyway...

Start with a voltage controlled clipping circuit - I have one somewhere from
Wireless World and I think there's one in the Formant. Subtract the input
signal from the clipping level. If the input is a +/-5v triangle wave and the
clipping level is set to 5v, then as the triangle ramps up, the clipping level
ramps down, so at 2.5v the two meet causing the triangle to fold down as it
ramps higher - at it's peak, the triangle wave will fold back to 0v.

Then cascade several such stages - say 4. Each clipper would have a reference
level half that of the previous one.

As the input signal level rises, it will be folded down by the last stage
until the peaks reach 0v, then the second to last stage will start to fold
over so the level going into the last stage will remain constant.

The end result would be a triangle wave with 16 positive peaks followed by 16
negative peaks.

I've tried simulating this using Csound (i.e. cheating!) and it sounds very good.

PS: Actually, a voltage controlled clipper would be a handy circuit in itself
- you could presumably create resonant filter or sync like sounds by clipping
one waveform with another, higher pitched.

Thanks,

Steven Cook.




From jlarryh at iquest.net  Sat Aug  8 18:28:19 1998
From: jlarryh at iquest.net (J. Larry Hendry)
Date: Sat, 8 Aug 1998 11:28:19 -0500
Subject: Strange english language - was AC Safety Questions
Message-ID: <199808081625.SAA04490@mailhost.bpa.nl>

> Christopher Jeris wrote:
> > (apologies to Commonwealth English speakers; `earth' always sounded
> > strange to this particular unwashed Yankee)
> 
> Ingo Debus wrote:
> Isn't the term "PE" (for Protection Earth) used in the US too?

In the midwestern US, the term "ground" is more commonly used to describe
protection earth.  I work in the utility industry.  I rarely hear anyone
use the term earth when making that reference.

I did get a good chuckle from the original intended humor suggesting a good
grip would be necessary when bolting the "planet" Earth to a chassis.  That
certainly provides a good example for understanding another's intended
message rather than taking words too literally.  Here in the USA, something
might be stained if it was "bloody."  To you UK guys, I guess that might be
associated with swearing?  There are even places in the deep south USA
where the term "Yankee" might raise a red flag.

All this is just another reason to try and assume the best possible
intended message when interpreting other's writings.  I read this group
everyday, but rarely contribute as most of you guys are light years ahead
of my electronics knowledge.  However, I have learned a lot and thanks
everyone for the generous way in which they share their knowledge and
circuit ideas.  Most of my electrical knowledge involves terms like
kilovolts and megawatts.  I sure am glad someone had the foresight to
introduce metrics to the measurement of electrical quantities instead of
our strange US measuring standards.   If not, perhaps my neighbor might
want to borrow a quart of electricity.

Sorry to wander off topic.
Larry Hendry





From paul at darlow.powernet.co.uk  Sat Aug  8 19:14:20 1998
From: paul at darlow.powernet.co.uk (paul darlow)
Date: Sat, 08 Aug 1998 18:14:20 +0100
Subject: ring mod
References: <01BDC2BE.340A31A0@dal16-03.ppp.iadfw.net>
Message-ID: <35CC876C.4BC4@darlow.powernet.co.uk>

Paul Schreiber wrote:
> 
> I sell a kit that is a ring mod + VCA, the MOTM-110. See
> 
> www.synthtech.com
> 
> Paul Schreiber
> Synthesis Technology
> 
paul ive looked at the MOTM 110 and all the other stuff there is and may
if funds alow build one but at the moment funds are to a bare minimum 
also Im building to a Euro rack with a doepfer power supply +-12v
the MOTM looks good but not just yet
		paul D



From synth1 at airmail.net  Sat Aug  8 22:34:53 1998
From: synth1 at airmail.net (Paul Schreiber)
Date: Sat, 8 Aug 1998 20:34:53 -0000
Subject: WTB: 1U Stereo Power Amp
Message-ID: <01BDC30C.00D93260@dal12-02.ppp.iadfw.net>

Looking for a 1U high rack stereo power amp. Wattage not
big, maybe 50-60W/ch.

For monitoring analog synths, 'natch.

Paul Schreiber
Synthesis Technology




From 104065.2340 at compuserve.com  Sat Aug  8 23:07:35 1998
From: 104065.2340 at compuserve.com (terry michaels)
Date: Sat, 8 Aug 1998 17:07:35 -0400
Subject: commercial synth circuits
Message-ID: <199808081707_MC2-5585-4D70@compuserve.com>



-------------Forwarded Message-----------------

From:   terry michaels, 
To:     INTERNET:ijfritz at earthlink.net, INTERNET:ijfritz at earthlink.net
        
Date:   8/8/98 12:05 PM

RE:     commercial synth circuits

Dear Ian:

I've looked through most of the synth related web sites during the last
week, and I have seen only a few examples of commercial designs from the
hayday of analog synthesizers.  I'm new to the DIY list, and I was
expecting a good bit of the early Moog, ARP and other designs to be
available on the net.  I suspect the lack of such postings are due to any
of the following:

There is a concern over the copyright issue.

The above referenced schematics aren't available to those posting things on
their websites.

No one is interested.

It's been done already, and I missed it.


Any thoughts?

Sincerely,

Terry



From clark at andrews.edu  Sat Aug  8 23:56:03 1998
From: clark at andrews.edu (Tony Clark)
Date: Sat, 8 Aug 1998 17:56:03 -0400 (EDT)
Subject: commercial synth circuits
In-Reply-To: <199808081707_MC2-5585-4D70@compuserve.com>
Message-ID: <Pine.SOL.3.91.980808173333.2057A-100000@edmund.cs.andrews.edu>

> I've looked through most of the synth related web sites during the last
> week, and I have seen only a few examples of commercial designs from the
> hayday of analog synthesizers.

   Only a few?  Which ones were you looking for?

> I suspect the lack of such postings are due to any
> of the following:
> 
> There is a concern over the copyright issue.

   This really isn't an issue.  Not only are most of the companies out of 
business, but if are still in business, aren't _making_ analog synths.  
So there's no trouble from that side.  Also, the electronic designs in 
many of the old synths aren't proprietary any more so it's not like 
anyone is going to complain if a circuit is "rediscovered".

> The above referenced schematics aren't available to those posting things on
> their websites.

   Sure, they are available.  But there are numerous factors in getting 
schematics posted:
   One, you need someone willing to scan them in.  Unfortunately not 
everyone who owns schematics are willing to do so.  
   Two, many schematics were printed on massive single sheets (some 
standard engineering document size) and cannot be scanned easily.  Moog 
is notorious for this.  Sections can be scanned and then pieced together, 
but this is no fun task (something I did for many of the Aries scans I 
have on my site).
   Three, after scanning in schematics, you may have to spend a LOT of 
hours doing touchup work (like what I have been doing to the Moog 960 
scans).

> No one is interested.

   Sure, we're all interested.  But again, there are many hours of labor 
that go into getting these things online.  And all of us that are doing 
so are doing it out of our own personal time, not getting paid for it.  
So that puts certain projects at a premium.

> It's been done already, and I missed it.

   It is _being_ done!  ;)  Slowly but surely, many of us are adding more 
and more schematics online.  Perhaps if there was something in specific 
that you are looking for, then those of us that have access to said 
documents can move 'em a bit faster.
   I would dearly love to have any of the following donated:

   Arp 2500
   Roland 700
   Buchla _anything_
   E-mu modular
   PPG 300

   These would be the most beneficial as they are primarily modules and 
are easier to browse and compare designs.  However, I'd love to see more 
of the polyphonics too.  Memorymoog, Jupiter-8, CS-50/60/80, etc.
   Unfortunately I'm sure that most of the polyphonics are going to be 
lots of trouble due to oversized sheets.  That, and the service docs get 
really wordy...equating to MANY scans!
   Anyway, rest assured that there are people that are working to add 
more schematics online.  Just be patient!
   Also, if you are in need of schematics for a specific machine, you 
would do well to give Mark Glinsky a look as he can fire off a copy of 
any of the schematics/service manuals that he owns.  You can find a link 
to his site from the DIY Archive here:

http://aupe.phys.andrews.edu/diy_archive/manuals

   Hope I've been of some help!

   Tony

------------------------------------,----------------------------------
I can't drive (my Moog) 55!         |     The E-Music DIY Archive
------------------------------------|  
Tony Clark -- clark at andrews.edu     | aupe.phys.andrews.edu/diy_archive
http://aupe.phys.andrews.edu/~clark |     Contributions welcomed!
------------------------------------'----------------------------------




From magnus at analogue.org  Sun Aug  9 01:07:54 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Sun, 09 Aug 1998 01:07:54 +0200
Subject: Strange english language - was AC Safety Questions
In-Reply-To: Your message of "Sat, 8 Aug 1998 11:28:19 -0500"
References: <199808081625.SAA04490@mailhost.bpa.nl>
Message-ID: <199808082307.BAA01559@piraya.electrum.kth.se>

>>>>> "JLH" == J Larry Hendry <jlarryh at iquest.net> writes:

 >> Christopher Jeris wrote:
 >> > (apologies to Commonwealth English speakers; `earth' always sounded
 >> > strange to this particular unwashed Yankee)
 >> 
 >> Ingo Debus wrote:
 >> Isn't the term "PE" (for Protection Earth) used in the US too?

 JLH> In the midwestern US, the term "ground" is more commonly used to describe
 JLH> protection earth.  I work in the utility industry.  I rarely hear anyone
 JLH> use the term earth when making that reference.

Isn't ground in a sense very much in use such as GND?

The connection to ground or earth is obvious since the protective
earth or ground is done in powerstations with big plates into the
ground. The potential is about the same all over the planet and it can
infact be shown that between any two points of a sphere with
homogenous surface conductance one get the same resistance. So, when
you connect protective earth to your chassi you are indeed connecting
it to mother earth even if it is more or less poluted due to common
impedances and ground loops.

BTW. The earth does not have even surface conductivity.

There are places where people have to dig up their garden in order to
get a few square meters of copperplates down so that they get a
propper earth for their studio. Actually is this more common than one
might originally think. Also, even mother earth (moder of all earth's)
gets poluted every now and then with creeping currents from bad engines.

 JLH> I did get a good chuckle from the original intended humor suggesting a good
 JLH> grip would be necessary when bolting the "planet" Earth to a chassis.  That
 JLH> certainly provides a good example for understanding another's intended
 JLH> message rather than taking words too literally.  Here in the USA, something
 JLH> might be stained if it was "bloody."  To you UK guys, I guess that might be
 JLH> associated with swearing?  There are even places in the deep south USA
 JLH> where the term "Yankee" might raise a red flag.

Fortunatly there is allready many bolts applied on planet earth, if
not you can get one yourself. 

 JLH> All this is just another reason to try and assume the best possible
 JLH> intended message when interpreting other's writings.  I read this group
 JLH> everyday, but rarely contribute as most of you guys are light years ahead
 JLH> of my electronics knowledge.  However, I have learned a lot and thanks
 JLH> everyone for the generous way in which they share their knowledge and
 JLH> circuit ideas.  Most of my electrical knowledge involves terms like
 JLH> kilovolts and megawatts.  I sure am glad someone had the foresight to
 JLH> introduce metrics to the measurement of electrical quantities instead of
 JLH> our strange US measuring standards.   If not, perhaps my neighbor might
 JLH> want to borrow a quart of electricity.

Shouldn't we measure our amps in horsepower? Shouln't we extend the
length system downwards with anoying 12's 3's and all that in a nice
combination? Wavelenghts measures in microinch? Too simple.

I had a neighbor come over the other day to borrow a cup of electrons,
I said he had to borrow some protons as well but he didn't want to
overdo it. Well, since I could not convince him that Coloumb had an
opinion on this he went slowly away. It was a not a pretty sight, the
neighbor was smashed to the wall with a large flashburn where the
electrons had returned back... I am sure that Coloumb also tried this.

Cheers,
Magnus






From moda at online.no  Sun Aug  9 03:52:25 1998
From: moda at online.no (Morten Davidsen)
Date: Sun, 9 Aug 1998 02:52:25 +0100
Subject: OT:How to repair a key not working on a D-50?
Message-ID: <v04011701b1f2b03a794e@[130.67.8.92]>

Well the subject says it all...

I have one key on the keyboard (Roland D-50) that doesn?t trigger to well,
I have to hit it hard to get it to respond (if at all). How can I get to
the keys inside the machine and repair it?

Thanks for any help.

Please respond privatly via e-mail...
--
Mvh
Morten Davidsen



From peterc at pop.onwe.co.za  Sun Aug  9 13:12:03 1998
From: peterc at pop.onwe.co.za (peter_cornell)
Date: Sun, 9 Aug 1998 11:12:03 +0000
Subject: SN 76001 query
Message-ID: <199808090909.LAA12738@pop.onwe.co.za>

Hi gang

I was digging through my chip box the other day and came across an 
unknown device - the SN 76001. 

Any one know what this is, I've a strong feeling it's a music 
orientated chip, and are there any circuits for it. Made by Texas, 
there seem to be no details on the TI web site.

Many thanks
Peter Cornell
Johannesburg



From hekovala at lyseolukio2.kajaani.fi  Sun Aug  9 19:52:33 1998
From: hekovala at lyseolukio2.kajaani.fi (Henri Kovalainen)
Date: Sun, 9 Aug 1998 20:52:33 +0300 (EEST)
Subject: snapping
In-Reply-To: <199808070307.XAA19097@mailnfs0.tiac.net>
Message-ID: <Pine.LNX.3.96.980809202727.3081A-100000@lyseolukio2.kajaani.fi>

> > ...but modern compnents are much better than they used to be and if you
> > keep the oscillators in one locale they wont drift too much...
> > No flame intended, but I always thought that temperature compensation 
> of the type seen in VCOs and VCFs has nothing at all to with the 
> quality of the components, but everything to do with the laws of physics!

 Again, I would like to point out that the compensation amplifier,
 designed by Rene Schmitz, works beautifully. It solved all my
 compensating needs and I can't imagine a reason why somebody would want
 to go back to heating etc. I have also designed a board for the whole VCO
 design (by Rene. I added a sumup amp to control the pulse width on the
 waveshape/comparator amp), which fits on a 80x100mm board. If anyone is
 interested, I can mail you the pics (if it's OK to Rene).

 Please, note that I probably won't read my mail during the next week or
 so.

 ------------------.
 theadvancementand |  henri kovalainen    hoikankatu 19
 diffusionofknowle |  phone: +08-626555   87100 kajaani
 dgeistheonlyguard |  irc: acidrain       finland
 ianoftrueliberty. |  http://lyseolukio2.kajaani.fi/~dh
                   '-




From costello at seanet.com  Sun Aug  9 20:09:03 1998
From: costello at seanet.com (Sean Costello)
Date: Sun, 09 Aug 1998 11:09:03 -0700
Subject: Free Schematic Drawing Programs?
Message-ID: <35CDE5BF.C43071A@seanet.com>

Hi all:

I'm finally starting to get some of my projects off of the ground, and
I'd like to be able to share my ideas with people (I'm actually looking
for criticism, so that I can get these circuits to be better).  Can
anyone on the list recommend any good freeware (or shareware) schematics
drawing programs?  I'm running Windoze 98 (i.e. Windows 95 with the "5"
crossed out and replaced with an "8") and Linux, but I can't say I
really know my way around Linux yet, so Windows applications are
preferred.

Thanks,

Sean Costello





From lfo at pacifier.com  Sun Aug  9 21:15:50 1998
From: lfo at pacifier.com (if.then.else)
Date: Sun, 09 Aug 1998 12:15:50 -0700
Subject: obie manuals and parts
Message-ID: <35CDF566.3F384A74@pacifier.com>

all.

i'm looking any and all the manuals for the obie 4 or 8 voice.  i just
got a 6 voice that needs some work.

also where should i look for replacement parts?  ie.  new fuse holder.

thanks,
deno




From jocke at netcontrol.fi  Sun Aug  9 21:18:31 1998
From: jocke at netcontrol.fi (Joachim Verghese)
Date: Sun, 9 Aug 1998 22:18:31 +0300 (EET DST)
Subject: VP-330 (analog speech synthesis)
In-Reply-To: <1BF5E20E0C4DD111BBAB00805FE2D582951CF7@nbgm336a.nbgm.siemens.de>
Message-ID: <Pine.LNX.3.95.980809215408.25072A-100000@home.netcontrol.fi>

Juergen wrote:

> Rumors go that Vangelis has changed to the 330 when he abandoned
> the Mellotron.

Tony Banks of Genesis did the same thing in 1980. The VP-330 choir
can be heard on "Afterglow" off the "Three Sides Live" album, and
vocoder effects on "Duchess" (off the same album). 

I really like the VP-330 choir, although it isn't nearly as dramatic
as that of the Mellotron. And the analog filter bank sound shaping
method is quite fascinating of course.

BTW, I seem to recall that the main internal differences between the
two VP-330 versions were in the choir section. Does anyone know what
those differences were? I've only got the service manual for the
later version (the one with momentary LED buttons instead of rocker
switches).

-joachim





From mwmjr at ix.netcom.com  Sun Aug  9 23:04:56 1998
From: mwmjr at ix.netcom.com (Michael Maloney)
Date: Sun, 09 Aug 1998 17:04:56 -0400
Subject: Linear response VCA's
Message-ID: <3.0.5.32.19980809170456.00797240@popd.ix.netcom.com>

Thanks to everyone for their responses.

Just to address the questions or speculations that have arisen:

The envelope generator prototype running right now is based an an 8-bit
microcontroller running at 12 MHz (Z86E31) driving a 16 bit parallel DAC
(AD660). I got it running, watched it on a scope, and then got slammed with
work. So I don't have any hard numbers to throw around yet.

Ripple or zipper effect won't be a problem at this resolution. I can't see
speed being a problem either...but I'll see when I get a bit more time to
test.

However:

I "borrowed" the DAC from another system, and priced it later - oops!
$22.00 ea. It seems that a 16-bit parallel DAC capable of near-DC will cost
at least $15.00. I think that's overkill for the application. 

So I'm working on alternatives - will probably spend the next couple of
weeks playing with things: semi-discrete DACs, PWM techniques, switched
integrators, etc.


Mike Maloney




From 104065.2340 at compuserve.com  Mon Aug 10 00:39:29 1998
From: 104065.2340 at compuserve.com (terry michaels)
Date: Sun, 9 Aug 1998 18:39:29 -0400
Subject: commercial synth circuits
Message-ID: <199808091839_MC2-558E-2F29@compuserve.com>



-------------Forwarded Message-----------------

From:   terry michaels, 
To:     INTERNET:ijfritz at earthlink.net, INTERNET:ijfritz at earthlink.net
        
Date:   8/9/98  5:45 PM

RE:     Re: commercial synth circuits

Hi Ian

I chose the KE4859 primarily because of its low on resistance. FET leakage
is also important.   At the time I designed this circuit (October 1973),
this part was the best choice I could find that was easily available.  It
was sold by National Semiconductor, and I could buy National parts over the
counter here in Milwaukee.  The combination of this part, the .0024 cap,
and the CA3130 slew rate and settling time yields a sawtooth flyback time
of less than 2 microseconds, as recently measured on modern test equipment.
 Since the flyback time is a source of frequency error at the higher ranges
of the VCO, I sought to minimize it by using the KE4859.  I am currently
redesigning all of my synth circuits, and I will get to this one soon.  I
will look at currently available parts, and I will be happy to let you know
what I find as a modern replacement. 

I do not prefer the resistance in series with the timing cap method of
high-end compensation.  The steady state voltage drop across the resistor
at high frequencies alters the end points of the sawtooth waveform. This in
turn affects the purity of the other waveforms usually derived from the
sawtooth.  However, it has the benefit of accomplishing high-end
compensation very simply, with only one component. This comes down to
personal design philosophy and goals.  Mine is generally to achieve the
best performing, most precise circuits, with only a secondary consideration
to the number of components needed.  I recognize the desire of others to
create simple, inexpensive designs, and there is clearly a need out there
for that design approach.  The great value of the DIY list is providing a
forum for all types of designs 
to be shared, so everyone can find what they want.

Using the Franco method doesn't alter the design considerations with
regards to FET switching time.  The goal is the same - discharge the
integrating cap as fast as possible. 



From uzs159 at uni-bonn.de  Mon Aug 10 01:00:11 1998
From: uzs159 at uni-bonn.de (Rene Schmitz)
Date: Mon, 10 Aug 1998 01:00:11 +0200
Subject: snapping
Message-ID: <199808092301.BAA23852@mailhost.bpa.nl>

At 20:52 09.08.1998 +0300, you wrote:
>> > ...but modern compnents are much better than they used to be and if you
>> > keep the oscillators in one locale they wont drift too much...
>> > No flame intended, but I always thought that temperature compensation
>> of the type seen in VCOs and VCFs has nothing at all to with the
>> quality of the components, but everything to do with the laws of physics!
>
> Again, I would like to point out that the compensation amplifier,
> designed by Rene Schmitz, works beautifully. It solved all my
> compensating needs and I can't imagine a reason why somebody would want
> to go back to heating etc. I have also designed a board for the whole VCO
> design (by Rene. I added a sumup amp to control the pulse width on the
> waveshape/comparator amp), which fits on a 80x100mm board. If anyone is
> interested, I can mail you the pics (if it's OK to Rene).

Hey, its fine that someone besides me has finally build it.
And of course I would like to see it my self!

> Please, note that I probably won't read my mail during the next week or
> so.
>
Too bad! But go for it when youre back online..

Bye 

 Ren?

=(uzs159 at uni-bonn.de)========================
             ,          : 
|") [" |\ | ["          :   This space 
|"\ [_ | \| [_          :   intentionally   
                        :   left blank
                        :
=(http://www.uni-bonn.de/~uzs159)============




From sasami at blaze.net.au  Mon Aug 10 02:04:53 1998
From: sasami at blaze.net.au (Ken Stone)
Date: Mon, 10 Aug 1998 02:04:53 +0200 (MET DST)
Subject: LM394
Message-ID: <199808100004.CAA24507@mailhost.bpa.nl>

Found this. Don't know how long the sale will last.

IC  LM394CH Supermatched  
 * NPN Transistor Pair  
Code........RM1022 
Price........$1.00   (Australian)

http://www.rocom.com.au/
_____________________________________________________________

                Ken Stone  sasami at blaze.net.au
                   ** Catgirl Paradise **
               <http://www.anime.net/~kens/>
         ** Australian Miniature Horses and ponies **
             <http://www.blaze.net.au/~sasami/>
_____________________________________________________________





From tomg at vivid.net  Mon Aug 10 03:42:49 1998
From: tomg at vivid.net (tomg)
Date: Sun, 09 Aug 1998 20:42:49 -0500
Subject: Maxx VCO-4A Scope Scans
Message-ID: <yam7525.2480.119068472@mail.vivid.net>

I thought I would ask my friend with the digi-camera to 
come over and snap some waveform shots off my scope and
then started thinking maybe I can scan it....

It's not like having a 35mm shot but you can see the 
waveforms.

Load the page

http://www.tomg.vivid.net/maxx/page_031.html

or the pics.

Ramp output - you can see the little hook at the top of
the wave. That the tri and sine converter also exibit.

http://www.tomg.vivid.net/maxx/pics/vco4a_7.jpg

Tri output - You can see the effect the ramp has at the
top of the wave.

http://www.tomg.vivid.net/maxx/pics/vco4a_8.jpg

Sine output Again the small amount of distortion caused 
by the hook in the tri effects the sine.

http://www.tomg.vivid.net/maxx/pics/vco4a_9.jpg

I hope this clears up any questions about the sine 
converter. It's clear to see that if the ramp was
perfect the tri and sine would follow.

-tg







From pfperry at melbpc.org.au  Mon Aug 10 03:45:55 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Mon, 10 Aug 1998 11:45:55 +1000 (EST)
Subject: commercial synth circuits
Message-ID: <1.5.4.16.19970101182112.0e8f34ba@popa.melbpc.org.au>

At 06:39 PM 9/08/98 -0400, terry michaels wrote:

>Using the Franco method doesn't alter the design considerations with
>regards to FET switching time.  The goal is the same - discharge the
>integrating cap as fast as possible. 
>
I cant quite see why one has to discharge the integrating cap in one hit..
wouldn't it make sense to integrate up and then down at the same rate, to 
give a triangle instead of a sawtooth? Isn't this how it is usually done?
Admittedly, one now has to make a sawtooth from a triangle instead of 
vice-versa, but this is no worse..

paul perry melbourne australia




From clark at andrews.edu  Mon Aug 10 04:58:39 1998
From: clark at andrews.edu (Tony Clark)
Date: Sun, 9 Aug 1998 22:58:39 -0400 (EDT)
Subject: commercial synth circuits
In-Reply-To: <1.5.4.16.19970101182112.0e8f34ba@popa.melbpc.org.au>
Message-ID: <Pine.SOL.3.91.980809225130.7810B-100000@edmund.cs.andrews.edu>

> I cant quite see why one has to discharge the integrating cap in one hit..
> wouldn't it make sense to integrate up and then down at the same rate, to 
> give a triangle instead of a sawtooth? Isn't this how it is usually done?
> Admittedly, one now has to make a sawtooth from a triangle instead of 
> vice-versa, but this is no worse..

   Well that depends on how you do the transformation.  In order to keep 
the frequency the same, you have to invert the down-slope of the triangle 
wave and then offset BOTH parts in order to create a saw wave.  You then 
tend to get two sets of glitches, one at the mid-point of the saw wave 
and one at the reset.  At low frequencies, the glitching is unacceptable 
for LFO use.
   Now if you were just inverting the down-slope and creating a 2X freq. 
saw, then it wouldn't be so bad.
   Just my observations.

   Tony

------------------------------------,----------------------------------
I can't drive (my Moog) 55!         |     The E-Music DIY Archive
------------------------------------|  
Tony Clark -- clark at andrews.edu     | aupe.phys.andrews.edu/diy_archive
http://aupe.phys.andrews.edu/~clark |     Contributions welcomed!
------------------------------------'----------------------------------




From cmacdon at ix.netcom.com  Mon Aug 10 09:07:28 1998
From: cmacdon at ix.netcom.com (Christopher MacDonald)
Date: Mon, 10 Aug 1998 00:07:28 -0700
Subject: Power Supply Installed
Message-ID: <35CE9C30.5D8B@ix.netcom.com>

Greetings,

I have installed my power supply, thanks to everyone for the AC help.  I
put some pictures of it up at http://www.evenfall.com/diy/index.html if
anyone is interested.

-Chris MacDonald



From ka4hjh at gte.net  Mon Aug 10 09:34:56 1998
From: ka4hjh at gte.net (KA4HJH)
Date: Mon, 10 Aug 1998 03:34:56 -0400
Subject: Linear response VCA's
In-Reply-To: <3.0.5.32.19980809170456.00797240@popd.ix.netcom.com>
Message-ID: <v04011701b1f450556242@[208.255.152.194]>

>I "borrowed" the DAC from another system, and priced it later - oops!
>$22.00 ea. It seems that a 16-bit parallel DAC capable of near-DC will cost
>at least $15.00. I think that's overkill for the application.
>
>So I'm working on alternatives - will probably spend the next couple of
>weeks playing with things: semi-discrete DACs, PWM techniques, switched
>integrators, etc.

You already have an MCU, just mulitplex the DAC! For this application you
should be able to support 8, 16 or even 32 channels! For an example, check
out the MIDI gadgets at Midwest Analog Products (where's that url?). They
have schematics and source code for the whole thing.

Or you could use a smaller DAC and voltage-control current sources/sinks
connected to capacitors, which would eliminate the zipper effect.

Terry Bowman, KA4HJH
"The Mac Doctor"



From martin.czech at intermetall.de  Mon Aug 10 10:58:06 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Mon, 10 Aug 1998 10:58:06 +0200 (MET DST)
Subject: archive up and running
Message-ID: <199808100858.KAA14803@window.intermetall.de>

The unofficial diy archive is up and running.  Please read the
disclaimer before flaming me.

http://www.internet-club.com/germany/martin_czech/

The page provides the unofficial mail archive.

(I have written a little program to delete any unnecessary mail bla
bla, ie. XMAILER: bla bla..., this saves a lot of disk space. Only the
mail body is kept as it is, with all attachments etc. And date:, from:,
subject:, to:.  This way the year 1995 takes only 302648 bytes
compressed).

So far available only 1995. This year is complete now, I have made any
attempt to enshure this. But this was a very good year, lots of
valuable information. It takes some time to download (3 min), I have no
explanation why it takes so long.  But it is free web space with
commercials, perhaps they want to send some commercials while you
download...  Ok, I think this is acceptable.

Further this page provides some usefull links to diy pages.  The list
of links is not complete yet. Suggestions for other pages of interest?

If you have a nice diy homepage, please let me know.  Please give me a
short description of the content (like Moog high passs filter
schematics, photos,...).

If you don't want that a link points towards your homepage, let me
know.  I'll take you off ASAP.

If you think that my desciption of your page is wrong, please give me a
better one, so I can cut and paste it.


Hope you'll enjoy.


m.c.




From Per.Mattsson at mkv.mh.se  Mon Aug 10 12:08:44 1998
From: Per.Mattsson at mkv.mh.se (Per.Mattsson at mkv.mh.se)
Date: Mon, 10 Aug 1998 11:08:44 +0100
Subject: ssm-2040
In-Reply-To: <3.0.2.16.19980810134105.2e7f85f8@mail.internet-zahav.net>
References: <3.0.2.16.19980810134105.2e7f85f8@mail.internet-zahav.net>
Message-ID: <7806.36519013@mkv.mh.se>

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From blacet at metro.net  Mon Aug 10 12:42:05 1998
From: blacet at metro.net (John Blacet)
Date: Mon, 10 Aug 1998 10:42:05 +0000
Subject: Last call: 76477 synth chip
Message-ID: <35CECE7D.B9B@metro.net>

I have a few  extra (new) 76477s left. $12 each, min 2. $2 for 16 page
data sheet, $3 mail anywhere.

Quantities limited; e-mail first.

Regards.
-------------------------
John Blacet
Blacet Research
15210 Orchard Rd
Guerneville CA 95446
USA
-------------------------
blacet at metro.net
http://metro.net/blacet/music.html



From pfperry at melbpc.org.au  Mon Aug 10 13:31:22 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Mon, 10 Aug 1998 21:31:22 +1000 (EST)
Subject: commercial synth circuits
Message-ID: <1.5.4.16.19970102040640.3837a7fe@popa.melbpc.org.au>

At 02:55 AM 10/08/98 GMT, Scott Gravenhorst wrote:

>Can you point me to some resources with respect to tri -> saw
>conversion?  
....well no, not now you mention it.... 
exept, if you have a switch that is toggled at the peak of the 
waveform (and you do, if this is the method you use)
you can multiply the output by -1 when it toggles, then by +1 when it hits
bottom, and so on... this gives a saw at twice the triangle frequency.

paul perry melb aust
(I think all this is in the Linear Technology app notes..)




From Juergen.Haible at nbgm.siemens.de  Mon Aug 10 14:19:23 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Mon, 10 Aug 1998 14:19:23 +0200
Subject: AW: 1U Stereo Power Amp
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5829790B4@nbgm336a.nbgm.siemens.de>

	>Looking for a 1U high rack stereo power amp. Wattage not
	>big, maybe 50-60W/ch.
	>
	>For monitoring analog synths, 'natch.

Hi Paul,

have you checked the MAM ? (Don't know exact model
number)
It's 1U, has the basic protection circuits, and should
be pretty cheap.

JH.




From Juergen.Haible at nbgm.siemens.de  Mon Aug 10 14:47:10 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Mon, 10 Aug 1998 14:47:10 +0200
Subject: tri2saw (was:commercial synth circuits)
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D582979119@nbgm336a.nbgm.siemens.de>

What about this method (haven't tried it yet):
Build a triangle VCO, and use an additional transistor 
(matched) in the expo converter to get a second control 
current. Use this current to charge a second capacitor,
and discharge this capacitor every time when the triangle
has a positive zero crossing. Shouldn't use more components
than other converters, and all you get might be a little amplitude
error in the saw wave.

JH.



From martin.czech at intermetall.de  Mon Aug 10 15:21:47 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Mon, 10 Aug 1998 15:21:47 +0200 (MET DST)
Subject: tri2saw (was:commercial synth circuits)
Message-ID: <199808101321.PAA15752@window.intermetall.de>

> What about this method (haven't tried it yet):
> Build a triangle VCO, and use an additional transistor 
> (matched) in the expo converter to get a second control 
> current. Use this current to charge a second capacitor,
> and discharge this capacitor every time when the triangle
> has a positive zero crossing. Shouldn't use more components
> than other converters, and all you get might be a little amplitude
> error in the saw wave.
> 
If one uses a design with ota as current polarity switch (ca3080 app.
note) it would be possible to use a dual type, there you are, this
should be an allmost perfect current mirror.  No need to touch the expo
converter. I wonder if the toggle-the-tri-and-add-a-square method is so
bad at all. How does it the curtis 3340?  This is a tri osc. Must be
the same circuit. Any glitches could be filtered out. If you use a
simple 6db lowpass with "reset" at the right square toggling point, so
that the fast edge is not filtered.

m.c.

------------------------------------------------------------------------
m.c. has made it finally:  3 CDs out now; 72 min. minimum; "1"
(1994-1995),"2" (95-96),"three" (96-97); experimental stuff; mostly
Eimert/Stockhausen style; but also modern popular style





From tim at redragon.demon.co.uk  Mon Aug 10 15:29:25 1998
From: tim at redragon.demon.co.uk (Tim Cockram)
Date: Mon, 10 Aug 1998 14:29:25 +0100
Subject: tri2saw (was:commercial synth circuits)
In-Reply-To: <1BF5E20E0C4DD111BBAB00805FE2D582979119@nbgm336a.nbgm.siemens.de>
Message-ID: <gMmTJBA1Wvz1EwBM@redragon.demon.co.uk>

In message <1BF5E20E0C4DD111BBAB00805FE2D582979119 at nbgm336a.nbgm.siemens
.de>, Haible Juergen <Juergen.Haible at nbgm.siemens.de> writes
>What about this method (haven't tried it yet):
>Build a triangle VCO, and use an additional transistor 
>(matched) in the expo converter to get a second control 
>current. Use this current to charge a second capacitor,
>and discharge this capacitor every time when the triangle
>has a positive zero crossing. Shouldn't use more components
>than other converters, and all you get might be a little amplitude
>error in the saw wave.
>
>JH.

Good Idea
The Aries modular used this method quite succesfully.

It can be extended to do more bizare stuff too, especialy if you include
an independant reset circuit with a soft /hard sync input:- sink half of
the current... Sub octave,  1.5 times the current +5th, 2 times the
current octave up, or add offsets for linear detuning

It's quite easy to build a "fat" Moog 901 type oscillator bank (with all
of the ideosyncracies too). 
-- 
Tim Cockram



From Juergen.Haible at nbgm.siemens.de  Mon Aug 10 15:32:08 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Mon, 10 Aug 1998 15:32:08 +0200
Subject: AW: tri2saw (was:commercial synth circuits)
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D58297A776@nbgm336a.nbgm.siemens.de>

	>If one uses a design with ota as current polarity switch (ca3080
app.
	>note) it would be possible to use a dual type, there you are, this
	>should be an allmost perfect current mirror.  No need to touch the
expo
	>converter. 

Good idea ...
But you need a pnp-type expo converter, or a pnp current mirror,
in the first place, to drive this OTA ...

JH.



From Juergen.Haible at nbgm.siemens.de  Mon Aug 10 15:33:52 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Mon, 10 Aug 1998 15:33:52 +0200
Subject: AW: tri2saw (was:commercial synth circuits)
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D58297A780@nbgm336a.nbgm.siemens.de>


	>The Aries modular used this method quite succesfully.

I knew it *must* have been done before (;->).
What does their expo converter look like ?

JH.




From gur-m at internet-zahav.net  Mon Aug 10 13:41:05 1998
From: gur-m at internet-zahav.net (Gur Milstein)
Date: Mon, 10 Aug 1998 13:41:05
Subject: ssm-2040
Message-ID: <3.0.2.16.19980810134105.2e7f85f8@mail.internet-zahav.net>

hi guy's.
do any body know where i can get some SSM-2040 chips ?
do analog device produce them ?

thanx
Gur Milstein




From marc at outputs.com  Mon Aug 10 16:00:58 1998
From: marc at outputs.com (Marc Houle)
Date: Mon, 10 Aug 1998 10:00:58 -0400
Subject: synching casios?
Message-ID: <3.0.32.19980810100055.006d8f28@wingate>

Would anyone know if it is possible to somehow regulate 
those casio keyboard drum beats? maybe with a trigger in, 
a timimg chip or anything else?

Thanks,
Marc.



From b.layer at vikingelectronics.com  Mon Aug 10 16:07:51 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Mon, 10 Aug 1998 09:07:51 -0500
Subject: OT: Synth recording sought
Message-ID: <3.0.5.32.19980810090751.007c8370@192.168.210.18>

Hi All,

This is a bit OT, so reply via private emails if appropriate.

I'm looking for a copy of a RECORD by Michael Bundt, titled "Just Landed
Cosmic Kid". Can anyone help me find this? It has an outragous pic of
Michael on the cover in a bizzarre outfit. Also looking for any Klaus
Schultze I don't own.

Good trades! Electronica, ambient, classical, bizzarre etc.

Thanks


Bill Layer
"Heavy old junk wanted"



From lavaud at pratique.fr  Mon Aug 10 18:43:32 1998
From: lavaud at pratique.fr (Denis Lavaud)
Date: Mon, 10 Aug 1998 18:43:32 +0200
Subject: questions CA3084 and uA726
In-Reply-To: <199808060128.DAA12615@absinthe.pratique.fr>
Message-ID: <199808101705.TAA28673@absinthe.pratique.fr>

Hi there,

Thanks to Andrew Schrock, Edward Leckie,Martin Czech ans Steve Ridley
for your answers. I got the uA726 datasheet, allowing me to look for
similar ICs, but I did not find anything on Internet about the CA3084.
Does anybody have scanned datasheet or know a site where I could get
its specs ?

			Thanks,

			Denis Lavaud





From tic at vossnet.de  Mon Aug 10 20:57:54 1998
From: tic at vossnet.de (tim0 (Timo Christ))
Date: Mon, 10 Aug 1998 20:57:54 +0200
Subject: soldid-state keyboards
Message-ID: <35CF42B2.3FA289D@vossnet.de>

hello, 

i would like to start a discussion on solid-state keyboards (i.e. a
keyboard without mechanical switches like on a piano/organ). i have no
real idea how solid-state keyboards work but i can clearly see the
advantage of no moving parts ... .

only as a proof that such keyboards exist, look at the Buchla
Music-Easel. 

How does this design (buchla) work ? Are there alternative solutions to
a solid-state keyboard ? 

what are the diadvantages of this style keyboards ? i see that people
used to ordinary keyboards probably wouldn?t like it.. => no keys to
press.

any ideas ? 

inquisitive greetings, ;-))
Timo

BTW: i have desoldered four 726 ICs from a 100% working radio. how much
are these worth ? anybody (europe please) interested ?

-- 
Timo Christ -- Germany -- Europe
root at dist0rter -- tic at vossnet.de -- LEDflash at gmx.net




From magnus at analogue.org  Mon Aug 10 21:23:00 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Mon, 10 Aug 1998 21:23:00 +0200
Subject: Free Schematic Drawing Programs?
In-Reply-To: Your message of "Sun, 09 Aug 1998 11:09:03 -0700"
References: <35CDE5BF.C43071A@seanet.com>
Message-ID: <199808101923.VAA02444@piraya.electrum.kth.se>

>>>>> "SC" == Sean Costello <costello at seanet.com> writes:

 SC> Hi all:
 SC> I'm finally starting to get some of my projects off of the ground, and
 SC> I'd like to be able to share my ideas with people (I'm actually looking
 SC> for criticism, so that I can get these circuits to be better).  Can
 SC> anyone on the list recommend any good freeware (or shareware) schematics
 SC> drawing programs?  I'm running Windoze 98 (i.e. Windows 95 with the "5"
 SC> crossed out and replaced with an "8") and Linux, but I can't say I
 SC> really know my way around Linux yet, so Windows applications are
 SC> preferred.

Well, since you said that you didn't know your way around in Linux I
obviously have to propose a software available on Linux. Althought in
heavy development you might find GEDA interesting to test. It is a GNU
project which involves a schematic editor and a PCB layout program is
comming along. These guys are being very serious about what they are
doing and spend time to figure out how things ought to work. GEDA is
now Guile powered (a Scheme implementation, scheme is a LISP dialect).
It is free allright, but still a bit rought. I have just tried it
briefly so I can't really say weither it is good, but there is
potential. I think at least that you should look at it and give it a
try, it is free so... 

Please check http://www.geda.seul.org/

Have fun!
Magnus



From steve at babcom.u-net.com  Mon Aug 10 22:20:34 1998
From: steve at babcom.u-net.com (Steven Cook)
Date: Mon, 10 Aug 1998 21:20:34 +0100
Subject: Minimoog Vcf
Message-ID: <35CF5612.3432478B@babcom.u-net.com>

Hi,

I've built the Minimoog vcf from the "minifilt.gif" schematic available on the
Music Machines site and others and it doesn't work! Nothing does first time,
but I can't find anything wrong.

The ladder network part works fine, as I have tested it using another
differential amp circuit, but the output amp is dead.

Has anyone built this circuit successfully or does anyone know if the
schematic is correct?

Thanks,

Steve.





From john at clutter.globalnet.co.uk  Mon Aug 10 22:26:34 1998
From: john at clutter.globalnet.co.uk (john tuffen)
Date: Mon, 10 Aug 1998 21:26:34 +0100
Subject: AKAI SO1 question..... memory
Message-ID: <E0z5yXE-0007Ne-00@sand2.global.net.uk>

Hi,
	Anyone got any hints on how I could upgrade my S01 memory? I have an
unexpanded version (1MB) which it is possible to take to 2MB (woo hoo!!). I
have loads of SIMMs, memory chips etc. lying around and I thought that it
might be an interesting thing to do..... The PCB has an expansion
connector, so any details on pinouts here would be very helpful...


Anyone?

My web pages will shortly be moved (and updated) so look out for PIC-based
MIDI-processing stuff soooon :)

cheers,

john..

---<john at clutter.globalnet.co.uk>---



From frequency91 at hotmail.com  Mon Aug 10 23:21:24 1998
From: frequency91 at hotmail.com (Graeme Nelson)
Date: Mon, 10 Aug 1998 14:21:24 PDT
Subject: Free Schematic Drawing Programs?
Message-ID: <19980810212124.5679.qmail@hotmail.com>

hi -

i found this ftp address that contains a program called circad, it seems 
to be a dos schematic drawing program.  easytrax PCB programs is also in 
this directory.

http://ftp.unina.it/pub/electronics/ftp.armory.com/PCBDRW/

hope this helps.
graeme

>From owner-synth-diy at mailhost.bpa.nl Mon Aug 10 13:14:08 1998
>Received: (from majordom at localhost)
>	by mailhost.bpa.nl (8.8.8/8.8.8) id VAA12281
>	for synth-diy-outgoing; Mon, 10 Aug 1998 21:23:11 +0200 (MET DST)
>Received: from piraya.electrum.kth.se (piraya.electrum.kth.se 
[130.237.212.130])
>	by mailhost.bpa.nl (8.8.8/8.8.8) with ESMTP id VAA12277
>	for <synth-diy at mailhost.bpa.nl>; Mon, 10 Aug 1998 21:23:09 +0200 (MET 
DST)
>Received: from drum.it.kth.se (drum.it.kth.se [130.237.213.23])
>	by piraya.electrum.kth.se (8.8.8/8.8.8) with ESMTP
>	id VAA02444;
>	Mon, 10 Aug 1998 21:23:01 +0200 (MET DST)
>Message-Id: <199808101923.VAA02444 at piraya.electrum.kth.se>
>To: costello at seanet.com
>Cc: synth-diy at mailhost.bpa.nl
>From: Magnus Danielson <magnus at analogue.org>
>Subject: Re: Free Schematic Drawing Programs?
>In-Reply-To: Your message of "Sun, 09 Aug 1998 11:09:03 -0700"
>References: <35CDE5BF.C43071A at seanet.com>
>X-Mailer: Mew version 1.06 on Emacs 19.34.1
>Mime-Version: 1.0
>Content-Type: Text/Plain; charset=us-ascii
>Date: Mon, 10 Aug 1998 21:23:00 +0200
>Sender: owner-synth-diy at mailhost.bpa.nl
>Precedence: bulk
>
>>>>>> "SC" == Sean Costello <costello at seanet.com> writes:
>
> SC> Hi all:
> SC> I'm finally starting to get some of my projects off of the ground, 
and
> SC> I'd like to be able to share my ideas with people (I'm actually 
looking
> SC> for criticism, so that I can get these circuits to be better).  
Can
> SC> anyone on the list recommend any good freeware (or shareware) 
schematics
> SC> drawing programs?  I'm running Windoze 98 (i.e. Windows 95 with 
the "5"
> SC> crossed out and replaced with an "8") and Linux, but I can't say I
> SC> really know my way around Linux yet, so Windows applications are
> SC> preferred.
>
>Well, since you said that you didn't know your way around in Linux I
>obviously have to propose a software available on Linux. Althought in
>heavy development you might find GEDA interesting to test. It is a GNU
>project which involves a schematic editor and a PCB layout program is
>comming along. These guys are being very serious about what they are
>doing and spend time to figure out how things ought to work. GEDA is
>now Guile powered (a Scheme implementation, scheme is a LISP dialect).
>It is free allright, but still a bit rought. I have just tried it
>briefly so I can't really say weither it is good, but there is
>potential. I think at least that you should look at it and give it a
>try, it is free so... 
>
>Please check http://www.geda.seul.org/
>
>Have fun!
>Magnus
>


______________________________________________________
Get Your Private, Free Email at http://www.hotmail.com



From cyborg0 at GlobalEyes.net  Tue Aug 11 00:54:01 1998
From: cyborg0 at GlobalEyes.net (cyborg0 at GlobalEyes.net)
Date: Mon, 10 Aug 1998 17:54:01 -0500
Subject: OT: Synth recording sought
References: <3.0.5.32.19980810090751.007c8370@192.168.210.18>
Message-ID: <35CF7A09.EBF0AF31@globaleyes.net>

Bill Layer wrote:
> 
>It has an outragous pic of
> Michael on the cover in a bizzarre outfit.
Cant be more bizarre than Klaus Nomi.. :)
All you late 70s-early-80s new wave fans know who im talking about! 

rob



From paul at darlow.powernet.co.uk  Tue Aug 11 01:19:29 1998
From: paul at darlow.powernet.co.uk (paul darlow)
Date: Tue, 11 Aug 1998 00:19:29 +0100
Subject: PhilRees MidiCV /midi problem
References: <v04011707b1f4ce85ebf7@[10.3.2.238]>
Message-ID: <35CF8001.4534@darlow.powernet.co.uk>

this could be a bit OT I am having problems with a philrees MCV and a
freebass fb383 (same as the MAM bass synth) when runing a fast sequence
from cubase the units lock up also my DX100 has been hanging notes could
this be cased by the SBAWE32 I am using as a midi inteface its starting
to get on my tits so any help gratfully receved
all thanks 
		paul


David Bivins wrote:
> 
> Hey,
> Just a quick "I had a Phil Rees MIDI->DinSync converter and it worked
> great; sold it to someone else on this list who hasn't complained so I
> assume it's still working; can't complain about it being glued together as
> I've opened a NuLogic equivalent and been confronted with obscene amounts
> of silicone (I guess) goo so can't complain" post to defend Phil based on
> my limited experience.
> 
> Whew.
> 
> David.



From thelab at sprint.ca  Tue Aug 11 01:59:06 1998
From: thelab at sprint.ca (|[| Philip Pilgrim |]|)
Date: Mon, 10 Aug 1998 20:59:06 -0300
Subject: OT: Synth recording sought
References: <3.0.5.32.19980810090751.007c8370@192.168.210.18> <35CF7A09.EBF0AF31@globaleyes.net>
Message-ID: <35CF894A.49F5@sprint.ca>

cyborg0 at GlobalEyes.net wrote:

> Cant be more bizarre than Klaus Nomi.. :)
> All you late 70s-early-80s new wave fans know who im talking about!

Yeah, also he was the first celebraty to die from AIDS too. 

aside: I was in university at the time. I would take blood from people
in the hospital as a part time job. I was watching the AIDS epidemic
closely. 

Philip

           
-- 
Philip Pilgrim          	The Lab 
5 Evan's Drive          	- Analog/Digital Recording/Processing
Hammonds Plains       		- Computer/Synth Interfacing
Nova Scotia, Canada   		- Hardware/Software Development
B4B 1M8                   

   <<<<< Home of SH-101 NovaMod and UP Midi Programmer
>>>>>                     

Phone     +1.902.835.7844
Email     mailto:thelab at sprint.ca
Web Page: http://www.robotnik.com/the_lab/




From cstecker at barr642.berkeley.edu  Tue Aug 11 02:00:29 1998
From: cstecker at barr642.berkeley.edu (Chris Stecker)
Date: Mon, 10 Aug 98 17:00:29 -0700
Subject: Solid-state keyboards
Message-ID: <9808110000.AA05597@barr642.berkeley.edu>

I am currently restoring several Buchla 400 instruments, which use a  
solid-state/switchless/touch-sensitive keyboard.   The keyboard  
itself is very robust: after years of storage, they still work, and I  
haven't been spending any time repairing the keyboards themselves.  


They work on the principle of sensing a change in the capacitance of  
between key elements as your skin makes contact.  I'll have a look at  
the schematics and see if I can tell you more about how this is  
accomplished.  


As an aside, some of the 400's were built with weighted-action piano  
keyboards.  I've had a look at the insides of one, and it operates in  
the same way (!) as the touch keyboard.  Rather than skin contact,  
however, a little copper strip (one for each key) is bent by the key  
action.  These strips rest on a steel or aluminum plate connected to  
ground.  The capacitance between the copper strip and the plate  
changes as the key moves the strip.  The remainder of the sensing  
logic is the same as for the touch keyboard: look for abrupt changes  
in this capacitance, and you've got a note.  Somehow, it gets  
velocity from the same signal (that part I haven't yet figured out).

-Chris Stecker



From tomg at vivid.net  Tue Aug 11 02:24:28 1998
From: tomg at vivid.net (tomg)
Date: Mon, 10 Aug 1998 19:24:28 -0500
Subject: AKAI SO1 question..... memory
In-Reply-To: <E0z5yXE-0007Ne-00@sand2.global.net.uk>
Message-ID: <yam7526.1420.119319976@mail.vivid.net>

On 10-Aug-98, john tuffen wrote:
>Hi,
>Anyone got any hints on how I could upgrade my S01 memory? I have an
>unexpanded version (1MB) which it is possible to take to 2MB (woo hoo!!). I
>have loads of SIMMs, memory chips etc. lying around and I thought that it
>might be an interesting thing to do..... The PCB has an expansion
>connector, so any details on pinouts here would be very helpful...


1/2   - D 5V
3/4   - D GND
5     - ECONE
6     - ERD
7     - ERW
8     - EOE
9     - ECE2
10    - D GND
11/29 - EA 0/EA 18
30    - D GND
31/46 - ED 0/ED 15
47/47 - D GND
49/50 - D 5V

Good Luck

-tg




From eleckie at cochlear.com.au  Tue Aug 11 03:23:41 1998
From: eleckie at cochlear.com.au (Edward Leckie)
Date: Tue, 11 Aug 98 11:23:41 +1000
Subject: PhilRees MidiCV /midi problem
Message-ID: <9808119027.AA902798868@cplgate.cochlear.com.au>


I tried several sound cards as MIDI interfaces including the SBAWE64 and SB16
clones and had MIDI problems galore. Maybe it's my PC, other people I know don't
have any problems with MIDI from their sound card. Basically, if want better
MIDI timing don't use a sound card. I now use a Midiquest 2 port/SE and have had
no problems. 

Ed.

____________________Reply Separator____________________
Subject:    Re: PhilRees MidiCV /midi problem
Author: paul darlow <paul at darlow.powernet.co.uk>
Date:       11/08/98 19:00

this could be a bit OT I am having problems with a philrees MCV and a
freebass fb383 (same as the MAM bass synth) when runing a fast sequence
from cubase the units lock up also my DX100 has been hanging notes could
this be cased by the SBAWE32 I am using as a midi inteface its starting
to get on my tits so any help gratfully receved
all thanks 
                paul


David Bivins wrote:
> 
> Hey,
> Just a quick "I had a Phil Rees MIDI->DinSync converter and it worked
> great; sold it to someone else on this list who hasn't complained so I
> assume it's still working; can't complain about it being glued together as
> I've opened a NuLogic equivalent and been confronted with obscene amounts
> of silicone (I guess) goo so can't complain" post to defend Phil based on
> my limited experience.
> 
> Whew.
> 
> David.






From cyborg0 at GlobalEyes.net  Tue Aug 11 04:01:45 1998
From: cyborg0 at GlobalEyes.net (cyborg0 at GlobalEyes.net)
Date: Mon, 10 Aug 1998 21:01:45 -0500
Subject: PhilRees MidiCV /midi problem
References: <v04011707b1f4ce85ebf7@[10.3.2.238]> <35CF8001.4534@darlow.powernet.co.uk>
Message-ID: <35CFA609.F212E170@globaleyes.net>

well, it could be either your soundcard or your converter box/cable.. i
think theres a few components in there, and if the thing isnt designed
very well.. oops. I had this prob with one of those all in one deals..
it had a cubase midi converter box in the software, and it wouldnt sync
properly, it wouldnt give proper note offs, etc..
changed the converter cable and bam..all was good.

rob


paul darlow wrote:
> 
> this could be a bit OT I am having problems with a philrees MCV and a
> freebass fb383 (same as the MAM bass synth) when runing a fast sequence
> from cubase the units lock up also my DX100 has been hanging notes could
> this be cased by the SBAWE32 I am using as a midi inteface its starting
> to get on my tits so any help gratfully receved
> all thanks
>                 paul
> 
> David Bivins wrote:
> >
> > Hey,
> > Just a quick "I had a Phil Rees MIDI->DinSync converter and it worked
> > great; sold it to someone else on this list who hasn't complained so I
> > assume it's still working; can't complain about it being glued together as
> > I've opened a NuLogic equivalent and been confronted with obscene amounts
> > of silicone (I guess) goo so can't complain" post to defend Phil based on
> > my limited experience.
> >
> > Whew.
> >
> > David.



From nighthawk at mci2000.com  Tue Aug 11 04:40:04 1998
From: nighthawk at mci2000.com (NIGHTHAWK)
Date: Mon, 10 Aug 1998 19:40:04 -0700 (PDT)
Subject: any mini-3 builders???
Message-ID: <MAPI.Id.0016.00306539767231693030304330303043@MAPI.to.RFC822>

Hi,

I tried searching archives but no luck.  If any of you have
tried building the keyboard interface from the Mini-3 schametics
that Electronics for Musicians has, I need a little assistance.

I know the circuit board drawing has at least three mistakes.
My data on what I now have with respect to voltages is at the
shop.

If you have successfully built the Mini-3 keyboard interface
please e-mail me, and I would love to discuss my situation.

Many thanks, and I believe I will end up joining this list if I
can tear myself from Analogue Heaven!  One list is about all
I can handle right now!

Jimmy Williams





From jorgen.bergfors at idg.se  Tue Aug 11 08:44:49 1998
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Tue, 11 Aug 1998 7:44:49 +0100
Subject: questions CA3084 and uA726
Message-ID: <TFSGDDVO@idg.se>

I have a bunch of CA3084s. It is a transistor array like the CA3046 but with 
PNP-transistors. There was a french guy on this list a couple of months ago, 
who ordered them from some distributor. So they are possible find, although you 
will probably will have to buy at least 50 of them. 
Here is the e-mail address to the frenchman: jbv.silences at wanadoo.fr. Maybe he 
has a couple more to spare.

/Jorgen





MIME:lavaud at pratique.fr on 98-08-10 20.58.57
To:  synth-diy at mailhost.bpa.nl @ SMTP 
cc:  (bcc: Jorgen Bergfors/IDGSE)
Subject: Re: questions CA3084 and uA726 

Hi there,

Thanks to Andrew Schrock, Edward Leckie,Martin Czech ans Steve Ridley
for your answers. I got the uA726 datasheet, allowing me to look for
similar ICs, but I did not find anything on Internet about the CA3084.
Does anybody have scanned datasheet or know a site where I could get
its specs ?

   Thanks,

   Denis Lavaud











From jorgen.bergfors at idg.se  Tue Aug 11 08:53:44 1998
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Tue, 11 Aug 1998 7:53:44 +0100
Subject: Free Schematic Drawing Programs?
Message-ID: <TFSGGEZG@idg.se>

Please tell me what a dedicated schematics drawing program does, that you can't 
do in a generic drawing program. I use Corel Draw and I produce very 
professional looking schemos with it.

/Jorgen





MIME:magnus at analogue.org on 98-08-10 23.17.53
To:  costello at seanet.com @ SMTP 
cc:  synth-diy at mailhost.bpa.nl @ SMTP  (bcc: Jorgen Bergfors/IDGSE)
Subject: Re: Free Schematic Drawing Programs? 

>>>>> "SC" == Sean Costello <costello at seanet.com> writes:

 SC> Hi all:
 SC> I'm finally starting to get some of my projects off of the ground, 
and
 SC> I'd like to be able to share my ideas with people (I'm actually 
looking
 SC> for criticism, so that I can get these circuits to be better).  Can
 SC> anyone on the list recommend any good freeware (or shareware) 
schematics
 SC> drawing programs?  I'm running Windoze 98 (i.e. Windows 95 with 
the "5"
 SC> crossed out and replaced with an "8") and Linux, but I can't say I
 SC> really know my way around Linux yet, so Windows applications are
 SC> preferred.

Well, since you said that you didn't know your way around in Linux I
obviously have to propose a software available on Linux. Althought in
heavy development you might find GEDA interesting to test. It is a GNU
project which involves a schematic editor and a PCB layout program is
comming along. These guys are being very serious about what they are
doing and spend time to figure out how things ought to work. GEDA is
now Guile powered (a Scheme implementation, scheme is a LISP dialect).
It is free allright, but still a bit rought. I have just tried it
briefly so I can't really say weither it is good, but there is
potential. I think at least that you should look at it and give it a
try, it is free so... 

Please check http://www.geda.seul.org/

Have fun!
Magnus









From ka4hjh at gte.net  Tue Aug 11 09:16:31 1998
From: ka4hjh at gte.net (KA4HJH)
Date: Tue, 11 Aug 1998 03:16:31 -0400
Subject: moog 905 spring reverb
In-Reply-To: <3.0.2.16.19980811172053.21ff1746@mail.internet-zahav.net>
Message-ID: <v04011702b1f59f34f65f@[208.255.152.197]>

>allso can some one tell me how is paia reverb sound(i hope not
>like the fat man) ?

Actually, it sounds pretty good for a spring. Larry Fast used a pair for
years. The trick is to take two springs, wire the inputs in parallel and
the outputs in series OUT OF PHASE. This cancels most of the direct signal
out, and most of the the "sproing" as well, leaving just the reverb. As
long as you don't overdrive it, it sounds a lot like plate.

Terry Bowman, KA4HJH
"The Mac Doctor"



From pfperry at melbpc.org.au  Tue Aug 11 09:39:06 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Tue, 11 Aug 1998 17:39:06 +1000 (EST)
Subject: questions CA3084 and uA726
Message-ID: <1.5.4.16.19970103001253.39975b62@popa.melbpc.org.au>

 Denis Lavaud wrote:
, but I did not find anything on Internet about the CA3084.
>Does anybody have scanned datasheet or know a site where I could get
>its specs ?

....might be at the Harris site, was a Harris chip once....

paul perry melbourne australia




From jorgen.bergfors at idg.se  Tue Aug 11 09:46:16 1998
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Tue, 11 Aug 1998 8:46:16 +0100
Subject: Free Schematic Drawing Programs?
Message-ID: <TFSGYDGI@idg.se>

Hi Martin
I use version 8. From version 6 the precision was improved a lot. That's 
because they went from 16 bit to 32 bit coordinates.
I doesn't have rubber wires and snap to pin pe se, but if you use snap to grid 
with a grid of 0,5 mm everything snaps to where it should. It has snap to 
objects, but I think snap to grid works best. Then you always get lines that 
are truly horisontal or vertical, without any effort. As long as you design 
your symbols on the same grid, everything line up perfectly. I designed my 
sybols to look exactly like in Elektor magazine, so all schemos that I make 
look like they are taken from Elektor.
By the way I also use Corel Draw for making circuit boards. The routing of 
course is completely manual then. Bu with typical analog circuitry the routing 
of the traces isn't difficult. Actually I think it's rather enjoyable. It's a 
bit like playing Solitaire, to optimise the layout by hand.
The advantage with using Corel Draw for circuit boards is that you can let a 
service bureau typeset it on film. That film can be used directly for exposing 
the photoresist.

/Jorgen





MIME:martin.czech at intermetall.de on 98-08-11 09.27.39
To:  Jorgen Bergfors at IDGSE
cc:  
Subject: Re: Free Schematic Drawing Programs? 

Of course you can draw. But I don't know if there are things like 
"rubber
wires" and "snap to pin". I aggree with you, that a complete CAD package
is far too complicated for our purposes. To much organasation.


What is the actual version you use? Version 6.0 was very cheap for sale
here. At the moment I have 3.0, and the most negative aspect is
that the grid can't be finer than 0.2 mm or so, which is a hoax.
What grid resolution does a more modern version have ?


m.c.










From tim at redragon.demon.co.uk  Tue Aug 11 10:01:41 1998
From: tim at redragon.demon.co.uk (Tim Cockram)
Date: Tue, 11 Aug 1998 09:01:41 +0100
Subject: AW: tri2saw (was:commercial synth circuits)
In-Reply-To: <1BF5E20E0C4DD111BBAB00805FE2D58297A780@nbgm336a.nbgm.siemens.de>
Message-ID: <fcScNAAlp$z1EwmT@redragon.demon.co.uk>

In message <1BF5E20E0C4DD111BBAB00805FE2D58297A780 at nbgm336a.nbgm.siemens
.de>, Haible Juergen <Juergen.Haible at nbgm.siemens.de> writes
>
>       >The Aries modular used this method quite succesfully.
>
>I knew it *must* have been done before (;->).
>What does their expo converter look like ?
>
>JH.
>
Aries use what appears to be the Dynasyn DY-1210-P Temperature
compensated module which consists of a NPN transistor (loging element)
with a trad three input tempco potential divider, the collector and
emitter are available at pins.  The emitter is also connected to the
base's of 2 PNP transistors whose collector and emitters are available
at pins.

All of the transistors are matched.........


For more data see electronotes #45 pp16-17

Regards

Tim

-- 
Tim Cockram



From chris at scp.de  Tue Aug 11 11:03:17 1998
From: chris at scp.de (Christian Hofmann)
Date: Tue, 11 Aug 1998 11:03:17 +0200
Subject: OT: Synth recording sought
In-Reply-To: <35CF7A09.EBF0AF31@globaleyes.net>
References: <3.0.5.32.19980810090751.007c8370@192.168.210.18> <35CF7A09.EBF0AF31@globaleyes.net>
Message-ID: <199808110903.LAA21046@dilbert.scp.de>

On Mon, 10 Aug 1998 17:54:01 -0500
cyborg0 at GlobalEyes.net wrote:

> Cant be more bizarre than Klaus Nomi.. :)
> All you late 70s-early-80s new wave fans know who im talking about! 

Right, Klaus Nomi...
Pretty weird at times, and beautiful analog stuff too!

cu
Christian




From lavaud at pratique.fr  Tue Aug 11 13:11:50 1998
From: lavaud at pratique.fr (Denis Lavaud)
Date: Tue, 11 Aug 1998 13:11:50 +0200
Subject: questions CA3084 and uA726
In-Reply-To: <1.5.4.16.19970103001253.39975b62@popa.melbpc.org.au>
Message-ID: <199808111119.NAA21244@absinthe.pratique.fr>

At 17:39 11/08/98 +1000, Paul Perry wrote:
> Denis Lavaud wrote:
>, but I did not find anything on Internet about the CA3084.
>>Does anybody have scanned datasheet or know a site where I
>>could get its specs ?
>
>....might be at the Harris site, was a Harris chip once....

Yes, it used to be. Nothing about it on their site. Harris
told me it is not produced anymore.

As there seem to be near enough ICs to replace it in the VCF
schematics, it does not seem to be a problem. 
I do not have the same feelings about the uA726 in the VCO !

			Thanks a lot

			Denis Lavaud




From chris at scp.de  Tue Aug 11 14:04:52 1998
From: chris at scp.de (Christian Hofmann)
Date: Tue, 11 Aug 1998 14:04:52 +0200
Subject: questions CA3084 and uA726
In-Reply-To: <199808101705.TAA28673@absinthe.pratique.fr>
References: <199808060128.DAA12615@absinthe.pratique.fr> <199808101705.TAA28673@absinthe.pratique.fr>
Message-ID: <199808111204.OAA00604@dilbert.scp.de>

On Mon, 10 Aug 1998 18:43:32 +0200
Denis Lavaud <lavaud at pratique.fr> wrote:

> Thanks to Andrew Schrock, Edward Leckie,Martin Czech ans Steve Ridley
> for your answers. I got the uA726 datasheet, allowing me to look for
> similar ICs, but I did not find anything on Internet about the CA3084.
> Does anybody have scanned datasheet or know a site where I could get
> its specs ?

Hi all,
I just emailed that 3084 data sheet to Denis. If anyone else is
interested, tell me.

cu
Christian




From Juergen.Haible at nbgm.siemens.de  Tue Aug 11 15:02:24 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Tue, 11 Aug 1998 15:02:24 +0200
Subject: AW: moog 905 spring reverb
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D582986EDC@nbgm336a.nbgm.siemens.de>

	>The trick is to take two springs, wire the inputs in parallel and
	>the outputs in series OUT OF PHASE. This cancels most of the direct
signal
	>out, and most of the the "sproing" as well, leaving just the
reverb. As
	>long as you don't overdrive it, it sounds a lot like plate.

Very interesting idea !
Just to know if I got this right, you take two complete reverb *tanks*,
each with 2 or 3 springs, and connect them together?

JH.




From tomg at vivid.net  Tue Aug 11 15:25:18 1998
From: tomg at vivid.net (tomg)
Date: Tue, 11 Aug 1998 08:25:18 -0500
Subject: any mini-3 builders???
In-Reply-To: <MAPI.Id.0016.00306539767231693030304330303043@MAPI.to.RFC822>
Message-ID: <yam7527.940.119337000@mail.vivid.net>

On 10-Aug-98, NIGHTHAWK wrote:
>Hi,

>I tried searching archives but no luck.  If any of you have
>tried building the keyboard interface from the Mini-3 schametics
>that Electronics for Musicians has, I need a little assistance.

>I know the circuit board drawing has at least three mistakes.
>My data on what I now have with respect to voltages is at the
>shop.

>If you have successfully built the Mini-3 keyboard interface
>please e-mail me, and I would love to discuss my situation.

>Many thanks, and I believe I will end up joining this list if I
>can tear myself from Analogue Heaven!  One list is about all
>I can handle right now!

>Jimmy Williams


Yeah...email me and I'll help.

-tg




From yoh212 at lulu.acns.nwu.edu  Tue Aug 11 16:29:06 1998
From: yoh212 at lulu.acns.nwu.edu (Yoshiki Ohmura (Yoshi))
Date: Tue, 11 Aug 1998 09:29:06 -0500 (CDT)
Subject: very basic Q
Message-ID: <Pine.HPP.3.93.980811092637.28377A-100000@lulu.acns.nwu.edu>

I'm about to embark on building my first LFO ;)  now here is my
fundamental question.  The signal of the LFO is +-5V and cv is 0-10V,
right?  Now I how I use the LFO signal to modulate the CV inputs of a
filter, etc.?

Thanks

YOshi





From b.layer at vikingelectronics.com  Tue Aug 11 16:29:22 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Tue, 11 Aug 1998 09:29:22 -0500
Subject: OT: Synth recording sought
In-Reply-To: <199808110903.LAA21046@dilbert.scp.de>
References: <35CF7A09.EBF0AF31@globaleyes.net>
 <3.0.5.32.19980810090751.007c8370@192.168.210.18>
 <35CF7A09.EBF0AF31@globaleyes.net>
Message-ID: <3.0.5.32.19980811092922.007aa900@192.168.210.18>

At 11:03 AM 8/11/98 +0200, you wrote:
>On Mon, 10 Aug 1998 17:54:01 -0500
>cyborg0 at GlobalEyes.net wrote:
>
>> Cant be more bizarre than Klaus Nomi.. :)
>> All you late 70s-early-80s new wave fans know who im talking about! 
>
>Right, Klaus Nomi...
>Pretty weird at times, and beautiful analog stuff too!
>
He was pretty unusual... I remember a performance of the Aria from Sampson
and Delilah in Urrgh! a Music War. 

Since we're so far OT, is anyone familiar with the soundtrack from Liquid
Sky? I just noticed a few days ago that it was composed at the New York
public access Electronic Music Studio, entirely on the Fairlight CMI.

I'm still not sure if I like it, though.

 


Bill Layer
"Heavy old junk wanted"



From ryckebu at subasehp.san.mrms.navy.mil  Tue Aug 11 16:39:32 1998
From: ryckebu at subasehp.san.mrms.navy.mil (Jules Ryckebusch)
Date: Tue, 11 Aug 1998 14:39:32 +0000
Subject: Variable Caps
In-Reply-To: <8525665D.0064E017.00@Albatross.educate.com>
Message-ID: <199808112141.OAA04420@subasehp.san.mrms.navy.mil>

> From:          jmcmahon at prometric.com
> To:            synth-diy at mailhost.bpa.nl
> Date:          Tue, 11 Aug 1998 14:25:54 -0400
> Subject:       Variable Caps

> I'm having trouble finding some parts, maybe one of you can help me.  I am
> looking for variable capacitors. Not just any variable capacitor, but ones
> that can be turned like a pot.  Ones large enough to attach a knob to and
> allow realtime control of it.  I have found an abundance of surface/pc
> mount and medium sized ones, but nothing to really fit my current project.
> Right now, I'm not concerned about which values of caps, but just where I
> can find them.  By the way, I am in the US, so a distributor/manufacturer
> in the US would be a plus.  Thanks guys, I know you'll come through for me.
> 
>        Jason McMahon
>   experimental musician
> i break things on purpose
> 
> 
> 
Jason, They don't really make what you are looking for. The ones 
available are usually in the hundred pico farad range and expensive. 
HP used a bank of three in some of there distortion analyzers and 
they were in the hundred$ range. Sorry man!

Jules
 



From jhusted at halcyon.com  Tue Aug 11 17:21:09 1998
From: jhusted at halcyon.com (James Husted)
Date: Tue, 11 Aug 1998 08:21:09 -0700
Subject: ssm-2040
Message-ID: <3.0.32.19980811082105.007b2430@mail.halcyon.com>

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From nc0839 at netcom.com  Tue Aug 11 18:43:20 1998
From: nc0839 at netcom.com (David Lee)
Date: Tue, 11 Aug 1998 11:43:20 -0500
Subject: ssm-2040
Message-ID: <199808111642.JAA13082@k9gw.corp.netcom.com>

I have a few SSM 2040's as well (3 of them) from a Siel Expander. It came
with six 2040's but I use these chips in an Emax I would like to keep
functioning. I might consider selling up to 3 of the chips if anyone needs
them.

David Lee

----------
From: James Husted <jhusted at halcyon.com>
To: Per.Mattsson at mkv.mh.se; gur-m at internet-zahav.net
Cc: synth-diy at mailhost.bpa.nl
Subject: Re: ssm-2040
Date: Tuesday, August 11, 1998 10:21 AM

I have a stash of ssm2040's (about 10 I think - I'll have to dig them
out) some ssm2010's and som other SSM stuff , mainly VCAs. What is the
going prices for them now days. The only thing I have that uses them is a
couple of Symetrix Phase Filters that use 2 each. I'll dig around and
post a list of what I have.

-James 


At 11:08 AM 8/10/98 +0100, Per.Mattsson at mkv.mh.se wrote:

>>>> 

<excerpt>Gur Milstein,gur-m at internet-zahav.net,Internet skriver:


>do any body know where i can get some SSM-2040 chips ?

Nope.

>do analog device produce them ?

Nope.


The 2040's IMO are very hard to find and IF you find them they normally
do not come cheap.

2044 is the lowpass only version and it somewhat easier to find but is
only limited to 4-pole lowpass use.


Juergen has also done a 2040 emulating circuit. 

<<http://aupe.phys.andrews.edu/diy_archive/schematics/synthmodules/jh_2040.g
if>


//I'd buy a couple if I found them at a resonable price - I love the
sweet sound of the SSM filters.


-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

        Sent from The Department of Media and Communication

                      Mid Sweden University

              Information available at Info at mkv.mh.se

-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-




</excerpt><<<<<<<<



*******************************************************

* James Husted - The Ersatz Planet Graphics and Sound *

*               jhusted at halcyon.com                   *

*     http://www.halcyon.com/jhusted/welcome.htm      *

*******************************************************



From tomg at vivid.net  Tue Aug 11 18:43:50 1998
From: tomg at vivid.net (tomg)
Date: Tue, 11 Aug 1998 11:43:50 -0500
Subject: Maxx VCF-6A EMS type
Message-ID: <yam7527.2519.119336608@mail.vivid.net>

The Maxx and Mad Mouse get a 4P diode ladder LP VCF. I didn't
like the BP VCF in the MM so the EMS got another chance.
Worked out pretty nicely. There is a wave file on the page.

http://www.tomg.vivid.net/maxx/page_033.html

http://www.tomg.vivid.net/maxx/pics/vcf6a.wav

-tg




From ebarbour at svetlana.com  Tue Aug 11 19:01:24 1998
From: ebarbour at svetlana.com (Eric Barbour)
Date: Tue, 11 Aug 1998 10:01:24 -0700
Subject: new magazine article you must see!
Message-ID: <01BDC50F.015B8BC0.ebarbour@svetlana.com>

Get the new August issue of IEEE SPECTRUM magazine.
You'll find the cover story most fascinating. (I wrote it...)

If your local digital nerds have been giving you grief because of
your interest in tube audio, this article is great ammunition
in your favor. You can point out the distortion tests showing
that tubes have electrical advantages over transistors for audio
design. (You can also point out that this article passed the standard
IEEE peer-review procedure with flying colors.)

SPECTRUM is available from large book dealers and newsstands,
and is carried in virtually every university library.

Eric Barbour
Svetlana Electron Devices
Portola Valley CA USA




From gur-m at internet-zahav.net  Tue Aug 11 17:20:53 1998
From: gur-m at internet-zahav.net (Gur Milstein)
Date: Tue, 11 Aug 1998 17:20:53
Subject: moog 905 spring reverb
Message-ID: <3.0.2.16.19980811172053.21ff1746@mail.internet-zahav.net>

hi guy's.
i would like to build a spring reverb to fit
in to my modular.
i hear the MOOG 905 on Emrson Triology record and wow isn't this
sound great.
so any info on this one or other GOOD reverb
would be great.
allso can some one tell me how is paia reverb sound(i hope not
like the fat man) ?

thanx
Gur Milstein



From aschrock at cs.brandeis.edu  Tue Aug 11 19:32:25 1998
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Tue, 11 Aug 1998 13:32:25 -0400 (EDT)
Subject: final switching Q
In-Reply-To: <3.0.5.32.19980811092922.007aa900@192.168.210.18>
Message-ID: <Pine.HPP.3.95.980811132357.22599A-100000@bay.cs.brandeis.edu>

Ok.. this is a followup to my earlier question about switching. I have
decided to abandon the idea of a 4-toggle switch and have instead opted to
go for a simpler 2-toggle switch. This is super-easy to do with digital
logic, but... 

I've gotten together a hex schmitt inverter for debouncing and a hex D
flip-flop for switching... my final question is what serves as the "gate"
to allow the actual switch from A to B? Ie when the output from a
flip-flop goes high, how does this change the flow? (ie, instead of A to
B, A to C) Is my question making sense? It's pretty simple.. A transistor
switch perhaps? This is for a mixing module, BTW, so when a user presses
the switch it will have to change the mixing output from output 1 to
output 2... it's not just pinning an input to high or ground. 

Thanks, sorry to keep bugging the list with such basic questions.. please
email me privately. 
Andrew

| Andrew Schrock							|
| Network Programmer, Synthesizer and electronic music enthusiast	|
| aschrock at cs.brandeis.edu						|





From aschrock at cs.brandeis.edu  Tue Aug 11 19:36:04 1998
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Tue, 11 Aug 1998 13:36:04 -0400 (EDT)
Subject: ssm-2040
In-Reply-To: <199808111642.JAA13082@k9gw.corp.netcom.com>
Message-ID: <Pine.SGI.3.95.980811133421.23724A-100000@pearl.cs.brandeis.edu>

I know this has been tossed around before, but has anybody come up with a
good non-CEM, non-SSM VCA solution? I mean, there's nothing WRONG with
using a 3080, except the quality won't be terrific. All the designs I've
seen online have been of the CEM3330 or 3080+dual opamp variety. 

Andrew

| Andrew Schrock							|
| Network Programmer, Synthesizer and electronic music enthusiast	|
| aschrock at cs.brandeis.edu						|




From jmcmahon at prometric.com  Tue Aug 11 20:25:54 1998
From: jmcmahon at prometric.com (jmcmahon at prometric.com)
Date: Tue, 11 Aug 1998 14:25:54 -0400
Subject: Variable Caps
Message-ID: <8525665D.0064E017.00@Albatross.educate.com>

I'm having trouble finding some parts, maybe one of you can help me.  I am
looking for variable capacitors. Not just any variable capacitor, but ones
that can be turned like a pot.  Ones large enough to attach a knob to and
allow realtime control of it.  I have found an abundance of surface/pc
mount and medium sized ones, but nothing to really fit my current project.
Right now, I'm not concerned about which values of caps, but just where I
can find them.  By the way, I am in the US, so a distributor/manufacturer
in the US would be a plus.  Thanks guys, I know you'll come through for me.

       Jason McMahon
  experimental musician
i break things on purpose





From ka4hjh at gte.net  Tue Aug 11 20:28:48 1998
From: ka4hjh at gte.net (KA4HJH)
Date: Tue, 11 Aug 1998 14:28:48 -0400
Subject: AW: moog 905 spring reverb
In-Reply-To:  <1BF5E20E0C4DD111BBAB00805FE2D582986EDC@nbgm336a.nbgm.siemens.de>
Message-ID: <v04011700b1f6394f32c3@[208.255.152.197]>

>	>The trick is to take two springs, wire the inputs in parallel and
>	>the outputs in series OUT OF PHASE. This cancels most of the direct
>signal
>	>out, and most of the the "sproing" as well, leaving just the
>reverb. As
>	>long as you don't overdrive it, it sounds a lot like plate.
>
>Very interesting idea !
>Just to know if I got this right, you take two complete reverb *tanks*,
>each with 2 or 3 springs, and connect them together?


Exactly. I forget who gets the credit for this one; it's either John
Simonton or Craig Anderton. I don't have the info handy. Is it archived at
the PAiA site?

I bought four surplus tanks (some time ago) and the instructions and rigged
up a stereo pair. I still have a slight ground loop buzzing away somewhere
waiting to be exorcised, and the outputs aren't exactly the same tonally
and even the overall volume is't quit the same, but then these were surplus
tanks so who knows how well matched they are? That's an important
consideration since phase cancellation is involved. Nevertheless, it's the
closest thing to tank you'll probably ever hear in the analog (electronic)
domain. Physically a lot more convenient, too. You can whack 'em when
you're covering "The End".

Terry Bowman, KA4HJH
"The Mac Doctor"



From nebula at wavefront.com  Tue Aug 11 21:00:49 1998
From: nebula at wavefront.com (Patrick O'Melia)
Date: Tue, 11 Aug 1998 13:00:49 -0600
Subject: Light Weight 88 Key Weighted Controller
Message-ID: <l03130300b1f6442006b1@[205.198.126.153]>

It's more of a CONTROLLER DIY question, but I was wondering if anyone had
any insight or may have tried this idea.

Basically how light can you make an 88 Key (Weighted) Controller ?

The lightest commercial product I've seen is probably 50 lbs. Has anyone
tried to experiment with making one that is lighter ?





From jonas.k at swipnet.se  Tue Aug 11 21:36:10 1998
From: jonas.k at swipnet.se (Jonas Karlsson)
Date: Tue, 11 Aug 1998 21:36:10 +0200
Subject: Schematic symbols
Message-ID: <000101bdc55f$4c35c840$1f5af482@win95.swipnet.se>

I have added some schematic symbols in Freehand 5 format on my homepage. Maybe some one is interested after the latest discussion.
_______________________________________
       Jonas Karlsson
       G?tgatan 40
       582 31 Link?ping
       jonas.k at swipnet.se
       http://home5.swipnet.se/~w-53332/index.html
_______________________________________




From smart at nn.com  Tue Aug 11 21:39:36 1998
From: smart at nn.com (Mark Smart)
Date: Tue, 11 Aug 1998 14:39:36 -0500 (CDT)
Subject: VP-330 (analog speech synthesis)
In-Reply-To: <Pine.LNX.3.95.980809215408.25072A-100000@home.netcontrol.fi> from "Joachim Verghese" at Aug 9, 98 10:18:31 pm
Message-ID: <199808111939.OAA27532@medusa.nn.com>

> Juergen wrote:
> 
> Tony Banks of Genesis did the same thing in 1980. The VP-330 choir
> can be heard on "Afterglow" off the "Three Sides Live" album, and
> vocoder effects on "Duchess" (off the same album). 

I checked this out a couple of days ago. It's used on "The Cage" medley,
too.

> 
> I really like the VP-330 choir, although it isn't nearly as dramatic
> as that of the Mellotron. And the analog filter bank sound shaping
> method is quite fascinating of course.
> 
> BTW, I seem to recall that the main internal differences between the
> two VP-330 versions were in the choir section. Does anyone know what
> those differences were? I've only got the service manual for the
> later version (the one with momentary LED buttons instead of rocker
> switches).
> 
> -joachim

In my search for info I found a note somewhere saying that the Mark I and
Mark II versions had different chorus circuits (the effect, not the group
of people singing). I think the note said the Mark I used Reticon chips and
the Mark II used Panasonic chips. My experiences with ARP Omni's leads me
to believe that the Reticon chips have a much better high end response at
the same clock speed than the Panasonic chips. Of course it's possible that
this is only true of an SAD512 vs. an MN3002. Dunno.

That and the different buttons are the only difference I've heard of so
far.



************************************************
*     Mark Smart                               *
*     Electronics Engineer                     *
*     NovaNET Learning, Inc.                   *
*     smart at medusa.nn.com                      *
************************************************



From tic at vossnet.de  Tue Aug 11 21:45:02 1998
From: tic at vossnet.de (tim0 (Timo Christ))
Date: Tue, 11 Aug 1998 21:45:02 +0200
Subject: soldid-state keyboards/ua726
References: <8bba1b0c.35cf6eb8@aol.com>
Message-ID: <35D09F3E.2353E966@vossnet.de>

hi All, 

Dragonser at aol.com wrote:
> 
> Dear Timo,
> IF the ic's are Ua726 , and the same dual transistor pair with built in heater
> , then anthing from about ? 50-00 UK pounds upwards [ I think].
> Interestingly I hear a rumour that one tech here in the uk was doing this ,
> but when I asked I coulnd,t get the name of the tech. .
> I can't think why they would be used in a radio ?
> and they haven't been in production for some time now ..........
> the ic I have seen [ In music synths ] has been a metal can with ten legs .

then my 726 chips are different :-((((( ,
3-pin ICs , exact label:  D726 7M2 , look like voltage
regulators..(TO-220).. hmmm i guess i took them out of the PS unit of
the radio.. 
sorry for the confusion!

> I think the Buchla uses touch sensitive  plates like the wasp synth uses

i would be very pleased if someone could post details on this approach.

Chris Stecker, please ! :-) 

keep up the fun,
T.
-- 
Timo Christ -- Germany -- Europe
root at dist0rter -- tic at vossnet.de -- LEDflash at gmx.net





From b.layer at vikingelectronics.com  Tue Aug 11 22:02:01 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Tue, 11 Aug 1998 15:02:01 -0500
Subject: Free schematic drawing progs
Message-ID: <3.0.5.32.19980811150201.0079e910@192.168.210.18>

Hi All,

Has anoyone had a chance to download the Ciruit CAD 2.0 as hyperlinked in a
prior post? I've been playing with it this afternoon, and it seems to have
a major limitation.

I can't get it to PRINT on my network Lexmark laser printer. The readme
mentions that it requires an Epson compatible printer, so is this software
trying to write to the Epson in some native (unsupported) mode then?

When I go to print a drawing, DOS returns 'device not ready' abort, retry
etc. Has anyone else had any success with it?

PS Thanks for the hyperlink to Graeme Nelson.
Bill Layer
"Heavy old junk wanted"



From pwayman at laserfiche.com  Tue Aug 11 22:07:14 1998
From: pwayman at laserfiche.com (Peter Wayman)
Date: Tue, 11 Aug 1998 13:07:14 -0700
Subject: Variable Caps -Reply
Message-ID: <98Aug11.131101pdt.12545@cerberus.laserfiche.com>

Many many years ago (like in the 80's man), my dad
was helping me make a little radio tuner. We
simply went to the local electronics store and
picked up a variable cap designed for the purpose.
It already had a dial attached to it. It was about
an inch square, and half an inch high.

I'd be surprised if they don't make these any
more, but if not, you can probably get one out of
a Radio Shack crystal radio kit.

:P W
>>> <jmcmahon at prometric.com> 08/11/98 11:25am >>>
I'm having trouble finding some parts, maybe one
of you can help me.  I am
looking for variable capacitors. Not just any
variable capacitor, but ones
that can be turned like a pot.  Ones large enough
to attach a knob to and




From b.layer at vikingelectronics.com  Tue Aug 11 22:08:55 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Tue, 11 Aug 1998 15:08:55 -0500
Subject: Variable Caps
In-Reply-To: <8525665D.0064E017.00@Albatross.educate.com>
Message-ID: <3.0.5.32.19980811150855.007a8b50@192.168.210.18>

Hi Jason,

 >I'm having trouble finding some parts, maybe one of you can help me.  I am
>looking for variable capacitors. Not just any variable capacitor, but ones
>that can be turned like a pot.  Ones large enough to attach a knob to and
>allow realtime control of it.  I have found an abundance of surface/pc
>mount and medium sized ones, but nothing to really fit my current project.
>Right now, I'm not concerned about which values of caps, but just where I
>can find them.  By the way, I am in the US, so a distributor/manufacturer
>in the US would be a plus.  Thanks guys, I know you'll come through for me.

Expensive stuff you want here. But maybe not... This is HAM stuff.

Have you considered pulling apart an old AM tube-type radio? These
universally (well, almost universally, excepting the slug-tuned units) have
a 2 or three section air-variable cap, usually with attached trimmers.
Since they tuned the set directly, they generally have the standard 1/4"
shaft, usually with the D-style or spline shape. Typical values I recall
are 120-300pF per section>

This type of cap mounts via screws, or tapped holes, to a (metal) chassis.

Hit the Salvation Army or Goodwill, or wait for a garage sale.

Hope this helps.

 
Bill Layer
Sales Technician
<b.layer at vikingelectronics.com>

----------------------------------
Viking Electronics, Inc.
Hudson, WI. U.S.A
715.386.8861 (ext. 210)
<http://www.vikingelectronics.com>
----------------------------------

"Telecommunications Solutions for the 21st Century"



From aschrock at cs.brandeis.edu  Tue Aug 11 22:15:17 1998
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Tue, 11 Aug 1998 16:15:17 -0400 (EDT)
Subject: odd question about homebrew akai s2000
In-Reply-To: <01BDC50F.015B8BC0.ebarbour@svetlana.com>
Message-ID: <Pine.SGI.3.95.980811160008.24619A-100000@pearl.cs.brandeis.edu>

Here's a strange question: 

Has anybody hacked a card to do multiple outs on the akai s2000? I want
multiple outs, but I a) don't have $300 to spare and b) don't need digital
ins/outs. 

I imagine it's a simple procedure if there's no DtoA involved, but I
doubt akai will give me docs and I don't have access to funds right now. 

Any hints? 

Andrew

| Andrew Schrock							|
| Network Programmer, Synthesizer and electronic music enthusiast	|
| aschrock at cs.brandeis.edu						|




From a-davidh at microsoft.com  Tue Aug 11 22:32:01 1998
From: a-davidh at microsoft.com (David Halliday (Volt Computer))
Date: Tue, 11 Aug 1998 13:32:01 -0700
Subject: Variable Caps
Message-ID: <C35556591D34D111BB5600805F1961B906183F25@RED-MSG-47>

This is something that Amateur Radio operators use all the time.  

Check your local phone book to see if there is a ham radio store near you.
You will be much better off getting used ones - the new ones are probably
very very expensive and you could pick up a junky radio set and salvage a
decent unit from it for a lot less...

Also, check magazine stores for " 73 " and " QST " as these two zines have a
lot of ads from smaller mail-order places.

The values will be a little bit on the small side though ( for audio work )
- PicoFarads instead of MicroFarads...



-----Original Message-----
From: jmcmahon at prometric.com [mailto:jmcmahon at prometric.com]
Sent: Tuesday, August 11, 1998 11:26 AM
To: synth-diy at mailhost.bpa.nl
Subject: Variable Caps


I'm having trouble finding some parts, maybe one of you can help me.  I am
looking for variable capacitors. Not just any variable capacitor, but ones
that can be turned like a pot.  Ones large enough to attach a knob to and
allow realtime control of it.  I have found an abundance of surface/pc
mount and medium sized ones, but nothing to really fit my current project.
Right now, I'm not concerned about which values of caps, but just where I
can find them.  By the way, I am in the US, so a distributor/manufacturer
in the US would be a plus.  Thanks guys, I know you'll come through for me.

       Jason McMahon
  experimental musician
i break things on purpose




From urekar.m at EUnet.yu  Tue Aug 11 23:01:17 1998
From: urekar.m at EUnet.yu (<<marjan>>)
Date: Tue, 11 Aug 1998 23:01:17 +0200
Subject: Variable Caps -Reply
References: <98Aug11.131101pdt.12545@cerberus.laserfiche.com>
Message-ID: <35D0B11D.518A@eunet.yu>

> Many many years ago (like in the 80's man), my dad
> was helping me make a little radio tuner. We
> simply went to the local electronics store and
> picked up a variable cap designed for the purpose.
> It already had a dial attached to it. It was about
> an inch square, and half an inch high.

Can be found in any old radio but they are AFAIK 
rather small capacitance less than 10-500 pF
not very usable in synth maybe theremin


marjan



From ebarbour at svetlana.com  Tue Aug 11 23:06:32 1998
From: ebarbour at svetlana.com (Eric Barbour)
Date: Tue, 11 Aug 1998 14:06:32 -0700
Subject: variable capacitors
Message-ID: <01BDC531.3F206940.ebarbour@svetlana.com>

Try Antique Electronic Supply (602) 820-5411. They carry such
capacitors, in a variety of sizes. Their website is www.tubesandmore.com.


>I'm having trouble finding some parts, maybe one of you can help me.  I am
>looking for variable capacitors. Not just any variable capacitor, but ones
>that can be turned like a pot.  Ones large enough to attach a knob to and
>allow realtime control of it.  I have found an abundance of surface/pc
>mount and medium sized ones, but nothing to really fit my current project.


Eric Barbour
Svetlana Electron Devices
Portola Valley CA USA




From oakley at enterprise.net  Tue Aug 11 23:33:51 1998
From: oakley at enterprise.net (Tony Allgood)
Date: Tue, 11 Aug 1998 22:33:51 +0100
Subject: nuvista
Message-ID: <00a101bdc56f$e095d740$72c648c2@default>

Hi all,

Blimey I go away for a week and what do I get, 251 messages, and most of
them berating Tom's nice site.

Anyway, my question, I was reading a Hi-Fi magazine in the library (sad
is'nt it?) and an article about a new pre-amp caught my eye. It uses
Nuvistas, some sort of mini-valve, with all the inherent advantages of
valves/tubes and the compactness of trannies. Small metal canisters about
the size of a BFY33, I think. Pictures can be deceptive. Does anyone know
more about these wee beasties?

Regards,

Tony Allgood, Cumbria, UK

e-mail: oakley at enterprise.net

Rack mounted Moog VCF module. Details to be found at...

http://aupe.phys.andrews.edu/diy_archive/schematics/effects/filter.html








From magnus at analogue.org  Wed Aug 12 00:39:30 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Wed, 12 Aug 1998 00:39:30 +0200
Subject: Free Schematic Drawing Programs?
In-Reply-To: Your message of "Tue, 11 Aug 1998 7:53:44 +0100"
References: <TFSGGEZG@idg.se>
Message-ID: <199808112239.AAA26018@piraya.electrum.kth.se>

>>>>> "jb" == jorgen bergfors <jorgen.bergfors at idg.se> writes:

 jb> Please tell me what a dedicated schematics drawing program does, that you can't 
 jb> do in a generic drawing program. I use Corel Draw and I produce very 
 jb> professional looking schemos with it.

Well, there are many things that becomes far more streamlined with a
electronic design process than a Corel Dravel or similar (this even
include AutoCad). For instance, there are more finished libraries of
component symbols. You can generate netlist files which plug into many
layout programs. You may get a Spice netlist. Backannotation becomes
simpler. These are just some out of the top of my head, there is many
more good reasons.

If you worked with a even halfgood set of tools you will apprechiate
the things that it will do for you. I have been waiting for something
similar in years, since I gave up a broken OS platform and found
myself hacking raw Postscript to get some simple schematics out (ASM-1
schematics is down this way). Let's just say that it is a pain in the
ass and the only reason I can do it is since it was such a challange
to have done it.

So please test GEDA and similar tools.

Cheers,
Magnus



From IXQY at aol.com  Wed Aug 12 01:28:11 1998
From: IXQY at aol.com (IXQY at aol.com)
Date: Tue, 11 Aug 1998 19:28:11 EDT
Subject: AW: moog 905 spring reverb
Message-ID: <26af5a70.35d0d38c@aol.com>

In a message dated 98-08-11 14:37:44 EDT, you write:

<< Exactly. I forget who gets the credit for this one; it's either John
 Simonton or Craig Anderton. I don't have the info handy. Is it archived at
 the PAiA site? >>

 Hello,
 This is my 1st posting to the list, and don't plan to post very often, as
most things discussed here are way over my head. This is one thing I thought
might be of some help though.

 If I'm not mistaken , I seem to remember reading about this reverb circuit
years ago in Anderton's book "Electonics Projects for Musicians". I think he
called it "Hot Springs or Hot Plate reverb".  What Anderton had wrote about
the circuit and the sound of the reverb got me really curious but I never
built it.
 I do however, remember building the ring modulator from this book when I was
in high school and taking it to a friends house to try it with his guitar. He
had no idea what it was and probably thought I was from Mars! He did say that
he liked it though.

 Andrew Sanchez
 



From moxie at idonex.se  Wed Aug 12 01:34:27 1998
From: moxie at idonex.se (Johan Gustavsson)
Date: Wed, 12 Aug 1998 01:34:27 +0200 (MET DST)
Subject: very basic Q
In-Reply-To: <Pine.HPP.3.93.980811092637.28377A-100000@lulu.acns.nwu.edu>
	(yoh212@lulu.acns.nwu.edu)
Message-ID: <199808112334.BAA19728@jolt.idonex.se>

> I'm about to embark on building my first LFO ;)  now here is my
> fundamental question.  The signal of the LFO is +-5V and cv is 0-10V,
> right?  Now I how I use the LFO signal to modulate the CV inputs of a
> filter, etc.?

Well, think adding and subtracting. If you put, say, the filter CV at
4v, using the cutoff knob, and then modulate with +-3, then you'll go
from 1v to 7v...And usually, when using an LFO, you *will* use it for
some already set voltage, right?

What happens if you don't? Well, that really depends on the module on
the receiving end, doesn't it? Some will behave nicely with a negative
CV, some will just use the parts that are positive (giving, say, a
chopped effect to a VCA), some others might do something completely
weird, I suppose :-)

Then again, it ought to be simple to hack in a bias voltage to keep
the LFO oscillating in the 0-10v range, if wanted. Or a variable bias.
/Moxie (Just too sleepy)





From ebarbour at svetlana.com  Wed Aug 12 01:42:39 1998
From: ebarbour at svetlana.com (Eric Barbour)
Date: Tue, 11 Aug 1998 16:42:39 -0700
Subject: Musical Fidelity preamp
Message-ID: <01BDC547.0E6398C0.ebarbour@svetlana.com>

>Nuvistas, some sort of mini-valve, with all the inherent advantages of
>valves/tubes and the compactness of trannies. Small metal canisters about
>the size of a BFY33, I think. Pictures can be deceptive. Does anyone know
>more about these wee beasties?

That's "Nuvistor". Introduced by RCA in 1959. All metal and ceramic
tube using indirectly-heated cathode. Intended for RF applications
at VHF and up, which transistors of the time were not capable of.
Used as RF front-end in Fisher and Scott FM tuners and receivers,
later used in audio equipment. Specifically the Ampex MR-70 reel
tape recorder, one of the best all-tube machines ever made. Also
used in condenser microphones and in the Conrad-Johnson PV-3
stereo hi-fi preamp of 1982.

Nuvistors have been out of production since 1988. They will probably
never be made again due to low demand. Musical Fidelity bought a
large stock of NOS Nuvistors, still, I think this was a bad idea. They are
very good little tubes (except for some microphony) and have low
distortion and low noise. A shame--they are likely to be dead products.

See my nuvistor phono stage article in GLASS AUDIO magazine,
4/93 issue.

Eric Barbour
Svetlana Electron Devices
Portola Valley CA USA




From moxie at idonex.se  Wed Aug 12 01:44:50 1998
From: moxie at idonex.se (Johan Gustavsson)
Date: Wed, 12 Aug 1998 01:44:50 +0200 (MET DST)
Subject: ssm-2040
In-Reply-To: <Pine.SGI.3.95.980811133421.23724A-100000@pearl.cs.brandeis.edu>
	(message from Andrew Schrock on Tue, 11 Aug 1998 13:36:04 -0400 (EDT))
Message-ID: <199808112344.BAA19954@jolt.idonex.se>

> I know this has been tossed around before, but has anybody come up with a
> good non-CEM, non-SSM VCA solution? I mean, there's nothing WRONG with
> using a 3080, except the quality won't be terrific. All the designs I've
> seen online have been of the CEM3330 or 3080+dual opamp variety. 


Issue 5 of Paul Maddox' "Modulus" has a quad vca based on a 3046 and a
TL074. Don't remember the URL to the modulus site, but it sould be
pretty easy to find.

Whatever happened to Paul? The site have been saying "Next issue out
januari -98" for quite some time now...
/Moxie (Curious)




From blayer at uswest.net  Wed Aug 12 02:48:49 1998
From: blayer at uswest.net (Bill Layer)
Date: Tue, 11 Aug 1998 19:48:49 -0500
Subject: nuvista
In-Reply-To: <00a101bdc56f$e095d740$72c648c2@default>
Message-ID: <3.0.5.32.19980811194849.007adc50@pop.mpls.uswest.net>

 Hi Tony,

 It uses
>Nuvistas, some sort of mini-valve, with all the inherent advantages of
>valves/tubes and the compactness of trannies. Small metal canisters about
>the size of a BFY33, I think. Pictures can be deceptive. Does anyone know
>more about these wee beasties?

The Nuvista, or Nuvistor as RCA called it, was a latter day vacuum-valve
entrant into the race for compactness. When they were introduced in the
mid-late 1960's, Nuvistors outperformed the crude solid state devices
(mostly germanium) in many areas, especially in terms of noise. Physically,
they were not much larger, either.

In our times, the devices are now out of production, and fairly scarce
(unless you care not about expense...) A construction article was written
last year in Glass Audio describing an original Hi-Fi preamp design
employing four Nuvistors. I'm sure EB recalls the article, I don't have a
subscription  

If you are genuinely interested in implementing a tube circuit, there are
MANY more simple designs, which employ common devices, and offer plenty of
performance. Consider the fact that both (discrete) solid state and vacuum
devices are both fully mature technologies (at least in our realm), and are
not likely to change in the forseeable future. This means that future
generations will likely be hearing the same difference between tubes and
solid state that we are hearing today. (This bit of wisdom courtesy Ralph
Karsten)

Ok. Enough propaganda.


Bill Layer
St.Paul, Minnesota USA
"Quantity has a quality all of it's own"



From stochastic at mindspring.com  Wed Aug 12 03:28:15 1998
From: stochastic at mindspring.com (Charlie Mann)
Date: Tue, 11 Aug 1998 21:28:15 -0400
Subject: Variable Caps
References: <8525665D.0064E017.00@Albatross.educate.com>
Message-ID: <35D0EFAF.CF2076E3@mindspring.com>

check out a local "ham" fest--amateur radio folks use large (phys) variable
caps (w/knobs) to tune antennas.  Check out this URL:

http://www.arrl.com/

73s and best of luck,
Charlie Mann



jmcmahon at prometric.com wrote:

> I'm having trouble finding some parts, maybe one of you can help me.  I am
> looking for variable capacitors. Not just any variable capacitor, but ones
> that can be turned like a pot.  Ones large enough to attach a knob to and
> allow realtime control of it.  I have found an abundance of surface/pc
> mount and medium sized ones, but nothing to really fit my current project.
> Right now, I'm not concerned about which values of caps, but just where I
> can find them.  By the way, I am in the US, so a distributor/manufacturer
> in the US would be a plus.  Thanks guys, I know you'll come through for me.
>
>        Jason McMahon
>   experimental musician
> i break things on purpose






From pfperry at melbpc.org.au  Wed Aug 12 03:33:44 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Wed, 12 Aug 1998 11:33:44 +1000 (EST)
Subject: Variable Caps
Message-ID: <1.5.4.16.19970103180729.0e4fef12@popa.melbpc.org.au>

Variable caps are still readily available....
search out the electronics faq lists, or better, get a
copy of Electronics Now, or Nuts&Volts or QST and send
for parts catalogs.
paul perry melbourne australia




From pfperry at melbpc.org.au  Wed Aug 12 03:33:50 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Wed, 12 Aug 1998 11:33:50 +1000 (EST)
Subject: vca: no CEM, no SSM (was: ssm-2040)
Message-ID: <1.5.4.16.19970103180735.2ddf188c@popa.melbpc.org.au>

At 01:36 PM 11/08/98 -0400, Andrew Schrock  wrote:
>I know this has been tossed around before, but has anybody come up with a
>good non-CEM, non-SSM VCA solution?

Jim Williams published one in EDN using 3 LF421 op amps and a LM394 matched
pair and a 2n2222. The hard part is bleedthrough, in his there isn't much,
even with 10v pp input. There is a separate "cancellation" part of the ckt 
with a phase shift and freq response tailored to match the multiplier
feed through.
It is reprinted in 'A Designer's Guide to: Innovative Linear Circuits' by
Jim Williams 1985 (also there is a high spec oct/v vco with the transistor 
heater trick)

But, if I had to do a good enough one with almost no parts I'd just use an
AD633 multiplier. Built carefully, I think it would equal anything (ducks!)

paul perry melbourne australia  




From ijfritz at earthlink.net  Wed Aug 12 04:50:38 1998
From: ijfritz at earthlink.net (Ian Fritz)
Date: Tue, 11 Aug 1998 20:50:38 -0600
Subject: vca: no CEM, no SSM (was: ssm-2040)
References: <1.5.4.16.19970103180735.2ddf188c@popa.melbpc.org.au>
Message-ID: <35D102FE.96DBCFBE@earthlink.net>

This sounds the same as the circuit in the National Semiconductor
Application Note 299. (The op amps are LF412 there). You can get this
app. note off the National Web site.

  Ian


Paul Perry wrote:
> 
> At 01:36 PM 11/08/98 -0400, Andrew Schrock  wrote:
> >I know this has been tossed around before, but has anybody come up with a
> >good non-CEM, non-SSM VCA solution?
> 
> Jim Williams published one in EDN using 3 LF421 op amps and a LM394 matched
> pair and a 2n2222. The hard part is bleedthrough, in his there isn't much,
> even with 10v pp input. There is a separate "cancellation" part of the ckt



From costello at seanet.com  Wed Aug 12 05:01:49 1998
From: costello at seanet.com (Sean Costello)
Date: Tue, 11 Aug 1998 20:01:49 -0700
Subject: vca: no CEM, no SSM (was: ssm-2040)
References: <1.5.4.16.19970103180735.2ddf188c@popa.melbpc.org.au>
Message-ID: <35D1059D.3C9B8DE4@seanet.com>

> At 01:36 PM 11/08/98 -0400, Andrew Schrock  wrote:
> >I know this has been tossed around before, but has anybody come up with a
> >good non-CEM, non-SSM VCA solution?

Well, I don't know if this is a good solution, but it might be an
interesting one: Nyle Steiner describes a circuit in "Voltage-Controlled
Amplifier Covers 70dB Range" in EDN (March 5, 1975, p.72).  Apparently
the circuit uses 5 transistors and a series string of 8 diodes. 
According to Bernie Hutchin's description of the article, "Carefully
matched components are not required."  

I was going to go to UW to photocopy the article today after work, but I
ended up staying at home and making a loop of "Sister Ray" by the Velvet
Underground on my little SP-202 sampler.  Not terribly conducive to
sanity.

Steiner also has an article in the December 6, 1974 issue of Electronic
Design, describing a voltage controlled low pass/high pass/bandpass
filter.  I only know 3 things about it:

1) It uses diodes as the CV elements;
2) It is NOT a state-variable design; and
3) The University of Washington doesn't have that issue of Electronic
Design.

So, any kind souls out there have access to a good university library, a
photocopier, and a scanner? 

Later,

Sean Costello



From honcho at paia.com  Wed Aug 12 05:20:07 1998
From: honcho at paia.com (honcho at paia.com)
Date: Tue, 11 Aug 98 22:20:07 CDT
Subject: AW: moog 905 spring reverb
Message-ID: <9808120320.AA02302@qns1.qns.net>

>>Very interesting idea !
>>Just to know if I got this right, you take two complete reverb 
>>*tanks*, each with 2 or 3 springs, and connect them together?


>Exactly. I forget who gets the credit for this one; it's either John
>Simonton or Craig Anderton. I don't have the info handy. Is it 
>archived at the PAiA site?
>>>

Credit where it's due, this is one of Craig's. It isn't at the site 
linked to anything but I did put up a quick and dirty schematic a 
while ago at www.paia.com/hotsp001.jpg . Apologies that time isn't 
available for something prettier but I'm deep in module land.

Note in particular, though, the reversal of polarity on the send 
transducer(s) on _one_ of the tanks and that the tanks _must_ be 
identical.

It's still in production, BTW, but is listed only in our print 
catalog. More details will make their way to the site one of these 
days - probably about the time all the stomp-boxes and so on do.

-JS

---------------------------------------------------------
John Simonton                  PAiA Electronics, Inc
3200 Teakwood Ln.              honcho at paia.com
Edmond OK 73013                http://www.paia.com
405-340-6300                   fax 405-340-6378



From ka4hjh at gte.net  Wed Aug 12 06:01:16 1998
From: ka4hjh at gte.net (KA4HJH)
Date: Wed, 12 Aug 1998 00:01:16 -0400
Subject: nuvista
In-Reply-To: <00a101bdc56f$e095d740$72c648c2@default>
Message-ID: <v04011701b1f6c2742c8a@[208.255.152.190]>

>Anyway, my question, I was reading a Hi-Fi magazine in the library (sad
>is'nt it?) and an article about a new pre-amp caught my eye. It uses
>Nuvistas, some sort of mini-valve, with all the inherent advantages of
>valves/tubes and the compactness of trannies. Small metal canisters about
>the size of a BFY33, I think. Pictures can be deceptive. Does anyone know
>more about these wee beasties?

One place you'll find them is at the front end of transition-era Tek 'scope
amplifiers. Everytime I see some modules for sale at a hamfest the first
thing I do is check to see if they've been pulled--they usually have. If
you're lucky you'll find some for sale at the same event.

I hate to say it but maybe this is another one of those parts that should
be left for repairs, attractive as they might be. But this IS a free
country...

Terry Bowman, KA4HJH
"The Mac Doctor"



From ka4hjh at gte.net  Wed Aug 12 06:04:55 1998
From: ka4hjh at gte.net (KA4HJH)
Date: Wed, 12 Aug 1998 00:04:55 -0400
Subject: AW: moog 905 spring reverb
In-Reply-To: <26af5a70.35d0d38c@aol.com>
Message-ID: <v04011702b1f6c3e883f2@[208.255.152.190]>

> If I'm not mistaken , I seem to remember reading about this reverb circuit
>years ago in Anderton's book "Electonics Projects for Musicians". I think he
>called it "Hot Springs or Hot Plate reverb".  What Anderton had wrote about
>the circuit and the sound of the reverb got me really curious but I never
>built it.
> I do however, remember building the ring modulator from this book when I was
>in high school and taking it to a friends house to try it with his guitar. He
>had no idea what it was and probably thought I was from Mars! He did say that
>he liked it though.

I've built the ring modulator, the tube-sound fuzz, and the compressor. I
don't have a proper-sounding guitar to really evaluate the fuzz (althogh it
does work and is idiotically simple to build), but the other two work
pretty well. I was rather surprised at how effective (and clean) the
compressor was for such a simple circuit.

Terry Bowman, KA4HJH
"The Mac Doctor"



From 9705146x at lux.levels.unisa.edu.au  Wed Aug 12 06:11:04 1998
From: 9705146x at lux.levels.unisa.edu.au (BuDWeiSeR)
Date: Wed, 12 Aug 1998 13:41:04 +0930 (CST)
Subject: Transistors used in Tomg's projects...
Message-ID: <Pine.SOL.3.91.980812133409.18815B-100000@lux.levels.unisa.edu.au>

In general, reffering to the EMS filter design VCF-6A, could BC547 and 
548s be used instead of the 2n3904 and 2n3906? The transistors used are 
harder to obtain at local electronic stores here in Australia...

you'll have to excuse the qulaitym of my typing.. ive just had a 
barbarque with the student association with lots of free 
beer......................



<b   U d >


wooooops



From martin.czech at intermetall.de  Wed Aug 12 08:56:46 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Wed, 12 Aug 1998 08:56:46 +0200 (MET DST)
Subject: Variable Caps -Reply
Message-ID: <199808120656.IAA09208@window.intermetall.de>

> Many many years ago (like in the 80's man), my dad
> was helping me make a little radio tuner. We
> simply went to the local electronics store and
> picked up a variable cap designed for the purpose.
> It already had a dial attached to it. It was about
> an inch square, and half an inch high.
> 
> I'd be surprised if they don't make these any
> more, but if not, you can probably get one out of
> a Radio Shack crystal radio kit.
> 
Well, modern tuners have PLLs and VCOs and the like.  They use variable
capacitance diodes instead of costly mechanics.  These mechanical
things need quite exact manufacturing, the cap plates must fit very
good, otherwise you'll get a short, on the other hand the distance
between plates is reduced to minimum...  Most of these things have a
gear, one knob revolution is turned into 1/5 of the plate package or
so. Maybe you can try to find old radios to slay them...

m.c.




From debus at cityweb.de  Wed Aug 12 09:06:00 1998
From: debus at cityweb.de (Ingo Debus)
Date: Wed, 12 Aug 1998 09:06:00 +0200
Subject: soldid-state keyboards
References: <35CF42B2.3FA289D@vossnet.de>
Message-ID: <35D13ED6.55D0@cityweb.de>

tim0 (Timo Christ) wrote:
> what are the diadvantages of this style keyboards ? i see that people
> used to ordinary keyboards probably wouldn?t like it.. => no keys to
> press.

IMO any controller (be it a keyboard or something else) has its own
advantages and allows playing techniques that others don't.
I never played on such a solid state keyboard, but I'm sure glissandi
and staccato notes are much easier to play than on a piano-type
keyboard. On the other hand, key velocity might be controlled better on
a keyboard with moving keys. 

> Are there alternative solutions to a solid-state keyboard ?

What about the "Touch Responsive Keyboard" from Serge? Someone on this
list posted a link.

> BTW: i have desoldered four 726 ICs from a 100% working radio.

Which function does a 726 have in a radio?

Ingo




From karlto at invalid.ed.ntnu.no  Wed Aug 12 09:11:19 1998
From: karlto at invalid.ed.ntnu.no (Karl Helmer Torvmark)
Date: Wed, 12 Aug 1998 09:11:19 +0200 (MET DST)
Subject: ssm-2040
In-Reply-To: <Pine.SGI.3.95.980811133421.23724A-100000@pearl.cs.brandeis.edu>
Message-ID: <Pine.LNX.3.96.980812090440.508A-100000@invalid.ed.ntnu.no>


On Tue, 11 Aug 1998, Andrew Schrock wrote:

> I know this has been tossed around before, but has anybody come up with a
> good non-CEM, non-SSM VCA solution? I mean, there's nothing WRONG with
> using a 3080, except the quality won't be terrific. All the designs I've
> seen online have been of the CEM3330 or 3080+dual opamp variety. 
> 

There's one based on a Gilbert multiplier, using the CA3046 transistor
array in issue 5 of Modulus (www.geocities.com/SiliconValley/Park/2707/).
Haven't tried it yet, but it looks promising.

BTW, anybody know if/when Paul Maddox is going to update the site? (I know
he's had some personal problems, he said he'd be back early in '98)

---------------
Karl H.




From tim at redragon.demon.co.uk  Wed Aug 12 09:55:04 1998
From: tim at redragon.demon.co.uk (Tim Cockram)
Date: Wed, 12 Aug 1998 08:55:04 +0100
Subject: Doepfer VCO
Message-ID: <fnasDCAYpU01Ewtc@redragon.demon.co.uk>

Doepfer have the "service manual" for thier 110 vco on line@  

www.doepfer.de/a110_tec.htm

It's quite interesting.

The octave selection is clever (a bcd switch with 3 reference currents
derived from R, R//R and R+R)

I bought a "RS Integrator" VCO which was claimed to be of higher quality
but the circuitry (I drew the schematic before plugging it in, sad) IMO
is not as good an engineering solution as the a110.  Having said that
the Integrator vco does it's job.

May be I'm more engineer than musician but I do like multiturn presets
for setting scaling etc.

Regards 

Tim
  
-- 
Tim Cockram



From Juergen.Haible at nbgm.siemens.de  Wed Aug 12 11:01:29 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Wed, 12 Aug 1998 11:01:29 +0200
Subject: AW: VP-330 (analog speech synthesis)
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5829906FE@nbgm336a.nbgm.siemens.de>

	>My experiences with ARP Omni's leads me
	>to believe that the Reticon chips have a much better high end
response at
	>the same clock speed than the Panasonic chips. Of course it's
possible that
	>this is only true of an SAD512 vs. an MN3002. Dunno.

The BBD chips have a HF loss all by themselves ?
I thought it was all because of the anti-aliasing filter,
but I have never thought any further ... So, do you really
loose HF in the buckets ?

JH.



From jorgen.bergfors at idg.se  Wed Aug 12 11:29:38 1998
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Wed, 12 Aug 1998 10:29:38 +0100
Subject: VCO in AN-299
Message-ID: <TFSIGYMA@idg.se>

Has anybody tried the VCO in National Semiconductor's Application Note 299, 
figure 1? It is a 1 V/oct VCO that is supposed to be virtually free of 
temperature dependence. And it does not use tempco resistors or heaters. It is 
a sipmle circuit with two opamps and one CA3046, that produces a sawtooth 
output. It seems a bit too good to be true. Are there any gotchas? The 
exponential conformity is said to be within 0,25% from 20 Hz to 15 kHz.

/Jorgen




From martin.czech at intermetall.de  Wed Aug 12 11:33:53 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Wed, 12 Aug 1998 11:33:53 +0200 (MET DST)
Subject: AW: VP-330 (analog speech synthesis)
Message-ID: <199808120933.LAA10003@window.intermetall.de>

> 	>My experiences with ARP Omni's leads me
> 	>to believe that the Reticon chips have a much better high end
> response at
> 	>the same clock speed than the Panasonic chips. Of course it's
> possible that
> 	>this is only true of an SAD512 vs. an MN3002. Dunno.
> 
> The BBD chips have a HF loss all by themselves ?
> I thought it was all because of the anti-aliasing filter,
> but I have never thought any further ... So, do you really
> loose HF in the buckets ?
> 
> JH.
> 
I'd say no specific hf loss, but specific noise.

This is a sampling system and thus the frequency response is multiplied
with the famous sin(x)/x function. This means hf loss, the first zero
appears right at Fs (sampling frequency). Remember the preemphasis bit
and circuit for early cd players ? HF was emphased (sp?) during
recording in order to correct the sin(x)/x loss when playing.
Oversampling made this obsolete, the first zero is now very far away.
Do the chips have very different sampling frequencys ? This would have
the same effect, moving the zero.

Just from my head.

m.c.




From eboyz at obv-records.com  Wed Aug 12 11:53:43 1998
From: eboyz at obv-records.com (Steve)
Date: Tue, 11 Aug 1998 23:53:43 -1000
Subject: Gate LED ckt
Message-ID: <35D16627.DD10F498@obv-records.com>

Over the weekend I was talking to Paul
S. about all things synth like and he
spewed out a very simple circuit that
will light a LED when given a gate.  I
know this is trivial electronics to
many, however to those of us who love to

make and wish we could engineer these
simple circuits can be a ton of fun in
our projects.  I think it's so sweet, I
want to share it.  Again, this 4
component circuit is a gift from someone
else.  I think it would be very nice if
anyone else has a simple utility circuit
to share would do so.  Here goes:

3904 transistor, 2 resistors and a LED.

E - tied to ground
B - tie to one end of 4.7K resistor.
Other end of resistor to GATE.
C- tie to cathode of LED. Tie anode to
1.5k resistor. Tie other end of
1.5K to +15V

Have fun,
Steve in Hawaii


PS I would like a design for a simple
mixer (say 3 or 4 inputs) to be used for
mixing CV signals.





From Colin.Fraser at scottishpower.plc.uk  Wed Aug 12 12:13:32 1998
From: Colin.Fraser at scottishpower.plc.uk (Fraser, Colin J)
Date: Wed, 12 Aug 1998 11:13:32 +0100
Subject: AW: VP-330 (analog speech synthesis)
Message-ID: <81880CC73125D211BC6800805F0D83070C4B@spresource.cat.scottishpower.plc.uk>

> -----Original Message-----
> From: Martin Czech [mailto:martin.czech at intermetall.de]
> Sent: 12 August 1998 10:34
> To: synth-diy at mailhost.bpa.nl; smart at nn.com;
> Juergen.Haible at nbgm.siemens.de
> Subject: Re: AW: VP-330 (analog speech synthesis)
> 
> I'd say no specific hf loss, but specific noise.
> 
 

I would have thought that the resistance of the analogue switches
between 'buckets' and the capacitor buckets themselves would have a low
pass filter behaviour.

Just a thought... Do the specs for these chips detail the on resistance
of the switches between stages ?

Colin f



From pfperry at melbpc.org.au  Wed Aug 12 12:22:54 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Wed, 12 Aug 1998 20:22:54 +1000 (EST)
Subject: VCO in AN-299
Message-ID: <1.5.4.16.19970104025646.22a77834@popa.melbpc.org.au>

At 10:29 AM 12/08/98 +0100, jorgen.bergfors wrote:
>Has anybody tried the VCO in National Semiconductor's Application Note 299, 
>figure 1? It is a 1 V/oct VCO that is supposed to be virtually free of 
>temperature dependence. And it does not use tempco resistors or heaters. 

....er, the CA3046 in this ckt IS the heater, at least, one of the transistors
 in it is. The circuit does work.
Incidentally, the vca ckt also in this app note is also designed by Jim
Williams..

paul perry melbourne australia




From jorgen.bergfors at idg.se  Wed Aug 12 14:21:26 1998
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Wed, 12 Aug 1998 13:21:26 +0100
Subject: VCO in AN-299
Message-ID: <TFSKOBOI@idg.se>

MIME:pfperry at melbpc.org.au on 98-08-12 14.02.04
To:  synth-diy at mailhost.bpa.nl @ SMTP 
cc:  (bcc: Jorgen Bergfors/IDGSE)
Subject: Re: VCO in AN-299 

At 10:29 AM 12/08/98 +0100, jorgen.bergfors wrote:
>>Has anybody tried the VCO in National Semiconductor's Application Note 
299, 
>>figure 1? It is a 1 V/oct VCO that is supposed to be virtually free of 
>>temperature dependence. And it does not use tempco resistors or 
heaters. 

>....er, the CA3046 in this ckt IS the heater, at least, one of the 
>transistors
 >in it is. The circuit does work.
>Incidentally, the vca ckt also in this app note is also designed by Jim
>Williams..

>paul perry melbourne australia

Well, the text says "Figure 1 shows a circuit which eliminates all temperature 
compensation requirements".
But yes, you are right. It is the seme circuit as before, they just have 
redrawn it and removed all text about heating and temperature compensation. 
Sneaky of them. The old schematic is in Modulus 1, I just checked. 

/Jorgen









From deknow at tiac.net  Wed Aug 12 14:25:27 1998
From: deknow at tiac.net (dean stiglitz)
Date: Wed, 12 Aug 1998 08:25:27 -0400
Subject: new magazine article you must see!
References: <01BDC50F.015B8BC0.ebarbour@svetlana.com>
Message-ID: <35D189B7.6B525C82@tiac.net>

i haven't finished the article yet, but so far i have found it quite
informitive (much better then the article they had on "new" controlers
for music a few months back).

deknow

Eric Barbour wrote:

> Get the new August issue of IEEE SPECTRUM magazine.
> You'll find the cover story most fascinating. (I wrote it...)
>
> If your local digital nerds have been giving you grief because of
> your interest in tube audio, this article is great ammunition
> in your favor. You can point out the distortion tests showing
> that tubes have electrical advantages over transistors for audio
> design. (You can also point out that this article passed the standard
> IEEE peer-review procedure with flying colors.)
>
> SPECTRUM is available from large book dealers and newsstands,
> and is carried in virtually every university library.
>
> Eric Barbour
> Svetlana Electron Devices
> Portola Valley CA USA






From ka4hjh at gte.net  Wed Aug 12 15:26:25 1998
From: ka4hjh at gte.net (KA4HJH)
Date: Wed, 12 Aug 1998 09:26:25 -0400
Subject: AW: moog 905 spring reverb
In-Reply-To: <1.5.4.16.19970104031620.396f8a9c@popa.melbpc.org.au>
Message-ID: <v04011701b1f746ffc03b@[208.255.152.42]>

>were you suprised how unlike a 'real' ring modulator the RM was? ;-)

Whaddaya want from a triangle wave? Besides, with a guitar it still sounds
a hell of a lot like DEVO. And it was a lot cheaper than Paul's, which
wasn't available quite yet at the time, although I bought the essentials
while they were on sale. Maybe I could add Tom's sine convertor...

Which reminds me: I have a bunch of AD533's that were pulled from equipment
and don't know how to test them without going to a lot of trouble. Can you
believe they used to shotgun them and throw the old ones away???

Terry Bowman, KA4HJH
"The Mac Doctor"



From ijfritz at earthlink.net  Wed Aug 12 15:46:26 1998
From: ijfritz at earthlink.net (Ian Fritz)
Date: Wed, 12 Aug 1998 07:46:26 -0600
Subject: VCO in AN-299
References: <TFSIGYMA@idg.se>
Message-ID: <35D19CB2.476669ED@earthlink.net>

Jorgen --

It *does* use a heater. Q3 is the heater, Q6 is a clamp, Q4 is the
sensor and A2 is the servo amp. This is explained on p. 2 of the
article.

  Ian

jorgen.bergfors at idg.se wrote:
> 
> Has anybody tried the VCO in National Semiconductor's Application Note 299,
> figure 1? It is a 1 V/oct VCO that is supposed to be virtually free of
> temperature dependence. And it does not use tempco resistors or heaters. It is
> a sipmle circuit with two opamps and one CA3046, that produces a sawtooth
> output. It seems a bit too good to be true. Are there any gotchas? The
> exponential conformity is said to be within 0,25% from 20 Hz to 15 kHz.
> 
> /Jorgen



From sky36919 at skynet.be  Wed Aug 12 16:26:58 1998
From: sky36919 at skynet.be (Hugo Haesaert)
Date: Wed, 12 Aug 1998 16:26:58 +0200
Subject: AW: VP-330 (analog speech synthesis)
In-Reply-To: <199808120933.LAA10003@window.intermetall.de>
Message-ID: <199808121545.RAA24734@papagena.skynet.be>

Hi All !

The sampling rate for the panasonic ics goes only to 100KHz or 200KHz 
for the LP ones (Maplin catalogue) .  The Reticons got up to 1.5MHz
(SAD1024, 512) or 1MHz (SAD4096) .
Roland might have used a lower cutoff to be on the safe side with the 
Panasonics .  Only the schematics can tell, and i haven't got them 
:)

Later .

Keep 'em oscillating :)

Hugo
=



From martin.czech at intermetall.de  Wed Aug 12 17:10:21 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Wed, 12 Aug 1998 17:10:21 +0200 (MET DST)
Subject: additive
Message-ID: <199808121510.RAA11571@window.intermetall.de>

> hi guy's.
> theoretcly any acostic sound can be made in a modular
> ether by addtive or FM but this is hard to be made.
> so my qustion is can i play a acostic instrument like a
> pino or violin or other in to a mic and then in to a scope
> and see its waveshape and envelope and then calculaite
> this data and creat the same sound on a modular ?

If I've got you right you mean that if you hear a sound, you'll be not
able to derive a patch and parameters in order to emulate this sound.
And you hope to find these parameters by a scope printout.
Well, for simple sounds, like a recorder (softly blown) this will work,
but in this case you don't need it, because you allready hear what's going on
and it is simple to derive a patch.

For very complex sounds this won't work at all, you will not be able to
even trigger the scope, since the waveform is changing all the time. It can
even be hard to see the envelope. Of course you can use a DSO and
record the instrument in full length, but then you are on the way to
sampling. The waveform does not determine the sound, there are a lot of
waveforms that sound equal, but they don't look equal (simply do
Fourier analysis of, say, a saw wave, and then mix the partials
together again, but with random phase values. Gives very differnent
scope shots, but sounds the same.

No sorry, there is nothing better then listening/patching experience.

> all so is ther any scope or other unit that can take a waveshape
> and do the calculate and give a data of how many sine osc in
> what freq, amplitude and phase do i need to creat the
> same waveshape.

Well there is, it's called Resynthesis and it is usually a software
package for one of these big digital audio workstations (like Fairlight
or Synclavier or Waveterm (or my Atari with Microwave ;->)). You have
to chop the incomming waveform into chunks (windows) of proper size, do
a FFT and voila, you've got an approximation of harmonic content.  This
harmonic data can be used to resynthesize a chunk of waveform (inverse
FFT). For good results you'll need > 128 harmonics, and I think this
amount can't be handled with analog methods any more, this is clearly
for the digital domain. Of course there is no reason why it can't be
done analog, but cost. You also need a clever method to avoid
problems at the ends of the chunks, so overlapping windows etc. might
be neccessary. I've tryed to do this with speech, and it worked
surprisingly good (only 64 harmonics and 63 chunks).  Noise components
are resynthesized by always changing from chunk to chunk, so the method
uses harmonic functions, but is (via windowing) able to cope with
inharmonic stuff as well.

m.c.






From aschrock at cs.brandeis.edu  Wed Aug 12 17:18:20 1998
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Wed, 12 Aug 1998 11:18:20 -0400 (EDT)
Subject: additive
In-Reply-To: <3.0.2.16.19980813011131.2147381a@mail.internet-zahav.net>
Message-ID: <Pine.HPP.3.95.980812110751.23983A-100000@bay.cs.brandeis.edu>

On Thu, 13 Aug 1998, Gur Milstein wrote:
> hi guy's.

Hi Gur! 

> theoretcly any acostic sound can be made in a modular
> ether by addtive or FM but this is hard to be made.
> so my qustion is can i play a acostic instrument like a
> pino or violin or other in to a mic and then in to a scope
> and see its waveshape and envelope and then calculaite
> this data and creat the same sound on a modular ?
> all so is ther any scope or other unit that can take a waveshape
> and do the calculate and give a data of how many sine osc in
> what freq, amplitude and phase do i need to creat the
> same waveshape.
> or even a unit that is cv conected to sin vco's and automaticly
> creat the waveshape.

Well, the main problem with doing additive synthesis on a modular in my
eyes is that to get a decent number of harmonics, you would need at bare
minimum a VCO and VCA _per_ harmonic. This means 64 or 128 sinewave VCO's
and VCA's... eek! A lot of trouble. 

Basically a modular is made to do subtractive synthesis. I'm sure you
_could_ do other stuff, but it would be difficult. Remember that VCO's
already output waves with lots of signature harmonics (squarewave for
example).. it's more typical to take those waves which are already
"constructed" if you will and use those. You could do some very basic
additive synthesis on a large-ish modular, much as you can do very basic
FM synthesis on a large-ish modular, but it's kinda difficult IMO. 

I will keep praises of my newly aquired k5000 off this list due to obvious
off-topic-ness, but it's simply amazing. Some of the sharpest sounds and
lushest pads I've ever heard, and it's all additive... 128 harmonics per
"voice", up to 6 "voices" per "patch".. a VCA per harmonic, formant
filter, PCM samples for non-harmonic stuff like noise.. it's all here... I
haven't delved too deeply into it yet, but I salivate in anticipation at
having enough time to. 

As another somewhat relavent answer to your question, apparently the k5000
is supposed to be able to load in a .wav directly via sounddiver, but it
doesn't work too well. Or so I hear. 

Andrew

| Andrew Schrock							|
| Network Programmer, Synthesizer and electronic music enthusiast	|
| aschrock at cs.brandeis.edu						|





From smart at nn.com  Wed Aug 12 17:25:12 1998
From: smart at nn.com (Mark Smart)
Date: Wed, 12 Aug 1998 10:25:12 -0500 (CDT)
Subject: AW: VP-330 (analog speech synthesis)
In-Reply-To: <1BF5E20E0C4DD111BBAB00805FE2D5829906FE@nbgm336a.nbgm.siemens.de> from "Haible Juergen" at Aug 12, 98 11:01:29 am
Message-ID: <199808121525.KAA02665@medusa.nn.com>

> The BBD chips have a HF loss all by themselves ?
> I thought it was all because of the anti-aliasing filter,
> but I have never thought any further ... So, do you really
> loose HF in the buckets ?
> 
> JH.

Yep.

My test was very simple. After I got an Omni II it became clear how much
better the chorus sounded on the Omni II than on the Omni I. I poked around
to figure out why. The sampling frequency is actually slightly HIGHER on
the Omni I, so that wasn't it. Listening to different places on the chorus
board of the Omni I, I found that the signal sounded fine when it went into
the analog delay chip, and muddy when it came out (before the antialiasing
filter). It seemed pretty clear that the MN3002 chip was the entire reason
why the Omni I sounded muddy. Since I don't have data on either of these
chips, I can't really speculate as to why this is true. But the 16-pin
SAD512's on the Omni II do not degrade nearly as much between input and
output. I read somewhere on the net that 16-pin SAD512's are actually
SAD1024's which only have one working half. The chips were
mis-manufactured, then the working half was wired to the pins the same way
every time so they could still use them.


************************************************
*     Mark Smart                               *
*     Electronics Engineer                     *
*     NovaNET Learning, Inc.                   *
*     smart at medusa.nn.com                      *
************************************************



From tomg at vivid.net  Wed Aug 12 17:28:14 1998
From: tomg at vivid.net (tomg)
Date: Wed, 12 Aug 1998 10:28:14 -0500
Subject: Transistors used in Tomg's projects...
In-Reply-To: <Pine.SOL.3.91.980812133409.18815B-100000@lux.levels.unisa.edu.au>
Message-ID: <yam7528.713.120210504@mail.vivid.net>


On 11-Aug-98, BuDWeiSeR wrote:
>In general, reffering to the EMS filter design VCF-6A, could BC547 and 
>548s be used instead of the 2n3904 and 2n3906? The transistors used are 
>harder to obtain at local electronic stores here in Australia...

any gen purpose npn/pnp should work. ie 2sc945/2sa733.

-tg




From frequency91 at hotmail.com  Wed Aug 12 17:35:26 1998
From: frequency91 at hotmail.com (Graeme Nelson)
Date: Wed, 12 Aug 1998 08:35:26 PDT
Subject: free electronic software links
Message-ID: <19980812153526.3430.qmail@hotmail.com>

hi all -

for those of you looking for some free electronic software here is the 
link for you:

http://www.hut.fi/Misc/Electronics/software.html

I tried out the Simetrix schematic/simulation software for about 10 
minutes.  It was easy to print out the schematic on a network laser 
printer.  I too tried the other software products circad and pads, but I 
was unable to print out anything.

I hope this helps.  by the way, I am new to this list and electronics.  
So at this time I am only able to contribute software links to this 
list. But I want to thank you all for supplying your knowledge on the 
art of synth building.

graeme

______________________________________________________
Get Your Private, Free Email at http://www.hotmail.com



From don at till.com  Wed Aug 12 17:35:41 1998
From: don at till.com (Don Tillman)
Date: Wed, 12 Aug 1998 08:35:41 -0700 (PDT)
Subject: Differential Reverb (better subject line!)
In-Reply-To: <9808120320.AA02302@qns1.qns.net> (honcho@paia.com)
Message-ID: <199808121535.IAA16993@shell9.ba.best.com>

   From: honcho at paia.com
   Date: Tue, 11 Aug 98 22:20:07 CDT

   >>Just to know if I got this right, you take two complete reverb 
   >>*tanks*, each with 2 or 3 springs, and connect them together?

This is a very interesting and clever idea.  I'm eager to hear the
nuances of the reverb sound as you subtract the signal from the second
tank.

Does Accutronics know about this?  I could imagine a high-end reverb
tank product from those guys with four separate reverb spring sets
(for stereo!) all mounted on a common subassembly mechanically tweaked
to fit in a 1-rack high unit.

Each of the current Accutronics spring reverb tanks, the higher
quality models, contains three spring pairs.  So this monster tank
would have 12 spring pairs!  For a better stereo sound make the
springs designated for one channel a little less delay than the
springs for the other.

   Credit where it's due, this is one of Craig's. It isn't at the site 
   linked to anything but I did put up a quick and dirty schematic a 
   while ago at www.paia.com/hotsp001.jpg .

   Note in particular, though, the reversal of polarity on the send 
   transducer(s) on _one_ of the tanks and that the tanks _must_ be 
   identical.

A couple of friendly suggestions for this circuit:

Invert the receive transducers instead of the send transducers; hum
cancelling for free!

Accutronics recommends using lots of drive current; more than an opamp
could provide.  Their application note has half-a-dozen drive
circuits.

  -- Don



From martin.czech at intermetall.de  Wed Aug 12 17:59:27 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Wed, 12 Aug 1998 17:59:27 +0200 (MET DST)
Subject: additive
Message-ID: <199808121559.RAA11681@window.intermetall.de>

> 
> Basically a modular is made to do subtractive synthesis. I'm sure you
> _could_ do other stuff, but it would be difficult. Remember that VCO's

mmh, let put it this way, many people do only substractive synthesis,
you know, if you are used to a mini-moog likle structure...  I think
the expression "subtractive synthesis" is not very helpfull nor good.
Ok, you can read it in the books. But really, if you take a saw wave
and mix it with two bandpass filtered versions of this very saw wave,
can this be described as "subtractive"? I hear the saw wave with two
formant peaks ADDED, nothing substracted. This was a very simple patch,
nothing sophisticated.  Or take a ringmodulator, or a waveshaper, etc.
etc.  etc. This is not substractive at all. I don't know how this
expression came up in the public, but I gues it was in the mid 70's,
when polyphony led to synthis which where basically substractive, like 
a Prophet 5.


> As another somewhat relavent answer to your question, apparently the k5000
> is supposed to be able to load in a .wav directly via sounddiver, but it
> doesn't work too well. Or so I hear. 
> 
Ok, but what happens after loading the wave? Is there any chance to do 
resynthesis ? I've never heard about this, but this could be very
interesting. After a while the K5000 was really sold out, for ridicolous
prizes.

m.c.




From jamos at technotoys.com  Wed Aug 12 18:12:27 1998
From: jamos at technotoys.com (Jim Johnson)
Date: Wed, 12 Aug 1998 09:12:27 -0700
Subject: additive
In-Reply-To: <3.0.2.16.19980813011131.2147381a@mail.internet-zahav.net>
References: <3.0.2.16.19980813011131.2147381a@mail.internet-zahav.net>
Message-ID: <199808120912270860.11B54C7E@mail.proaxis.com>

>theoretcly any acostic sound can be made in a modular
>ether by addtive or FM but this is hard to be made.

No, it's not theoretically possible to do that.

>so my qustion is can i play a acostic instrument like a
>pino or violin or other in to a mic and then in to a scope
>and see its waveshape and envelope and then calculaite
>this data and creat the same sound on a modular ?

I've never heard of such a tool. I doubt that it is possible. 

Remember that there is a lot more to recreating a sound than simply knowing
its "waveshape and envelope". Both of these change over time, with pitch,
playing technique, etc.

Sampling was the first-generation attempt at creating fully realistic
electronic simulations of acoustic instruments. Physical modeling is the
second-generation attempt. People did attempt to simulate acoustic
instruments with analog synths, digital FM synths, even organs (!), but
nobody ever claimed that these were or are substitutes for the originals.
Fortunately, synthesizers are now mostly used for the purpose God intended:
the creation of sounds not possible with other instruments.

Jim Johnson 
Metaphoric Software
-------------------
Makers of Techno Toys
Software for Electronic Music
http://www.technotoys.com
info at technotoys.com

*********** REPLY SEPARATOR ***********

On 8/13/98, at 1:11 AM, Gur Milstein wrote: 

>hi guy's.
>theoretcly any acostic sound can be made in a modular
>ether by addtive or FM but this is hard to be made.
>so my qustion is can i play a acostic instrument like a
>pino or violin or other in to a mic and then in to a scope
>and see its waveshape and envelope and then calculaite
>this data and creat the same sound on a modular ?
>all so is ther any scope or other unit that can take a waveshape
>and do the calculate and give a data of how many sine osc in
>what freq, amplitude and phase do i need to creat the
>same waveshape.
>or even a unit that is cv conected to sin vco's and automaticly
>creat the waveshape.
>
>thanx
>Gur Milstein



From mmcintos at ball.com  Wed Aug 12 18:32:20 1998
From: mmcintos at ball.com (McIntosh, Malcolm)
Date: Wed, 12 Aug 1998 10:32:20 -0600
Subject: additive
Message-ID: <09DB74475204D1119C8200805F19D0032D12AF@aeromsg1.ball.com>

Hi all,

This is a subject I have been thinking about with no idea how to
implement.

Would it be possible to use frequency multiplication and one really good
sine wave VCO for limited additive synthesis?  Would it be necessary to
have 64 or 128 harmonics if you just wanted to make some really nice
sounds but not be totally imitative?  Could you get away with 16 or
maybe 8 (!) harmonics to make really interesting non-imitative sounds?

Forgive anything I have over looked.

Malcolm

> -----Original Message-----
> From:	Andrew Schrock [SMTP:aschrock at cs.brandeis.edu]
> Sent:	Wednesday, August 12, 1998 8:18 AM
> To:	Gur Milstein
> Cc:	synth-diy
> Subject:	Re: additive
> 
> On Thu, 13 Aug 1998, Gur Milstein wrote:
> > hi guy's.
> 
> Hi Gur! 
> 
> > theoretcly any acostic sound can be made in a modular
> > ether by addtive or FM but this is hard to be made.
> > so my qustion is can i play a acostic instrument like a
> > pino or violin or other in to a mic and then in to a scope
> > and see its waveshape and envelope and then calculaite
> > this data and creat the same sound on a modular ?
> > all so is ther any scope or other unit that can take a waveshape
> > and do the calculate and give a data of how many sine osc in
> > what freq, amplitude and phase do i need to creat the
> > same waveshape.
> > or even a unit that is cv conected to sin vco's and automaticly
> > creat the waveshape.
> 
> Well, the main problem with doing additive synthesis on a modular in
> my
> eyes is that to get a decent number of harmonics, you would need at
> bare
> minimum a VCO and VCA _per_ harmonic. This means 64 or 128 sinewave
> VCO's
> and VCA's... eek! A lot of trouble. 
> 
> Basically a modular is made to do subtractive synthesis. I'm sure you
> _could_ do other stuff, but it would be difficult. Remember that VCO's
> already output waves with lots of signature harmonics (squarewave for
> example).. it's more typical to take those waves which are already
> "constructed" if you will and use those. You could do some very basic
> additive synthesis on a large-ish modular, much as you can do very
> basic
> FM synthesis on a large-ish modular, but it's kinda difficult IMO. 
> 
> I will keep praises of my newly aquired k5000 off this list due to
> obvious
> off-topic-ness, but it's simply amazing. Some of the sharpest sounds
> and
> lushest pads I've ever heard, and it's all additive... 128 harmonics
> per
> "voice", up to 6 "voices" per "patch".. a VCA per harmonic, formant
> filter, PCM samples for non-harmonic stuff like noise.. it's all
> here... I
> haven't delved too deeply into it yet, but I salivate in anticipation
> at
> having enough time to. 
> 
> As another somewhat relavent answer to your question, apparently the
> k5000
> is supposed to be able to load in a .wav directly via sounddiver, but
> it
> doesn't work too well. Or so I hear. 
> 
> Andrew
> 
> | Andrew Schrock
> |
> | Network Programmer, Synthesizer and electronic music enthusiast
> |
> | aschrock at cs.brandeis.edu
> |
> 



From aschrock at cs.brandeis.edu  Wed Aug 12 19:01:55 1998
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Wed, 12 Aug 1998 13:01:55 -0400 (EDT)
Subject: additive
In-Reply-To: <199808121559.RAA11681@window.intermetall.de>
Message-ID: <Pine.SGI.3.95.980812125259.27936B-100000@pearl.cs.brandeis.edu>

On Wed, 12 Aug 1998, Martin Czech wrote:
> mmh, let put it this way, many people do only substractive synthesis,
> you know, if you are used to a mini-moog likle structure...  I think
> the expression "subtractive synthesis" is not very helpfull nor good.
> Ok, you can read it in the books. But really, if you take a saw wave
> and mix it with two bandpass filtered versions of this very saw wave,
> can this be described as "subtractive"? I hear the saw wave with two
> formant peaks ADDED, nothing substracted. This was a very simple patch,
> nothing sophisticated.  Or take a ringmodulator, or a waveshaper, etc.
> etc.  etc. This is not substractive at all. I don't know how this
> expression came up in the public, but I gues it was in the mid 70's,
> when polyphony led to synthis which where basically substractive, like 
> a Prophet 5.

I think the term is just used as a generic rule of thumb.. as a 
comparison, the k5000 is additive, but has subtractive filters. In the
example you gave, what was subtracted was everything not inside of the BP
filters you used. You are correct, many modules are in fact not
subtractive, but in terms of a _general_ description it fits. (And as a
description goes, it fits much better than "analog" synthesis IMO) 

> Ok, but what happens after loading the wave? Is there any chance to do 
> resynthesis ? I've never heard about this, but this could be very
> interesting. After a while the K5000 was really sold out, for ridicolous
> prizes.
  ^^^^^^ prices? 

A k500 should do the job fine, too, from what I understand. Yes, the k5000
is pretty cheap right now. I had to pay a little more for mine, but hey,
I'm quite happy with it. You can resynthesize and twiddle individual
envelopes / harmonics to your hearts content. 

Andrew

| Andrew Schrock							|
| Network Programmer, Synthesizer and electronic music enthusiast	|
| aschrock at cs.brandeis.edu						|






From cstecker at ovenguard.com  Wed Aug 12 19:42:58 1998
From: cstecker at ovenguard.com (Chris Stecker)
Date: Wed, 12 Aug 1998 09:42:58 -0800
Subject: additive
Message-ID: <v02110100b1f781abb6e4@[205.134.244.189]>

The difficulty with the analysis-synthesis approach you describe
comes from the large number of oscillators necessary to produce
a convincing reproduction of a natural acoustic sound.  Anywhere
from 50 to 300 or more may be necessary, depending on what other
processes you use to produce transients, noises, etc.  This tends
to be more oscillators than found in modular analog synths, so
the obvious solution is to go digital, emulating these oscillators
in software.

This approach has been studied extensively at Berkeley's CNMAT
(http://cnmat.berkeley.edu), where they have used SGI machines
to do real-time (controllable!) digital additive synthesis.
With the advent of MSP for PowerPC Macintoshes, similar techniques
can be achieved with more modest computational setups.
(see http://www.cycling74.com about MSP)

The main difficulty in doing this is not the synthesis itself
(if you know the freq, amp, and phase data, it can easily be
programmed), but the analysis.  You can take an FFT of a signal,
which will show you its spectral makeup, and from this you can
identify the main harmonic peaks (for harmonic sounds).  But it's
the quiet stuff that really makes a difference in the realism of
the simulation, and these quieter components can be difficult to
pick out.  In real instruments, many of these may be inharmonic,
making the analysis procedure even more difficult.

Of course you can take the FFT representation, perform an IFFT
and resynthesize your original signal.  With MSP, you do both
the FFT and the IFFT in real-time, modifying the data in between.
You can even (as mentioned above) design procedures that try to
match an additive-resynthesized version to the real signal.  If
you have a Power Mac, and about $600 for the software (Max + MSP),
you're ready to try some experiments.  I can not recommend this
program(ming language) highly enough for prototyping ideas like
this.

-Chris Stecker



>hi guy's.
>theoretcly any acostic sound can be made in a modular
>ether by addtive or FM but this is hard to be made.
>so my qustion is can i play a acostic instrument like a
>pino or violin or other in to a mic and then in to a scope
>and see its waveshape and envelope and then calculaite
>this data and creat the same sound on a modular ?
>all so is ther any scope or other unit that can take a waveshape
>and do the calculate and give a data of how many sine osc in
>what freq, amplitude and phase do i need to creat the
>same waveshape.
>or even a unit that is cv conected to sin vco's and automaticly
>creat the waveshape.
>
>thanx
>Gur Milstein


___________________________________________________________________________

Chris Stecker

cstecker at cogsci.berkeley.edu

Graduate Student, Psychoacoustics
3210 Tolman Hall, #1650
University of California, Berkeley
Berkeley CA 94720-1650

Auditory Lab, B-50 Tolman Hall, (510)642-5352   http://ear.berkeley.edu

!!Ask me about Space Mesa, Ovenguard Music, Receptacle Culture, and CELL!!





From Romeo_Fahl at stream.com  Wed Aug 12 20:36:40 1998
From: Romeo_Fahl at stream.com (Romeo_Fahl at stream.com)
Date: Wed, 12 Aug 1998 13:36:40 -0500
Subject: Serge Negative Slewer Question
Message-ID: <0005849E.C21295@stream.com>

     I built one of these from a very old schematic.  It almost works, but 
     not quite.  The Slew output has a constant 7 V DC output with nothing 
     going into the circuit.  When I do send a sequence of voltages through 
     it, it comes out slewed, but I have no control over it from the CV 
     input or Rate control.  I disconnected the 1Meg resistor from pin 12 
     of the 3900 and that brought the DC at the output to ground.  I've 
     checked my layout, so I don't think that's the problem.  I am 
     wondering if the schematic might have any errors in it.  
     
     The schematic can be found here:  
     
     www.spiritone.com/~8brain/schems/srgslew.gif
     
     Also, no pulse at the pulse output.  I'm hoping that once I get the 
     slew output going, the pulse output will work.  
     
     Any input is appreciated!
     
     Romeo
     



From greg.be at caramail.com  Wed Aug 12 20:47:41 1998
From: greg.be at caramail.com (Greg)
Date: Wed, 12 Aug 1998 20:47:41 +0200
Subject: Doepfer VCO
Message-ID: <199808121851.UAA07179@skycorp.skynet.be>

Hi all,
I just wondered if there was any way to get the pcb's and schems for
Doepfer modules... copies or originals from Doepfer... 

greg.

----------
> De : Tim Cockram <tim at redragon.demon.co.uk>
> A : synth-diy at mailhost.bpa.nl
> Objet : Doepfer VCO
> Date?: mercredi 12 ao?t 1998 09:55
> 
> Doepfer have the "service manual" for thier 110 vco on line@  
> 
> www.doepfer.de/a110_tec.htm
> 
> It's quite interesting.
> 
> The octave selection is clever (a bcd switch with 3 reference currents
> derived from R, R//R and R+R)
> 
> I bought a "RS Integrator" VCO which was claimed to be of higher quality
> but the circuitry (I drew the schematic before plugging it in, sad) IMO
> is not as good an engineering solution as the a110.  Having said that
> the Integrator vco does it's job.
> 
> May be I'm more engineer than musician but I do like multiturn presets
> for setting scaling etc.
> 
> Regards 
> 
> Tim
>   
> -- 
> Tim Cockram
-------------- next part --------------
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From ka4hjh at gte.net  Wed Aug 12 21:12:26 1998
From: ka4hjh at gte.net (KA4HJH)
Date: Wed, 12 Aug 1998 15:12:26 -0400
Subject: Differential Reverb (better subject line!)
In-Reply-To: <199808121535.IAA16993@shell9.ba.best.com>
References: <9808120320.AA02302@qns1.qns.net> (honcho@paia.com)
Message-ID: <v04011703b1f795a059e3@[208.255.152.106]>

>A couple of friendly suggestions for this circuit:
>
>Invert the receive transducers instead of the send transducers; hum
>cancelling for free!
>
>Accutronics recommends using lots of drive current; more than an opamp
>could provide.  Their application note has half-a-dozen drive
>circuits.

I don't know what brand my tanks are, but with just op-amps they can be
overdriven, which is rather jarring.

Found some interesting info/$ on Accutronics tanks on the web:

http://www.teleport.com/~vibroman/parts/tech18.html

and

http://www.stf-electronics.com/Page0014.Html

Check it out.

Terry Bowman, KA4HJH
"The Mac Doctor"



From uzs159 at ibm.rhrz.uni-bonn.de  Wed Aug 12 22:28:03 1998
From: uzs159 at ibm.rhrz.uni-bonn.de (uzs159 at ibm.rhrz.uni-bonn.de)
Date: Wed, 12 Aug 1998 22:28:03 +0200
Subject: Minimoog Vcf
References: <35CF5612.3432478B@babcom.u-net.com>
Message-ID: <35D1FAD3.1693@ibm.rhrz.uni-bonn.de>

Steven Cook wrote:
> 
> Hi,
> 
> I've built the Minimoog vcf from the "minifilt.gif" schematic available on the
> Music Machines site and others and it doesn't work! Nothing does first time,
> but I can't find anything wrong.
> 
> The ladder network part works fine, as I have tested it using another
> differential amp circuit, but the output amp is dead.
> 
> Has anyone built this circuit successfully or does anyone know if the
> schematic is correct?
> 
> Thanks,
> 
> Steve.

In my attempt to build it from the schematic in this gif it didn't work 
either.
I suspect there is a mistake in the diff amp. (Collector of one of the 
trannies is directly connected to +10V, this one heats up in my ckt)
This "+10" seems not to be part of the original scan, but merely added 
later.
So I would be thankfull if someone could give a few hints.


Bye
 Reni



From tuan_td at yahoo.com  Wed Aug 12 22:38:55 1998
From: tuan_td at yahoo.com (Tuan Nguyen)
Date: Wed, 12 Aug 1998 13:38:55 -0700 (PDT)
Subject: additive
Message-ID: <19980812203855.12035.rocketmail@send1c.yahoomail.com>


TAKE ME OFF THIS LIST!!! thank you





_________________________________________________________
DO YOU YAHOO!?
Get your free @yahoo.com address at http://mail.yahoo.com




From oakley at enterprise.net  Wed Aug 12 23:28:19 1998
From: oakley at enterprise.net (Tony Allgood)
Date: Wed, 12 Aug 1998 22:28:19 +0100
Subject: Is this stupid?
Message-ID: <001001bdc638$804adce0$bec448c2@default>

Hi all,

This may be a stupid question but I'll ask it anyway. Has anyone ever tried
using inductors in a Moog ladder instead of the capacitors to make a VCHPF?
I guess you would need to put some cap in series with the Ls to block any
DC.

And secondly, has anyone found a need for taking a differential tap off the
ladder at another point other than below the top pair to create reduced
steepness of slope?

Regards,

Tony Allgood, Cumbria, UK

e-mail: oakley at enterprise.net




From costello at seanet.com  Thu Aug 13 00:03:03 1998
From: costello at seanet.com (Sean Costello)
Date: Wed, 12 Aug 1998 15:03:03 -0700
Subject: Minimoog Vcf
References: <35CF5612.3432478B@babcom.u-net.com> <35D1FAD3.1693@ibm.rhrz.uni-bonn.de>
Message-ID: <35D21116.9C49476@seanet.com>

uzs159 at ibm.rhrz.uni-bonn.de wrote:

> In my attempt to build it from the schematic in this gif it didn't work
> either.
> I suspect there is a mistake in the diff amp. (Collector of one of the
> trannies is directly connected to +10V, this one heats up in my ckt)
> This "+10" seems not to be part of the original scan, but merely added
> later.
> So I would be thankfull if someone could give a few hints.

Hi:

The schematic in question is one that I scanned in.  There were some
components in error on the original schematic (as compared to other
schematics) which I corrected; I may have typed in a value that is
incorrect.  I'll look at my other Minimoog VCF schematics, and see where
the problem might lie.  I'll keep the list posted.

Sean Costello





From gosd at lankaster.com  Thu Aug 13 00:55:05 1998
From: gosd at lankaster.com (Crystal)
Date: Wed, 12 Aug 1998 15:55:05 -0700
Subject: spring reverb
References: <v04011702b1f59f34f65f@[208.255.152.197]>
Message-ID: <35D21D48.3DB3@lankaster.com>

The trick is to take two springs, wire the inputs in parallel and
> the outputs in series OUT OF PHASE. This cancels most of the direct signal
> out, and most of the the "sproing" as well, leaving just the reverb. As
> long as you don't overdrive it, it sounds a lot like plate.
> 
> Terry Bowman, KA4HJH
> "The Mac Doctor"


hi Terry,
i'm not so sure i understand what you mean by "outputs in series."
this topic arrived in good timing as i have a volt controlled reverb on
my bench half finished.
 i am very interested in combining reverb & chorus circuits somehow if
anyone has any ideas.         happy synth fiddling,  crystal




From gur-m at internet-zahav.net  Thu Aug 13 01:11:31 1998
From: gur-m at internet-zahav.net (Gur Milstein)
Date: Thu, 13 Aug 1998 01:11:31
Subject: additive
Message-ID: <3.0.2.16.19980813011131.2147381a@mail.internet-zahav.net>

hi guy's.
theoretcly any acostic sound can be made in a modular
ether by addtive or FM but this is hard to be made.
so my qustion is can i play a acostic instrument like a
pino or violin or other in to a mic and then in to a scope
and see its waveshape and envelope and then calculaite
this data and creat the same sound on a modular ?
all so is ther any scope or other unit that can take a waveshape
and do the calculate and give a data of how many sine osc in
what freq, amplitude and phase do i need to creat the
same waveshape.
or even a unit that is cv conected to sin vco's and automaticly
creat the waveshape.

thanx
Gur Milstein 



From cyborg0 at GlobalEyes.net  Thu Aug 13 04:15:14 1998
From: cyborg0 at GlobalEyes.net (cyborg0 at GlobalEyes.net)
Date: Wed, 12 Aug 1998 21:15:14 -0500
Subject: Is this stupid?
References: <001001bdc638$804adce0$bec448c2@default>
Message-ID: <35D24C32.EAC2E07A@globaleyes.net>

yknow, theoretically, I have often wondered the SAME thing!
Not stupid at all..(well, if it is, then we are stupid in a group, which
is always easier to swallow) :))
rob


Tony Allgood wrote:
> 
> Hi all,
> 
> This may be a stupid question but I'll ask it anyway. Has anyone ever tried
> using inductors in a Moog ladder instead of the capacitors to make a VCHPF?
> I guess you would need to put some cap in series with the Ls to block any
> DC.
> 
> And secondly, has anyone found a need for taking a differential tap off the
> ladder at another point other than below the top pair to create reduced
> steepness of slope?
> 
> Regards,
> 
> Tony Allgood, Cumbria, UK
> 
> e-mail: oakley at enterprise.net



From cyborg0 at GlobalEyes.net  Thu Aug 13 04:35:11 1998
From: cyborg0 at GlobalEyes.net (cyborg0 at GlobalEyes.net)
Date: Wed, 12 Aug 1998 21:35:11 -0500
Subject: additive
References: <3.0.2.16.19980813011131.2147381a@mail.internet-zahav.net> <199808120912270860.11B54C7E@mail.proaxis.com>
Message-ID: <35D250DF.3435E368@globaleyes.net>

Jim Johnson wrote:
> 
> >theoretcly any acostic sound can be made in a modular
> >ether by addtive or FM but this is hard to be made.
> 
> No, it's not theoretically possible to do that.


well, thats not what they are teaching in engineering school these days!
They say that (loosely quoted from textbook) "Any sound can be broken up
into its harmonic series using fourier analysis. Once these basic
frequencies and amplitudes are known, then, all that needs to be done to
replicate the original sound is to do a time domain analysis of the
amplitude changes of each of the various harmonics." 
> 
> >so my qustion is can i play a acostic instrument like a
> >pino or violin or other in to a mic and then in to a scope
> >and see its waveshape and envelope and then calculaite
> >this data and creat the same sound on a modular ?
> 
> I've never heard of such a tool. I doubt that it is possible.

BUT, it IS possible.. there used to be a program for the atari ST that
would take a sampled sound and break it down using fourier analysis and
turn it into sysex and send it to the ol Kawai K5.. I believe it worked
on the dx7 too..mind you, the replication of the samples were often
terrible, but some were very close.

Actually, the first generation attempt was the mellotron (sampling) and
FM additive was the second.
But, now Im sounding like a know it all dickhead, sooo..  :))

whatever!
rob



From Yourreward at iname.com  Thu Aug 13 05:04:24 1998
From: Yourreward at iname.com (Opportunities Marketing Intl.)
Date: Wed, 12 Aug 1998 23:04:24 -0400
Subject: IF YOU READ NOTHING ELSE....READ THIS!!
Message-ID: <199808123879YAA11800@post.113.32.4>


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Well, there is a way to pay off all these debts, and more, up to
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From jamos at technotoys.com  Thu Aug 13 05:37:45 1998
From: jamos at technotoys.com (Jim Johnson)
Date: Wed, 12 Aug 1998 20:37:45 -0700
Subject: additive
In-Reply-To: <35D250DF.3435E368@globaleyes.net>
References: <3.0.2.16.19980813011131.2147381a@mail.internet-zahav.net>
 <199808120912270860.11B54C7E@mail.proaxis.com>
 <35D250DF.3435E368@globaleyes.net>
Message-ID: <199808122037450960.1428CE43@mail.proaxis.com>

>well, thats not what they are teaching in engineering school these days!
>They say that (loosely quoted from textbook) "Any sound can be broken up
>into its harmonic series using fourier analysis. Once these basic
>frequencies and amplitudes are known, then, all that needs to be done to
>replicate the original sound is to do a time domain analysis of the
>amplitude changes of each of the various harmonics." 

Yeah, that's what they said when I was in engineering school 20 years ago,
too. This is the kind of oversimplification that is rampant in engineering
texts - as exemplified by the statement "any sound can be broken into its
harmonic series"... As has been discussed on the list, not all sounds
consist only of integer harmonics. Furthermore, no musical instrument
produces a single sound - there is an incredible range of variability in
the sound produced by any single instrument.

And to top it off - the statement had to do with modular and FM synths, not
Fourier (additive) synthesis. Yes, we can talk about modulars that can do
128 harmonics, with separate envelopes and phase control for each partial -
but there is no such instrument. Nor is it possible to build one, in
practical terms.

>BUT, it IS possible.. there used to be a program for the atari ST that
>would take a sampled sound and break it down using fourier analysis and
>turn it into sysex and send it to the ol Kawai K5.. I believe it worked
>on the dx7 too..mind you, the replication of the samples were often
>terrible, but some were very close.

That's digital resynthesis, not modular synthesis.

>Actually, the first generation attempt was the mellotron (sampling) and
>FM additive was the second.
>But, now Im sounding like a know it all dickhead, sooo..  :))

I suppose I should have counted the Mellotron in there, but that was such a
strange and unique instrument.... But what is "FM additive"? 

Jim Johnson 
Metaphoric Software
-------------------
Makers of Techno Toys
Software for Electronic Music
http://www.technotoys.com
info at technotoys.com



*********** REPLY SEPARATOR ***********

On 8/12/98, at 9:35 PM, cyborg0 at globaleyes.net wrote: 

>Jim Johnson wrote:
>> 
>> >theoretcly any acostic sound can be made in a modular
>> >ether by addtive or FM but this is hard to be made.
>> 
>> No, it's not theoretically possible to do that.
>
>
>well, thats not what they are teaching in engineering school these days!
>They say that (loosely quoted from textbook) "Any sound can be broken up
>into its harmonic series using fourier analysis. Once these basic
>frequencies and amplitudes are known, then, all that needs to be done to
>replicate the original sound is to do a time domain analysis of the
>amplitude changes of each of the various harmonics." 
>> 
>> >so my qustion is can i play a acostic instrument like a
>> >pino or violin or other in to a mic and then in to a scope
>> >and see its waveshape and envelope and then calculaite
>> >this data and creat the same sound on a modular ?
>> 
>> I've never heard of such a tool. I doubt that it is possible.
>
>BUT, it IS possible.. there used to be a program for the atari ST that
>would take a sampled sound and break it down using fourier analysis and
>turn it into sysex and send it to the ol Kawai K5.. I believe it worked
>on the dx7 too..mind you, the replication of the samples were often
>terrible, but some were very close.
>
>Actually, the first generation attempt was the mellotron (sampling) and
>FM additive was the second.
>But, now Im sounding like a know it all dickhead, sooo..  :))
>
>whatever!
>rob



From ka4hjh at gte.net  Thu Aug 13 06:04:35 1998
From: ka4hjh at gte.net (KA4HJH)
Date: Thu, 13 Aug 1998 00:04:35 -0400
Subject: spring reverb
In-Reply-To: <35D21D48.3DB3@lankaster.com>
References: <v04011702b1f59f34f65f@[208.255.152.197]>
Message-ID: <v04011700b1f81418a8d0@[208.255.152.106]>

>i'm not so sure i understand what you mean by "outputs in series."
>this topic arrived in good timing as i have a volt controlled reverb on
>my bench half finished.
> i am very interested in combining reverb & chorus circuits somehow if
>anyone has any ideas.         happy synth fiddling,  crystal

I had this backwards. You take two reverb tanks. You wire the two send
transducers in parallel, out of phase. Then you wire the two receive
transducers in series which increases the signal level, lowering the
noise/hum.

Terry Bowman, KA4HJH
"The Mac Doctor"



From honcho at paia.com  Thu Aug 13 06:20:25 1998
From: honcho at paia.com (honcho at paia.com)
Date: Wed, 12 Aug 98 23:20:25 CDT
Subject: Differential Reverb (better subject line!)
Message-ID: <9808130420.AA19990@qns1.qns.net>

Don Tillman writes:

>A couple of friendly suggestions for this circuit:

>Invert the receive transducers instead of the send transducers; hum
>cancelling for free!

>Accutronics recommends using lots of drive current; more than an 
>opamp could provide.  Their application note has half-a-dozen drive
>circuits.
>>>

Really good suggestions, Don, thanks. But remember that the 
transducers are in two tanks and not particularly close together so 
that hum rejection _might_ not be that great. There's not much reason 
to expect that the transducers in each tank will have the same 
exposure to flux because of their physical separation - it still would 
be wise to keep tanks away from magnetic fields from transformers and 
such in the first place.

Better drivers might be better, but several folks have pointed out 
already that the Hot Springs is a pretty incredible little reverb and 
who's to say that some of the magic doesn't come from the driving 
properties of the op-amps :-)

-John

---------------------------------------------------------
John Simonton                  PAiA Electronics, Inc
3200 Teakwood Ln.              honcho at paia.com
Edmond OK 73013                http://www.paia.com
405-340-6300                   fax 405-340-6378



From shusoran at yahoo.com  Thu Aug 13 07:50:06 1998
From: shusoran at yahoo.com (Jonathan Lippard)
Date: Wed, 12 Aug 1998 22:50:06 -0700 (PDT)
Subject: Minimoog Service Manual question...
Message-ID: <19980813055006.28306.rocketmail@send1c.yahoomail.com>

Alrighty, first off let me thank everyone who replied to my question
about the Mini ladder filter. It helped me quite a bit.

A few of you recommended that I try to obtain a copy of the Mini SM.
I've seen a couple people who said on their websites that they had it.
Problem is, I can'y remember where these sites are.

Can anyone help me with this? Or better yet, does anybody know who I
could e-mail about this?

Thanks,
Jonathan Lippard

(I know this is sort of off topic for the list, but I've been looking
for a while and can't find anything I'd seen before.)




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Get your free @yahoo.com address at http://mail.yahoo.com




From sky36919 at skynet.be  Thu Aug 13 08:03:30 1998
From: sky36919 at skynet.be (Hugo Haesaert)
Date: Thu, 13 Aug 1998 08:03:30 +0200
Subject: additive
In-Reply-To: <199808122037450960.1428CE43@mail.proaxis.com>
References: <35D250DF.3435E368@globaleyes.net>
Message-ID: <199808130603.IAA03585@papagena.skynet.be>

Hi Jim and List !

>But what is "FM additive"? 

Saw this mentioned somewhere in the last few days, can't remember 
where tho (at 150+ mails a day :)

Using tx816 with each patch taking 6 harmonics gives 48 with 16 
voices, sounded plausible .

Later .

Keep 'em oscillating :)

Hugo
=



From martin.czech at intermetall.de  Thu Aug 13 09:02:47 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Thu, 13 Aug 1998 09:02:47 +0200 (MET DST)
Subject: Is this stupid?
Message-ID: <199808130702.JAA01972@window.intermetall.de>

> yknow, theoretically, I have often wondered the SAME thing!
> Not stupid at all..(well, if it is, then we are stupid in a group, which
> is always easier to swallow) :))
> rob
> 
> 
> Tony Allgood wrote:
> > 
> > Hi all,
> > 
> > This may be a stupid question but I'll ask it anyway. Has anyone ever tried
> > using inductors in a Moog ladder instead of the capacitors to make a VCHPF?
> > I guess you would need to put some cap in series with the Ls to block any
> > DC.
> > 
> > And secondly, has anyone found a need for taking a differential tap off the
> > ladder at another point other than below the top pair to create reduced
> > steepness of slope?
> > 
> > Regards,
> > 
> > Tony Allgood, Cumbria, UK
> > 
> > e-mail: oakley at enterprise.net
> 
> 
Part one:

I can't see any major problem in using inductors, just the problems
that inductors have: size,quality, cost, availability.  With no audio
signal, the dc potentials of the ladder should be the same for each
stage, so no problem to clamp these together with the inductor.  The
circuit might suffer from inductive hum, and the low frequencys might
not be damped as expected, because of nonzero resistance of the
inductor coils. And the feedback will not work any more (from my head),
I think the loop has to be attached to the other side of the diff.
signal input.

No , part two is not stupid but interesting.

Sometimes I would like to have the same cutoff point, but not such a
sharp decrease in brightness. So you need 6dB,12 dB and maybe 18dB,
too. I'd say there is a need, have a look at the formant 24dB filter.


If you have a high impedance diff.  buffer you can of course tap the
other 3 points in the ladder. Instead of using a (expensive) 2 way 4
position switch I'd rather build 4 output stages. But the resonance
loop should contain only the last 24dB tap, it is obvious that it won't
work as expected with the other 3 taps.  But it could be a nice
experiment to do this (via external feedback). 




From martin.czech at intermetall.de  Thu Aug 13 09:16:50 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Thu, 13 Aug 1998 09:16:50 +0200 (MET DST)
Subject: additive
Message-ID: <199808130716.JAA02005@window.intermetall.de>

> well, thats not what they are teaching in engineering school these days!
> They say that (loosely quoted from textbook) "Any sound can be broken up
> into its harmonic series using fourier analysis. Once these basic
> frequencies and amplitudes are known, then, all that needs to be done to
> replicate the original sound is to do a time domain analysis of the
> amplitude changes of each of the various harmonics." 

I'd say this has two sides:
First the textbook is right, IT CAN BE DONE. You simply FFT window after window
after that you take the IFFT and attach window to window. This is trivial,
of course the signal is the same after this procedure, but only (!) if no
window function (like Hamming, Kaiser, Blackman ...) are applied to
the windows.

But there is the other side as well:  Does the above mentioned method
of FFTing with no window function make sense in the meaning of spectral
content ? I'd say no! Chopping the signal into window chunks creates
(artificial) discontinuities, if you treat a long sine wave sample,
you'll get very strange "spectra", this is clear , because after
chopping the signal is no sine wave any more. If you wan't to have a
meaningfull spectral representation, you'll have to apply a window
function w(t), and this means convolution with the spectral equivalent
W(s), ie. smearing.  This smearing or unsharpness will hide the little
dirty "harmonics", that makes the sound of instruments so interesting.

Does this remind you of something? It is the Heisenberg theorem applied
to music instead of quantum physics (the math is the same in this
case):  time resolution rivals with spectral resolution. If you want
good spectral resolution, the window has to be very long, thus time
resolution suffers and vice versa.

I had to learn this the hard way, when I wrote this little program
to feed my microwave with wavetables (a poor man's wave).

So, with this perspective: NO, IT CAN'T BE DONE.

m.c.






From mglnsky at magicnet.net  Thu Aug 13 09:23:28 1998
From: mglnsky at magicnet.net (Mark Glinsky)
Date: Thu, 13 Aug 1998 03:23:28 -0400 (EDT)
Subject: Minimoog Service Manual question...
Message-ID: <199808130723.DAA04614@magicnet.magicnet.net>

>A few of you recommended that I try to obtain a copy of the Mini SM.
>I've seen a couple people who said on their websites that they had it.
>Problem is, I can'y remember where these sites are.

II have, along with a "few" other manuals....

http://www.magicnet.net/~mglnsky/msg4.html


_______________________________________________________
 Mark Glinsky -   Orlando, Florida
 Email:                 mglnsky at magicnet.net
 Manual Manor:   http://www.magicnet.net/~mglnsky/msg4.html
 "Be seeing you...."  [ No. 6  -  The Prisoner ]
 "Don't Panic!"   [ HitchHiker's Guide ]
-------------------------------------------------------




From kimmo at ecdl.hut.fi  Thu Aug 13 09:30:20 1998
From: kimmo at ecdl.hut.fi (Kimmo Koli)
Date: Thu, 13 Aug 1998 10:30:20 +0300 (EETDST)
Subject: additive
In-Reply-To: <35D250DF.3435E368@globaleyes.net>
Message-ID: <Pine.HPP.4.02.9808131014080.7901-100000@tankgirl.hut.fi>

On Wed, 12 Aug 1998 cyborg0 at GlobalEyes.net wrote:

> Jim Johnson wrote:
> > 
> > >theoretcly any acostic sound can be made in a modular
> > >ether by addtive or FM but this is hard to be made.
> > 
> > No, it's not theoretically possible to do that.
> 
> 
> well, thats not what they are teaching in engineering school these days!
> They say that (loosely quoted from textbook) "Any sound can be broken up
> into its harmonic series using fourier analysis. Once these basic
> frequencies and amplitudes are known, then, all that needs to be done to
> replicate the original sound is to do a time domain analysis of the
> amplitude changes of each of the various harmonics." 
> 
Well, that actually means that if you have for example a 1 second long
sample you can do a HUGE FFT from the from the whole sample to get the
spectral components from 0Hs, 1Hz, 2Hz etc. Then you can do a huge IFFT
which results in a continuous sound with a period of 1 second. So the FFT
know nothing of the harmonic or inharmonic content of the sample. Also this
means that a FFT has poor frequency resolution if the window is short.
That's why some people try to find different transforms that have
reasonable resolution both in time and frequency simultaneusly, would be
good in speech analysis/synthesis.  
 
So when they teach in engineering school theory they really mean theory,
not practice :-)

Best regards, 
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
   Kimmo Koli                         Helsinki University of Technology 
   kimmo at ecdl.hut.fi                  Electronic Circuit Design Laboratory
   http://www.ecdl.hut.fi/~kimmo      P.O.Box 3000
   Tel:  +358 9 451 2273              FIN-02015 HUT
   Fax:  +358 9 451 2269              Finland 
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=




From Juergen.Haible at nbgm.siemens.de  Thu Aug 13 10:55:43 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Thu, 13 Aug 1998 10:55:43 +0200
Subject: AW: Is this stupid?
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D58299F605@nbgm336a.nbgm.siemens.de>

	>No , part two is not stupid but interesting.
	>
	>Sometimes I would like to have the same cutoff point, but not such
a
	>sharp decrease in brightness. So you need 6dB,12 dB and maybe 18dB,
	>too. I'd say there is a need, have a look at the formant 24dB
filter.

A 6dB/8ve filter with resonance is a nice thing. When I made the filter
modification for my OB-8, I found that the same node that carries the
HP output in 2-pole mode (SVF), is the first of four stages in 4-pole
mode. It's not a ladder filter, but the idea is the same.
It is useful if you want to have resonance without too much loss
above (or below) the cutoff frequency. Good for all kinds of
"bright" sounds.
See <http://www.synthfool.com/diy/hjob8mod.html> for details.

JH.




From Juergen.Haible at nbgm.siemens.de  Thu Aug 13 11:56:45 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Thu, 13 Aug 1998 11:56:45 +0200
Subject: AW: Differential Reverb (better subject line!)
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5829A0B25@nbgm336a.nbgm.siemens.de>

	>Their application note has half-a-dozen drive
	>circuits.

Are they on the web somewhere ?

JH.




From urekar.m at EUnet.yu  Thu Aug 13 12:05:03 1998
From: urekar.m at EUnet.yu (<<marjan>>)
Date: Thu, 13 Aug 1998 12:05:03 +0200
Subject: Is this stupid?
References: <001001bdc638$804adce0$bec448c2@default>
Message-ID: <35D2BA4F.69A4@eunet.yu>

Tony Allgood wrote:

> And secondly, has anyone found a need for taking a differential tap off the
> ladder at another point other than below the top pair to create reduced
> steepness of slope?

look at Kris Ulfes site
http://www.ing.umu.se/~me96kus/stuff/moogvcf.GIF
moog ladder filter with 6/12/18/24 db and VC resonance


marjan



From Juergen.Haible at nbgm.siemens.de  Thu Aug 13 12:11:34 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Thu, 13 Aug 1998 12:11:34 +0200
Subject: AW: Differential Reverb (better subject line!)
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5829A0B53@nbgm336a.nbgm.siemens.de>

	>Better drivers might be better, but several folks have pointed out 
	>already that the Hot Springs is a pretty incredible little reverb
and 
	>who's to say that some of the magic doesn't come from the driving 
	>properties of the op-amps :-)

In my EMS Synthi Clone, I have used an LM380 (with feedback
for high output impedance) to drive the reverb tank. At high
input levels, the "sproing" noises increase dramatically, so
maybe one doesn't loose that much with a limited input power.
But with this dual reverb tank trick, these noises should partially
cancel each other, so higher drive levels might be even more
interesting (?). Haven't tried it, but it seems reasonable ...

JH.




From Juergen.Haible at nbgm.siemens.de  Thu Aug 13 12:20:38 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Thu, 13 Aug 1998 12:20:38 +0200
Subject: AW: additive
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5829A0B6D@nbgm336a.nbgm.siemens.de>

	>This is not substractive at all. I don't know how this
	>expression came up in the public, but I gues it was in the mid
70's,
	>when polyphony led to synthis which where basically substractive,
like 
	>a Prophet 5.

You're absolutely right. And even the Minimoog can do more than
sustractive: Audio Rate Filter FM.
My Prophet *can* do substractive synthesis, too, but often
I concentrate on things like audio rate PWM (*very* nice on the P5 !)
I guess this is the reason why I keep the Prophet.

	JH.



From Juergen.Haible at nbgm.siemens.de  Thu Aug 13 12:31:44 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Thu, 13 Aug 1998 12:31:44 +0200
Subject: AW: additive
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5829A0B97@nbgm336a.nbgm.siemens.de>

If you want to make analogue additive synthesis (rather)
simple, you might try this:

Start with a triangle VCO, and derive as many triangle
"harmonics" as possible with waveshaping.
Then use 3080's or similar OTAs for creating sine waves
from the triangles. Use the control input of the same OTAs
to get the VCA function. Connect all OTA outputs directly
together.
Try simple Envelopes. A 1ms-attack / variable decay
might be enough for higher harmonics, if you have a master
VCA at the end with a standard envelope.

Just an idea - haven't tried it.

JH.



From martin.czech at intermetall.de  Thu Aug 13 12:43:46 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Thu, 13 Aug 1998 12:43:46 +0200 (MET DST)
Subject: update archive 
Message-ID: <199808131043.MAA02933@window.intermetall.de>

The unofficial diy archive has moved:

http://www2.crosswinds.net/stuttgart/~mczech/

Reason: I was not able to download my stuff to the old place any
more. Don't know why, but the connection was super slow.


New: mailing list archive files:

all1995.zip  revised version (the program left a bit of trash, which
                              may cause problems if you write your own search tool,
                              this trash was now removed)

all1996.zip

Does anybody know a better place for this page ?
It is still very slow to download (400 bytes/sec).
Any hints would be helpfull.


Further this page provides some usefull links to diy pages.  The list
of links is not complete yet. Suggestions for other pages of interest?

If you have a nice diy homepage, please let me know.  Please give me a
short description of the content (like Moog high passs filter
schematics, photos,...).

If you don't want that a link points towards your homepage, let me
know.  I'll take you off ASAP.

If you think that my desciption of your page is wrong, please give me a
better one, so I can cut and paste it.


Hope you'll enjoy.


m.c.





From batzman at all-electric.com  Thu Aug 13 12:53:30 1998
From: batzman at all-electric.com (The Dark force of dance)
Date: Thu, 13 Aug 1998 19:53:30 +0900
Subject: additive
Message-ID: <3.0.32.19980813165742.006b3900@mail.chariot.net.au>

Y-ellow Y'all.
	I'm only breezing through and I've not caught up with the rest of this
thread. But!

The process is called "RE-SYNTHESIS" There are loads of tools available to
do it. From simple software programs on a PC through to synthesis systems
such as the creamware scope.

Indeed. it uses a fourier transform to break down the original sample into
it's component sinewaves (harmonics) and assignes them to their envelopes
over time. The more transforms (sinewaves) and the more detailed the
envelopes, the more actuate it will reproduce the sound.

Once you have this data and the means to reproduce it, there is very little
you can't do with the sound. At the very least you get a sampler that
allows you to play the same sound at any pitch and maintain the same
transient. At it's best you can gene splice seemingly unrelated sounds
together. A chromatic cymbal springs to mind. A drum cross with a piano
perhaps. Or simply encode an entire piano using just 9 samples. Instead of
the thousands it takes to do it using the usual brute force method.

But the thing to note here is that all these systems that do this remotely
well are "DIGITAL". It is very difficult and cumbersome to do this stuff
using analogue. The Kawai K5000 for example, has 6 layers. Each layer
consists of 64 sinewaves. Each with 64 envelopes. Plus filter. And there
are 32 voices of it at once. Try doing that with a modular. I mean a
modular that you can fit inside your house instead of a 4 story office block.

The K5K also comes with knobs so you can adjust stuff in real time. But
before I sound like an advert for Kawai, it should be pointed out that they
don't do re-synthesis as such. The envelopes are only ADSR types. These are
nowhere near good enough to do re-synthesis over all. For that your
envelopes need to be a uni-polar sample of the harmonic's amplitude. It
doesn't necessarily have to be particularly high resolution in either the
time or amplitude domain but it does have to be significantly better than
that of which a simple ADSR can provide.

FM is another matter entirely. FM synthesis is only classed as "additive"
because it's certainly not "Subtractive" This could be viewed as a lateral
form of synthesis. Or perhaps recombinant harmonic synthesis. At first
glance there seems to be no direct relationship between any two operators.
The harmonic content of any given operator is pushed but the phase of any
operator preceding it. In order to make it "re-synthesize" some very tricky
software is required. Yamaha's second foray into FM synthesis, the GS1 and
GS2, did just that. Only what you had to do was send a tape to Yamaha
containing the sound you wanted encoded. They would take that sound and run
it through a fairly time consuming process which would reduce it to control
data for their (3 operator) FM synthesis engine. Finally you'd get a little
bus ticket thing back which you could insert into your instrument and it
would do a half decent job of replaying the sound. (Of course Yamaha's
first foray into FM was on the some what funky GX1. 2 operator analogue FM)

Whilst it should be theoretically possible to back-calculate a sample into
an FM control set for a DX7, to my knowledge, no-one has actually done it.
But it should also be noted that a DX7 has better envelopes than a simple
ADSR type as well. Which is one of the reasons it's better at simulating
the noiances of real-world sounds. Possessing 8 parameters instead of 4, it
allows for harmonics to swell. In subtractive you need to dedicate an
entire chain to do it.

In short. If you wanna do this stuff, it's possible to do it using an
analogue subtractive system but why would you want to?

Be absolutely Icebox.




From Juergen.Haible at nbgm.siemens.de  Thu Aug 13 13:18:11 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Thu, 13 Aug 1998 13:18:11 +0200
Subject: additive question
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5829A1FD7@nbgm336a.nbgm.siemens.de>

	>While periodic sounds have spectra
	>with energy found only at integer multiples (harmonics) of the
fundamental
	>frequency, aperiodic sounds possess energy at many more
frequencies, some
	>harmonically related to each, and some not.   

No more discrete frequencies for non periodic signals.
Continuous spectrum.

OTAH, a sine wave with an *envelope* applied isn't a  discrete
frequency either. 

(Academical) Question: 
Imagine a sound that was created *only* by a number of periodic 
waveforms, a linear (no overdrive) VCF with envelope, and a linear 
VCA with envelope. Is it possible to resynthesize such a sound 
with a *finite* number of *fixed* frequency oscillators and individual
VCAs / envelopes ?
I know this is far from real life sounds, but I just wonder if this can work
 or not.

JH.




From cstecker at ovenguard.com  Thu Aug 13 13:20:08 1998
From: cstecker at ovenguard.com (Chris Stecker)
Date: Thu, 13 Aug 1998 03:20:08 -0800
Subject: additive
Message-ID: <v02110102b1f8746640a1@[205.134.244.186]>

>>well, thats not what they are teaching in engineering school these days!
>>They say that (loosely quoted from textbook) "Any sound can be broken up
>>into its harmonic series using fourier analysis. Once these basic
>>frequencies and amplitudes are known, then, all that needs to be done to
>>replicate the original sound is to do a time domain analysis of the
>>amplitude changes of each of the various harmonics."
>
>Yeah, that's what they said when I was in engineering school 20 years ago,
>too. This is the kind of oversimplification that is rampant in engineering
>texts - as exemplified by the statement "any sound can be broken into its
>harmonic series"... As has been discussed on the list, not all sounds
>consist only of integer harmonics. Furthermore, no musical instrument
>produces a single sound - there is an incredible range of variability in
>the sound produced by any single instrument.
>

I'm almost totally certain that the textbook in question says "Any _periodic_
signal can be represented by a set of basis waveforms (sin or not) at
integer multiple of the fundamental period," or something like that.  The
Fourier transform is a linear transformation from one form of signal
representation (time-domain waveform) to another (frequency-domain spectrum).
The math may be complex, but the solution is exact; inverting the fourier
transform gives you your input signal back, unchanged.  This is not an
oversimplification, it's just math.  Adding these frequency components
together,
with the proper phase and amplitude relationships, reconstructs the original
signal.

"Now," you may be saying, "that only holds true for periodic signals, when
sounds in the world are aperiodic."  Good point.  In fact, the resynthesis
I just described could only really work for steady-state (non-varying) signals.
Most signals change over time in non-repeating patterns, which makes them
aperiodic.  However, an aperiodic signal can still be analyzed using
Fourier techniques.  It can even be resynthesized.   The difference is in
the
frequencies which are present in the sound.  While periodic sounds have spectra
with energy found only at integer multiples (harmonics) of the fundamental
frequency, aperiodic sounds possess energy at many more frequencies, some
harmonically related to each, and some not.   Resynthesis becomes a much
more difficult task for these signals.  With an infinite number of
oscillators sounding for an infinite duration and aligning in an exact
phase relationship at one specific moment in all of time, the signal can be
recreated exactly.
Of course, if we had the power to do all that, we'd have more important things
to think about than analog synthesizers.  It's simply not a possibility.

Digital techniques can be used to simulate hundreds or thousands of
oscillators, which, although not an infinite number, can sound very
realistic.  Add to this the ability to do short, overlapping FFT's to
generate time-varying spectral data, and you come close to the quality you
would achieve using a sampler (although you've gained a whole lot of
flexibility).  The technology to do
this kind of thing, IN REAL TIME, is available in relatively inexpensive form
right now!  I find this very exciting.  If you have a PowerMac, go to
www.cycling74.com and find your way to "Download MSP" and download a copy
of "MSP Runtime."  This is a runtime-only version of the MSP programming
language.
When you run the application, open the file "Forbidden Planet Demo" and
check it out.  Real-time FFT analysis and resynthesis, with arbitrary
(analog junkies read as "highly resonant and tweakable") filtering performed
by simple multiplication in the frequency domain.  If you're not floored,
you should be.   And soon you'll start thinking of prototyping all your
synth modules in software, because you can, (again) IN REAL TIME.  Neat.

PS - Martin Czech's comments about temporal and frequency resolution
trading off are absolutely true.  You can't have perfect signal
reconstruction (of aperiodic signals) with window lengths shorter than
eternity.  But you can get surprisingly close (please don't write back
saying "close" doesn't count...you may have to listen yourself to be
convinced), and like many computational problems, this one yields pretty
well when you get enough horsepower behind it.

-----

Okay, I started this message as "know-it-all prick" and ended it like an
advertisement.  I'm embarassed,

-Chris


>And to top it off - the statement had to do with modular and FM synths, not
>Fourier (additive) synthesis. Yes, we can talk about modulars that can do

Oh, yeah...you're right.  Ooops.





From martin.czech at intermetall.de  Thu Aug 13 14:08:28 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Thu, 13 Aug 1998 14:08:28 +0200 (MET DST)
Subject: additive question
Message-ID: <199808131208.OAA03462@window.intermetall.de>


> 
> 	>While periodic sounds have spectra
> 	>with energy found only at integer multiples (harmonics) of the
> fundamental
> 	>frequency, aperiodic sounds possess energy at many more
> frequencies, some
> 	>harmonically related to each, and some not.   
> 
> No more discrete frequencies for non periodic signals.
> Continuous spectrum.
> 
> OTAH, a sine wave with an *envelope* applied isn't a  discrete
> frequency either. 
> 
> (Academical) Question: 
> Imagine a sound that was created *only* by a number of periodic 
> waveforms, a linear (no overdrive) VCF with envelope, and a linear 
> VCA with envelope. Is it possible to resynthesize such a sound 
> with a *finite* number of *fixed* frequency oscillators and individual
> VCAs / envelopes ?
> I know this is far from real life sounds, but I just wonder if this can work
>  or not.
> 

AFAIK it is not neccessary to map the odd frequencies, ie. inharmonic
partials exactly. If you're in the digital domain you have only the
discrete fourier transform, and this works only for periodic signals
and spectra. But: by clever windowing/chopping you can transform any
input wave into a stream of spectral chunks. Ie. you get a series of
harmonic waveforms which make any input signal if they are chained
together. Or in other words:  An inharmonic input gives ever changing
spectra, a harmonic input which is synchronous to sampling rate and has
an integer freqeuency ratio to the window size is a very seldom special
case, and  gives a constant spectrum. 

Don't think too much about the meaning of these spectra. You can
manipulate them and transform back, but you have to be carefull at the
window boundarys.  I mean, isn't this the way that mpeg audio
compression works ?  AFAIK the data is windowed, transformed (phase
information thrown away), "unneccessary" spectral information is
dropped, the stuff is then coded (compressed). On the reciever side the
data is uncompressed and time domain information is obtained via revers
transformation. And then something must be done at the window boundarys
to avoid artefacts. This works, as you can hear.

Or think about fast convolution algorithms. Again the input stream is
chopped into windows, transformed, the convolution becomes
multiplication in the frequency domain, and then the whole stuff is
back transformed and reasembled into the now convoluted (filtered) data
stream.  This gives exactly the same result as if you do the
convolution in the time domain, you need not worry about inharmonic
input data, it works for every input signal.

So academical answer: I'd say the above case could be done, the
question is however how manipulations in the time domain map into the
frequency domain.  It's not quite straight forward, because one has
always to keep the windowing in mind, and this requires additional
steps to be taken.

m.c.




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Date: Thu, 13 Aug 1998 12:26:53
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From blacet at metro.net  Thu Aug 13 15:26:26 1998
From: blacet at metro.net (John Blacet)
Date: Thu, 13 Aug 1998 13:26:26 +0000
Subject: SAFE wall wart supplies
Message-ID: <35D2E982.19D0@metro.net>

The discussion of wall warts the past few days prompts me to mention the
safe, fully enclosed and REGULATED wall wart system available from
Blacet Research. While it may not be suitable for a large modular
system, it is a very cool way to power up a small rack. Especially when
you add the power distribution board!

Spend your time building cool modules and not power supplies (mostly
pretty boring). :>

Regards.
-------------------------
John Blacet
Blacet Research Music Electronics
-------------------------
blacet at metro.net
http://metro.net/blacet/music.html



From pfperry at melbpc.org.au  Thu Aug 13 15:30:14 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Thu, 13 Aug 1998 23:30:14 +1000 (EST)
Subject: AW: additive
Message-ID: <1.5.4.16.19970105060355.37d7033a@popa.melbpc.org.au>

At 12:31 PM 13/08/98 +0200, Haible Juergen  wrote:
>If you want to make analogue additive synthesis (rather)
>simple, you might try this:
>Start with a triangle VCO, and derive as many triangle
>"harmonics" as possible with waveshaping.
...snip.....
I'm not a mathematician.... but,can anyone say whether it
is possible to additively synthesise an arbitrary periodic
waveform from a series of triangles?

paul perry melb aust

but, in the real world, anything made from frequency locked
harmonics is more flat than phat..




From eli at gs160.sp.cs.cmu.edu  Thu Aug 13 16:01:06 1998
From: eli at gs160.sp.cs.cmu.edu (Eli Brandt)
Date: Thu, 13 Aug 1998 10:01:06 -0400 (EDT)
Subject: additive
In-Reply-To: <199808122037450960.1428CE43@mail.proaxis.com> from "Jim Johnson" at Aug 12, 98 08:37:45 pm
Message-ID: <199808131401.QAA19756@mailhost.bpa.nl>

Jim Johnson wrote:
> Yeah, that's what they said when I was in engineering school 20 years ago,
> too. This is the kind of oversimplification that is rampant in engineering
> texts - as exemplified by the statement "any sound can be broken into its
> harmonic series"... As has been discussed on the list, not all sounds
> consist only of integer harmonics.

Even an aperiodic signal can in principle be converted to and from a
basis of sinusoids: you use the actual Fourier transform, not the
discretized thing that engineers call by that name. :-)

> Furthermore, no musical instrument
> produces a single sound - there is an incredible range of variability in
> the sound produced by any single instrument.

Very true.  Additive synthesis may seem like the Holy Grail, but
really it's a lot like the "huh huh huh just draw the waveform, coool"
method.  Not a synthesis model with nice knobs on it; unless you're
into organs you need an analysis to drive your synthesis and it ends
up like sampling, except with some nice stretch/shift ability.

-- 
     Eli Brandt  |  eli+ at cs.cmu.edu  |  http://www.cs.cmu.edu/~eli/



From eli at gs160.sp.cs.cmu.edu  Thu Aug 13 16:25:13 1998
From: eli at gs160.sp.cs.cmu.edu (Eli Brandt)
Date: Thu, 13 Aug 1998 10:25:13 -0400 (EDT)
Subject: AW: additive
In-Reply-To: <1.5.4.16.19970105060355.37d7033a@popa.melbpc.org.au> from "Paul Perry" at Aug 13, 98 11:30:14 pm
Message-ID: <199808131425.QAA20316@mailhost.bpa.nl>

Paul Perry wrote:
> I'm not a mathematician.... but,can anyone say whether it
> is possible to additively synthesise an arbitrary periodic
> waveform from a series of triangles?

Excepting DC, I think so.  Take the sine spectrum {x_i} that you want;
start off with tri1=x1 to match the fundamental and tri2=x2 to match
the second partial.  Then you have to match the third plus cancel the
junk you put in with tri1, so tri3=x3-x1/9.  And so forth.  Ought to
converge.

Deconvolution of {x_i} by {1, 0, 1/9, 0, 1/25, ...} I guess.

-- 
     Eli Brandt  |  eli+ at cs.cmu.edu  |  http://www.cs.cmu.edu/~eli/



From mmcintos at ball.com  Thu Aug 13 16:32:39 1998
From: mmcintos at ball.com (McIntosh, Malcolm)
Date: Thu, 13 Aug 1998 08:32:39 -0600
Subject: additive
Message-ID: <09DB74475204D1119C8200805F19D0032D12B1@aeromsg1.ball.com>

Hi,

This is a subject I have been thinking about with no idea how to
implement.

Would it be possible to use frequency multiplication and one really good
sine wave VCO for limited additive synthesis?  Would it be necessary to
have 64 or 128 harmonics if you just wanted to make some really nice
sounds but not be totally imitative?  Could you get away with 16 or
maybe 8 (!) harmonics to make really interesting non-imitative sounds?

Forgive anything I have over looked.

Malcolm

P.S This is the 2'nd time I sent this because the first time it didn't
seem to show up.

> -----Original Message-----
> From:	Haible Juergen [SMTP:Juergen.Haible at nbgm.siemens.de]
> Sent:	Thursday, August 13, 1998 3:32 AM
> To:	DIY
> Subject:	AW: additive
> 
> If you want to make analogue additive synthesis (rather)
> simple, you might try this:
> 
> Start with a triangle VCO, and derive as many triangle
> "harmonics" as possible with waveshaping.
> Then use 3080's or similar OTAs for creating sine waves
> from the triangles. Use the control input of the same OTAs
> to get the VCA function. Connect all OTA outputs directly
> together.
> Try simple Envelopes. A 1ms-attack / variable decay
> might be enough for higher harmonics, if you have a master
> VCA at the end with a standard envelope.
> 
> Just an idea - haven't tried it.
> 
> JH.



From don at till.com  Thu Aug 13 17:22:29 1998
From: don at till.com (Don Tillman)
Date: Thu, 13 Aug 1998 08:22:29 -0700 (PDT)
Subject: Differential Reverb (better subject line!)
In-Reply-To: <9808130420.AA19990@qns1.qns.net> (honcho@paia.com)
Message-ID: <199808131522.IAA12078@shell9.ba.best.com>

   From: Haible Juergen <Juergen.Haible at nbgm.siemens.de>
   Date: Thu, 13 Aug 1998 11:56:45 +0200

   >Their application note has half-a-dozen drive circuits.

   Are they on the web somewhere ?

No, unfortunately.  You have to phone or write to them to get the
application notes.

Sound Enhancements, Inc.  (Accutronics)
185 Detroit Street
Cary, IL  60013
Phone: 847 639-4646
Fax:   847 639-4723

   From: honcho at paia.com
   Date: Wed, 12 Aug 98 23:20:25 CDT

   Don Tillman writes:
   >Invert the receive transducers instead of the send transducers; hum
   >cancelling for free!

   Really good suggestions, Don, thanks. But remember that the 
   transducers are in two tanks and not particularly close together so 
   that hum rejection _might_ not be that great. 

Ahh, I was picturing a situation where you'd try to get the tanks as
physically close together as possible.  Hum pickup can be a drag if
you mount a spring reverb in the same rack as a Carver power amp.
(How's that for asking for trouble?)

Another advantage of wiring the receive coils out of phase is some
immunity to physical bumps and reverb feedback.

So I'm thinking that to really take advantage of all that you'd want
to disassemble the two reverb tanks and mount the two spring units
very close together on a larger common shock-mounted subassembly.
That way the receive coils would share almost all physical and
electrical disturbances and would cancel somewhat.

  -- Don




From moylan at eden.rutgers.edu  Thu Aug 13 17:55:56 1998
From: moylan at eden.rutgers.edu (David MOYLAN)
Date: Thu, 13 Aug 1998 11:55:56 -0400 (EDT)
Subject: AW: additive
In-Reply-To: <199808131425.QAA20316@mailhost.bpa.nl>
Message-ID: <Pine.GSO.3.96.980813114309.13825A-100000@er4.rutgers.edu>




On Thu, 13 Aug 1998, Eli Brandt wrote:

> Paul Perry wrote:
> > I'm not a mathematician.... but,can anyone say whether it
> > is possible to additively synthesise an arbitrary periodic
> > waveform from a series of triangles?
> 
> Excepting DC, I think so.  Take the sine spectrum {x_i} that you want;
> start off with tri1=x1 to match the fundamental and tri2=x2 to match
> the second partial.  Then you have to match the third plus cancel the
> junk you put in with tri1, so tri3=x3-x1/9.  And so forth.  Ought to
> converge.
> 
> Deconvolution of {x_i} by {1, 0, 1/9, 0, 1/25, ...} I guess.
> 
> -- 
>      Eli Brandt  |  eli+ at cs.cmu.edu  |  http://www.cs.cmu.edu/~eli/
> 
I can definitely see the use here.  Using triangle vco's would greatly
simplify an analogue design by avoiding the need for sin conversion.
Also, if we're not going for true realism (that is ignoring non-harmonic
components) all the triangles could be derived from a fundamental using
non-linear techniques (as JH suggested in a related post).  That means
one VCO, some diodes, and a bunch of VCA/EG units.  Things are getting
simpler. Now for the tough part: figure out a formula analogous to the
Fourier Transform but for triangular components.  Then program a computer
to do the analysis.

As the previous post shows, it is possible.  Actually, I think
any periodic can be synthesized by any other periodic + harmonics
(since any periodic can be decomposed to  a sum of sin waves).  Just a gut
feeling, but a strong gut feeling.  Triangles do provide a couple
great advantages though.  dave moylan




From moylan at eden.rutgers.edu  Thu Aug 13 18:30:38 1998
From: moylan at eden.rutgers.edu (David MOYLAN)
Date: Thu, 13 Aug 1998 12:30:38 -0400 (EDT)
Subject: more analogue additive (fwd)
Message-ID: <Pine.GSO.3.96.980813122945.18018A-100000@er4.rutgers.edu>



The more I think about this, the more intrigued I become.
I think what we're dealing with here is almost a step
back to organ technology followed by a few steps foward.
Draw bars anyone?  If this project is pursued, it seems
like a perfect candidate for a digital/analogue hybrid.
(blasphemy?)  I'm talking about a computer to do the 
analysis and possibly VCA envelopes coupled with analogue
wave sources (and of course filters). 
    There's been a fair ammount of valid criticism:
smearing, non-harmonic components, etc., but most synth
enthusiasts are more concerned with the sounds and less with
the math.  We won't know what the possibilities are until
someone builds it.
    I have seen pictures (maybe Barry Klein's book) of an
additive synth with a computer terminal.  Obviously it lost
a popularity contest to subtractive synthesis.  But the
important question is why.  Most likely because of cost
and simplicity.  Computers have come a long way.  I think
this type of setup could be a very useful addition to
someone's arsenal, specifically because it's an entirely
different way to look at the process of synthesis.
(Maybe I should consider a career in lobbying).
dave moylan







From Neil.Johnson at camcon.co.uk  Thu Aug 13 18:31:49 1998
From: Neil.Johnson at camcon.co.uk (Neil Johnson)
Date: Thu, 13 Aug 1998 17:31:49 +0100
Subject: Walsh function website update
Message-ID: <5d3158d0@camcon.co.uk>

     
     All,
     
     I have added some more goodies to my website regarding Walsh 
     functions.  Point your browser at:
     
     http://members.xoom.com/Neil_Johnson/walsh.html
     
     and have a read.  I've also included a Walsh waveform tool, written in 
     Tcl, which you can play with.  You will need to install the Tcl plugin 
     before you can run it - a link to where you can find the plugin is 
     included.
     
     Errors, corrections, suggestions all welcome.
     
     Neil
     ----
     
     
     +======================================================+
     |     Neil Johnson  BEng(Hons) MSc CEng MIEE MIEEE     |
     |         http://members.xoom.com/Neil_Johnson         |
     |       "I speak for myself, not for my employer"      |
     +======================================================+



From Chris.List at sc.siemens.com  Thu Aug 13 18:42:05 1998
From: Chris.List at sc.siemens.com (List, Christopher)
Date: Thu, 13 Aug 1998 12:42:05 -0400
Subject: more analogue additive (fwd)
Message-ID: <81A062BC5305D111A9D700805F065968CE94BB@maildepo.sc.siemens.com>

Maybe I'm missing something simple here, but how does one easily
generate a triangle with a period _other_ than F^n Hz, where F is the
fundamental? I mean, I've forgotten a lot of my theory on audio waves
and stuff, but don't you want to add up waveforms with a period of F*2,
F*3, F*4, F*n... ? Simply doing FWR on the triangle wave won't get you
those waves...

- CList



From magnus at analogue.org  Thu Aug 13 19:04:29 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Thu, 13 Aug 1998 19:04:29 +0200
Subject: Is this stupid?
In-Reply-To: Your message of "Wed, 12 Aug 1998 22:28:19 +0100"
References: <001001bdc638$804adce0$bec448c2@default>
Message-ID: <199808131704.TAA01499@piraya.electrum.kth.se>

>>>>> "TA" == Tony Allgood <oakley at enterprise.net> writes:

Hi Tony!

 TA> Hi all,
 TA> This may be a stupid question but I'll ask it anyway.

It is a good startingpoint to learn something.

 TA> Has anyone ever tried
 TA> using inductors in a Moog ladder instead of the capacitors to make a VCHPF?
 TA> I guess you would need to put some cap in series with the Ls to block any
 TA> DC.

Well, it is an interesting thought, but I am not sure that the result
would be acceptable. Also, be aware of mutual inductances...

 TA> And secondly, has anyone found a need for taking a differential tap off the
 TA> ladder at another point other than below the top pair to create reduced
 TA> steepness of slope?

Well, if you added more taps as you proposed, then you would get a
result similar to a state-variable filter. You could sum the outputs
differently to create the diffrent responces. I haven't done the
homework so I doesn't know the exact small-signal responces and thus
can't calculate the scaling formulas. I am however confident that this
could be done.

It is however interesting to consider that the Moog 904B HP filter has
a very different layout and this was for some now forgotten reason.

Cheers,
Magnus



From moylan at eden.rutgers.edu  Thu Aug 13 19:25:35 1998
From: moylan at eden.rutgers.edu (David MOYLAN)
Date: Thu, 13 Aug 1998 13:25:35 -0400 (EDT)
Subject: more analogue additive (fwd)
In-Reply-To: <81A062BC5305D111A9D700805F065968CE94BB@maildepo.sc.siemens.com>
Message-ID: <Pine.GSO.3.96.980813131531.20403A-100000@er6.rutgers.edu>




On Thu, 13 Aug 1998, List, Christopher wrote:

> Maybe I'm missing something simple here, but how does one easily
> generate a triangle with a period _other_ than F^n Hz, where F is the
> fundamental? I mean, I've forgotten a lot of my theory on audio waves
> and stuff, but don't you want to add up waveforms with a period of F*2,
> F*3, F*4, F*n... ? Simply doing FWR on the triangle wave won't get you
> those waves...
> 
> - CList
> 
It helps to draw out the waves, but I'm not that good at ascii
graphics so.  If the wave is centered about 0 volts and it is
full wave rectified you do get a wave of twice the frequency
f*2.  f*3 is a bit more difficult to explain but can be done with
rectification.  It's kind of like a folding of the waveform.
This was discussed a couple months back.  I think it was in 
relation to a Serge waveshaper module.  You can check the archive.
Anyone else want to get a bit more detailed?

Also, if multiplying seems to difficult we could always use divide
down technology (again, organ technology).  dave moylan




From cmacdon at ix.netcom.com  Thu Aug 13 19:31:47 1998
From: cmacdon at ix.netcom.com (Christopher MacDonald)
Date: Thu, 13 Aug 1998 10:31:47 -0700
Subject: ladder filter operation
Message-ID: <35D32303.18AE@ix.netcom.com>

Could someone describe how a ladder filter works?  I've been tinkering
with a diode ladder filter for a while on my breadboard and I'm
realizing that actually understanding how the circuit operates might be
useful...

BTW does anyone else out there spend hours listening to the same
sawtooth wave while turning knobs, swapping components, and staring at
an oscilloscope or have I just completely lost my mind?   :)

-Chris MacDonald



From urekar.m at EUnet.yu  Thu Aug 13 19:39:47 1998
From: urekar.m at EUnet.yu (<<marjan>>)
Date: Thu, 13 Aug 1998 19:39:47 +0200
Subject: Minimoog Vcf
References: <35CF5612.3432478B@babcom.u-net.com> <35D1FAD3.1693@ibm.rhrz.uni-bonn.de>
Message-ID: <35D324E3.5BF0@eunet.yu>

Here's the one 

R20 resistor from Q6 emitter to -10 is 100k not 220k
as in MM archives.

If it still won't work ,maybe there is mistake in
original schematic ?

( +10V should go not to col. of Q6 but to other side 
of R6 47ohm resistor and + node of C9 100uF ? )



marjan



From b.layer at vikingelectronics.com  Thu Aug 13 20:26:39 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Thu, 13 Aug 1998 13:26:39 -0500
Subject: more analogue additive (fwd)
In-Reply-To: <Pine.GSO.3.96.980813122945.18018A-100000@er4.rutgers.edu>
Message-ID: <3.0.5.32.19980813132639.007a7100@192.168.210.18>

At 12:30 PM 8/13/98 -0400, you wrote:
>
>
>The more I think about this, the more intrigued I become.
>I think what we're dealing with here is almost a step
>back to organ technology followed by a few steps foward.
>Draw bars anyone?  If this project is pursued, it seems
>like a perfect candidate for a digital/analogue hybrid.
>(blasphemy?)  I'm talking about a computer to do the 
>analysis and possibly VCA envelopes coupled with analogue
>wave sources (and of course filters). 
 
No blasphemy here; my feeling is "give to Caesar that which is Caesar's".
What a splendid notion, to let digital do what it does best (control) and
let analog do what it does best (sound right). 

Consider the Korg PolySix, or even better: the Korg Delta. I seem to recall
that the Delta is rougly 1/2 organ (it has drawbars...) and 1/2 synth,
utilising digital control, and analog VCOs/VCFs.

Back to the future.


Bill Layer
"Quantity has a Quality all of it's own." -JL



From ebarbour at svetlana.com  Thu Aug 13 20:47:24 1998
From: ebarbour at svetlana.com (Eric Barbour)
Date: Thu, 13 Aug 1998 11:47:24 -0700
Subject: ladder filter operation
Message-ID: <01BDC6B0.243F16A0.ebarbour@svetlana.com>

>BTW does anyone else out there spend hours listening to the same
>sawtooth wave while turning knobs, swapping components, and staring at
>an oscilloscope or have I just completely lost my mind?   :)

You are entering the realm of the audiophile. Congratulations.

Can I sell you a nice tube amplifier? It will make all your personal
problems disappear, as you sink into the warm, sweet wash of
beautiful music..........your eyelids are getting very heavy........

Eric Barbour
Svetlana Electron Devices
Portola Valley CA USA




From steve.ridley at bbc.co.uk  Thu Aug 13 22:10:51 1998
From: steve.ridley at bbc.co.uk (steve.ridley at bbc.co.uk)
Date: Thu, 13 Aug 1998 20:10:51 +0000
Subject: Is this stupid?
In-Reply-To: <E6AC8F360103376C@c2-smtp.radio.bbc.co.uk>
Message-ID: <0AB78F360103376C@c2-smtp.radio.bbc.co.uk>


Moog used a two pole version of the ladder
filter in the "Satellite".  It was preceeded
by a bandpass filter (3 x CA3080).

STEVE RIDLEY




From b.layer at vikingelectronics.com  Thu Aug 13 22:18:54 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Thu, 13 Aug 1998 15:18:54 -0500
Subject: more analogue additive (fwd)
Message-ID: <3.0.5.32.19980813151854.007ae140@192.168.210.18>

>>From mmcintos at ball.com Thu Aug 13 14:55:52 1998
>From: "McIntosh, Malcolm" <mmcintos at ball.com>
>To: "'b.layer at vikingelectronics.com'" <b.layer at vikingelectronics.com>
>Subject: RE: more analogue additive (fwd)
>Date: Thu, 13 Aug 1998 13:40:43 -0600
>X-Mailer: Internet Mail Service (5.0.1458.49)
>
>Hey Bill,
>
>I have tried to post this twice and it hasn't shown up!  Post it for me
>if you think it has value.
>
>Tanks
>
>Malcolm
>
><SNIP>
>
>Hi,
>
>This is a subject I have been thinking about with no idea how to
>implement.
>
>Would it be possible to use frequency multiplication and one really good
>sine wave VCO for limited additive synthesis?  Would it be necessary to
>have 64 or 128 harmonics if you just wanted to make some really nice
>sounds but not be totally imitative?  Could you get away with 16 or
>maybe 8 (!) harmonics to make really interesting non-imitative sounds?
>
>Forgive anything I have over looked.
>
>Malcolm
>
><SNIP>
>
>
>
>> -----Original Message-----
>> From:	Bill Layer [SMTP:b.layer at vikingelectronics.com]
>> Sent:	Thursday, August 13, 1998 11:27 AM
>> To:	David MOYLAN
>> Cc:	synth-diy at mailhost.bpa.nl
>> Subject:	Re: more analogue additive (fwd)
>> 
>> At 12:30 PM 8/13/98 -0400, you wrote:
>> >
>> >
>> >The more I think about this, the more intrigued I become.
>> >I think what we're dealing with here is almost a step
>> >back to organ technology followed by a few steps foward.
>> >Draw bars anyone?  If this project is pursued, it seems
>> >like a perfect candidate for a digital/analogue hybrid.
>> >(blasphemy?)  I'm talking about a computer to do the 
>> >analysis and possibly VCA envelopes coupled with analogue
>> >wave sources (and of course filters). 
>>  
>> No blasphemy here; my feeling is "give to Caesar that which is
>> Caesar's".
>> What a splendid notion, to let digital do what it does best (control)
>> and
>> let analog do what it does best (sound right). 
>> 
>> Consider the Korg PolySix, or even better: the Korg Delta. I seem to
>> recall
>> that the Delta is rougly 1/2 organ (it has drawbars...) and 1/2 synth,
>> utilising digital control, and analog VCOs/VCFs.
>> 
>> Back to the future.
>> 
>> 
>> Bill Layer
>> "Quantity has a Quality all of it's own." -JL
>
Bill Layer
Sales Technician
<b.layer at vikingelectronics.com>

----------------------------------
Viking Electronics, Inc.
Hudson, WI. U.S.A
715.386.8861 (ext. 210)
<http://www.vikingelectronics.com>
----------------------------------

"Telecommunications Solutions for the 21st Century"



From b.layer at vikingelectronics.com  Thu Aug 13 22:48:00 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Thu, 13 Aug 1998 15:48:00 -0500
Subject: more analogue additive (fwd)
In-Reply-To: <09DB74475204D1119C8200805F19D0032D12B3@aeromsg1.ball.com>
Message-ID: <3.0.5.32.19980813154800.007a8340@192.168.210.18>

 
Hi Malcom,

>This is a subject I have been thinking about with no idea how to
>implement.
>
>Would it be possible to use frequency multiplication and one really good
>sine wave VCO for limited additive synthesis?  Would it be necessary to
>have 64 or 128 harmonics if you just wanted to make some really nice
>sounds but not be totally imitative?  Could you get away with 16 or
>maybe 8 (!) harmonics to make really interesting non-imitative sounds?

I think the limitation here is that you would be limited to natural
harmonics; most complex sounds contain much enharmonic information as well.
You are right in that freq. multiplication could provide a palette of
harmonics...

Perhpas if one employed eight oscillators, set to different microtonal
increments, and then created a palete of harmonics from each of those. Now
then, that might give you some real flexibility, and without running a
mega-array of HP204s. 

>
 
Bill Layer
Sales Technician
<b.layer at vikingelectronics.com>

----------------------------------
Viking Electronics, Inc.
Hudson, WI. U.S.A
715.386.8861 (ext. 210)
<http://www.vikingelectronics.com>
----------------------------------

"Telecommunications Solutions for the 21st Century"



From eli at gs160.sp.cs.cmu.edu  Thu Aug 13 23:01:27 1998
From: eli at gs160.sp.cs.cmu.edu (Eli Brandt)
Date: Thu, 13 Aug 1998 17:01:27 -0400 (EDT)
Subject: AW: additive
In-Reply-To: <Pine.GSO.3.96.980813114309.13825A-100000@er4.rutgers.edu> from "David MOYLAN" at Aug 13, 98 11:55:56 am
Message-ID: <199808132101.XAA28699@mailhost.bpa.nl>

David MOYLAN wrote:
> Now for the tough part: figure out a formula analogous to the
> Fourier Transform but for triangular components.

I tried to do the deconvolution to get the triangular spectrum of a sine.
Even after fixing the sign errors in my last post, I still had to hack the
signs some more, and the resynthesis doesn't seem to _quite_ converge.  So
I'm not putting the (Matlab) code up, though I'll mail it if you want to
fix things.

Anyway, here's a trispectrum, out to 64, that seems to work pretty well.
Use the FFT to get your signal's sine-harmonic series, then convolve with
this to get a tri-harmonic series:

 1.0000000e+000 0.0000000e+000 -1.1111111e-001 0.0000000e+000
-2.7654321e-002 0.0000000e+000 -1.2891016e-002 0.0000000e+000
-7.5395973e-003 0.0000000e+000 -4.9749731e-003 0.0000000e+000
-3.5400341e-003 0.0000000e+000 -2.6530804e-003 0.0000000e+000
-2.0652085e-003 0.0000000e+000 -1.6548627e-003 0.0000000e+000
-1.3567445e-003 0.0000000e+000 -1.1331476e-003 0.0000000e+000
-9.6102572e-004 0.0000000e+000 -8.2563102e-004 0.0000000e+000
-7.1716096e-004 0.0000000e+000 -6.2888900e-004 0.0000000e+000
-5.5607210e-004 0.0000000e+000 -4.9528640e-004 0.0000000e+000
-4.4400919e-004 0.0000000e+000 -4.0034788e-004 0.0000000e+000
-3.6285975e-004 0.0000000e+000 -3.3042918e-004 0.0000000e+000
-3.0218235e-004 0.0000000e+000 -2.7742681e-004 0.0000000e+000
-2.5560804e-004 0.0000000e+000 -2.3627769e-004 0.0000000e+000
-2.1907000e-004 0.0000000e+000 -2.0368421e-004 0.0000000e+000
-1.8987112e-004 0.0000000e+000 -1.7742283e-004 0.0000000e+000
-1.6616475e-004 0.0000000e+000 -1.5594941e-004 0.0000000e+000

-- 
     Eli Brandt  |  eli+ at cs.cmu.edu  |  http://www.cs.cmu.edu/~eli/



From synth1 at airmail.net  Thu Aug 13 23:35:32 1998
From: synth1 at airmail.net (Paul Schreiber)
Date: Thu, 13 Aug 1998 21:35:32 -0000
Subject: SAFE wall wart supplies
Message-ID: <01BDC704.2E3713C0@dal11-30.ppp.iadfw.net>

John has a great small sized unit. For more ooommmph, see the MOTM-900 supply at:

www.synthtech.com

Several folks are using it for powering everything from old PAiA modules to an ARP 2600.

Paul Schreiber
Synthesis Technology


----------
From: 	cyborg0 at GlobalEyes.net[SMTP:cyborg0 at GlobalEyes.net]
Sent: 	Friday, August 14, 1998 1:57 AM
To: 	synth-diy
Subject: 	Re: SAFE wall wart supplies

John Blacet wrote:
> 
> The discussion of wall warts the past few days prompts me to mention the
> safe, fully enclosed and REGULATED wall wart system available from
> Blacet Research. While it may not be suitable for a large modular
> system, it is a very cool way to power up a small rack. Especially when
> you add the power distribution board!
> 
> Spend your time building cool modules and not power supplies (mostly
> pretty boring). :>
> 
I second this! I mean, these power supplys actually are probably CHEAPER
to buy from John than to build! And, they work great!!
I would say to buy the bigger of the two though...just in case you need
more current..can never have enough current..
Extremely stiff regulation with no ripple..
rob






From cyborg0 at GlobalEyes.net  Thu Aug 13 23:38:37 1998
From: cyborg0 at GlobalEyes.net (cyborg0 at GlobalEyes.net)
Date: Thu, 13 Aug 1998 16:38:37 -0500
Subject: ladder filter operation
References: <35D32303.18AE@ix.netcom.com>
Message-ID: <35D35CDD.F3949EAA@globaleyes.net>

Christopher MacDonald wrote:

> BTW does anyone else out there spend hours listening to the same
> sawtooth wave while turning knobs, swapping components, and staring at
> an oscilloscope or have I just completely lost my mind?   :)
> 
yep. I do all the time ever since I got my scope..I also have gained
about 10lbs and am now horribly out of shape for someone who used to run
amateur triathalons a few years ago
.
I have also realized many wonderful and fantastic mods by taking a pot
and jumpering across certain key areas and looking at the output.. Some
of them being everything from pulse width modulation to increased env.
modulation to Filter modulation to beyond..

Also, I unfortunately do not do well with textual descriptions of whats
going on in a ladder filter..From what I gather, it seems to me like a
giant voltage slope dependent capacitance where you artificially set the
point at which the capacitance starts at by messing with the voltage
bias of the ladder, thereby nullifying the effects of some of the
capacitors therefore opening the filter..but im prolly way off base..
I have trouble understanding how the voltage bias and current bias work
together..I know that a constant current source nullifies the
exponential voltage change in a capacitive circuit.. but beyond that..


rob



From cyborg0 at GlobalEyes.net  Thu Aug 13 23:47:38 1998
From: cyborg0 at GlobalEyes.net (cyborg0 at GlobalEyes.net)
Date: Thu, 13 Aug 1998 16:47:38 -0500
Subject: additive
References: <v02110102b1f8746640a1@[205.134.244.186]>
Message-ID: <35D35EFA.51F47C83@globaleyes.net>

Chris Stecker wrote:

> >And to top it off - the statement had to do with modular and FM synths, not
> >Fourier (additive) synthesis. Yes, we can talk about modulars that can do
> 
> Oh, yeah...you're right.  Ooops.

Well, no.. we *could* do this, and remain in the analog domain, albeit,
with digital control.. I mean, honestly, we are finding things that can
be done in analog every day that we thought would have once been
impossible (tube filters anyone?)
rob



From cyborg0 at GlobalEyes.net  Fri Aug 14 00:00:16 1998
From: cyborg0 at GlobalEyes.net (cyborg0 at GlobalEyes.net)
Date: Thu, 13 Aug 1998 17:00:16 -0500
Subject: dying sequential 440 
Message-ID: <35D361F0.AEE0511D@globaleyes.net>

anybody know about these wonderful machines?
I need to know how good the sequencer is, cuz, if its 32 channels and
has good implementation, im saying bye bye to the ole pc on stage
thing..
I also need to know some of the bad things about the unit, cuz Wine
Country is telling me NOT to buy it cuz they have Power supply probs,
but, I mean, honestly, if I have to build a big external PS for it, I
dont care as long as it works.. I mean, what, does it run off of a
Jacobs ladder coil or some other Tesla inspired wierdness? Anyone know
why wine country is trying to scare me offa it? Perhaps so they can scam
it out from under me?
rob



From mmcintos at ball.com  Fri Aug 14 00:44:14 1998
From: mmcintos at ball.com (McIntosh, Malcolm)
Date: Thu, 13 Aug 1998 16:44:14 -0600
Subject: additive
Message-ID: <09DB74475204D1119C8200805F19D0032D12B7@aeromsg1.ball.com>

Yes, it sounds very difficult.  But I was thinking of an analog module
which uses additive synthesis theory in a practical way to create new
sounds and timbers.  Not imitative at all.  I think you would have to
limit the number of envelope generators to a reasonable number like 8 or
16.  Maybe you could use 2 or 3 VOCs to feed 8 or 16 frequency
multipliers each with a VCA and ADSR.  Whew!  Maybe by de-tuning the
VCO's just a little you might avoid the problem that Bill Layer
mentioned:

<SNIP>
>I think the limitation here is that you would be limited to natural
>harmonics; most complex sounds contain much enharmonic information as
well.
>You are right in that freq. multiplication could provide a palette of
>harmonics...
>
>Perhaps if one employed eight oscillators, set to different microtonal
>increments, and then created a palette of harmonics from each of those.
<SNIP>

I don't know.  I haven't finished or supplying my prototyping Lab with
enough stuff to try and I think that's the only way to see if the idea
has merit.  Combine the above scheme with filters and waveshapers and it
just seems like it may sound, well, very interesting (or as Spock would
say, "Fascinating Doctor").

Malcolm

PS  "thnaks" again Bill

> -----Original Message-----
> From:	Steven Curtin [SMTP:sdcurtin at lucent.com]
> Sent:	Thursday, August 13, 1998 2:40 PM
> To:	McIntosh, Malcolm
> Subject:	RE: additive
> 
> At 08:32 AM 8/13/98 -0600, you wrote:
> >Hi,
> >
> >This is a subject I have been thinking about with no idea how to
> >implement.
> >
> >Would it be possible to use frequency multiplication and one really
> good
> >sine wave VCO for limited additive synthesis?  Would it be necessary
> to
> >have 64 or 128 harmonics if you just wanted to make some really nice
> >sounds but not be totally imitative?  Could you get away with 16 or
> >maybe 8 (!) harmonics to make really interesting non-imitative
> sounds?
> 
> There's been some research done on this subject by James Beauchamp and
> Andrew Horner- they gave a paper at an International Computer Music
> Conference a number of years ago.  It's theoretically possible but
> rather
> hairy technically, since they used genetic algorithms for spectrum
> matching
> between different c:m ratios and the expected spectrum, etc.  Additive
> is
> such a control monster that it's hard to build an interface to it
> that's as
> elegant as modular analog synths, which is why it's been hard to get
> lots
> of people to buy into using it.
> 
> Steve C
> 
> --------------------------------------------------------------
> Steven Curtin  
> http://www.emf.org/people_curtin.html
> Lucent Technologies - Bell Labs Innovations
> rm. 1A-229, 200 Laurel Ave S
> Middletown, NJ 07748-4801  U S A
> ph: (732)957-2996   fax: (732)957-6878
> --------------------------------------------------------------



From tomg at vivid.net  Fri Aug 14 02:28:19 1998
From: tomg at vivid.net (tomg)
Date: Thu, 13 Aug 1998 19:28:19 -0500
Subject: Mad Mouse - Update
Message-ID: <yam7529.966.119686512@mail.vivid.net>

The Mad Mouse sports it's new ladder filter and sub-oct 
mixer. I've broken almost all of my design rules at this
point but the Mouse is getting very happy. I'm almost 
ready to build it but I may swap the VCO for a 3A type
and 86 the unj.

I'm a little suprised by all the interest..

http://www.tomg.vivid.net/madm/title.html

-tg




From cyborg0 at GlobalEyes.net  Fri Aug 14 02:33:35 1998
From: cyborg0 at GlobalEyes.net (cyborg0 at GlobalEyes.net)
Date: Thu, 13 Aug 1998 19:33:35 -0500
Subject: dying sequential 440
References: <35D361F0.AEE0511D@globaleyes.net>
Message-ID: <35D385DF.9F546704@globaleyes.net>

Oh, in case anyone wants to know...
For some reason, Wine Country kept asking me for the phone # of the guy
I was buying it from...
When I call just to ask about an upgrade, why the HELL would they need
HIS phone #?! I mean, I WILL be the owner of this unit, right?!
Or perhaps I wouldnt if i had given them the phone #..

Seems a bit suspicious..
rob



From asher at nanaimo.ark.com  Fri Aug 14 02:35:30 1998
From: asher at nanaimo.ark.com (Al Sherlock)
Date: Thu, 13 Aug 1998 17:35:30 -0700
Subject: Prophet 5 problem
Message-ID: <1.5.4.32.19980814003530.006b3ad4@nanaimo.ark.com>


Hello fellow synth junkies...

I have just had a couple if Prophet 5's delivered to me and the problem is
this...the one that is still making sounds is fine in unison mode (all keys
functional) but when I switch it to poly, notes on the keyboard start to
drop out.  Now, they don't just cease to exist, it's more like it comes and
goes.  For instance...if the middle A doesn't work...I alternate a pattern
between it and say the C lower down.  After bouncing back and forth a few
times the A will become active.  I have been told be some other Prophet
owners that they have seen this "bug" other units.  What I need to know is
if anyone out there has come across the problem and what they might have
done to repair it...or any ideas on what may be that problem.  Any
suggestions are greatly appreciated

Thanx

                                     Talk to ya later
                                      **---AL---**

ps...the other one only makes grunting noises (big problems) :(




From tomg at vivid.net  Fri Aug 14 03:46:58 1998
From: tomg at vivid.net (tomg)
Date: Thu, 13 Aug 1998 20:46:58 -0500
Subject: Mad Mouse Waveforms
Message-ID: <yam7529.2947.119322184@mail.vivid.net>

The mixing of the sub-octives and the VCO in the Mad Mouse
produce some of the more interesting wave shapes I've seen. 
One of the combinations actually looks like a string of MMs.

  MM  MM
MM  MM  MM

.....I thought it was cool... oh well I guess you had to be 
there. BTW sounds pretty good too.:-)


-tg




From cyborg0 at GlobalEyes.net  Fri Aug 14 03:57:16 1998
From: cyborg0 at GlobalEyes.net (cyborg0 at GlobalEyes.net)
Date: Thu, 13 Aug 1998 20:57:16 -0500
Subject: SAFE wall wart supplies
References: <35D2E982.19D0@metro.net>
Message-ID: <35D3997C.CDCF17C9@globaleyes.net>

John Blacet wrote:
> 
> The discussion of wall warts the past few days prompts me to mention the
> safe, fully enclosed and REGULATED wall wart system available from
> Blacet Research. While it may not be suitable for a large modular
> system, it is a very cool way to power up a small rack. Especially when
> you add the power distribution board!
> 
> Spend your time building cool modules and not power supplies (mostly
> pretty boring). :>
> 
I second this! I mean, these power supplys actually are probably CHEAPER
to buy from John than to build! And, they work great!!
I would say to buy the bigger of the two though...just in case you need
more current..can never have enough current..
Extremely stiff regulation with no ripple..
rob



From cyborg0 at GlobalEyes.net  Fri Aug 14 04:16:31 1998
From: cyborg0 at GlobalEyes.net (cyborg0 at GlobalEyes.net)
Date: Thu, 13 Aug 1998 21:16:31 -0500
Subject: sequential 440 is mine!
References: <ISSMTP.1.3(1).19980813155130.4294802403E@Corp.wdc.com>
Message-ID: <35D39DFF.7EA92747@globaleyes.net>

Well, I am now the proud owner of a 220v sequential 440..
>From what the guy tells me, it really sounds like a power supply problem
ie after about 30 mins to 3 hrs, it starts to get a little hot, and then
starts to act strange..
BUT, all the audio path is intact and working, so Im happy..Perhaps it
will stabilize with the software update.

Next, I need to know if anyone has the schematics for the Seq. 440.
If so, I would like to procure a copy with moola for yer troubles..

Also, does all the sequential stuff run offa +/- 15v and 5v? As far as I
can remember, they did, but its been a couple of yrs since I worked on
one. If so, I can get that PS changed out before it does any damage.
Anybody know the current it takes to run it? 

Finally, anyone have any idea how good the sequencer is on it?
Supposedly it rivals the mpc60/mpc3000... Is it loop based? Hardware
muting in real time?

Thanx, and sorry for all the bw..and, Im sorry for all those fellows who
don't have one yet! ;)
rob



From rowenal at nimrod.itg.telstra.com.au  Fri Aug 14 04:24:40 1998
From: rowenal at nimrod.itg.telstra.com.au (Rowena Larkins)
Date: Fri, 14 Aug 1998 12:24:40 +1000
Subject: additive
Message-ID: <199808140224.MAA01607@satyr.design>

> But there is the other side as well:  Does the above mentioned method
> of FFTing with no window function make sense in the meaning of spectral
> content ? I'd say no! Chopping the signal into window chunks creates
> (artificial) discontinuities, if you treat a long sine wave sample,
> you'll get very strange "spectra", this is clear , because after
> chopping the signal is no sine wave any more. If you wan't to have a
> meaningfull spectral representation, you'll have to apply a window
> function w(t), and this means convolution with the spectral equivalent
> W(s), ie. smearing.  This smearing or unsharpness will hide the little
> dirty "harmonics", that makes the sound of instruments so interesting.
> 
> Does this remind you of something? It is the Heisenberg theorem applied
> to music instead of quantum physics (the math is the same in this
> case):  time resolution rivals with spectral resolution. If you want
> good spectral resolution, the window has to be very long, thus time
> resolution suffers and vice versa.

> 



Given that both are dealing with wave theory, then this is not really suprising.


Rowena



From 9705146x at lux.levels.unisa.edu.au  Fri Aug 14 05:12:29 1998
From: 9705146x at lux.levels.unisa.edu.au (BuDWeiSeR)
Date: Fri, 14 Aug 1998 12:42:29 +0930 (CST)
Subject: Mad Mouse - Update
In-Reply-To: <yam7529.966.119686512@mail.vivid.net>
Message-ID: <Pine.SOL.3.91.980814124125.23391A-100000@lux.levels.unisa.edu.au>




> The Mad Mouse sports it's new ladder filter and sub-oct 
> mixer. I've broken almost all of my design rules at this
> point but the Mouse is getting very happy. I'm almost 
> ready to build it but I may swap the VCO for a 3A type
> and 86 the unj.
> 
> I'm a little suprised by all the interest..
> 


you just don't stop churning little synth beasts out! :)
Keep up the work. I wish i actually had the time to construct thsome of 
the devices on your site...


<bUd>



From pfperry at melbpc.org.au  Fri Aug 14 05:13:25 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Fri, 14 Aug 1998 13:13:25 +1000 (EST)
Subject: AW: additive
Message-ID: <1.5.4.16.19970105194705.0d475cf4@popa.melbpc.org.au>

At 11:55 AM 13/08/98 -0400, David MOYLAN  wrote:

>I can definitely see the use here.  Using triangle vco's would greatly
>simplify an analogue design by avoiding the need for sin conversion.

.....well nobody will ever accuse me of being on "smart" drugs.....
what we shd be using is walsh functions! squares are even easier!

paul perry melb aust




From chordman at flash.net  Fri Aug 14 05:37:30 1998
From: chordman at flash.net (Scott Gravenhorst)
Date: Fri, 14 Aug 1998 03:37:30 GMT
Subject: Nonlinear Feedback Filter (idea only) schematic on the web
Message-ID: <35d9ae3e.82903603@mail.lan>

This is as yet untested, but I worked out a circuit I want to
prototype and test.

http://members.xoom.com/chordman/NonlinearFeedbackFilter.html

Have a look if you like.

-- Scott Gravenhorst
-- FatMan Site: www.teklab.com/~chordman



From chordman at flash.net  Fri Aug 14 05:43:29 1998
From: chordman at flash.net (Scott Gravenhorst)
Date: Fri, 14 Aug 1998 03:43:29 GMT
Subject: Mad Mouse - Update
In-Reply-To: <Pine.SOL.3.91.980814124125.23391A-100000@lux.levels.unisa.edu.au>
References: <Pine.SOL.3.91.980814124125.23391A-100000@lux.levels.unisa.edu.au>
Message-ID: <35dab1d9.83826559@mail.lan>

TomG writes:
> The Mad Mouse sports it's new ladder filter and sub-oct 
> mixer. I've broken almost all of my design rules at this
> point but the Mouse is getting very happy. I'm almost 
> ready to build it but I may swap the VCO for a 3A type
> and 86 the unj.

Oh, but do try it first before you deep 6 it...  The UJT is so
uncommon!

-- Scott Gravenhorst
-- FatMan Site: www.teklab.com/~chordman



From tadej.bozicko at uni-mb.si  Fri Aug 14 08:58:20 1998
From: tadej.bozicko at uni-mb.si (Tadej Bozicko)
Date: Fri, 14 Aug 1998 08:58:20 +0200
Subject: Crumar things (Stratus, Spirit)
Message-ID: <01bdc750$ec2068e0$0100007f@localhost>

Hello!

I just happen to have a chance to buy some Crumar synth! The guy who's selling it, doesnt know exact type, but I suspect it is Stratus. He said, there is something like S-2 or D-2 marked on it. So I'm confused, because there is no ino on the net about these models. Anyone of you have something??? Specs, recommendations... and as fast as possible, because the price for this synth is around 80$.

Thanks!

Tadej Bozicko
E-Mail   : tadej.bozicko at uni-mb.si
WWW  : http://imola.uni-mb.si/~bozicko
WWW2: http://www.uni-mb.si/~uelelt68b

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From jorgen.bergfors at idg.se  Fri Aug 14 09:11:32 1998
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Fri, 14 Aug 1998 8:11:32 +0100
Subject: more analogue additive (fwd)
Message-ID: <TFSGMGYY@idg.se>

The additive synth with a computer terminal was probably a Crumar GDS. I have 
the album "Dig it" by Klaus Schulze, that was created entirely on the GDS. It 
was recorded in 1980. 
The sounds are rather impressive by themselves, but they sound rather static. 
They lack animation, like you can get with filter sweeps, PWM and waveshapers. 
It is probably very difficult to get *good sounding* animation with additive 
synthesis.
I didn't particularly like this record when it came out, even though the sounds 
were new and fresh. If he had used the GDS for just some of the sounds and 
combined it with other instruments, it would probably have been better.

/Jorgen





MIME:moylan at eden.rutgers.edu on 98-08-13 20.33.24
To:  synth-diy at mailhost.bpa.nl @ SMTP 
cc:  (bcc: Jorgen Bergfors/IDGSE)
Subject: more analogue additive (fwd) 



The more I think about this, the more intrigued I become.
I think what we're dealing with here is almost a step
back to organ technology followed by a few steps foward.
Draw bars anyone?  If this project is pursued, it seems
like a perfect candidate for a digital/analogue hybrid.
(blasphemy?)  I'm talking about a computer to do the 
analysis and possibly VCA envelopes coupled with analogue
wave sources (and of course filters). 
    There's been a fair ammount of valid criticism:
smearing, non-harmonic components, etc., but most synth
enthusiasts are more concerned with the sounds and less with
the math.  We won't know what the possibilities are until
someone builds it.
    I have seen pictures (maybe Barry Klein's book) of an
additive synth with a computer terminal.  Obviously it lost
a popularity contest to subtractive synthesis.  But the
important question is why.  Most likely because of cost
and simplicity.  Computers have come a long way.  I think
this type of setup could be a very useful addition to
someone's arsenal, specifically because it's an entirely
different way to look at the process of synthesis.
(Maybe I should consider a career in lobbying).
dave moylan













From debus at cityweb.de  Fri Aug 14 17:55:05 1998
From: debus at cityweb.de (Ingo Debus)
Date: Fri, 14 Aug 1998 17:55:05 +0200
Subject: more analogue additive (fwd)
References: <Pine.GSO.3.96.980813131531.20403A-100000@er6.rutgers.edu>
Message-ID: <35D45DD9.1EDC@cityweb.de>

David MOYLAN wrote:
> It helps to draw out the waves, but I'm not that good at ascii
> graphics so.  If the wave is centered about 0 volts and it is
> full wave rectified you do get a wave of twice the frequency
> f*2.  f*3 is a bit more difficult to explain but can be done with
> rectification.  It's kind of like a folding of the waveform.
> This was discussed a couple months back.  I think it was in
> relation to a Serge waveshaper module.  You can check the archive.
> Anyone else want to get a bit more detailed?

Add a dc offset to the triangle so that the positive peaks are twice as
high as the negative peaks. Then full-wave-rectify. Add a dc offset to
the result so that positive and negative peaks are of the same height
(this is not achieved by ac-coupling). Full-wave-rectify again, and you
get a triangle of 3* input frequency.

Ingo




From costello at seanet.com  Fri Aug 14 18:22:15 1998
From: costello at seanet.com (Sean Costello)
Date: Fri, 14 Aug 1998 09:22:15 -0700
Subject: Nonlinear Feedback Filter (idea only) schematic on the web
References: <35d9ae3e.82903603@mail.lan>
Message-ID: <35D46437.63A063FB@seanet.com>

Scott Gravenhorst wrote:
> 
> This is as yet untested, but I worked out a circuit I want to
> prototype and test.
> 
> http://members.xoom.com/chordman/NonlinearFeedbackFilter.html
> 
> Have a look if you like.

Looks cool.  One more idea for a nonlinear circuit: Dan Slater discusses
turning a state-variable circuit into a Ueda Attractor, using two
multipliers for an x to the 3rd function in the feedback loop.  I found
a circuit in Electronotes that is a nonselective frequency tripler, that
uses two transistors.  I can't do ASCIImatics, but I can describe it
pretty easily:

Use a 2N3904 and 2N3906.  The bases are tied together, and the input (+-
1.2 volts) is applied to the bases.  The emitter of the 2N3904 goes
through a 15K resistor to -15 volts, while the emitter of the 2N3906
goes through a 15K resistor to +15 volts.  The collectors of the two
transistors are connected, and the output (+_ 0.4 volts) is taken from
them.

Sean Costello



From jhaible at metronet.de  Fri Aug 14 18:46:24 1998
From: jhaible at metronet.de (jhaible)
Date: Fri, 14 Aug 1998 18:46:24 +0200
Subject: more analogue additive (fwd)
Message-ID: <19980814235228.28642.qmail@nuernberg2.pop.metronet.de>


> The additive synth with a computer terminal was probably a Crumar GDS. I
have 
> the album "Dig it" by Klaus Schulze, that was created entirely on the
GDS. It 
> was recorded in 1980. 
> The sounds are rather impressive by themselves, but they sound rather
static. 
> They lack animation, like you can get with filter sweeps, PWM and
waveshapers. 
> It is probably very difficult to get *good sounding* animation with
additive 
> synthesis.
> I didn't particularly like this record when it came out, even though the
sounds 
> were new and fresh. If he had used the GDS for just some of the sounds
and 
> combined it with other instruments, it would probably have been better.
> 
> /Jorgen

I happen to like "Dig It" (ironically my favorite track is "Death of an
Analogue" -
anybody figured out what exactly Schulze is singing thru the vocoder here
?),
but his next one, "Trancefer", was much better. The same kind of electronic
sound.
No idea if he still used the GDS here - the picture on the sleeve shows his
studio with all his analogue goodies, but the keyboard sounds are very
similar to
"Dig It", and much unlike "Timewind" or "Body Love", for example. What
makes
"Trancefer" a whole category better than "Dig It" is exactly what you
mentioned:
other instruments. In that case, the superb Cello playing of Wolfgang
Tiepold.

JH.



From tomg at vivid.net  Fri Aug 14 19:09:05 1998
From: tomg at vivid.net (tomg)
Date: Fri, 14 Aug 1998 12:09:05 -0500
Subject: Crumar things (Stratus, Spirit)
In-Reply-To: <01bdc750$ec2068e0$0100007f@localhost>
Message-ID: <yam7530.252.119336000@mail.vivid.net>

On 14-Aug-98, Tadej Bozicko wrote:
>Hello!

>I just happen to have a chance to buy some Crumar synth! The guy who's
selling
>it, doesnt know exact type, but I suspect it is Stratus. He said, there is
>something like S-2 or D-2 marked on it. So I'm confused, because there is no
>ino on the net about these models. Anyone of you have something??? Specs,
>recommendations... and as fast as possible, because the price for this synth
>is around 80$.

The Crumar DS-2 is your standard mono synth with a Opus style 
poly mode. DS stands for digital synth but the only real digital
part is the kbd. Weighs about 75lbs comes in it's own travel
case. Makes a good heater. Huge acid sound. All ics plug in
sockets makes it easy (ier) to fix.  

2 VCO ramp/tri/sine sync
2 ADSR
1 VCA
MS50 type filter 
2 LFOs ramp/tri/random w/LFO mixer and delay
Top Octive type poly mode

For $80 snatch it up. If you don't like it I'll buy it from
you and even pay shipping. BTW the DS-2 is a rare bird. I
think less than 100 were made, could be wrong..

-tg






From dbalvage at ptdcs2.ra.intel.com  Fri Aug 14 19:20:15 1998
From: dbalvage at ptdcs2.ra.intel.com (Duane R Balvage)
Date: Fri, 14 Aug 1998 10:20:15 -0700
Subject: SAD-1024 delay Q.
Message-ID: <35D471CF.794B@ptdcs2.intel.com>

Hello all -

Does anyone have a good sounding analog delay circuit designed around 

the SAD1024? I want to build an analog delay/reverb w/ the dual spring

reverb idea from PAIA, but have predelay taken care of by a SAD-1024.

Sooo...Anyone have any construction hints or ideas around the BBD

chip..?

			- Duane
-- 
   "That boy's got a mouth like a cannon ... Always shootin' it off..."
                                
                             - Foghorn Leghorn
                      ________________________________
                     / o o oo              o ooo o   /\
       -------------/ ////  Duane R. Balvage   //// / /---------
                   /    _________________________  / /
                  / // / // /// // /// // /// / / / /
                 /___ //////////////////////////_/ /
                 \____\________________________\_\/

                     Intel Corporation, RA1-303
                   Portland Technology Development
       =========================================================

              Phone: (503) 613-8055    FAX: (503) 613-8261
                   E-Mail: dbalvage at ptdcs2.intel.com



From oakley at enterprise.net  Fri Aug 14 19:37:38 1998
From: oakley at enterprise.net (Tony Allgood)
Date: Fri, 14 Aug 1998 18:37:38 +0100
Subject: additive
Message-ID: <004b01bdc7ab$257c9aa0$2ac448c2@default>

Malcolm said:
Maybe you could use 2 or 3 VOCs to feed 8 or 16 frequency
multipliers each with a VCA and ADSR.  Whew!  Maybe by de-tuning the
VCO's just a little you might avoid the problem that Bill Layer
mentioned


This is alright, but do not expect rich waveforms or swept filter sounds. An
adsr on each harmonic will not produce swept sounds unless you delay the
triggering. You are much better off using a Walsh bank, see Neil Johnson's
site. If you want enveloped sines then use a DX7 or similar like a previous
post suggested. Detunes are easier too. But you will not be thrilled, since
it will sound like a Hammond organ. One way to get good additive synthesis
is to use a piece wise linear voltage generator (32 steps) for each VCA.
This may give you nice moving textures but it takes a long time to set up
unless you have a Fairlight and a light pen. :-)

I had such a generator with 8 tri harmonics, but it was sadly too much
hassle to use. Give me two VCOs with sync and audio rate PWM any day. Having
said that, one of these days I will dust off my Walsh bank and update it.
This was more successful, but it never got further than eight Eurocards
stuck to a piece of ply-board.

Regards,

Tony Allgood, Cumbria, UK

e-mail: oakley at enterprise.net

Rack mounted Moog VCF module. Details to be found at...

http://aupe.phys.andrews.edu/diy_archive/schematics/effects/filter.html






From jfoster at lucasdigital.com  Fri Aug 14 20:04:48 1998
From: jfoster at lucasdigital.com (Jeff Foster)
Date: Fri, 14 Aug 1998 11:04:48 -0700
Subject: Crumar things (Stratus, Spirit)
References: <01bdc750$ec2068e0$0100007f@localhost>
Message-ID: <35D47C40.6DD2F848@lucasdigital.com>

take a look at sonicstate for pictures and other info about the DS-2
http://www.sonicstate.com

JF

Tadej Bozicko wrote:

>  Hello! I just happen to have a chance to buy some Crumar synth! The
> guy who's selling it, doesnt know exact type, but I suspect it is
> Stratus. He said, there is something like S-2 or D-2 marked on it. So
> I'm confused, because there is no ino on the net about these models.
> Anyone of you have something??? Specs, recommendations... and as fast
> as possible, because the price for this synth is around
> 80$. Thanks! Tadej Bozicko
> E-Mail   : tadej.bozicko at uni-mb.si
> WWW  : http://imola.uni-mb.si/~bozicko
> WWW2: http://www.uni-mb.si/~uelelt68b
>



--
Jeff Foster 415-662-1254
Unix Systems/Networks - Skywalkersound, LucasDigital Ltd.
"State machines are unnatural"





From eli at gs160.sp.cs.cmu.edu  Fri Aug 14 21:48:26 1998
From: eli at gs160.sp.cs.cmu.edu (Eli Brandt)
Date: Fri, 14 Aug 1998 15:48:26 -0400 (EDT)
Subject: Walsh function website update
In-Reply-To: <5d3158d0@camcon.co.uk> from "Neil Johnson" at Aug 13, 98 05:31:49 pm
Message-ID: <199808141948.VAA19541@mailhost.bpa.nl>

Neil Johnson wrote:
>      http://members.xoom.com/Neil_Johnson/walsh.html

Thanks, interesting stuff.  I want to code something up and see what
happens when you detune or PWM the Rademacher functions...

By the way, are there special tricks that Walsh functions do, compared
to using pulse waves or something?

-- 
     Eli Brandt  |  eli+ at cs.cmu.edu  |  http://www.cs.cmu.edu/~eli/



From gur-m at internet-zahav.net  Fri Aug 14 20:21:01 1998
From: gur-m at internet-zahav.net (Gur Milstein)
Date: Fri, 14 Aug 1998 20:21:01
Subject: additive
In-Reply-To: <v02110102b1f8746640a1@[205.134.244.186]>
Message-ID: <3.0.2.16.19980814202101.08674b7c@mail.internet-zahav.net>

hi guy's.
thank you all for so much info.
allso i'm looking for 
a good  book containing  info about this topic,
with all the Fourier mathematics ?

thanx
Gur Milstein




From oakley at enterprise.net  Fri Aug 14 22:38:51 1998
From: oakley at enterprise.net (Tony Allgood)
Date: Fri, 14 Aug 1998 21:38:51 +0100
Subject: Integrator Modular
Message-ID: <000801bdc87f$19098ce0$67c648c2@default>

Hi all,

Tom Carpenter/Analogue solutions is sourcing a thing called the Integrator
modular synth. It is very similar to Doepfer types, ie. cheap and cheerful.
If that is your thing, then it can be found at
http://www.netkonect.co.uk/a/analogue/

I've not heard it and I'm not connected to him at all, but he did sell me a
nice midi-cv converter once, and he used to work for Kenton.

Regards,

Tony Allgood, Cumbria, UK

e-mail: oakley at enterprise.net

Rack mounted Moog VCF module. Details to be found at...

http://aupe.phys.andrews.edu/diy_archive/schematics/effects/filter.html






From verbos at on-q.com  Fri Aug 14 23:20:50 1998
From: verbos at on-q.com (mark verbos)
Date: Fri, 14 Aug 1998 15:20:50 -0600
Subject: 4N37 opto-isolator?
Message-ID: <35D4AA31.84EA51E5@on-q.com>

I saw in some archive that Gene Stopp was suggesting to use a
4N37 for adding VC to the envelope stages on the ASM-1.

does this really work? How? any ideas?
--
mark verbos

"I think the future of analog modulars is to build them
yourself."

verbos at on-q.com
http://www.on-q.com/verbos
massive magazine... http://www.massivemag.com
current release...
 "Logic Circuits" as CMOS on Shokoy, Germany





From magnus at analogue.org  Sat Aug 15 00:36:33 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Sat, 15 Aug 1998 00:36:33 +0200
Subject: additive
In-Reply-To: Your message of "Fri, 14 Aug 1998 20:21:01"
References: <3.0.2.16.19980814202101.08674b7c@mail.internet-zahav.net>
Message-ID: <199808142236.AAA20922@piraya.electrum.kth.se>

>>>>> "GM" == Gur Milstein <gur-m at internet-zahav.net> writes:

 GM> hi guy's.

Hi Gur!

 GM> thank you all for so much info.
 GM> allso i'm looking for 
 GM> a good  book containing  info about this topic,
 GM> with all the Fourier mathematics ?

Well, there are many excelent books covering Fourier mathematics and
here are some that has a special place on my bookshelf:

"Theory and Application of Digital Signal Processing" by Lawrence
R. Rabiner and Bernard Gold. This book is more know as just Rabiner
and Gold... an very readable book on DSPs and various issues including
IIR, FIR, DFT, FFT, z-transfrom, bilinear transfrom, hardware
implementations (down to the transistor and chip design!), vocoders
(there are Bell Labs and MIT Lawrence labs people, check this out if
you want to learn about vocoders).
This book is very well refered to and this is for a good reason, it is
a good book and it has actually saved me much work at times even when
other books covered the same topic with more words (but obviously not
the right ones). It is from 1975 but theory hasn't changes since, some
optimations algorithms has improved thought...

"Digital Signal Processing" by Alan V. Oppenheim and Ronald
W. Schafer. Another very good book. It is also from 1975 and infact is
the backside of them recommending the other, so we have a
crossreference between them. The Oppenheim and Schafer is also being
well referenced in many articles and book on the topic. It is a very
good complement to the Rabiner and Gold book. I got this one for $86
when I was in Washington this December and I don't regret it. I feel
confident that it will pay out well the next time that I get into
trouble (and I have a gutfeeling it is coming my way soon).

My rule of thumb on books: Better get a good book that is a bit
expensive than many that just almost cover the topic.
Back at the time when I didn't have much money it was a really good
way of prioritizing, now I have the money to fill in the gaps and
depths where needed.

Fourier series, Fourier analysis and Fourier Transform is all very
powerfull tools. To some degree have people tended to overpraise their
authority as the truthsayer about things, this does not make it less
powerfull, just less powerfull for the things that people imagine that
it can do for them. Fourier analysis and Fourier Transfrom isn't
really much of a mystery, the more one learns how the formulas work
the more sense they make, to the point where it is hard to imagine
anything else. There is however a part of the world that is not well
covered with Fourier analysis by itself, for this we need to use a
diffrent approach. A approach wich is very powerfull and where Fourier
analysis is just a special case is LaPlace analysis and LaPlace
transforms. The LaPlace transform as an discrete equivalent just as
the Fourier Transform (which is called DFT or in it's optimized case
FFT), the z-transform. Knowing all four transforms well, their usage
and limits of applications and enougth to do the math and you can make
minor miracles. Analog or Digital, sampled or contingous...

BTW. Hammonds are a truely additive synth with 9 sines being controled
with the dragbars and true polyphony. I must say that I haven't heard
many that truely master the Hammond but just to make a great break
with tradition I did hear one such guy live this evening and I have
still not really come back to reallity from it :) :) :)
CBS had a camera there, so you migth find a snap of me digging the
music...

Cheers,
Magnus



From cyborg0 at GlobalEyes.net  Sat Aug 15 00:52:27 1998
From: cyborg0 at GlobalEyes.net (cyborg0 at GlobalEyes.net)
Date: Fri, 14 Aug 1998 17:52:27 -0500
Subject: [Digital_Hell] FS: Voyager 1 Beat Xtractors
References: <35D49CFD.14BB7475@execulink.com>
Message-ID: <35D4BFAB.4E22BAB4@globaleyes.net>

John Greczula wrote:
> 
> Voyager 1 Beat Xtractor *The Essential Modern DJ Device*
> 
> Convert Audio from two sources to MIDI Sync Clock
> Dual LED Displays
> 
> Brand New, Full Warranty
> 
> $349 USD plus shipping.
> 
Man, thats pretty hefty price tag for what is basically a bandpass
filter fed into a comparator w/ hysteresis (to set trigger point) then,
the micro computes the time differential and starts firing out midi
clocks..
Someone could build this thing for 50 bux..
I don't mean to down it, because I have actually been looking into
getting one, but, not for 350 bux my good man..
It better be DAMN good... It better know what records Im going to play
before I do..
Its sad actually.. The markets IS there, but when companies try to
decimate the consumer like this, I get a little irked..
forget it, tap tempo here I come..
DIY ppl, couldnt we build one of these??
rob



From steve at babcom.u-net.com  Sat Aug 15 01:24:43 1998
From: steve at babcom.u-net.com (Steven Cook)
Date: Sat, 15 Aug 1998 00:24:43 +0100
Subject: ASM1 ADSR Idea
Message-ID: <35D4C73C.E026B2AE@babcom.u-net.com>

Hi,

With regard to the ASM1 ADSR, would the following modification work?

Replace the 4002 dual 4 input NOR with a 4025 triple 3 input NOR. This gives a
spare gate which is wired as an invertor to replace U2. U2 is then used as a
comparator wired between the top of the sustain pot and the output of the
ADSR. The sustain peak trimmer is replaced by a fixed resistor - say 47k - to
give a peak attack / sustain of about 10v.

This would (If it works!) remove 2 trimmers and all setting up without any
increase in parts count.

Any problems?

Steve.





From cyborg0 at GlobalEyes.net  Sat Aug 15 01:25:02 1998
From: cyborg0 at GlobalEyes.net (cyborg0 at GlobalEyes.net)
Date: Fri, 14 Aug 1998 18:25:02 -0500
Subject: Studio 440 and Wine Country (retraction)
References: <199808142027.QAA11102@mercury.peganet.net>
Message-ID: <35D4C74E.99F464F9@globaleyes.net>

After talking with, I think, Dave (Smith?!?!, perhaps)
at Wine Country and dealing with his helpfulness and having a talk over
my  mostly dead studio 440 aquisition (albeit, he was a bit talkative,
prlly a coffee abuser such as myself:) I hereby repeal my suspicions of
all and any wrongdoing and exalt Wine Country back into the kingdom of
synth gods..

Praise be to Sequential,
And praise be to Dave of Wine,
Amen..

rob
ps I hope everyone is able to chuckle at this and not say that I am
making fun of catholics or anything..



From pfperry at melbpc.org.au  Sat Aug 15 04:40:01 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Sat, 15 Aug 1998 12:40:01 +1000 (EST)
Subject: [Digital_Hell] FS: Voyager 1 Beat Xtractors
Message-ID: <1.5.4.16.19970106191339.2cff4a04@popa.melbpc.org.au>

At 05:52 PM 14/08/98 -0500, Rob cyborg0 at GlobalEyes wrote:

>Its sad actually.. The markets IS there, but when companies try to
>decimate the consumer like this, I get a little irked..
>forget it, tap tempo here I come..
>DIY ppl, couldnt we build one of these??

I hate to say this Rob, but yes, you can build one for $50.....
and no, you couldnt build one, pay for staff, rent, taxes, phones,
lights, advertising and get it into a music store for less than $350.
Lets go backwards:
Retail $350
Price to store:$220
Freight & handling to store:$10.
Screenprinted custom box: $85, if at all fancy.
Components: $50, as you say.
Assembly wages: $30
oops, forgot the pcb: $24, depending on quantity

Well, thats $21 for advertising, phone , light, rent,
and any profit to put toward your own wage, PROVIDED
that nobody stiffs you on payment (which you get 90 days
AFTER it is delivered to the store).

paul perry (manufacturer... how did you guess?)




From tomg at vivid.net  Sat Aug 15 05:32:42 1998
From: tomg at vivid.net (tomg)
Date: Fri, 14 Aug 1998 22:32:42 -0500
Subject: Mad Mouse - BETA
Message-ID: <yam7530.2125.119218640@mail.vivid.net>

I think this is it. Had to drop the ujt vco because of 4013
drop out at higher freqs. Thats too bad because I really had
it sounding good just before I gave up on it. I'll put it
on a page with the other rejects when the MM is finished.
It's still a good cheep vco.

BTW now that I get a good look at it. The MM looks a lot like
the tb303 synth section... I wonder how that happened?

-tg




From squarewave at jps.net  Sat Aug 15 07:38:17 1998
From: squarewave at jps.net (Debby and Gene Stopp)
Date: Fri, 14 Aug 1998 22:38:17 -0700
Subject: commercial synth circuits
Message-ID: <02af01bdc80e$fab4eb60$f6c4edd0@oemcomputer>

How the heck did I miss the original posts? Ah well, new baby, new job, no
sleep, no time, the once beloved email list has become the occaisional
diversion for lurking...

So - "Terry Mikulic" now? Along with Ian Fritz? My gosh, who's next, Jan
Hall? Lovin' it. Where's Dave Rossum when you need him. Hey it's high school
all over.

As some of you archive-divers may know the KE4859 VCO made it to the top of
my test heap a couple years back, mainly because of its combination of range
and accuracy. Other deciding factors included the availability of the FET
still (a.k.a. the NTE 466), the fact that Harris still makes the CA3130/3140
(still as static sensitive as ever), the fact that the parts drawers at the
old job contained oodles of LM311's, and last but not least the fact that
2N3904's could be used in the expo converters. All this and not a lot of
parts! Thanks, Terry. Very nice, to-the-point VCO.

Close second still is the 3080-based tri-square VCO. Bernie's 3080
schmidt-trigger version from the PCC works great as well. No FETs to worry
about, just 3080's, but I can still get 'em and the current Harris parts
sure seem to act a lot better than the RCA crap from the 70's (many of which
still survive in my original modular somehow).

I guess I like the sawtooth-based VCO better philosophically - the thought
of piecing together the saw from an alternatingly-inverted tri plus
one-sixth the square just doesn't seem to me to be capable of being as
"pure" as a fast-reset ramp generator. I admit it, a nice 3-VCO sawtooth
minimoog lead solo still makes me wake up the neighbors. Call me biased.
Maybe someday I'll learn to appreciate the beauty of a perfect triangle, and
the tri-square will become my favorite. Come to think of it, a clean 50%
square wave in headphones can be inspiring...

Anyway, while I do appreciate the concept that perfect operational
parameters should override any parts-count considerations, the fact is that
the 3130-FET-LM311 VCO core is both accurate and simple, a tribute to the
designer. Interestingly, the Roland 700 modular has pretty much the same
design.

- Gene



-----Original Message-----
From: terry michaels <104065.2340 at compuserve.com>
To: synth <synth-diy at mailhost.bpa.nl>
Date: Sunday, August 09, 1998 4:47 PM
Subject: Re: commercial synth circuits


>
>
>-------------Forwarded Message-----------------
>
>From:   terry michaels,
>To:     INTERNET:ijfritz at earthlink.net, INTERNET:ijfritz at earthlink.net
>
>Date:   8/9/98  5:45 PM
>
>RE:     Re: commercial synth circuits
>
>Hi Ian
>
>I chose the KE4859 primarily because of its low on resistance. FET leakage
>is also important.   At the time I designed this circuit (October 1973),
>this part was the best choice I could find that was easily available.  It
>was sold by National Semiconductor, and I could buy National parts over the
>counter here in Milwaukee.  The combination of this part, the .0024 cap,
>and the CA3130 slew rate and settling time yields a sawtooth flyback time
>of less than 2 microseconds, as recently measured on modern test equipment.
> Since the flyback time is a source of frequency error at the higher ranges
>of the VCO, I sought to minimize it by using the KE4859.  I am currently
>redesigning all of my synth circuits, and I will get to this one soon.  I
>will look at currently available parts, and I will be happy to let you know
>what I find as a modern replacement.
>
>I do not prefer the resistance in series with the timing cap method of
>high-end compensation.  The steady state voltage drop across the resistor
>at high frequencies alters the end points of the sawtooth waveform. This in
>turn affects the purity of the other waveforms usually derived from the
>sawtooth.  However, it has the benefit of accomplishing high-end
>compensation very simply, with only one component. This comes down to
>personal design philosophy and goals.  Mine is generally to achieve the
>best performing, most precise circuits, with only a secondary consideration
>to the number of components needed.  I recognize the desire of others to
>create simple, inexpensive designs, and there is clearly a need out there
>for that design approach.  The great value of the DIY list is providing a
>forum for all types of designs
>to be shared, so everyone can find what they want.
>
>Using the Franco method doesn't alter the design considerations with
>regards to FET switching time.  The goal is the same - discharge the
>integrating cap as fast as possible.
>




From ka4hjh at gte.net  Sat Aug 15 09:07:11 1998
From: ka4hjh at gte.net (KA4HJH)
Date: Sat, 15 Aug 1998 03:07:11 -0400
Subject: SAD-1024 delay Q.
In-Reply-To: <35D471CF.794B@ptdcs2.intel.com>
Message-ID: <v04011700b1fae3176674@[153.37.233.34]>

>Does anyone have a good sounding analog delay circuit designed around
>
>the SAD1024? I want to build an analog delay/reverb w/ the dual spring
>
>reverb idea from PAIA, but have predelay taken care of by a SAD-1024.

Are you dead-set on the Reticon chip? The Panasonic chips are better (so
I'm told--the specs certainly look more impressive) and readily available
from Digi-Key.

You'll also probably need compansion for noise reduction. Thomas Henry's
new book on the NE570 looks pretty interesting--a good start at least. It's
at the Midwesst Analog Products site (never have that URL).

Terry Bowman, KA4HJH
"The Mac Doctor"



From yoh212 at lulu.acns.nwu.edu  Sat Aug 15 17:23:55 1998
From: yoh212 at lulu.acns.nwu.edu (Yoshiki Ohmura (Yoshi))
Date: Sat, 15 Aug 1998 10:23:55 -0500 (CDT)
Subject: LM307 substitute?
Message-ID: <Pine.HPP.3.93.980815101940.14656A-100000@lulu.acns.nwu.edu>

Since I do most of my ordering from Mouser which does not carry that op
amp, I was wondering if I could substitute another op amp for this.  Don't
think I'm to lazy to place an order for just one product somewhere else,
but since I have to order this stuff to Europe from the US it would be a
real hassle.  I  have lots of TL71/81 and LF356/351, would those work?

Thanks for the i nfo

Yoshi











From costello at seanet.com  Sat Aug 15 20:09:17 1998
From: costello at seanet.com (Sean Costello)
Date: Sat, 15 Aug 1998 11:09:17 -0700
Subject: SAD-1024 delay Q.
References: <v04011700b1fae3176674@[153.37.233.34]>
Message-ID: <35D5CECD.EDF5DFC2@seanet.com>

KA4HJH wrote:
> 
> >Does anyone have a good sounding analog delay circuit designed around
> >the SAD1024? I want to build an analog delay/reverb w/ the dual spring
> >reverb idea from PAIA, but have predelay taken care of by a SAD-1024.
> 
> Are you dead-set on the Reticon chip? The Panasonic chips are better (so
> I'm told--the specs certainly look more impressive) and readily available
> from Digi-Key.

>From what I've heard, the Reticon chips are capable of far wider delay
time sweeps than the Panasonic chips.  The ADA flanger originally used a
Reticon chips to achieve super wide sweep ranges (35:1); it had to be
substantially redesigned to accomodate the narrower sweep of the
Panasonic chips.

BTW, anyone know what analog delay chips were used in the Marshall Time
Machine?  That device was supposedly capable of extreme sweeps (100:1).  

Anyway, for the reverb, a Panasonic chip would probably do the job just
fine.  The Reticon chips should probably be sought out primarily for
swept-delay functions, where wide sweep ranges are important.

Sean Costello



From ka4hjh at gte.net  Sat Aug 15 20:42:03 1998
From: ka4hjh at gte.net (KA4HJH)
Date: Sat, 15 Aug 1998 14:42:03 -0400
Subject: SAD-1024 delay Q.
In-Reply-To: <35D5CECD.EDF5DFC2@seanet.com>
References: <v04011700b1fae3176674@[153.37.233.34]>
Message-ID: <v04011700b1fb84fb3b16@[208.255.152.193]>

>From what I've heard, the Reticon chips are capable of far wider delay
>time sweeps than the Panasonic chips.  The ADA flanger originally used a
>Reticon chips to achieve super wide sweep ranges (35:1); it had to be
>substantially redesigned to accomodate the narrower sweep of the
>Panasonic chips.

The PAiA HyperFlanger pushes the 1024 to it's limit, well under a ms.

>
>BTW, anyone know what analog delay chips were used in the Marshall Time
>Machine?  That device was supposedly capable of extreme sweeps (100:1).

I seem to remember that the Electric Mistress used some kind of BBD based
some other technology--CCD, if my memory is intact. Not sure about the
Marshall.

>Anyway, for the reverb, a Panasonic chip would probably do the job just
>fine.  The Reticon chips should probably be sought out primarily for
>swept-delay functions, where wide sweep ranges are important.

Exactly. Now go break the rules.

BTW, Midwest Analog Products still had a few 4096's left the last time I
checked, at a fraction of what they used to cost.

Terry Bowman, KA4HJH
"The Mac Doctor"



From LEG at btinternet.com  Sat Aug 15 20:45:56 1998
From: LEG at btinternet.com (george & lorraine)
Date: Sat, 15 Aug 1998 19:45:56 +0100
Subject: test please ignore
Message-ID: <01bdc87c$f0407d20$LocalHost@windows95>

Men were mice and mice were men once upon a time.But now that it's the opposite it's twice upon a time.
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From jhaible at metronet.de  Sat Aug 15 22:06:55 1998
From: jhaible at metronet.de (jhaible)
Date: Sat, 15 Aug 1998 22:06:55 +0200
Subject: Neptune Phaser finished
Message-ID: <19980815205019.14905.qmail@nuernberg2.pop.metronet.de>

Yes, Neptune now - not Uranus anymore (;->).
Got the faceplate from Schaeffer Apparatebau a few
days ago. White lettering on dark red background.
Chose black ReAn knobs with blue caps and white
pointers, toggle switches with white caps, and blue
LEDs to match. Hope I will be able to publish photos and
schematics in a few weeks.
(I have drawn schemos on PSpice, but it's too large for
my usual method: Screenshot with Paint Shop Pro to make
a gif from the edito. Any ideas ?)

JH.



From jhaible at metronet.de  Sat Aug 15 22:45:22 1998
From: jhaible at metronet.de (jhaible)
Date: Sat, 15 Aug 1998 22:45:22 +0200
Subject: New project: Sequencer
Message-ID: <19980815205023.14905.qmail@nuernberg2.pop.metronet.de>

Something I carried around with me for a long time.
A big analogue sequencer to match my JH-3 system.
Finally started doing experiments now.
I want to have a random mode and skip function 
(like the ARP seq), and I want up/down modes like 
the Korg SQ-10.
Several Gate busses a la ARP, too.
Not yet sure about number of steps and rows.

The core of my Seq will be the CD4516 up /down counter.
What does "Reset" mean, when the counter counts backwards?
I think about using the4516's Preset function to jump to the
last stage in that case.

Skip and Random:
I have simulated things like that on my simple 4017-based 
sequencer that is part of the JH-3 system. The sequencer clock
does not trigger the counter directly, but opens a gate and lets
a HF VCO clock the counter. Works, but needs a lot of patching,
and my new Seq should also have a masking function to hide
these fast clocks at the beginning of a note.
I looked into the ARP schemos, and I was surprised how clever
their solution was: While the GATE is on, they do all the Random
calculation, and the last step number is stored in a latch. In the short
time when the capacitor of the seq clock VCO is discharged, they
do the Skip operation. Problem: How do you know which steps to skip
before the output is updated ? I'd almost used a separate MUX to
control the Skip bus, with the MUX connected directly to the counter,
while the main MUX for the potentiometers would be latched. But then
I found how ARP have done it: The used a *transparent* latch !
So, the "random" counting is masked by the latch, but the short
"skip" counting takes place while the latch is transparent. Brilliant.
I threw my first veroboard away, and use the ARP method now.

Something I did not like was ARP's way to implement the random
clock, which is actually pseudo random, and makes use of an 
(undocumented?) ability to slightly voltage control the time of a CMOS
monoflop. I'll use a 4046 instead: The zener voltage of the 4046 is
amplified 
by a single 741 (feedback 1megohm output to inv input, 10uF directly
from inv input to GND, the slew rate of the 741 does the rest ...), and
the 741 controls the VCO of the 4046. Works great - have just prototyped
it.

Quantizer:
I want to build a quantizer where I can select which chromatic tones I want

to include and which I won't, with a set of 12 individual switches. 
I guess I'll do this with a normal binary counter and resistor network
(main
DAC), and a second divide-by-12 counter plus 4067 MUX and a separate
resistor network for the semitones (semitone DAC). The two DAC outputs
would be exactly scaled to each other with trimpots, and then added.
Then I can put a switch into each 4067 output line, so I can remove evey
unwanted semitone. I couls also make each of the semitone DAC's
resistors slightly variable with a resistor + trimpot combination, so I can
tune each semitone (for all octaves in common), if I don't want equal
tempered
scales. What do you think about this ??

Back to the bench. If you have suggestions for features you wouldn't like
to miss in a sequencer, please tell me during the next days !

JH.

PS.: One last thing that has impressed me in the ARP sequencer: How they
built
        FET opamps from standard opamps plus a 4007 CMOS chip. Sure, they
have
        done this because thy didn't have these cheap LF356 or similar
chips (?),
        but one thing is still impressive today: The common mode range of
these 
        "4007-opamps" goes up to the positive supply voltage, which is a
great plus
        if you build a saw vco and discharge the cap to the positive rail.
No auxiliary
        voltage required ...



From magnus at analogue.org  Sat Aug 15 23:37:14 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Sat, 15 Aug 1998 23:37:14 +0200
Subject: commercial synth circuits
In-Reply-To: Your message of "Fri, 14 Aug 1998 22:38:17 -0700"
References: <02af01bdc80e$fab4eb60$f6c4edd0@oemcomputer>
Message-ID: <199808152137.XAA28903@piraya.electrum.kth.se>

>>>>> "DaGS" == Debby and Gene Stopp <squarewave at jps.net> writes:

Hi Gene (and all you others of course)!

 DaGS> How the heck did I miss the original posts? Ah well, new baby, new job, no
 DaGS> sleep, no time, the once beloved email list has become the occaisional
 DaGS> diversion for lurking...

Those RR (Real Reality) distractions and quite disturbing, don't you agree?

 DaGS> Anyway, while I do appreciate the concept that perfect operational
 DaGS> parameters should override any parts-count considerations, the fact is that
 DaGS> the 3130-FET-LM311 VCO core is both accurate and simple, a tribute to the
 DaGS> designer. Interestingly, the Roland 700 modular has pretty much the same
 DaGS> design.

This is a pretty amazing design. The more that I have gotten into it
the more impressed have I gotten. I have done the homework on it a few
times, each time with more details emerging.

BTW. What resettime where the ASM-1 VCO being designed for?

 >> I do not prefer the resistance in series with the timing cap method of
 >> high-end compensation.  The steady state voltage drop across the resistor
 >> at high frequencies alters the end points of the sawtooth waveform. This in
 >> turn affects the purity of the other waveforms usually derived from the
 >> sawtooth.  However, it has the benefit of accomplishing high-end
 >> compensation very simply, with only one component. This comes down to
 >> personal design philosophy and goals.  Mine is generally to achieve the
 >> best performing, most precise circuits, with only a secondary consideration
 >> to the number of components needed.  I recognize the desire of others to
 >> create simple, inexpensive designs, and there is clearly a need out there
 >> for that design approach.  The great value of the DIY list is providing a
 >> forum for all types of designs
 >> to be shared, so everyone can find what they want.

For the ASM-1 will this rise not be very noticable until you get up to
about 10kHz or so... I am not very happy about wave distorsion myself,
but I see it as an acceptable compromise. The neat thing is that when
this resistor is correctly selected one can completely eliminate the
frequency distorsion of the reset time. The reset waveform will never
be perfect, my ASM-1 VCO has a falltime of about 736 ns and many other
paths in the audio cursuit will not have similar speed. One can extend
the compensation to eliminate the DC offset error as well as the
amplitude error. Keeping the time from touchdown to start of the
rising ramp is also necessary. In my ASM-1 VCO I was forced to add a
cap in the reset cursuit for it to properly reset, this was due to
lack of propper understanding of the cursuit at the time, so my full
resettime was about 1.5 us which does not near the resettime that the
resistor and intergrator cap will compensate for.

Balancing these things will be a key to minimize waveform
distorsion. The resetperiod in itself is a wavedistorsion, so...

There also comes a time where improvements gets out of hand and does
not really contribute to the function of the cursuit and only
contributes to the designers foolish wish of making a "perfect"
design. Getting things as right as possible within certain limits is a
good thing. I daily encounter the question wiether a specific part of
a design effort is worth taking or not, the right answer only emerges
after asking the right questions and prior to that it is just
gutfeelings all the way.

Cheers,
Magnus



From cyborg0 at GlobalEyes.net  Sun Aug 16 02:10:46 1998
From: cyborg0 at GlobalEyes.net (cyborg0 at GlobalEyes.net)
Date: Sat, 15 Aug 1998 19:10:46 -0500
Subject: New project: Sequencer
References: <19980815205023.14905.qmail@nuernberg2.pop.metronet.de>
Message-ID: <35D62386.CB248E6F@globaleyes.net>

jhaible wrote:

> 
> Quantizer:
> I want to build a quantizer where I can select which chromatic tones I want
> 
> to include and which I won't, with a set of 12 individual switches.
> I guess I'll do this with a normal binary counter and resistor network
> (main
> DAC), and a second divide-by-12 counter plus 4067 MUX and a separate
> resistor network for the semitones (semitone DAC). The two DAC outputs
>

this is pretty complex as far as parts count..Also, too, there is a TON
of knobs this way..
I have though, perhaps, that one could have 1 knob, 1 octave switch, and
16 write toggles going to 16 different S&H's..
basically, you would feed the voltage info from the knob/octave select
into one (or as many toggles/buttons as you can mash at once!) or more
sample and holds...

As far as having a "scale" type note excluder, that would be rough.
I mean, what would happen to the notes that are the same as the ones you
want to exclude?
I mean, you could have a bunch of comparators check to see what voltage
on the cv is equal to an excluded voltage and then have it inhibit the
gate so the note is not heard, OR, you could have it so that it forces
the cv to the nearest (up or down) non-excluded CV value..
This is actually a good idea here.. :))
I gotta remember this..thanx for making me think..
rob



From jhaible at metronet.de  Sun Aug 16 03:33:07 1998
From: jhaible at metronet.de (jhaible)
Date: Sun, 16 Aug 1998 03:33:07 +0200
Subject: New project: Sequencer
Message-ID: <19980816014603.18862.qmail@nuernberg2.pop.metronet.de>


> As far as having a "scale" type note excluder, that would be rough.
> I mean, what would happen to the notes that are the same as the ones you
> want to exclude?
> I mean, you could have a bunch of comparators check to see what voltage
> on the cv is equal to an excluded voltage and then have it inhibit the
> gate so the note is not heard, OR, you could have it so that it forces
> the cv to the nearest (up or down) non-excluded CV value..
> This is actually a good idea here.. :))

Yes, choosing the next "allowed" note. Just to avoid that something too 
strange drops in when I turn the knobs on the fly.

I read this text "The making of Rubycon" again. TD created these impressive
sequences by running 2 sequencers in parallel, selecting one to control a
synth
while changing the pattern on the other in realtime.
I tried this, and it's a nice method, but a quantizer is really recommended
here ...

BTW, I finally found my way to synchronize sequence patterns to my 8 track
tape. No synchronizer, no extra trigger track. I start with the bass line,
then
I play this back into a comparator, and the comparator output triggers a AD
envelope (with retrigger disabled; built from a SSM2056). The AD output is
used
as clock for the new sequence.
I *do* loose some pulses sometimes, but then again this doesn't matter for
this kind of music.

JH.



From girard at enel.ucalgary.ca  Sun Aug 16 05:51:10 1998
From: girard at enel.ucalgary.ca (Arno)
Date: Sat, 15 Aug 1998 21:51:10 -0600
Subject: 76477 & museums
Message-ID: <199808152151100440.00177F76@mailhost.ucalgary.ca>


Hi, 

I am wondering why do I have no news of john blacet after my answer to his last call for 76477 sale ?
Does anyone else also answered his call in the list ?

I also would like to know if an "analog synth museum" exists somewhere in this small world ? I have heard about one in UK but I am not sure it really exists ..

Arno




From costello at seanet.com  Sun Aug 16 08:51:45 1998
From: costello at seanet.com (Sean Costello)
Date: Sat, 15 Aug 1998 23:51:45 -0700
Subject: New project: Sequencer
References: <19980816014603.18862.qmail@nuernberg2.pop.metronet.de>
Message-ID: <35D68181.846E21C1@seanet.com>

jhaible wrote:

> I read this text "The making of Rubycon" again. TD created these impressive
> sequences by running 2 sequencers in parallel, selecting one to control a
> synth
> while changing the pattern on the other in realtime.
> I tried this, and it's a nice method, but a quantizer is really recommended
> here ...

Uh, what text is this?  I would love to read more about how those
mid-period Tangerine dream albums were made.

Sean Costello

P.S. As far as sequencer designs go, the Serge TKB has some great
features in it. Check out
http://www.hyperreal.org/music/machines/schematics.html for a link to
it.  There is also a link to the Tom Henry Superseque schematics on that
site, which are also available from Midwest Analog Products in a nice
book of Tom Henry's reprinted articles.



From squarewave at jps.net  Sun Aug 16 09:13:18 1998
From: squarewave at jps.net (Debby and Gene Stopp)
Date: Sun, 16 Aug 1998 00:13:18 -0700
Subject: ASM1 ADSR Idea
Message-ID: <01d301bdc8e5$6b144b40$d9c4edd0@oemcomputer>

Sounds like a valid mod to me.... but let me give some history.

The main thing I had in mind when I designed the ASM-1 ADSR was simplicity,
using as many tricks and shortcuts as possible. First and foremost was the
idea of using the SPDT switch, rather than a bunch of SPST switches like
everyone else did (i.e. the 4053 rather than a 4016 or 4066). My thought
was, the cap was either charging up or charging down, so why not use on SPDT
switch to either attack or decay, and if decaying, either discharge down to
the sustain level or ground? Since the 4053 has three SPDT switches, and the
preceding algorithm only needs two, I could parallel two of them on the
attack/not attack to reduce the switch on-resistance for those critical
attack and decay times. This works great - I forget the actual rise/fall
times, but the time constants are real snappy.

The second trick was to use the voltage level of the buffered cap to reset
the S/R flip-flop built out of the dual 4-input NOR gate, just by relying on
the fact that CMOS switches at the V+/2 point (in theory). In other words,
an analog voltage (the final ADSR output) is used as a logic input to the
flip-flop to reset it. This is a text-book no-no, and the reason for the
existence of the "attack peak" trimpot. In practice, I find that some 4002's
don't really behave well so I usually socket those and swap around till
things work right (yeah I know, this would never fly in a production
environment). Specifically, sometimes I find that the ADSR will not
re-trigger properly if the decay time is set to a long value. Someday I
might scope this and see what is really happening.

The "sustain trim" trimpot is used to tweak the voltage that the decay phase
decays to - in other words, you can set it so that the EG attacks, then
"decays" *up* to the sustain voltage (assuming the sustain pot is set to
max). This is a trimpot because it is interactive with the "attack peak"
trimpot.

Another purpose I had in mind with this design was to be able to use this EG
as a precise pitch transient control. For example, you can truncate the
exponential attack so that it ramps up to some pitch, and actually reaches
that pitch after some short finite time (instead of never getting there,
like diode-based EG's). Then, if you want the pitch to stay at the sustain
level once attack is finished, you can tweak that to perfection too.

So - there were reasons behind the logic and the trimpots, albeit my own
reasons. If I were to change anything about this design, I'd probably loose
the 4002 and stick in a 555 as the set/reset flip/flop (in retrospect a much
better choice than the 4002). If you spend much time looking over commercial
synth schematics, I'm sure you've noticed how popular the 555/556 is in EG
circuits.....

BTW never try to drive the ASM-1 ADSR with bipolar gate waveforms! The input
comparator (LM358) is run off of ground and V+, and if the input goes below
a minus diode drop, the EG will falsely trigger because the chip will freak
out and disobey the +/- comparator rules. Use a blocking diode in modular
systems.

- Gene


-----Original Message-----
From: Steven Cook <steve at babcom.u-net.com>
To: Synth-Diy <synth-diy at mailhost.bpa.nl>
Date: Saturday, August 15, 1998 5:38 AM
Subject: ASM1 ADSR Idea


>Hi,
>
>With regard to the ASM1 ADSR, would the following modification work?
>
>Replace the 4002 dual 4 input NOR with a 4025 triple 3 input NOR. This
gives a
>spare gate which is wired as an invertor to replace U2. U2 is then used as
a
>comparator wired between the top of the sustain pot and the output of the
>ADSR. The sustain peak trimmer is replaced by a fixed resistor - say 47k -
to
>give a peak attack / sustain of about 10v.
>
>This would (If it works!) remove 2 trimmers and all setting up without any
>increase in parts count.
>
>Any problems?
>
>Steve.
>
>
>




From sky36919 at skynet.be  Sun Aug 16 09:33:47 1998
From: sky36919 at skynet.be (Hugo Haesaert)
Date: Sun, 16 Aug 1998 09:33:47 +0200
Subject: Anders' site down ?
Message-ID: <199808160734.JAA20607@papagena.skynet.be>

Hi List !

Got a "document contains no data" trying to access Anders Sponton's 
site .

Anyone knows what's up ?

Thanks .

Keep 'em oscillating :)

Hugo
=



From cuba at cyber-host.net  Sun Aug 16 08:13:55 1998
From: cuba at cyber-host.net (cuba at cyber-host.net)
Date: Sun, 16 Aug 1998 08:13:55
Subject: AD: Free 20 Minutes of International Phone Calls to Launch 'Call for Freedom' Movement
Message-ID: <199808161649.SAA18838@mailhost.bpa.nl>

This message is sent in compliance of the new e-mail bill: SECTION 301, Paragraph 
(a)(2)(C) of s. 1618

Sender : Hoek Industries, P.O. Box 130544, St Paul, MN  55113
Phone  : 1-612-646-8174
E-mail : cuba at cyber-host.net

To be removed from our mailing list, simply reply with "REMOVE" in the subject.

Free 20 Minutes of International Phone Calls     
(Si usted prefiere espa?ol, to Launch "Call for Freedom" Movement por favor vea 
debajo.)

The Digital Freedom Network (DFN), which promotes freedom of the press worldwide 
by publishing the works of imprisoned dissident authors on the net, invites you to 
make 20 minutes of free international calls from your PC to friends? or relatives? 
normal telephones as part of our worldwide "Call for Freedom" movement.

All we ask is that during the call you mention the plight of one of our imprisoned 
authors to your friends or relatives and ask them to visit or email us their 
support and then to make a free call on us to one of their friends. If millions 
and millions of people around the world do this and "call for freedom" the prison 
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Please visit our website at http://www.dfn.org today to download your free calling 
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terrible conditions in Cuba, is desperate and being ignored.

20 Minutos Gratis En Llamadas Internacionales
Para Lanzar El Movimiento "Llamada Por Libertad"

La Digital Freedom Network (FDN), la c?al promociona la libertad de prensa 
mundialmente publicando trabajos de autores del Web para los disidentes 
emprisionados le invita a hacer llamadas gratuitas a familiares y amigos desde su 
PC a tel?fonos convencionales por 20 minutos como parte de el movimiento "Llamda 
Por Libertad".

Todo lo que pedimos es que durante su llamada usted mencione a sus amigos y 
familiares el acontesimiento de uno de los autores emprisionados y que visite o 
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Por favor visite nuestra p?gina del web "http://www.dfn.org" hoy para bajar su 
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son terribles y est?n desesperadamente siendo ignorados.
 
 
 
 
 
 
 
 



From blacet at metro.net  Sun Aug 16 10:41:08 1998
From: blacet at metro.net (John Blacet)
Date: Sun, 16 Aug 1998 08:41:08 +0000
Subject: 76477 & museums
References: <199808152151100440.00177F76@mailhost.ucalgary.ca>
Message-ID: <35D69B23.1FC7@metro.net>

Hi Arno:

I either missed your mail or it was not delivered. Sometimes, if the
subject line does not include "Blacet" or one of our product names, I
will not open the mail because of the volume due to lists, etc.

If you want to order some chips or have a question, please include
"76477" or "Blacet" in the subject and I'll get right back to you!

Thanks for your interest. 

Regards.
-------------------------
John Blacet
Blacet Research Music Electronics
-------------------------
blacet at metro.net
http://metro.net/blacet/music.html



From urekar.m at EUnet.yu  Sun Aug 16 11:55:31 1998
From: urekar.m at EUnet.yu (<<marjan>>)
Date: Sun, 16 Aug 1998 11:55:31 +0200
Subject: New project: Sequencer / TD
References: <19980816014603.18862.qmail@nuernberg2.pop.metronet.de> <35D68181.846E21C1@seanet.com>
Message-ID: <35D6AC60.4833@eunet.yu>

> > I read this text "The making of Rubycon" again. TD created these impressive
> > sequences by running 2 sequencers in parallel, selecting one to control a
> > synth
> > while changing the pattern on the other in realtime.
> > I tried this, and it's a nice method, but a quantizer is really recommended
> > here ...
> 
> Uh, what text is this?  I would love to read more about how those
> mid-period Tangerine dream albums were made.

I think this is

http://star.arm.ac.uk/~ath/td/articles/tourbook.75

very inspirative text...

and some more

http://star.arm.ac.uk/~ath/td/articles/tour_gear_1982
http://star.arm.ac.uk/~ath/td/articles/article_emm84
http://star.arm.ac.uk/~ath/td/articles/td_several_articles.html
http://star.arm.ac.uk/~ath/td/interviews/interview.exit
http://star.arm.ac.uk/~ath/td/articles/tourbook.82


marjan


ps   "In fact I don't like this side very much because it's not as
well done as it could be. " - Froese about Phaedra.Hah...



From synth1 at airmail.net  Sun Aug 16 19:33:06 1998
From: synth1 at airmail.net (Paul Schreiber)
Date: Sun, 16 Aug 1998 17:33:06 -0000
Subject: MOTM status & 3340s <long>
Message-ID: <01BDC93C.3ABC94A0@dal17-05.ppp.iadfw.net>

MOTM is a series of analog synthesizer modules, currently offered only
in kit form. (www.synthtech.com) There have been 3 kits released to
date, with over 70 sold so far (thanks to all!!)

MOTM stand for Module of the Month, which was a tongue-in-cheek
way of saying that I was going to have a new module about every month.
Some of you thought this meant you HAD to buy one every month, which of
course in NOT the case!

Things were going along smoothly until June. Then, as we say in Texas, the wheels
came off. Without going into the whole mess in detail, MOTM development came to a halt.
I did continue to ship CEM chips, although some of you had to wait MUCH longer
than normal.

However, the good news is that as of tomorrow, MOTM is going FULL STEAM AHEAD!!
The best thing that came out of the mess of summer is that I now work full-time
out of my house, no 9-5 daily grind. So, I can MOTM much more time-wise than ever.

Also, ((shameless plug to follow)) I will be accepting repairs and mods for those of
you who wish to trust me with your babies (I'm in Fort Worth, TX).

I will now attempt to answer all of your main questions, if not, please email me PRIVATELY.

#1 - It's not fair that you are hoarding all the CEM chips for your stupid kits!

Hmmmm...no, I suppose it's not, in a way. But, they were offered for sale BEFORE MOTM,
and still are. I haven't changes the prices in 2 years.

MOTM kits are not ALL CEM-based. In fact, I'd guess that about 40% will be. Of those, I
ONLY use CEM chips I have over 1000 of. So, what does that leave out?? See #2.

#2 - It's not fair that you own every 3340 in the %$@#%#$ universe, and then will use them
in the MOTM VCO and so I can't fix my <<<fill in the blank>>.

OK, I own MOST of the &^#$&^ 3340 VCOs. Well, except for the fact I sold 132 of them
last year to SOME OF YOU!! <hee hee>. So when the pleas go out from X to please sell
me 3340s, if it's awful quiet in the response area, it's not JUST ME!! 

Yes, my inital plan was to offer a dual 3340 VCO kit for 2 reasons

a) I have the chips, and this makes the design easier for me
b) I was going to offer it without the 3340s, so those of you that have them
can use them

But....it turns out that if MOTM is to be a LONG TERM success, and not a "boutique" synth, 
this is a STUPID move.

So, I'm NOT using the 3340 in the MOTM VCO. I'm using the 3374 and 2 Analog Devices
laser-trimmed analog multipliers for the temperature compensation. Same 3340
stability/sound (sorry, Mark!), synch options, etc.

The same may be possible for the 3310 EG chip. At one time, I had 1100 3310's. I have
about 385 left. It SURE IS EASY to make a EG (not VC'd, necessarily) with one.
So I'm undecided about that. It is my policy to ALWAYS hold back extra chips for
repairs of MOTM. 

So here is what I plan to do:

I will auction off the 3340s every 3 months or so until they are "gone", meaning I'm
keeping some for my MemoryMoogs. They will be in batches of 20, 2 per customer.
Please wait for the official notice...the first auction will be first week of Sept.

Fair enough??!?!?

#3 - Why are they kits??? I can't solder, you moron!

They are kits so you can LEARN something. And, this keeps the price low.

However, due to demand I am THINKING about offering fully assembled kits
for a moderate fee.

Also, I didn't want to get in the way of some of you that have offered to build kits
for others. If I decide to offer fully assembled kits, it won't be until Jan. 

If anybody want names of "MOTM-builders-for-hire", drop me a line.

#4 - What/when are the next kits??

This is now part of the "wheels-coming-off" mentioned earlier. The reason is that
my old sheet metal supplier gave me the brush-off on future orders (I was "too small
to bother with") and so I have to find a new one. There are 2 prospects I am
going to check out by the end of the month. As many can vouch, I am VERY
PICKY about the quality of my kits. 

The next PLANNED module is a combination Moog filter/preamp/env. follower. The filter
is based on the Rogue (which is based on my design in the MG-1) except the
3046 is replaced with pre-matched pairs and the output buffer is different.

The preamp is designed (5534-based) and the env. follower is done as well (it's the DC
compensated version in Electronotes, 1 stage). The filter needs to be breadboarded
and tested, but that should be done in about 3 weeks. So, I'm guessing with the pc 
board layout simultaneous with sheet metal, we are looking at Oct 10.

Yes, this is like 2 months behind. I apoligize for this, but read the next paragraph before
hollerin'

The Moog takes lots of time tweaking to get just right. So, I decided in the meantime I
can do 2 more modules that take ZERO tweaking. So, I will have 3 new modules all
arriving in October. The 2 others are the dual 2:1 VC analog switch and the Cross-
Product Module.

Breifly, the Cross-Product Module is 2 4-stage sub-octave dividers that XOR the
stages together. In Vector algebra, this is called the cross-product (used in Maxwell's
Equations, but I digress). It is based on a Lester Ludwig design in Electronotes, with a few
surprises. The sounds that come out are best described ase "errie goa/trance drones".

Last point.

#5 - Where are the VCO/VCF/VCA/.........

Later this year, depends on Christams entropy factor. Yes, the 15-mode Xpander filter with MIDI
is on the plate. Yes, the "really big and expensive wood case" is on the plate. So, I just
need to get off my old 42yr butt and get busy!!

Sorry for the bandwidth, but I felt now is a good time as many of you are wondering just
where all this stuff sits. Thanks again for patience and your $$$. Remember, all this is
is a user funded hobby (not a bad gig!), and I want everyone to have working synths
that they can use 15 more years. I am not greedy: nothing would pleae me (and the wife,
tired of all these boxes everywhere) more that to sell all of these chips to fix every busted
synth out there that uses them.

Paul Schreiber
Synthesis Technology







From cyborg0 at GlobalEyes.net  Sun Aug 16 20:58:01 1998
From: cyborg0 at GlobalEyes.net (cyborg0 at GlobalEyes.net)
Date: Sun, 16 Aug 1998 13:58:01 -0500
Subject: Doepher Regelwerk and neo-analog sequencers
Message-ID: <35D72BB9.62390B9F@globaleyes.net>

Well, this looks like the most intense sequencer/faderbox in existence..
I am pretty sure I will be buying one shortly, since the studio 440 deal
has pretty much waned due to my being lied to quite a bit about the
wherabouts of the box and its condition. (Im very untrusting these days)

Anyone know of any known problems with the box so far? If so, post it,
because it really looks like a mini version of the Shaltwerk/maq16
combo, which is really good.

noteable features:

transmits 8 patterns at once
any track can produce any kind of controller info
only 1 track editable at a time, but 8 can be playing.
mutable tracks
can send controller info via faders in fader mode
can switch fader function from step to regular fader mode while playing

According to this, this seems like it could be hiccup central when
switching between modes..
many modern sequencers suffer from this (mc303, raveolution 309, mc505)
timing/data send hiccup during mode changes..
The Raveolution 309 used to be GREAT for this, but, somewhere along the
line one of my  ROM update/expansions destroyed its ability to go from
pattern select to pattern edit without errors. Sad really.

Well, the regelwerk is priced right..I am looking into it..
rob



From urekar.m at EUnet.yu  Sun Aug 16 22:24:49 1998
From: urekar.m at EUnet.yu (<<marjan>>)
Date: Sun, 16 Aug 1998 22:24:49 +0200
Subject: New project: Sequencer
References: <19980815205023.14905.qmail@nuernberg2.pop.metronet.de>
Message-ID: <35D74011.342B@eunet.yu>

> PS.: One last thing that has impressed me in the ARP sequencer: How they
> built
>         FET opamps from standard opamps plus a 4007 CMOS chip. Sure, they


It's trick from National app. note AN-4 (well,with matched fets but
noted that CMR is not good because of them and resistors as current
sources).



> have
>         done this because thy didn't have these cheap LF356 or similar
> chips (?),


Back then it was problem in technology to produce quality FETs and 
matched p and n channel MOSFETs on the same chip layer with opamp.
Before early '70ies it was even problem to make such things as 4007
as remaining Na in layers caused treshold/pinch voltage of n and p 
mosfets to move in oposite directions which was bad for using in 
logic gates.Sometimes it became depletion instead enhacement mode 
mosfet during diffusion.


>         but one thing is still impressive today: The common mode range of
> these
>         "4007-opamps" goes up to the positive supply voltage, which is a
> great plus
>         if you build a saw vco and discharge the cap to the positive rail.
> No auxiliary
>         voltage required ...




marjan



From chordman at flash.net  Mon Aug 17 02:27:21 1998
From: chordman at flash.net (Scott Gravenhorst)
Date: Mon, 17 Aug 1998 00:27:21 GMT
Subject: Nonlinear Feedback Filter
Message-ID: <35e377ab.29590309@mail.lan>

So far I have prototyped the basic LM13600 voltage controlled state
variable filter and it works.  Now I need to add the custom stuff to
allow for switchable nonlinear feedback.  I'm tired and it's hot, so
I'm calling it a good day and putting it down for now.  Hopefully,
next weekend will be cooler so that I can use the Oscope.  I hope to
have good things to post next week.

Worst case is that I just built another VCF.


-- Scott Gravenhorst
-- FatMan Site: www.teklab.com/~chordman



From cyborg0 at GlobalEyes.net  Mon Aug 17 03:18:20 1998
From: cyborg0 at GlobalEyes.net (cyborg0 at GlobalEyes.net)
Date: Sun, 16 Aug 1998 20:18:20 -0500
Subject: 3340s
References: <01BDC93C.3ABC94A0@dal17-05.ppp.iadfw.net>
Message-ID: <35D784DC.95FC68F4@globaleyes.net>

Paul Schreiber wrote:

> So, I'm NOT using the 3340 in the MOTM VCO. I'm using the 3374 and 2 Analog Devices
> laser-trimmed analog multipliers for the temperature compensation. Same 3340
> stability/sound (sorry, Mark!), synch options, etc.
> 

well, could you perhaps post some sort of application note for those of
us who would like to replace 3340s with your design?
Im SURE everyone would greatly appreciate this..

> I will auction off the 3340s every 3 months or so until they are "gone", meaning I'm
> keeping some for my MemoryMoogs. They will be in batches of 20, 2 per customer.
> Please wait for the official notice...the first auction will be first week of Sept.
> 
> Fair enough??!?!?

So this is a "highest bidder" affair then...
I guess my bill ridden rear end is outta THAT race! :))

rob



From 104065.2340 at compuserve.com  Mon Aug 17 05:57:49 1998
From: 104065.2340 at compuserve.com (terry michaels)
Date: Sun, 16 Aug 1998 23:57:49 -0400
Subject: DIY parts
Message-ID: <199808162358_MC2-5646-3E28@compuserve.com>

Hi Ian

I've got a few more thoughts on the KE4859.  Your suggestion of using a
MOSFET is interesting.  Actually, I hadn't even thought of it.  You're
right in that it typically has a low on resistance.  However, most MOSFET's
have a much greater gate capacitance.  When pulsed to discharge the timing
cap, this will dump a significant amount of charge into the integrator. 
The KE4859 has around 10 pf, which dumps a noticable amount of charge. 
That's one reason why the reset time on this VCO is longer than it should
be, and there are brief glitches on the ends of the sawtooth.

When I redo this circuit, I'll look at adding a small cap to dump an
opposite amount of charge to counter the gate capacitance.  I think it can
be done very simply,  I'll keep you posted.

Terry.




From 104065.2340 at compuserve.com  Mon Aug 17 06:30:58 1998
From: 104065.2340 at compuserve.com (terry michaels)
Date: Mon, 17 Aug 1998 00:30:58 -0400
Subject: commercial synth circuits
Message-ID: <199808170031_MC2-5644-974@compuserve.com>

Hi Debby, Gene

Thanks for the compliments on my VCO.  Not long ago I pulled the original
drawing for this circuit out of my file.  I hadn't seen it for a LONG time,
and I thought geez, this is a really simple design!

My current interest in reviving my work on analog synths is largely due to
my reading of Mark Vail's book last winter, a book your name appears in at
length.  Looks like you've had some interesting experiences with Moogs,
particularly Emerson's.  Want to trade jobs?

I first saw the Roland 700 at a Chicago NAMM show, and I remember being
impressed by that particular product.  I also remember visiting some booth
at NAMM, and being introduced to the designer for the company, and looking
at a schematic of their VCO, and it was nearly an exact copy of mine.  I'm
sure that guy read Electonotes.  I honestly can't remember if the VCO
design discussion happened at the Roland booth. or some other booth, as I
went to NAMM a number of years during the '70s.

Also at NAMM, I went into the Moog booth with a friend.  We went to a
corner where a modular system was set up and running, and Bob Moog was
standing a few feet away, talking to someone.  I started turning knobs on
the 960, and in a few minutes I had set it up to do a close approximation
to the ending riff from Karn Evil 9.  I started it running, and Bob turn
around with a smile and said something like "That sounds familiar"!

Terry



From batzman at all-electric.com  Mon Aug 17 07:37:32 1998
From: batzman at all-electric.com (The Dark force of dance)
Date: Mon, 17 Aug 1998 14:37:32 +0900
Subject: WTF (Re: AD: Free 20 Minutes of International Phone Calls to
  Launch 'Call for Freedom' Movement)
Message-ID: <3.0.32.19980817143547.006858d8@mail.chariot.net.au>

Y-ellow Y'all.
	Where is all this effing spam coming from? It's times like this I know I
should have bought those surplus ICBMs when I had the chance.

Be absolutely Icebox.




From Neil.Johnson at camcon.co.uk  Mon Aug 17 10:08:49 1998
From: Neil.Johnson at camcon.co.uk (Neil Johnson)
Date: Mon, 17 Aug 1998 09:08:49 +0100
Subject: Walsh function website update
Message-ID: <5d7ea900@camcon.co.uk>

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Subject: Re: Walsh function website update
To: smoking silicon <synth-diy at mailhost.bpa.nl>
Date: Fri, 14 Aug 1998 15:48:26 -0400 (EDT)
From: Eli Brandt <eli at gs160.sp.cs.cmu.edu>
In-Reply-To: <5d3158d0 at camcon.co.uk> from "Neil Johnson" at Aug 13, 98 05:31:49 p
m
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-------------- next part --------------
     Mmm, modulating the Rademacher functions could be interesting.
     
     Especially if you modulate only one Rademacher function, since if you 
     use the generator I've sketched (using ExOR gates) only a subset of 
     all the Walsh functions will be modified, eg:
     
     WAL(2)  = WAL(1)WAL(3)
     WAL(4)  = WAL(7)WAL(3)
     WAL(11) = WAL(15)WAL(4) <= since WAL(4) = WAL(7)WAL(3)
     WAL(12) = WAL(15)WAL(3)
     
     ... etc.
     
     I'd be interested to hear about your conclusions.
     
     Neil
     
     +======================================================+
     |     Neil Johnson  BEng(Hons) MSc CEng MIEE MIEEE     |
     |         http://members.xoom.com/Neil_Johnson         |
     |       "I speak for myself, not for my employer"      |
     +======================================================+
     


______________________________ Reply Separator _________________________________
Subject: Re: Walsh function website update
Author:  eli+ at cs.cmu.edu at Internet-PO
Date:    14/08/98 15:48


Neil Johnson wrote:
>      http://members.xoom.com/Neil_Johnson/walsh.html
     
Thanks, interesting stuff.  I want to code something up and see what 
happens when you detune or PWM the Rademacher functions...
     
By the way, are there special tricks that Walsh functions do, compared 
to using pulse waves or something?
     
-- 
     Eli Brandt  |  eli+ at cs.cmu.edu  |  http://www.cs.cmu.edu/~eli/

From martin.czech at intermetall.de  Mon Aug 17 10:17:50 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Mon, 17 Aug 1998 10:17:50 +0200 (MET DST)
Subject: additive
Message-ID: <199808170817.KAA02601@window.intermetall.de>

> 
> This is alright, but do not expect rich waveforms or swept filter sounds. An
> adsr on each harmonic will not produce swept sounds unless you delay the
> triggering. You are much better off using a Walsh bank, see Neil Johnson's
> site. If you want enveloped sines then use a DX7 or similar like a previous
> post suggested. Detunes are easier too. But you will not be thrilled, since
> it will sound like a Hammond organ. One way to get good additive synthesis
> is to use a piece wise linear voltage generator (32 steps) for each VCA.
> This may give you nice moving textures but it takes a long time to set up
> unless you have a Fairlight and a light pen. :-)

This is also my impression from toying with additive synthesis.
Don't expect too much. If you want to have interesting sounds
you need > 100 partials and then conrol becomes an interesting problem.
New ways of controls must be developed in order to keep up 
with these huge ammounts of control data. 

m.c.




From jhaible at metronet.de  Mon Aug 17 11:59:56 1998
From: jhaible at metronet.de (jhaible)
Date: Mon, 17 Aug 1998 11:59:56 +0200
Subject: New project: Sequencer
Message-ID: <19980817103033.13636.qmail@nuernberg2.pop.metronet.de>

> It's trick from National app. note AN-4 (well,with matched fets but
> noted that CMR is not good because of them and resistors as current
> sources).

Haven't see AN-4, but I do know about the use of matched FETs for
this purpose. Problem is that dual FETs are very expensive. So
I was impressed by the use of a cheap 4007 chip.

> Back then it was problem in technology to produce quality FETs and 
> matched p and n channel MOSFETs on the same chip layer with opamp.
> Before early '70ies it was even problem to make such things as 4007
> as remaining Na in layers caused treshold/pinch voltage of n and p 
> mosfets to move in oposite directions which was bad for using in 
> logic gates.Sometimes it became depletion instead enhacement mode 
> mosfet during diffusion.

Interesting !

JH.



From synth1 at airmail.net  Mon Aug 17 13:39:56 1998
From: synth1 at airmail.net (Paul Schreiber)
Date: Mon, 17 Aug 1998 11:39:56 -0000
Subject: 3340 replacement w/3374
Message-ID: <01BDC9D3.E79DC1C0@dal37-12.ppp.iadfw.net>

1) I probably will offer an App Note sort of thing on the website.

2) This is a new design, not published before.

3) Through-zero FM will be investigated, but no promises yet.

Paul Schreiber
Synthesis Technology




From jorgen.bergfors at idg.se  Mon Aug 17 14:00:13 1998
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Mon, 17 Aug 1998 13:00:13 +0100
Subject: Walsh function website update
Message-ID: <TFSKGVGE@idg.se>

Isn't this just adding square waves, like they used to do with electronic 
organs back in the 70s? Wersi did this, to get a sawtooth from a top octave and 
octave divider tone generator. 
I modified the Elektor electronic piano, which used square waves, by ORing with 
an octave higher. That created a 25% duty cycle pulse, which sounded better. I 
even ORed the higher octave vith a constant 1 or 0 so I could switch between 
the waveforms. This was around 1980.

/Jorgen





MIME:Neil.Johnson at camcon.co.uk on 98-08-17 12.39.30
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cc:  (bcc: Jorgen Bergfors/IDGSE)
Subject: Re[2]: Walsh function website update 

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Subject: Re: Walsh function website update
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Date: Fri, 14 Aug 1998 15:48:26 -0400 (EDT)
From: Eli Brandt <eli at gs160.sp.cs.cmu.edu>
In-Reply-To: <5d3158d0 at camcon.co.uk> from "Neil Johnson" at Aug 13, 98
05:31:49 p
m
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     Mmm, modulating the Rademacher functions could be interesting.
     
     Especially if you modulate only one Rademacher function, since if 
you 
     use the generator I've sketched (using ExOR gates) only a subset 
of 
     all the Walsh functions will be modified, eg:
     
     WAL(2)  = WAL(1)WAL(3)
     WAL(4)  = WAL(7)WAL(3)
     WAL(11) = WAL(15)WAL(4) <= since WAL(4) = WAL(7)WAL(3)
     WAL(12) = WAL(15)WAL(3)
     
     ... etc.
     
     I'd be interested to hear about your conclusions.
     
     Neil
     
     +======================================================+
     |     Neil Johnson  BEng(Hons) MSc CEng MIEE MIEEE     |
     |         http://members.xoom.com/Neil_Johnson         |
     |       "I speak for myself, not for my employer"      |
     +======================================================+
     


______________________________ Reply Separator
_________________________________
Subject: Re: Walsh function website update
Author:  eli+ at cs.cmu.edu at Internet-PO
Date:    14/08/98 15:48


Neil Johnson wrote:
>      http://members.xoom.com/Neil_Johnson/walsh.html
     
Thanks, interesting stuff.  I want to code something up and see what 
happens when you detune or PWM the Rademacher functions...
     
By the way, are there special tricks that Walsh functions do, compared 
to using pulse waves or something?
     
-- 
     Eli Brandt  |  eli+ at cs.cmu.edu  |  http://www.cs.cmu.edu/~eli/









From Neil.Johnson at camcon.co.uk  Mon Aug 17 14:44:12 1998
From: Neil.Johnson at camcon.co.uk (Neil Johnson)
Date: Mon, 17 Aug 1998 13:44:12 +0100
Subject: Walsh function website update
Message-ID: <5d826780@camcon.co.uk>

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-------------- next part --------------
     Jorgen,
     
     At a simple level, yes you can do it just with square waves.  However, 
     Walsh functions are much more powerful, in that you can, as for 
     Fourier functions, synthesize almost any waveform you care to create.  
     The square waves you mention, which can also be described as 
     Rademacher functions, form an incomplete set, limiting the number of 
     waveforms you can create.
     
     Its all in the maths really.
     
     And yes, the technology has been around for a long time!  The origin 
     of Walsh functions dates back to the late 1800's when engineers were 
     working out the best way to arrange telephone wires on telegraph 
     poles.  It was only until 1923 when Mr. Walsh documented them that 
     some mathematical description was available.
     
     Neil
     ----


______________________________ Reply Separator _________________________________
Subject: Re: Re[2]: Walsh function website update
Author:  jorgen.bergfors at idg.se at Internet-PO
Date:    17/08/98 13:00


Isn't this just adding square waves, like they used to do with electronic 
organs back in the 70s? Wersi did this, to get a sawtooth from a top octave and 
octave divider tone generator. 
I modified the Elektor electronic piano, which used square waves, by ORing with 
an octave higher. That created a 25% duty cycle pulse, which sounded better. I 
even ORed the higher octave vith a constant 1 or 0 so I could switch between 
the waveforms. This was around 1980.
     
/Jorgen
     
     
     
     
     

From ms6gpm at bath.ac.uk  Mon Aug 17 16:19:26 1998
From: ms6gpm at bath.ac.uk (Gez.)
Date: Mon, 17 Aug 1998 15:19:26 +0100 (BST)
Subject: Digisound 80 Ring Modulator questions....
In-Reply-To: <1.5.4.16.19961215172539.399f21b8@popa.melbpc.org.au>
Message-ID: <Pine.SOL.3.93.980817151123.22857A-100000@midge.bath.ac.uk>




 I'm hoping to biuld a stereo ring modulator based on the schematic that
was provided to the list by someone.  I have many questions, and would
appreciate it if someone could answer some of all of them.

 - Does the power supply have to be 15V and bi-polar?  - could I use a
   smaller voltage? 

 - I intend to make a R.Mod for each channel, L+R.  Could I use one power
   supply for this, or would I have to find two?

 - The carrier signal input; would any oscillator circuit suffice?  
   Should it be at line level voltage?   
   What waveforms and control would you need; - as many and as much as
   possible? - or a simple oscillator?


  Thank you.



Gez. 




From costello at seanet.com  Mon Aug 17 18:37:43 1998
From: costello at seanet.com (Sean Costello)
Date: Mon, 17 Aug 1998 09:37:43 -0700
Subject: 3340s
References: <01BDC93C.3ABC94A0@dal17-05.ppp.iadfw.net> <35D784DC.95FC68F4@globaleyes.net>
Message-ID: <35D85C57.32F71223@seanet.com>

cyborg0 at GlobalEyes.net wrote:
> 
> Paul Schreiber wrote:
> 
> > So, I'm NOT using the 3340 in the MOTM VCO. I'm using the 3374 and 2 Analog Devices
> > laser-trimmed analog multipliers for the temperature compensation. Same 3340
> > stability/sound (sorry, Mark!), synch options, etc.
> >
> 
> well, could you perhaps post some sort of application note for those of
> us who would like to replace 3340s with your design?
> Im SURE everyone would greatly appreciate this..

I'd second that.  The sooner you put up application notes for
temperature compensated 3374 oscillators, the sooner I will purchase
10+  of the suckers, so as to save my 3340's as spares for the synths I
own that use them.

BTW, is there an existing VCO design that features the 3374+multipliers
in a temperature compensated design?  Do any of the old Curtis
newsletters contain designs?  A big bonus would be a dual VCO built
around the 3374 that performed through-zero FM.

Speaking of the above: anyone have the schematics for the Buchla 208
Complex Oscillator?

Thanks,

Sean Costello, in beautiful rainy Seattle, Washington.  Sun is for
squares.



From cmacdon at ix.netcom.com  Mon Aug 17 19:04:06 1998
From: cmacdon at ix.netcom.com (Christopher MacDonald)
Date: Mon, 17 Aug 1998 10:04:06 -0700
Subject: filter waveform question
Message-ID: <35D86286.589A@ix.netcom.com>

Hi,

I have built a diode ladder filter and have a question about the output
waveforms I am getting.  I have posted some oscilloscope photos at:

http://www.evenfall.com/diy/dladder.html

I am wondering if anyone might know what is causing a "jump" or
discontinuity near the peak of the waveform when the resonance control
is turned up.  I have spent hours tinkering with the circuit and can't
figure out what is wrong.  Sigh.


Thanks,

-Chris MacDonald



From dbalvage at ptdcs2.ra.intel.com  Mon Aug 17 19:46:39 1998
From: dbalvage at ptdcs2.ra.intel.com (Duane R Balvage)
Date: Mon, 17 Aug 1998 10:46:39 -0700
Subject: Sub oscillator for CEM3394
Message-ID: <35D86C7F.31DF@ptdcs2.intel.com>

Hello all ...

I have a friend who has a SixTrak, and he was complaining about it's
lack of OOMPH in the bottom end department. So, I "borrowed" an idea
from my Juno-1 and put a sub-oscillator ckt. together.

Circuit desc.:

The CEM 3394 does NOT have seperate outputs for the waveforms, only a
VCA out. (it's a synth on a chip... see
http://www.synthtech.com/cem/cemdata.html
for more info.) Sooo... a simple flip-flop hookup was out of the
question.

This chip has the timing cap hooked up external to the chip (3000pF, if
I remember correctly),
so I thought I could pick off thecharging/discharging triangle off the
cap with an extremely 
high input impedance op amp (so as not to load it down unnecissarily).
Then I thought, "save a step (and parts) and make a comparator out of
the op amp." This worked... a nice square wave
resulted. I then fed this directly into a 4013 D flip flop with Qnot
tied to D to make a divider. Now I had a squarewave at 1/2 the initial
osc frequency. This is attenuated down by a 
100k/1k voltage divider, and a 47k trimmer pot (the ext. in of the 3394
can only handle about 80mV p-p). I bent pin 9 out of the socket,
attatched the output of the sub-oscillator circuit,
powered up, and turned up what used to be the noise/osc balance (is now
osc/sub osc balance).

It worked! I had to adjust trimmer 2 to get rid of distortion.

Oh, BTW you have to adjust trimmer 1 until you get a squarewave out of
the TL082...

so... I built 5 more, stuck 'em in his SixTrak, and he is now a happy
camper...

(he doesn't miss the "noise" generator too much.)

This circuit can be used in any synth that uses CEM 3394's, I.E. -

SixTrak, MAX, Multi-trak, Split-8

Akai AX-60, 73, VX90

others I can't think of right now ...

Anyways... Anyone who has one of these, and would like some more OOMPH
out of their synth
and don't mind losing the "noise input" ... see attatched GIF for
circuit.

		Hope someone can use it!

						- Duane



-- 
   "That boy's got a mouth like a cannon ... Always shootin' it off..."
                                
                             - Foghorn Leghorn
                      ________________________________
                     / o o oo              o ooo o   /\
       -------------/ ////  Duane R. Balvage   //// / /---------
                   /    _________________________  / /
                  / // / // /// // /// // /// / / / /
                 /___ //////////////////////////_/ /
                 \____\________________________\_\/

                     Intel Corporation, RA1-303
                   Portland Technology Development
       =========================================================

              Phone: (503) 613-8055    FAX: (503) 613-8261
                   E-Mail: dbalvage at ptdcs2.intel.com
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From mmcintos at ball.com  Mon Aug 17 22:16:55 1998
From: mmcintos at ball.com (McIntosh, Malcolm)
Date: Mon, 17 Aug 1998 14:16:55 -0600
Subject: VCO chips again
Message-ID: <09DB74475204D1119C8200805F19D0032D12BC@aeromsg1.ball.com>

Do any of you guys know if there is a difference between the XR8038M
produced by Exar and the ICL8038AM produced by Harris?  Is one of these
better suited for use with synth's?  Is there no difference at all?  I
seem to remember several posts on the difficulties of using an 8038 as a
VCO.

Also, has anyone tried using Exar's XR2206M VCO function generator?

Anyone?

Thanks,

Malcolm

synth-diy at mailhost.bpa.nl



From costello at seanet.com  Mon Aug 17 22:41:39 1998
From: costello at seanet.com (Sean Costello)
Date: Mon, 17 Aug 1998 13:41:39 -0700
Subject: filter waveform question
References: <35D86286.589A@ix.netcom.com>
Message-ID: <35D89583.8C4646AB@seanet.com>

Christopher MacDonald wrote:
> 
> Hi,
> 
> I have built a diode ladder filter and have a question about the output
> waveforms I am getting.  I have posted some oscilloscope photos at:
> 
> http://www.evenfall.com/diy/dladder.html
> 
> I am wondering if anyone might know what is causing a "jump" or
> discontinuity near the peak of the waveform when the resonance control
> is turned up.  I have spent hours tinkering with the circuit and can't
> figure out what is wrong.  Sigh.

Does it sound right?  Maybe the "jump" is simply the "ringing" caused by
high resonance.  I know square waves being run through highly resonant
filters exhibit similar behavior.

Sean Costello



From thelab at sprint.ca  Mon Aug 17 22:46:12 1998
From: thelab at sprint.ca (Philip)
Date: Mon, 17 Aug 1998 18:46:12 -0200
Subject: additive synthesis
Message-ID: <35D89693.4E06@sprint.ca>

hi all,

With all this talk of additive synthesis, I was motivated to finish some
additive synthesis software I wrote for the Waldorf Microwave 1/2/XT.
Check http://robotnik.com/the_lab/software/?Wave+/?Wave+.htm if you are
interested. there are some screen shots too.

btw I guess this topic is ok for the list because it is "synthesis" and
I "did it myself" :) 

Philip
-- 
Philip Pilgrim                  The Lab Audio Works
5 Evan's Drive                  - Analog/Digital Recording/Processing
Hammonds Plains                 - Computer/Synth Interfacing
Nova Scotia, Canada             - Hardware/Software Development
B4B 1M8

Phone     +1.902.835.7844
Email      mailto:thelab at sprint.ca

Web Page: http://www.robotnik.com/the_lab



From ijfritz at earthlink.net  Tue Aug 18 00:41:36 1998
From: ijfritz at earthlink.net (Ian Fritz)
Date: Mon, 17 Aug 1998 16:41:36 -0600
Subject: DIY parts
References: <199808162358_MC2-5646-3E28@compuserve.com>
Message-ID: <35D8B1A0.6BFA1C97@earthlink.net>

Terry --

Thanks for the information on FET switching. I was wondering about
MOSFETs because several designs on the Web use them. I did note the
larger input capacitance and I also noted leakage-current numbers that
looked like they might be problematic on the low-frequency end. At the
risk of advertizing my incredible ignorance of switching transistors,
why is it that the gate capacitance discharges into the integrator
rather than just into the gate driving circuit? Is it because there's
capacitance from the gate to the drain as well as to the source?

I haven't been able to find a spec sheet on the KE4859. How does it
compare to the 2N4392, which seems fairly easy to find these days?

Best regards,

  Ian


terry michaels wrote:
> 
> I've got a few more thoughts on the KE4859.  Your suggestion of using a
> MOSFET is interesting.  Actually, I hadn't even thought of it.  You're
> right in that it typically has a low on resistance.  However, most MOSFET's
> have a much greater gate capacitance.  When pulsed to discharge the timing
> cap, this will dump a significant amount of charge into the integrator.
> The KE4859 has around 10 pf, which dumps a noticable amount of charge.
> That's one reason why the reset time on this VCO is longer than it should
> be, and there are brief glitches on the ends of the sawtooth.
> 
> When I redo this circuit, I'll look at adding a small cap to dump an
> opposite amount of charge to counter the gate capacitance.  I think it can
> be done very simply,  I'll keep you posted.
>





From moxie at idonex.se  Tue Aug 18 00:45:29 1998
From: moxie at idonex.se (Johan Gustavsson)
Date: Tue, 18 Aug 1998 00:45:29 +0200 (MET DST)
Subject: And Moxie Scores!
Message-ID: <199808172245.AAA29759@jolt.idonex.se>

No, that subject line has nothing to do with the recent AH "Hang around
in bars" thread...Rather, I've scored a VZ-1 for around $25 from the
local music chain store! *much rejoicing* Only problem is, it's
completely fried, some of the circuit boards are missing and it's
got smatterings of weird black grime all over itself *crowd goes
"AAAaawwww"* Only it doesn't matter, 'cuz I'm goint to build a CV
keyboard out of it anyway! *wild cheering* I went into the store
asking whether they had any broken keyboards to spare, and they said
"Oh, yes, we've got this victim of a roof leak. You can have it for,
oh, 25 bucks perhaps?". They probably thought I was quite mad :-)

So to start off my "build a Maxx" project, I've gotten myself a five
octave, full sized keys keyboard (useful) with very accessible key
contacts and stuff (good), three wheels (pitch, mod and sprung mod)
and two sliders just waiting to be brought into action as CV or LFO
sources (nice) and a bunch of buttons that I'll find out something
good to do with. On top, the PS part of the keyboard was in prime
condition, consisting of IEC three-prong socket, fuse, and a
voltage-adjustable transformer that gives me +-16v and +8v - Just the
thing for nicely regulating down to +-12, +5...Now, that's nice :-)

Now, looking at Toms keyboard circuits, there's one for one switch per
key and one for two switches per key, the last one being the preferred
one. Now, this keyboard ends up at something like 1 1/2 switches per
key, in that it does indeed have two switches, but they are obviously
triggered by shorting to ground or something, since they share a
common bus line. So, where Toms circuit demands something like this:

   --- (resistor chain) 
    |
      /
     /
    |
   --- (CV bus)

   --- (V+)
    |
      /
     /
    |
   --- (gate bus)  ...on every key, I've got something like:




   ---
    |
      /
     /
    |
   ---
      |
      | ---
      |  |
      |    /
      |   /
      \  |
        ---

...on every key. Now, the question is of course: Is it possible to
build something to utilise the two switches, even though they have one
connection in common? My limited electronics knowledge and I have been
poring over the schematics and haven't found a solution, but then
again we're not very good at this, my brain and I :-) Of course, I
could go with the single-switch solution and just not care about the
second switch, but it seems a slight waste somehow ;-).

Then again, I suppose one could do something with the existing diode
net and a bunch of D/As, but I've got absolutely *no* idea on how to
do that...

Anyway, I'm going to spraypaint the shell of the keyboard some garish
colour (Green, probably) whilst keeping the wheels and sliders
black. Ought to look quite good, methinks. Still, it won't have quite
the portability I'd envisioned (My idea is to build a Maxx inside a
big suitcase, to make a portable modular system), but then again, it's
still time to find a small keyboard to convert, too.

And today I've also found a good room to put up my studio in, and I've
finished the work on a MIDI thru box cum MIDI switch that someone is
buying from me...Today, life is OK :-)
/Moxie (Happy)




From toni at itl.com.mk  Tue Aug 18 02:37:02 1998
From: toni at itl.com.mk (Toni Jovanovski)
Date: Tue, 18 Aug 1998 02:37:02 +0200
Subject: filter waveform question
Message-ID: <3.0.32.19980818023356.006971e0@206.99.216.1>

At 10:04 17-08-98 -0700, Christopher MacDonald wrote:
>Hi,
>
>I have built a diode ladder filter and have a question about the output
>waveforms I am getting.  I have posted some oscilloscope photos at:
>
>http://www.evenfall.com/diy/dladder.html
>
>I am wondering if anyone might know what is causing a "jump" or
>discontinuity near the peak of the waveform when the resonance control
>is turned up.  I have spent hours tinkering with the circuit and can't
>figure out what is wrong.  Sigh.
>
>
>Thanks,
>
>-Chris MacDonald
>

Hmm, I think that there isn't nothing wrong.The ' problem ' is the
resonance of the filter , who makes ' jumps ' in the peaks of signal.This
can be prove very simple using mathematics , like Fourier or Laplace
transform.Sometimes you must use math ( I hate to say ) , especially in
Filter design.There is a lot of analogue filters , like Butterworth ,
Chebyshev I & II ... But in a synth design with simple waveforms ( saw ,
pulse , triangle ) it's a question of luxury.BTW , it's not very easy to
make them voltage controlled...

I think , in synth-design , that fourth-order VCF ( four poles in same
place ) is fairly enough.

Toni Jovanoski





From pfperry at melbpc.org.au  Tue Aug 18 03:48:02 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Tue, 18 Aug 1998 11:48:02 +1000 (EST)
Subject: VCO chips again
Message-ID: <1.5.4.16.19970109182135.2cbf40bc@popa.melbpc.org.au>

At 02:16 PM 17/08/98 -0600, McIntosh, Malcolm wrote:
>Do any of you guys know if there is a difference between the XR8038M
>produced by Exar and the ICL8038AM produced by Harris?  
.....seem the same to me.....


>Also, has anyone tried using Exar's XR2206M VCO function generator?
>
dont think it has quite the range either....
I'd be using a tomg ckt myself...

paul perry melb aust
(actually, after giving up on those 2 chips, I use a LM13600 ckt, but to get the
full range out of this, you have to scrap the output buffers and use  a fet and
an op amp! The only ckt from Horowitz and Hill that didn't perform..

paul perry melb aust




From eduni at ucsd.edu  Tue Aug 18 03:56:09 1998
From: eduni at ucsd.edu (Ethan Duni)
Date: Mon, 17 Aug 1998 18:56:09 -0700 (PDT)
Subject: additive
Message-ID: <199808180156.SAA27141@smtp.ucsd.edu>

>>theoretcly any acostic sound can be made in a modular
>>ether by addtive or FM but this is hard to be made.
>
>No, it's not theoretically possible to do that.
-sure it is.  just you'd need one hell of a synthesizer and one hell of a
speaker system, etc.. i don't know of anything that exists that could REALLY
do it, but so far as theory goes, you could do any sound with a
sophisticated subtractive set-up as well.

>I've never heard of such a tool. I doubt that it is possible. 
-possible but again, extremely difficult.. you could theoretically use some
kind of really fancy time-frequency domain analyzer/resynthesizer, but
again, i don't know of any that exist and it'd probably be _really_ hard to
make.. but _possible_, yes.

Ethan




From tech4 at freshmilk.com  Tue Aug 18 05:37:36 1998
From: tech4 at freshmilk.com (tech4)
Date: Mon, 17 Aug 1998 23:37:36 -0400
Subject: to tomg
Message-ID: <35D8F6FE.DD016210@freshmilk.com>

    I lost your addy for the electro harmonix schematics (Mistress).  It
is at my old job.  Is it still  up?


Tech4




From ka4hjh at gte.net  Tue Aug 18 06:52:27 1998
From: ka4hjh at gte.net (KA4HJH)
Date: Tue, 18 Aug 1998 00:52:27 -0400
Subject: additive
In-Reply-To: <199808180156.SAA27141@smtp.ucsd.edu>
Message-ID: <v04011700b1feb8228aa1@[208.255.152.115]>

>>>theoretcly any acostic sound can be made in a modular
>>>ether by addtive or FM but this is hard to be made.
>>
>>No, it's not theoretically possible to do that.
>-sure it is.  just you'd need one hell of a synthesizer and one hell of a
>speaker system, etc.. i don't know of anything that exists that could REALLY
>do it, but so far as theory goes, you could do any sound with a
>sophisticated subtractive set-up as well.
>
>>I've never heard of such a tool. I doubt that it is possible.
>-possible but again, extremely difficult.. you could theoretically use some
>kind of really fancy time-frequency domain analyzer/resynthesizer, but
>again, i don't know of any that exist and it'd probably be _really_ hard to
>make.. but _possible_, yes.

On Star Trek (the original, before holodecks) they had food replicators
everywhere, even the transporter room. Therefore, in the future audio
synthesis should a snap. At least on TV. Now if only somebody could figure
out how the transporter works. There are some top physicists haggling over
that one...
Terry Bowman, KA4HJH
"The Mac Doctor"



From cmacdon at ix.netcom.com  Tue Aug 18 08:48:22 1998
From: cmacdon at ix.netcom.com (Christopher MacDonald)
Date: Mon, 17 Aug 1998 23:48:22 -0700
Subject: Filter waveform question
Message-ID: <35D923B6.1F4C@ix.netcom.com>

Thanks to everyone who responded about my filter waveforms.  No solution
yet but some ideas.  I neglected to mention that the discontinuity does
not change when adjusting the cutoff control as the normal resonance
peaks do.

-Chris MacDonald



From martin.czech at intermetall.de  Tue Aug 18 09:26:06 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Tue, 18 Aug 1998 09:26:06 +0200 (MET DST)
Subject: filter waveform question
Message-ID: <199808180726.JAA09969@window.intermetall.de>


> I have built a diode ladder filter and have a question about the output
> waveforms I am getting.  I have posted some oscilloscope photos at:
> 
> http://www.evenfall.com/diy/dladder.html
> 
> I am wondering if anyone might know what is causing a "jump" or
> discontinuity near the peak of the waveform when the resonance control
> is turned up.  I have spent hours tinkering with the circuit and can't
> figure out what is wrong.  Sigh.
> 
First impression: nothing wrong.

The problem is: if you use an input wave with harmonics (saw) and you
don't really know your filter transfer function for magnitude and
phase, you can't see much out of such a screen shoot.  Because every
single harmonic will get some (unknown) phase shift the output waveform
may have nothing to do with the incomming.  E.g.: you know that a saw
is combined of partials with magnitudes like 1/1, 1/2, 1/3, 1/4 ...
etc.  If you have got enough of them you can perfectly synthesize the
saw sound. The phase of each partial can have random value, it doesn't
matter in this case. If you look at the waveform, it will most probably
not look like a saw at all, the (unimportant) phase information gives
you a lot of freedom to make a lot of waveshapes that sound the same
(for the continous case).

Therefore it is a better idea to test a  (unknown) linear system with a
sine wave. If the amplitude is not to large, a nice sine wave should
appear at the output. The output wave can vary in magnitude and phase,
you can measure this with your scope for different input frequencys and
thus get an impression of the transfer function.

If your filter can't deal with a sine wave as described , then there's
something wrong, for shure.

m.c.

------------------------------------------------------------------------
m.c. (alias mad scientist) has made it finally: 3 CDs ? 72 minimum ready.
Visit my homepage at http://www.geocities.com/SoHo/Museum/4459/index.html








From debus at cityweb.de  Tue Aug 18 10:11:29 1998
From: debus at cityweb.de (Ingo Debus)
Date: Tue, 18 Aug 1998 10:11:29 +0200
Subject: Sub oscillator for CEM3394
References: <35D86C7F.31DF@ptdcs2.intel.com>
Message-ID: <35D9372F.141C@cityweb.de>

Duane R Balvage wrote:
> Then I thought, "save a step (and parts) and make a comparator out of
> the op amp." This worked... a nice square wave

I'm a bit sceptical about using TL07* or TL08* as comparators. It often
works, but sometimes they latch up. Seems to depend on manufacturer,
lot, maybe supply voltage or whatever. Another case where one should be
careful when replacing 741s, BTW.
Some comparator ICs have also the advantage that they can produce TTL
output levels although being operated from +/-15 volts.

Another note, the TL082's + input doesn't have any dc bias at all in
your circuit. Looks a bit scary to me.

Ingo





From tomg at vivid.net  Tue Aug 18 10:32:33 1998
From: tomg at vivid.net (tomg)
Date: Tue, 18 Aug 1998 03:32:33 -0500
Subject: Mad Mouse - Final SD
Message-ID: <yam7534.1661.120690024@mail.vivid.net>

Thanks to marjan who sent me the sh vca the MM is
ready to build. I modified (natch) the vca for vc or 
audio and replaced the LFO OTA and final vca with it
...nice and simple. I picked 18 controls and called 
it done. Ended up with 6 ics and 15 transistors. No
OTAs thanks again marjan! 

2  - 1n4002
1  - lm7812
1  - lm7912
1  - tlo71
1  - tlo72
2  - tlo74
1  - cd4013
1  - lm556
4  - 2n3906
11 - 2n3904
19 - 1n914
14 - pots/knobs
3  - spdt mini switches
1  - pot switch
1  - 1/4" jack
1  - db9 9 pin female

Looks like I might make that $35 mark after all.

The next post will be the pcb and a close look at the
pieces.  

-tg

I think I'm excited.. I just says final, I know better.

www.tomg.vivid.net/madm/title.html




From debus at cityweb.de  Tue Aug 18 11:02:01 1998
From: debus at cityweb.de (Ingo Debus)
Date: Tue, 18 Aug 1998 11:02:01 +0200
Subject: filter waveform question
References: <3.0.32.19980818023356.006971e0@206.99.216.1>
Message-ID: <35D94305.637B@cityweb.de>

Toni Jovanovski wrote:
> Filter design.There is a lot of analogue filters , like Butterworth ,
> Chebyshev I & II ... But in a synth design with simple waveforms ( saw ,
> pulse , triangle ) it's a question of luxury.

On a second-order filter (12dB/oct) it is the Q parameter that
determines whether the filter is a Butterworth or Chebysheff or
whatever.

> I think , in synth-design , that fourth-order VCF ( four poles in same
> place ) is fairly enough.

But the poles move when Q is changed, don't they?

Ingo





From synth1 at airmail.net  Tue Aug 18 11:29:53 1998
From: synth1 at airmail.net (Paul Schreiber)
Date: Tue, 18 Aug 1998 09:29:53 -0000
Subject: CEM3391?
Message-ID: <01BDCA8A.C543E2A0@dal07-22.ppp.iadfw.net>

No, they were never widely available. I think I have 1 in the junk box.

Paul Schreiber
Synthesis Technology


----------
From: 	steve.ridley at bbc.co.uk[SMTP:steve.ridley at bbc.co.uk]
Sent: 	Tuesday, August 18, 1998 2:03 PM
To: 	synth-diy at mailhost.bpa.nl
Subject: 	Re: CEM3391?


The only place I've ever seen the CEM3391 used was in the
Digisound DEV91 development board.  Are CEM3391s still
available?

STEVE RIDLEY







From yoh212 at lulu.acns.nwu.edu  Tue Aug 18 13:31:28 1998
From: yoh212 at lulu.acns.nwu.edu (Yoshiki Ohmura (Yoshi))
Date: Tue, 18 Aug 1998 06:31:28 -0500 (CDT)
Subject: CEM3391?
Message-ID: <Pine.HPP.3.93.980818063027.2656A-100000@lulu.acns.nwu.edu>

Has anybody used this chip?  Are there any schematics out there for it?
With the built in ADSR it looks pretty interesting.

Cheers

Yoshi





From martin.czech at intermetall.de  Tue Aug 18 13:32:20 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Tue, 18 Aug 1998 13:32:20 +0200 (MET DST)
Subject: additive
Message-ID: <199808181132.NAA11085@window.intermetall.de>

> hi guy's.
> thank you all for so much info.
> allso i'm looking for 
> a good  book containing  info about this topic,
> with all the Fourier mathematics ?
> 

Sorry for the delay, took a while to find how our company library
searcher works 8->.

-Theory and Application of Digital Signal Processing, Rabiner, Gold,
 Prentice Hall  ISBN 0-3-914101-4, The BIBLE, a must

-FFT, Brigham E. Oran , German Edition ISBN 3-486-25861-3 
 a very good book about all details of the fourier transform, examples,
 graphs, everything you need

These are texts for engineers, knowledge of usefull standard mathematics like
complex numbers, complex exponential-function, integration and differentiation
are neccessary to understand.

m.c.




From H.J.vanderlinden at stud.far.ruu.nl  Tue Aug 18 13:59:17 1998
From: H.J.vanderlinden at stud.far.ruu.nl (Heiko van der Linden)
Date: Tue, 18 Aug 1998 13:59:17 +0200
Subject: op-code for synths
Message-ID: <35D96C95.7C23BF28@stud.far.ruu.nl>

Hi,
is there anyone here who can tell me more about how a microprocessor
controls an analog synthesizer e.g. tb-303.
For example how does the processor control the tone length, how does the
interrupt clock work, how does the processor use the information from
the tempo circuit.
Book titles, sites etc very welcome.





From martin.czech at intermetall.de  Tue Aug 18 15:48:03 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Tue, 18 Aug 1998 15:48:03 +0200 (MET DST)
Subject: Sub oscillator for CEM3394
Message-ID: <199808181348.PAA11482@window.intermetall.de>

> Duane R Balvage wrote:
> > Then I thought, "save a step (and parts) and make a comparator out of
> > the op amp." This worked... a nice square wave
> 
> I'm a bit sceptical about using TL07* or TL08* as comparators. It often
> works, but sometimes they latch up. Seems to depend on manufacturer,
> lot, maybe supply voltage or whatever. Another case where one should be
> careful when replacing 741s, BTW.
> Some comparator ICs have also the advantage that they can produce TTL
> output levels although being operated from +/-15 volts.
> 

one observation:
I have a little parallel port expansion for Atari STE, a 8 bit
adc/dac.  It's called "Galactic Sound Sampler". It uses TL084. If the
microphone input recieves to much voltage (switching or line level),
the adc locks, ie. allways 255 comming out regardless what you do.
This won't even go away if the power is switched off.  It helps to swap
the TL084.

You may think, well + and - are high impedance inputs. No current can
flow (allmost no).

But: These are junction FETs. Ie. there is a breakdown voltage, where the
input acts like a breakdown diode, and in revers polarity there will be
normal forward diode current, if you exceed the potential of the jfet
by 0.6V. However, doing this via transients (like in my example above)
or even continuous will not even disturb the input
functionality/destroy the input junction, but it will also cause
substrat currents to flow in the opamp chip, and if you go too far the
whole chip will trigger as a scr: latchup, burnout. I think there is a National
app. note where series resistors and clamping diodes where proposed in
order to avoid such damage/malfunction.

This could well be the reason why a TL081 does not work as replacement for a
741. The input breakdown is different, and the whole chip layout and process
is different, so no wonder that some critical situations come out different.

This is just my $0.02.

m.c.




From steve.ridley at bbc.co.uk  Tue Aug 18 16:03:31 1998
From: steve.ridley at bbc.co.uk (steve.ridley at bbc.co.uk)
Date: Tue, 18 Aug 1998 14:03:31 +0000
Subject: CEM3391?
In-Reply-To: <41E28F360103376C@c2-smtp.radio.bbc.co.uk>
Message-ID: <C1E58F360103376C@c2-smtp.radio.bbc.co.uk>


The only place I've ever seen the CEM3391 used was in the
Digisound DEV91 development board.  Are CEM3391s still
available?

STEVE RIDLEY




From Chris.List at sc.siemens.com  Tue Aug 18 16:14:27 1998
From: Chris.List at sc.siemens.com (List, Christopher)
Date: Tue, 18 Aug 1998 10:14:27 -0400
Subject: Offtopic: Cool new synth? - Roland JP-8080
Message-ID: <81A062BC5305D111A9D700805F065968CE94CF@maildepo.sc.siemens.com>

Check this out - looks pretty wild, nice to see that the folks at a big
company like Roland are finally catching on to what folks like us like.
OTOH, I hate to see it coated with marketing sugar like "Super-Saw
Waveform" and "Smart-Media storage for ease of use". 

I'd love to see one of these in person, and I wonder how it's gonna be
priced...

http://www.rolandus.com/HOT/HOTPROD.HTM

- CList



From pfperry at melbpc.org.au  Tue Aug 18 16:23:22 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Wed, 19 Aug 1998 00:23:22 +1000 (EST)
Subject: op-code for synths
Message-ID: <1.5.4.16.19970110065704.22376bfe@popa.melbpc.org.au>

At 01:59 PM 18/08/98 +0200, you wrote:
>Hi,
>is there anyone here who can tell me more about how a microprocessor
>controls an analog synthesizer e.g. tb-303.

Musical Applications of Microprocessors, by Hal Chamberlin, is the book.
Out of print (there were 2 editions) but I believe you can buy a 
photocopy from him to this day.... anyone know where?

paul perry melbourne australia

BTW today I expect PICs would be used.... the Z80 was used a lot Way Back Then..




From mmcintos at ball.com  Tue Aug 18 16:40:46 1998
From: mmcintos at ball.com (McIntosh, Malcolm)
Date: Tue, 18 Aug 1998 08:40:46 -0600
Subject: VCO chips again
Message-ID: <09DB74475204D1119C8200805F19D0032D12BD@aeromsg1.ball.com>

Thanks for the info.  To bad about the range.

> -----Original Message-----
> From:	Paul Perry [SMTP:pfperry at melbpc.org.au]
> Sent:	Monday, August 17, 1998 6:48 PM
> To:	synth-diy at mailhost.bpa.nl
> Subject:	Re: VCO chips again
> 
> At 02:16 PM 17/08/98 -0600, McIntosh, Malcolm wrote:
> >Do any of you guys know if there is a difference between the XR8038M
> >produced by Exar and the ICL8038AM produced by Harris?  
> .....seem the same to me.....
> 
> 
> >Also, has anyone tried using Exar's XR2206M VCO function generator?
> >
> dont think it has quite the range either....
> I'd be using a tomg ckt myself...
> 
> paul perry melb aust
> (actually, after giving up on those 2 chips, I use a LM13600 ckt, but
> to get the
> full range out of this, you have to scrap the output buffers and use
> a fet and
> an op amp! The only ckt from Horowitz and Hill that didn't perform..
> 
> paul perry melb aust



From clark at andrews.edu  Tue Aug 18 17:28:11 1998
From: clark at andrews.edu (Tony Clark)
Date: Tue, 18 Aug 1998 11:28:11 -0400 (EDT)
Subject: Sub oscillator for CEM3394
In-Reply-To: <35D9372F.141C@cityweb.de>
Message-ID: <Pine.SOL.3.91.980818112153.3369A-100000@edmund.cs.andrews.edu>

> I'm a bit sceptical about using TL07* or TL08* as comparators. It often
> works, but sometimes they latch up. Seems to depend on manufacturer,
> lot, maybe supply voltage or whatever. Another case where one should be
> careful when replacing 741s, BTW.

   I've never had a TL0XX latch up on me, but that may be because I'm 
careful not to exceed (or come close to) the power supply on the input 
pins.  Whether or not these op-amps are latching up to something else, I 
have had no experience.  I don't usually use them as comparators if I 
want a specific voltage level out.

> Some comparator ICs have also the advantage that they can produce TTL
> output levels although being operated from +/-15 volts.

   Yes, LM311's are the boss for comparators.  Especially if you want TTL 
or CMOS logic outs.  And of course, anything else you could possibly 
dream up it can handle too.

   Tony

------------------------------------,----------------------------------
I can't drive (my Moog) 55!         |     The E-Music DIY Archive
------------------------------------|  
Tony Clark -- clark at andrews.edu     | aupe.phys.andrews.edu/diy_archive
http://aupe.phys.andrews.edu/~clark |     Contributions welcomed!
------------------------------------'----------------------------------




From costello at seanet.com  Tue Aug 18 18:06:29 1998
From: costello at seanet.com (Sean Costello)
Date: Tue, 18 Aug 1998 09:06:29 -0700
Subject: Offtopic: Cool new synth? - Roland JP-8080
References: <81A062BC5305D111A9D700805F065968CE94CF@maildepo.sc.siemens.com>
Message-ID: <35D9A685.99165F48@seanet.com>

List, Christopher wrote:
> 
> Check this out - looks pretty wild, nice to see that the folks at a big
> company like Roland are finally catching on to what folks like us like.
> OTOH, I hate to see it coated with marketing sugar like "Super-Saw
> Waveform" and "Smart-Media storage for ease of use".

For "Super-Saw Waveform," read "A Digital Implementation/Ripoff of the
Multiple-Saw Animator from Electronotes."  For "Smart Media" read
"Annoying Little Cards that are very expensive - oh, and we use the
version that is already out of date and no longer commonly available."

I still prefer the Nord Modular, as far as virtual synths go.  However,
my getting burned while trying to purchase the Nord has strengthened my
resolve in DIY Analog (this list) and Digital (Csound, Linux-based
apps).

Sean Costello




From costello at seanet.com  Tue Aug 18 18:12:00 1998
From: costello at seanet.com (Sean Costello)
Date: Tue, 18 Aug 1998 09:12:00 -0700
Subject: Mad Mouse - Final SD
References: <yam7534.1661.120690024@mail.vivid.net>
Message-ID: <35D9A7D0.A960C052@seanet.com>

tomg wrote:
> 
> Thanks to marjan who sent me the sh vca the MM is
> ready to build. I modified (natch) the vca for vc or
> audio and replaced the LFO OTA and final vca with it
> ...nice and simple. I picked 18 controls and called
> it done. Ended up with 6 ics and 15 transistors. No
> OTAs thanks again marjan!

What the hell sort of VCA is that?  How does it work?  I've seen the
same VCA design in the MS-20 (I was just looking at it a few minutes
ago), but I have to admit I am baffled.

BTW, the Mad Mouse looks like a very nice little synth at this point.
Lots of cool little designs sitting in there.

Sean Costello



From jhaible at metronet.de  Tue Aug 18 19:14:01 1998
From: jhaible at metronet.de (jhaible)
Date: Tue, 18 Aug 1998 19:14:01 +0200
Subject: TL08x as comparator
Message-ID: <19980818171754.8555.qmail@nuernberg2.pop.metronet.de>


> I'm a bit sceptical about using TL07* or TL08* as comparators. It often
> works, but sometimes they latch up. 

The Oberheim OB-X uses them for PWM.
Should be no problem if you take care of the common mode range,
i.e. don't go near the negative rails with the inputs.

JH.



From toni at itl.com.mk  Tue Aug 18 19:53:48 1998
From: toni at itl.com.mk (Toni Jovanovski)
Date: Tue, 18 Aug 1998 19:53:48 +0200
Subject: filter waveform question
Message-ID: <3.0.32.19980818195158.0069e33c@206.99.216.1>

At 11:02 18-08-98 +0200,  Ingo Debus wrote:

>> Filter design.There is a lot of analogue filters , like Butterworth ,
>> Chebyshev I & II ... But in a synth design with simple waveforms ( saw ,
>> pulse , triangle ) it's a question of luxury.
>
>On a second-order filter (12dB/oct) it is the Q parameter that
>determines whether the filter is a Butterworth or Chebysheff or
>whatever.

Well,I'm not so sure.I'm must check this ( I hate this complex math
).Butterworth and Chebysheff filter is a IIR ( infinite impulse response )
filter.There is a another class of filters FIR  ( finite impulse response
)filters.I say this because I wanna show how complex is Filter design.It's
not just electronics...


>> I think , in synth-design , that fourth-order VCF ( four poles in same
>> place ) is fairly enough.
>
>But the poles move when Q is changed, don't they?
>

Yes , of course!!!I forgot to mentiot it.When there isn't resonance ( Q )
the poles are simple ( real numbers ) and when you put resonance , poles
become complex-conjugate numbers.Changing the Q factor poles are moving in
complex-plane!The pole moving is in a circle line ( about this I'm not so
sure ).Thank you for the remark.

Toni Jovanoski




From random at montrealnet.net  Tue Aug 18 20:46:01 1998
From: random at montrealnet.net (random)
Date: Tue, 18 Aug 1998 14:46:01 -0400
Subject: Offtopic: Cool new synth? - Roland JP-8080
Message-ID: <35D9CBE9.7FCE6895@montrealnet.net>

Hi

The Jp8000/jp8080 are amogst the most useless machines you can come
accross. the only nice thing about them is the Feedback Osc and euhmmm..
euhmmm.. yeah thats it.

They are WAY to overpriced (2000$us +/- last time i checked) for what
they do. At that price I would expect a synth with more than one type of
synthesis, multitimbrality and a more 'professional' look to it. The
8000/8080 looks and sadly plays like toys.

For the same amount of money you can get a k2000 or a MiniWave. IMHO, go
testdrive it before you even consider saving money to buy it.

Jim





From jdec at mindspring.com  Tue Aug 18 21:52:24 1998
From: jdec at mindspring.com (Bright Boy)
Date: Tue, 18 Aug 1998 12:52:24 -0700
Subject: New Source For Japanese Transistors
Message-ID: <35D9DB78.4900@mindspring.com>

I just received the latest Mouser Electronics catalog
in the mail yesterday and noticed in their "what's new"
section that they are now carrying a pretty decent
selection of Japanese transistors.  This is good news
for anyone repairing/cloning old Roland gear and
anything else that uses Japanese transistors.

Their URL is www.mouser.com and the phone number is
1-800-346-6873

Cheers,

Jeff R. Dec



From moxie at idonex.se  Wed Aug 19 00:27:37 1998
From: moxie at idonex.se (Johan Gustavsson)
Date: Wed, 19 Aug 1998 00:27:37 +0200 (MET DST)
Subject: And Moxie Scores!
In-Reply-To: <199808172245.AAA29759@jolt.idonex.se> (message from Johan
	Gustavsson on Tue, 18 Aug 1998 00:45:29 +0200 (MET DST))
Message-ID: <199808182227.AAA03465@jolt.idonex.se>

...and not only that, but he replies to his own mails :-)

Someone wrote me a very nice mail, telling me that the two switches
were for measuring velocity...Thank you, but I already knew that :-)
However, a few cups of tea later and after bandying the problem around
with some of my more thinking-enabled friends, this kind of solution
presented itself:

   --- Resistor chain
    |
      /
     /
    |
   ---
      |
      | --- Gate bus
      |  |
      |    /
      |   /
      \  |
        --- CV bus

"But", I hear you say, "that wont work. The gate will be floating
around and when pressed down, it'll still have rather silly
values". That's true, so the next generation is:


   --- Resistor 
    |  chain	-12v
      /		|
     /		<	This is an opamp wired as a comparator,
    |		>      /  referenced to, oh, -6v maybe
   ---		<     /
      | pre-gate|  |\
      | ---Bus--+--| ---- Gate 
      |  |	   |/
      |    /
      |   /
      \  |
        --- CV bus

This way, the voltage on the pregate bus would be kept at about v- by
the resistor connected to v-, until a key was depressed. Then, the
voltage would rise to at least 0v (for the lowest key on the
keyboard), which is well above -6v and so the gate output would go
high.

Hmm...Looking at it this way, I suppose the pull-down resistor would
interfere with the CV bus when the key is depressed. could this be
counteracted in an easy way? Perhaps by putting another opamp in as a
voltage follower just *before* the resistor, to act as a buffer? Or
would it be cool enough just to compensate for it with the scale and
range trimmers?

Anyway, would this work? Of course I'd still need the electronics for
S&H and so on, but is it a valid way to get the voltages out of the
keyboard itself?
/Moxie (Quizzical)




From jhaible at metronet.de  Wed Aug 19 01:58:05 1998
From: jhaible at metronet.de (jhaible)
Date: Wed, 19 Aug 1998 01:58:05 +0200
Subject: Sequencer Update
Message-ID: <19980819000856.14880.qmail@nuernberg2.pop.metronet.de>

 I originally
> planned on using John Simontons 4-bit convert 
> http://www.paia.com/ek7.htm

Looks interesting !
I just wondered how to build a logic for 16 comparators ...
but this might be an alternative! Any drawbacks of
this design? John?


> My last idea involves creation of another module of which I have
> never seen an implementation of. A "random probability select".
> A gate input will trigger the module to randomly select a channel
> and output an associated voltage. Each channel would have two
> controls. One control is the voltage to be output. The other control
> determines the probability that this channel will be selected.

This might be useful. I think the OB-8 has a feature in its arpeggiator
that even in Random mode the first note you enter will have a higher
probabillity than the others. Easy in software, but probably not to
be included in my hardware only sequencer.

> Well, I have probably too many ideas for a single design. I would
> be very interested in your designs. I would also be interested
> if you decided to do something similar to the ASM-1, w/ circuit
> boards and/or faceplates. I know many on the list are interested
> in a good sequencer.

I think I won't make a PCB myself, but maybe a 3rd party may join 
in here. I will have my frontpanel made from Schaeffer Apparatebau,
and I will offer the design data to anybody who wants them for
private use.

But it's still a looong way to go before I can think of that.

Update:
I have just finished the "core" of the sequencer, that is up/down
counter, skip and random control, reset and preset, VC clock
and VC gate length. It's pretty much the ARP sequencer with
an improoved random generator and up/down counting.
Just a test board with 4 LEDs to monitor the binary output.

Next steps:
(2) A control board.
I like the ARP seq's way of handling start, stop, and step functions.
Use 2 buttons for start/stop, ore use one and toggle between the states.
Use an extarnal gate to trigger functions, or to *gate* the on/off
function.
I guess I will replicate that, too. And duplicate this whole section
for up/down control.

(3) The "vertical" stuff.
I looked at the Serge schemos again, and boy, do *they* have implemented
a wealth of functions ! The inputs for all these functions are very simple,
compared to the ARP (debouncing etc.). I wouldn't leave it this way ...
4 complete rows of 16 steps are a lot of potentiometers - to buy, to put
on a front panel, and to tweak. I really had something like 2x8 or 2x12
in mind when I started, and not 4x16 ...
I am not sure what I will do in the end, but the use of a separate vertical
clock has something for it. So at the moment I tend to go 4x8 or 3x8.
A skip function for the vertical clock would be useful. And the
possibillity
to derive the vertical clock pulses from one of the horizontal gate busses.
For comfortable live use, I have a special "delayed row selection" in mind:
When I want to change from one sequence to the next I hit a button,
and then this "change request" is stored in a latch until another event
takes place, like end of one sequence, or step #N in a sequence. This
should be fairly easy with Gate busses, too.

Ok, that's all for now. Thanks again for all suggestions (and keep them
coming 
in ...), they are all very helpful !

JH.

PS.:

Any Ideas where to get these highly ergonomic pushbuttons that several
commercial
Sequencers have built in? (Korg SQ-10, for example)



From jhaible at metronet.de  Wed Aug 19 02:00:55 1998
From: jhaible at metronet.de (jhaible)
Date: Wed, 19 Aug 1998 02:00:55 +0200
Subject: New Source For Japanese Transistors
Message-ID: <19980819000858.14880.qmail@nuernberg2.pop.metronet.de>

> section that they are now carrying a pretty decent
> selection of Japanese transistors.  This is good news
> for anyone repairing/cloning old Roland gear and
> anything else that uses Japanese transistors.

Dual ones, too ? 
Dual pnp's even ?

JH.



From ka4hjh at gte.net  Wed Aug 19 03:41:59 1998
From: ka4hjh at gte.net (KA4HJH)
Date: Tue, 18 Aug 1998 21:41:59 -0400
Subject: Offtopic: Cool new synth? - Roland JP-8080
In-Reply-To: <35D9CBE9.7FCE6895@montrealnet.net>
Message-ID: <v04011700b1ffdd251643@[208.255.152.131]>

>The Jp8000/jp8080 are amogst the most useless machines you can come
>accross. the only nice thing about them is the Feedback Osc and euhmmm..
>euhmmm.. yeah thats it.
>
>They are WAY to overpriced (2000$us +/- last time i checked) for what
>they do. At that price I would expect a synth with more than one type of
>synthesis, multitimbrality and a more 'professional' look to it. The
>8000/8080 looks and sadly plays like toys.
>
>For the same amount of money you can get a k2000 or a MiniWave. IMHO, go
>testdrive it before you even consider saving money to buy it.

The Crystal Method use both a JP-8000 and a Nord Modular (and a fuzz pedal)
live. For the money, I'd rather have the (virtual synthesis) Nord. You can
download a demo of the editor software from their website. Alas, it's
Windows95 only.

Terry Bowman, KA4HJH
"The Mac Doctor"



From chordman at flash.net  Wed Aug 19 04:19:51 1998
From: chordman at flash.net (Scott Gravenhorst)
Date: Wed, 19 Aug 1998 02:19:51 GMT
Subject: Nonlinear Feedback Filter Update
In-Reply-To: <35d9ae3e.82903603@mail.lan>
References: <35d9ae3e.82903603@mail.lan>
Message-ID: <35e03635.90023787@mail.lan>

Current schematic at:
http://members.xoom.com/chordman/NonlinearFeedbackFilter.html

I did the first test with inverse polarity parallel diodes (1N4148).
Injecting a sine wave and playing with resonance and cutoff makes for
obvious added harmonics where there were none without the
nonlinearity.  I noticed that the resonance was effected by the output
setting from the nonlinearity driver opamp.  I will add another opamp
to buffer the output of the nonlinearity circuit later this week.

Right now, I'm just using a non-VC test oscillator (it's the only one
I have that does sine, square, saw, triangle and pulse).  I can
already tell that one of the more interesting ways to apply this is by
allowing the filter to track a VCO.  Perhaps more interesting when the
slopes are not precisely the same (if that were even possible with
this design).

The circuit is also sensitive to the input level, in that the
harmonics produced vary with amplitude.  Because of this, it may be
useful as a device placed after a VCA.

It needs work, but it looks good so far.

-- Scott Gravenhorst
-- FatMan Site: www.teklab.com/~chordman



From honcho at paia.com  Wed Aug 19 05:13:45 1998
From: honcho at paia.com (honcho at paia.com)
Date: Tue, 18 Aug 98 22:13:45 CDT
Subject: Sub oscillator for CEM3394
Message-ID: <9808190313.AA02723@qns1.qns.net>



On Tue, 18 Aug 1998, Tony Clark <clark at andrews.edu> wrote:
>   I've never had a TL0XX latch up on me, but that may be because I'm 
>careful not to exceed (or come close to) the power supply on the 
input 
>pins.  
>>>

This is key and it's most likely to happen on power-up, as in a S/H 
where the sample cap returns to the negative supply rail instead of 
ground or a comparator that uses the negative rail for a reference.

-John

---------------------------------------------------------
John Simonton                  PAiA Electronics, Inc
3200 Teakwood Ln.              honcho at paia.com
Edmond OK 73013                http://www.paia.com
405-340-6300                   fax 405-340-6378



From blindfold at L2.lonet.ca  Wed Aug 19 07:02:44 1998
From: blindfold at L2.lonet.ca (Aaron Anderson)
Date: Wed, 19 Aug 1998 01:02:44 -0400
Subject: [Digital_Hell] Doepfer Regelwerk and neo-analog sequencers
In-Reply-To: <35D72BB9.62390B9F@globaleyes.net>
Message-ID: <v04003a00b2000c234b0d@[207.134.187.96]>

At 2:58 PM -0400 8/16/1998, cyborg0 at globaleyes.net wrote:
>Well, this looks like the most intense sequencer/faderbox in existence..
>I am pretty sure I will be buying one shortly, since the studio 440 deal
>has pretty much waned due to my being lied to quite a bit about the
>wherabouts of the box and its condition. (Im very untrusting these days)
>
>Anyone know of any known problems with the box so far? If so, post it,
>because it really looks like a mini version of the Shaltwerk/maq16
>combo, which is really good.
>
>noteable features:
>
>transmits 8 patterns at once
>any track can produce any kind of controller info
>only 1 track editable at a time, but 8 can be playing.
>mutable tracks
>can send controller info via faders in fader mode
>can switch fader function from step to regular fader mode while playing


anyone out there own one yet?

looks like a cool box....  i wonder if the cv outs do ms20 hz/vt........  i
have these visions of running samples thru my ms20 and 2600 and sequencing
the modulation...  they keep me awake at night... 8 sequencable cv outs
into a 2600???  holy fuck......  oh, i think it has some faders too.  ;)


--
aaron
All Things to All People Corporate Studios
http://www3.sympatico.ca/rorytate/studio
DOWN WITH BILL C-32!!!





From carrillo at herald.infi.net  Wed Aug 19 07:27:39 1998
From: carrillo at herald.infi.net (Martin Carrillo)
Date: Wed, 19 Aug 1998 01:27:39 -0400
Subject: OFFTOPIC Cool new synth? - Roland JP-8080
Message-ID: <35DA624B.7B17@herald.infi.net>

Watch the Roland JPs.  Their filter sweeps are digital and the stepping
is audible.  I agree that the Nord is better. Yaw.

Forgive this offtopic warning. nuff already. 

Martin





From fmsci at email.msn.com  Wed Aug 19 08:38:57 1998
From: fmsci at email.msn.com (.v/jek.)
Date: Wed, 19 Aug 1998 02:38:57 -0400
Subject: [Digital_Hell] Doepfer Regelwerk and neo-analog sequencers
Message-ID: <006901bdcb3c$0c09ff60$3ff1fed0@default>


>looks like a cool box....  i wonder if the cv outs do ms20 hz/vt........  i


Quote from the doepfer english page:

General features:

     2 MIDI In, 2 MIDI Out, SYNC (Roland compatible)
     8 CV outputs (3.5 mm miniature jack sockets), function only in
sequencer mode, range: 0...+5V, 1V/Octave
     characteristics
     8 Gate outputs (3.5 mm miniature jack sockets), function only in
sequencer mode, voltage gate 0/+5V light
     ------------------------

Sorry, looks like your outa luck... ;(

o0o[qiB.]o0o








From tomg at vivid.net  Wed Aug 19 09:48:39 1998
From: tomg at vivid.net (tomg)
Date: Wed, 19 Aug 1998 02:48:39 -0500
Subject: Mini1 morphing to UMaxx 1OO
In-Reply-To: <yam7505.1077.119300216@mail.vivid.net>
Message-ID: <yam7535.1992.119792632@mail.vivid.net>

On 20-Jul-98, tomg wrote:
>I went out looking for a couple of 3 space rack panels to do a pair of
>Mini1cv's on and got a great deal on a 6 space. The more I look at that 6
>space the more I see something very different.

>http://www.tomg.vivid.net/umaxx/pics/pic_001.gif

>-Tom

I didn't mean to send this yet. I got side tracked on the
Mad Mouse and put the whole thing on hold. I have changed
the layout several more times. If you want to look at it
go ahead but.. It's not what it looks like now. I'll
get back to it after and do it online the same way I'm 
doing the MM.

-tg


 





From hekovala at lyseolukio2.kajaani.fi  Wed Aug 19 10:43:24 1998
From: hekovala at lyseolukio2.kajaani.fi (Henri Kovalainen)
Date: Wed, 19 Aug 1998 11:43:24 +0300 (EEST)
Subject: Temp. compensated VCO
Message-ID: <Pine.LNX.3.96.980819110552.2598B-100000@lyseolukio2.kajaani.fi>


 The board pic is now available at

 http://lyseolukio2.kajaani.fi/~dh/compvco.ps

 I found out that (at least in my case, it was around 0.5v) the saw
 amplitude varied quite much. So you might have to twiddle the feedback
 resistor (470k) on the buffer amp (which also sums the offset trimmer).
 The squarewave is generated with an op-amp comparator, so purists may
 find it to be too slacky, but it was good enough for me. I haven't had
 any latching problems with the comparator, but (supposingly) the
 compensation amp config has latched a couple of times when I have whacked
 it with a hard negative pulse from a lfo etc. Also a small negative spike
 might be present at the bottom of the saw wave, which didn't bother me,
 and if I ever design a waveshaper board for this one I'll include a
 clipping amp that will shave these off. The resistors values it the cv
 summing amp depend on which way you hook the pitch pots. I didn't connect
 the arrays leftover tranny to the negative rail (this was suggested in
 Rene's schematics) which hasn't caused any problems that I'm aware of.
 Hop, skip and jump with a wire if you want this to be done. I have used
 IRF530s instead of BUZ20s too, and they all seem to work properly.

 Also, I would like to point out that only proper feedback is appreciated,
 any criticism or flaming is ignored and therefore futile.
 If you don't like the design, skip it.

 ------------------.                  
 theadvancementand |  henri kovalainen    hoikankatu 19
 diffusionofknowle |  phone: +08-626555   87100 kajaani
 dgeistheonlyguard |  irc: acidrain       finland
 ianoftrueliberty. |  http://lyseolukio2.kajaani.fi/~dh
                   '-




From martin.czech at intermetall.de  Wed Aug 19 11:40:32 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Wed, 19 Aug 1998 11:40:32 +0200 (MET DST)
Subject: archive moved due bandwidth
Message-ID: <199808190940.LAA18249@window.intermetall.de>

Due to persisting bandwidth problems the unofficial synth-diy archive
has moved again, I hope for the last time:

http://www.evenfall.com/diy/archive/index.html

A friendly soul offered me some web space there (thanx Christopher
MacDonald).  The previous used sites show nothing but a link to the new one.

I tryed it and could download with 13kb/s.

m.c.




From planet4 at swipnet.se  Wed Aug 19 12:38:38 1998
From: planet4 at swipnet.se (Johan Persson)
Date: Wed, 19 Aug 1998 12:38:38 +0200
Subject: Waveform morphing...
Message-ID: <35DAAB2E.6A341134@swipnet.se>

Hi all!

I'm doing some testing on morphing with my computer... The idea is to
morph between two simple (64 or 128 bytes or similar) waveforms. I know
this has been discussed before so I though someone would know a bit
about it. I'm looking for samples or some simple software just to hear
what it sounds like and if it is worth the work, before I dive into the
programming bit.
If things go the way I want, I plan to make two detuned morphing
oscillators and very limited polyphony... MIDI controlled... That is of
course just what I want, probably not what I'm able to do :)

It would also be interesting to hear about similar projects or just any
ideas whatsoever...

Johan





From hekovala at lyseolukio2.kajaani.fi  Wed Aug 19 13:01:42 1998
From: hekovala at lyseolukio2.kajaani.fi (Henri Kovalainen)
Date: Wed, 19 Aug 1998 14:01:42 +0300 (EEST)
Subject: Temp. compensated VCO
In-Reply-To: <TFSJUPCE@idg.se>
Message-ID: <Pine.LNX.3.96.980819133343.4618A-100000@lyseolukio2.kajaani.fi>


 The message was originally private, but I guess this is well suited to be
 on the list too.

On Wed, 19 Aug 1998 jorgen.bergfors at idg.se wrote:
> Hi Henri. I suppose this VCO is based on the temperature compensation circuit 
> on Rene Schmitz' web page. I'm thinking of building it too. Have you used his 
> circuit exactly or do you have a schematic on your web site? If you used his 
> circuit, which one - the one with a 4093 or the one with a 555?

 I suggest that you take a look at the actual board. The design is exactly
 the same, but I have added a simple inverting mode sumup op-amp to sum
 the pulsewidth modulation voltages. Rene said that there were some
 problems with the 4093, so the board is for the 555 version, as the 8 pin
 ic indicates.

> Have you done any tests to veryfy that the temperature compensation indeed 
> works?

 I have put all my oscillators through the same kind of torture. I used a
 small nut and a soldering iron to heat the array slightly (I guess the
 temp was about 80C at the max) and there was no actual noticeable drift
 in the frequency. I'm planning of setting up a proper heater and a
 frequency counter and plot a curve of the frequency over the whole
 realistic temperature range.

> If the amplitude of the saw wave varies, it will be difficult to convert
> it to triangle and sine waveforms. Do you think this can be fixed?

 The amplitude doesn't vary "on the fly". I meant that different component
 selections around the CCO may change the amplitude, but this will of 
 course result in a constant value. The final amplitude is determined with
 the feedback resistor. On the other hand, the saw amplitude makes a big 
 difference in the comparator which is used to generate the squarewave, so
 you could even use a trimmer if you wish

 ------------------.                  
 theadvancementand |  henri kovalainen    hoikankatu 19
 diffusionofknowle |  phone: +08-626555   87100 kajaani
 dgeistheonlyguard |  irc: acidrain       finland
 ianoftrueliberty. |  http://lyseolukio2.kajaani.fi/~dh
                   '-




From yoh212 at lulu.acns.nwu.edu  Wed Aug 19 13:32:39 1998
From: yoh212 at lulu.acns.nwu.edu (Yoshiki Ohmura (Yoshi))
Date: Wed, 19 Aug 1998 06:32:39 -0500 (CDT)
Subject: differences in VCA chips?
Message-ID: <Pine.HPP.3.93.980819063037.29527A-100000@lulu.acns.nwu.edu>

I have some SSM2020's, 2022's, CA3080, and can get some CEM3360's.  Now I
was wondering what is the difference between these (besides the price).  I
would rather stick with the 3080 or 3360 because i can still get those,
and preferable use th 3080 becuase its dirt cheap ;)  but is there a
quality difference?

Thanks

Yoshi





From martin.czech at intermetall.de  Wed Aug 19 13:51:48 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Wed, 19 Aug 1998 13:51:48 +0200 (MET DST)
Subject: Waveform morphing...
Message-ID: <199808191151.NAA18857@window.intermetall.de>

> Hi all!
> 
> I'm doing some testing on morphing with my computer... The idea is to
> morph between two simple (64 or 128 bytes or similar) waveforms. I know
> this has been discussed before so I though someone would know a bit
> about it. I'm looking for samples or some simple software just to hear
> what it sounds like and if it is worth the work, before I dive into the
> programming bit.
> If things go the way I want, I plan to make two detuned morphing
> oscillators and very limited polyphony... MIDI controlled... That is of
> course just what I want, probably not what I'm able to do :)
> 
> It would also be interesting to hear about similar projects or just any
> ideas whatsoever...
> 
> Johan
> 
Hi Johan,

what do you mean by "morphing"? If you mean simple adding of two waves
with mutual dependency, interpolation ( s(t)=k*a(t)+(1-k)*b(t)) , well
you can do this with almost any rom wave synth (rompler) that offers 2
or more patches,layers etc per voice.  Just select different waves for
the patches of one voice and then program the envelope such that you
hear first the first patch, then both and finally the second one. Ok,
this is very simple morphing, but it works as such.  Most experiments
of this kind that I did where not that much exiting...  But sometimes
they are, thought. If you're more in analog, well you could as well
take two vco and use a single pot to mix them, just to get the impression.


Or do you mean a method like , well, let's see ah, initial spectrum has
three formants, and final has only one , but at another location, so
I morph between the spectra by slowly shifting one formant to the
final position and fade out the superfluous two. 
Well, that's interesting, but also complicated....

However,this sounds like a lot of work.  If you do this all digital,
you'll end up with multirate and interpolation (well, you want to play
the waves at different pitches) and a hybrid solution requires a quite
high frequency for variable memory read out that must be exact enough
to match your scale (hf-vco, or pll vco).

(By the way:  Does anybody know how the very first Doepfer sampler
worked ?  I guess it used a 3340 vco, either with a smaller timing cap
then recommended or with a pll to get the sampling frequency.  I know
somebody who asked me if I would by/take his Doepfer sampler.  You
know, together with C64, this awfull floppy drive etc.  Should I?)

Anyway, I don't want to underestimate your skills, but this sounds
like a major hardware project. 

Maybe (there's the heretic! get him !) it'd be a better way to:

1. get a used sampler, e.g. old AKAI, and learn how to dump waves into
that via midi. I know somebody who must have the spec. You could write
a little program to implement whatever you mean by morphing, and you
could add more functionality afterwards.  Of course, this means: no
realtime, sit and wait...

2. get an old microwave (no oven), there are a lot of "fashion people"
who sell their MW to get an MWXT (I see adds every month in the German
Keyboards mag).  This machine can do real time "morphing", and it is
relativeley easy to download your own waves into. Even I could manage,
beeing a computer idiot ;->.

3. I'm not so shure about a Wavestation A/D, but you should (please
check) be able to interpolate and download your own waves, too.

Sometimes it is more fun to chain quite different waves together, even
with silence. This gives rythm loops, as well as strange moving, blobbing
sounds. The interpolation is done in your ears and brain, when
played fast enough.

Just my $0.02 

m.c.




From Chris.List at sc.siemens.com  Wed Aug 19 14:59:34 1998
From: Chris.List at sc.siemens.com (List, Christopher)
Date: Wed, 19 Aug 1998 08:59:34 -0400
Subject: Sequencer Update
Message-ID: <81A062BC5305D111A9D700805F065968CE94D5@maildepo.sc.siemens.com>

> -----Original Message-----
> From:	jhaible [SMTP:jhaible at metronet.de]
> Sent:	Tuesday, August 18, 1998 7:58 PM
> To:	Thomas Hudson; DIY
> Subject:	Sequencer Update
> 
>  I originally
> > planned on using John Simontons 4-bit convert 
> > http://www.paia.com/ek7.htm
> 
> Looks interesting !
> I just wondered how to build a logic for 16 comparators ...
> but this might be an alternative! Any drawbacks of
> this design? John?
> 
> 
	This is a very clever circuit, and one I keep meaning to check
out. I didn't know about this circuit when I built my sequencer, and
used the "brute force" 16 comparator + 2 encoders method for my 4bit
flash ADC. My ADC takes control of the counter anytime the input voltage
goes over ~0.3v (5v / 17, there are 16 steps + the "off" state for the
ADC). Using the "jam inputs" on the counter like this is so easy and
adds some neat functionality to the sequencer, I highly recommend it.
Controlling it with an ADSR or a sawtooth wave for example. OTOH, you
(Juergen) can probably do all the same tricks with the interpolating
scanner, and do them better that way!

	As always, I'm anxious to see what you end up with!

	- CList



From Chris.List at sc.siemens.com  Wed Aug 19 15:06:08 1998
From: Chris.List at sc.siemens.com (List, Christopher)
Date: Wed, 19 Aug 1998 09:06:08 -0400
Subject: Offtopic: Cool new synth? - Roland JP-8080
Message-ID: <81A062BC5305D111A9D700805F065968CE94D6@maildepo.sc.siemens.com>

Hmm, obviously I haven't been reading gear magazines or prowling music
shops in a while :). 
I was thinking it'd be priced around $1200 or so, then it might be more
enticing...

thanks,
CList

> -----Original Message-----
> From:	KA4HJH [SMTP:ka4hjh at gte.net]
> Sent:	Tuesday, August 18, 1998 9:42 PM
> To:	synth-diy at mailhost.bpa.nl
> Subject:	RE: Offtopic: Cool new synth? - Roland JP-8080
> 
> >The Jp8000/jp8080 are amogst the most useless machines you can come
> >accross. the only nice thing about them is the Feedback Osc and
> euhmmm..
> >euhmmm.. yeah thats it.
> >
> >They are WAY to overpriced (2000$us +/- last time i checked) for what
> >they do. At that price I would expect a synth with more than one type
> of
> >synthesis, multitimbrality and a more 'professional' look to it. The
> >8000/8080 looks and sadly plays like toys.
> >
> >For the same amount of money you can get a k2000 or a MiniWave. IMHO,
> go
> >testdrive it before you even consider saving money to buy it.



From aschrock at cs.brandeis.edu  Wed Aug 19 15:50:26 1998
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Wed, 19 Aug 1998 09:50:26 -0400 (EDT)
Subject: differences in VCA chips?
In-Reply-To: <Pine.HPP.3.93.980819063037.29527A-100000@lulu.acns.nwu.edu>
Message-ID: <Pine.SGI.3.95.980819094228.16247B-100000@amber.cs.brandeis.edu>

On Wed, 19 Aug 1998, Yoshiki Ohmura (Yoshi) wrote:
> I have some SSM2020's, 2022's, CA3080, and can get some CEM3360's. Now I
> was wondering what is the difference between these (besides the price).  I
> would rather stick with the 3080 or 3360 because i can still get those,
> and preferable use th 3080 becuase its dirt cheap ;)  but is there a
> quality difference?

I find CEM stuff to be quite nice. As a final VCA, 3080 and its ilk are
unacceptable to me right now. As an amp VCA for, say, an LFO or whatever, 
a 3080 is fine. You are correct about the price though.. it's nice to
throw together a VCA with a total cost of about $3. 

SSM stuff I just wouldn't use due to their impossibility to find. Ditto
for the CEM chips. (although currently they're supported pretty well by
synthtech, so i'm a bit less apprehensive about using them) See my
previous email to the list about non-SSM/CEM VCA designs, a few ideas were
tossed aorund in that thread which may prove useful to you. 

Andrew

| Andrew Schrock							|
| Network Programmer, Synthesizer and electronic music enthusiast	|
| aschrock at cs.brandeis.edu						|






From martin.czech at intermetall.de  Wed Aug 19 15:52:39 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Wed, 19 Aug 1998 15:52:39 +0200 (MET DST)
Subject: audio driver for more current and dual supply
Message-ID: <199808191352.PAA19173@window.intermetall.de>

I need a driver that is able to source 200mA to 500mA at audio
frequency. E.g. reverb coil driver, magnetic  core driver, little
speaker driver. I had a look at all these TDA audio amps (for car radio
etc.) but they all use only a single supply. Does somebody know a
convenient solution that uses both power rails ?  There is a
possibility to boost a normal op amp, add npn and pnp in collector
circuit, the driving and biasing is done by the opamp supply pins and
two restors attached to these.  Anybody tryed this?

Any help appreciated.

m.c.




From honcho at paia.com  Wed Aug 19 16:34:00 1998
From: honcho at paia.com (honcho at paia.com)
Date: Wed, 19 Aug 98 09:34:00 CDT
Subject: Sequencer Update
Message-ID: <9808191434.AA09298@qns1.qns.net>

On Wed, 19 Aug 1998, "jhaible" <jhaible at metronet.de> wrote:
> I originally
>> planned on using John Simontons 4-bit convert 
>> http://www.paia.com/ek7.htm
>
>Looks interesting !
>I just wondered how to build a logic for 16 comparators ...
>but this might be an alternative! Any drawbacks of
>this design? John?
>

None that I can recall. It's a lot simpler than 16 comparators and the 
logic of a 16/4 encoder, for sure. It's difficult to make the scheme 
work for greater than 5 or 6 bits, resistor precision gets to be a 
problem.

The same circuit was used in PAiA's Proteus 1 (not to be confused with 
the more recent synth of the same name from Eu) for digitizing knob 
positions and for digitizing switch positions. Switches switched 
resistors in a simple D/A to produce a voltage corresponding to the 
position of a group of 4 switches. That way all front panel parameters 
were represented by voltages, multiplexed into one of these eK7 
jobbers, and then came out as groups of 4 bit bytes. Sound like a long 
way 'round, I know, but in the greater scheme of things it simplified 
circuitry enormously. 

-John

---------------------------------------------------------
John Simonton                  PAiA Electronics, Inc
3200 Teakwood Ln.              honcho at paia.com
Edmond OK 73013                http://www.paia.com
405-340-6300                   fax 405-340-6378



From sdcurtin at lucent.com  Wed Aug 19 16:50:28 1998
From: sdcurtin at lucent.com (Steven Curtin)
Date: Wed, 19 Aug 1998 10:50:28 -0400
Subject: Programmable Logic Sequencer
Message-ID: <3.0.3.32.19980819105028.01153b0c@mtm3.ho.lucent.com>

The current traffic about sequencers is very relevant to my current project
which is finally making some music, a sequencer and pattern generator based
on the Phillips CoolPLD programmable logic device.  The chip's been
programmed with pulse and display outputs controlling the analog synth and
some control inputs affecting the order of the pulses.  The CoolPLD device
has the equivalent of 128 flipflops in it that can be programmed to connect
together with logic equations,  using a special cable connected to any PC
with a parallel port.  Since the program memory in the PLD is in flash
memory you can turn it off and on again and it will retain its program,
long after the PC has been disconnected.   

Phillips sells a demo board for $100 which includes the compiler and
programming tools.  It's preferable to programming a microcontroller since
everything happens in parallel and you have 70 pins that you can define as
inputs or outputs.  The current program could probably be done with a
couple of counters and inverters, but it's easy to expand out and do all
the gate bus programming inside the chip.    There will be more info on
this as I make progress.  What would be cool is if a number of us bought
these boards and traded programs.

The Phillips CoolPLD web site has details on the device at
http://www.coolpld.com.    Lucent doesn't make any PLDs but they do make
the PLDs big brother, known as the FPGA, they call theirs ORCA.  For info
on that see http://www.lucent.com/micro/fpga/.  I'll probably graduate to
these once my designs outgrow the PLDs.

The web site has recently been updated to include pictures of the various
DSP boards and instruments I've built over the years - check it out.

Steve C

--------------------------------------------------------------
Steven Curtin  
http://www.emf.org/people_curtin.html
Lucent Technologies - Bell Labs Innovations
rm. 1A-229, 200 Laurel Ave S
Middletown, NJ 07748-4801  U S A
ph: (732)957-2996   fax: (732)957-6878
--------------------------------------------------------------



From planet4 at swipnet.se  Wed Aug 19 17:16:57 1998
From: planet4 at swipnet.se (Johan Persson)
Date: Wed, 19 Aug 1998 17:16:57 +0200
Subject: Waveform morphing...
References: <199808191151.NAA18857@window.intermetall.de>
Message-ID: <35DAEC69.E42A5980@swipnet.se>

> what do you mean by "morphing"? If you mean simple adding of two waves

I thought of trying simple adding at a start and if the results are good,
there are no need to dig deeper. It has also struck me that it could sound
like a very uninteresting fading effect, but opposed to analog VCO's fading
into each other the two waveforms are exactly synced which probably makes the
fading not as obvious (that is at least what my sometimes illogical brain came
up with...). I have a friend who wrote a piece of software some years ago that
used another technique. From what I recall, it used several points adjustable
both in X and Y, and changed the positions of these points gradually. When I
think about it now, it's basically the same thing as "fade-morphing", but some
of the sounds where quite interesting...


> you can do this with almost any rom wave synth (rompler) that offers 2
> or more patches,layers etc per voice.  Just select different waves for
> the patches of one voice and then program the envelope such that you
> hear first the first patch, then both and finally the second one. Ok,
> this is very simple morphing, but it works as such.  Most experiments
> of this kind that I did where not that much exiting...  But sometimes

I was more thinking of doing the calculations in real-time and not have two
oscillators changing volume. This would just take up one voice! And the
thought was also to be able to change between more than two waveforms in time.




> Or do you mean a method like , well, let's see ah, initial spectrum has
> three formants, and final has only one , but at another location, so
> I morph between the spectra by slowly shifting one formant to the
> final position and fade out the superfluous two.
> Well, that's interesting, but also complicated....

I'm not quite sure what you mean. Anyway, this would probably be more than I
could handle. My DSP skills is not what they should be...



> However,this sounds like a lot of work.  If you do this all digital,
> you'll end up with multirate and interpolation (well, you want to play
> the waves at different pitches) and a hybrid solution requires a quite
> high frequency for variable memory read out that must be exact enough
> to match your scale (hf-vco, or pll vco).

Yep.. It would too much, if it weren't for the fact that I'm going to cheat!!
(hehe...). If I do my testing on a computer, why not have the finished project
running on a computer aswell..? I planned on using my ol' Amiga 500 (it's just
stuffed away in a closet anyway), which has built in four voices audio-chip
and a serial port. Why do a lot of work already done? It's not actually the
sound I'm looking for (there are more interesting ways and machines for
producing sounds), but it's a nice project. If I would be smart, I would give
up these ideas right now and go buy me a microwave (still not an oven).

Johan





From thudson at cygnus.com  Wed Aug 19 17:52:15 1998
From: thudson at cygnus.com (Thomas Hudson)
Date: Wed, 19 Aug 1998 11:52:15 -0400
Subject: differences in VCA chips?
In-Reply-To: <Pine.SGI.3.95.980819094228.16247B-100000@amber.cs.brandeis.edu>
Message-ID: <000601bdcb89$5624c3d0$2d90e2cd@thudson1.cygnus.com>


I just received some samples of the SSM2164 Quad VCA.
http://products.analog.com/products/info.asp?product=SSM2164

Has anyone worked with this chip? Does anyone know the
availability? It seems to have really good specs.

Thomas

> -----Original Message-----
> From: owner-synth-diy at mailhost.bpa.nl
> [mailto:owner-synth-diy at mailhost.bpa.nl]On Behalf Of Andrew Schrock
> Sent: Wednesday, August 19, 1998 9:50 AM
> To: Yoshiki Ohmura (Yoshi)
> Cc: synth-diy at mailhost.bpa.nl
> Subject: Re: differences in VCA chips?
>
>
> On Wed, 19 Aug 1998, Yoshiki Ohmura (Yoshi) wrote:
> > I have some SSM2020's, 2022's, CA3080, and can get some CEM3360's. Now I
> > was wondering what is the difference between these (besides the
> price).  I
> > would rather stick with the 3080 or 3360 because i can still get those,
> > and preferable use th 3080 becuase its dirt cheap ;)  but is there a
> > quality difference?
>
> I find CEM stuff to be quite nice. As a final VCA, 3080 and its ilk are
> unacceptable to me right now. As an amp VCA for, say, an LFO or whatever,
> a 3080 is fine. You are correct about the price though.. it's nice to
> throw together a VCA with a total cost of about $3.
>
> SSM stuff I just wouldn't use due to their impossibility to find. Ditto
> for the CEM chips. (although currently they're supported pretty well by
> synthtech, so i'm a bit less apprehensive about using them) See my
> previous email to the list about non-SSM/CEM VCA designs, a few ideas were
> tossed aorund in that thread which may prove useful to you.
>
> Andrew
>
> | Andrew Schrock							|
> | Network Programmer, Synthesizer and electronic music enthusiast	|
> | aschrock at cs.brandeis.edu						|
>
>
>
>




From Barry.L.Klein at wdc.com  Wed Aug 19 18:14:33 1998
From: Barry.L.Klein at wdc.com (Barry L Klein)
Date: Wed, 19 Aug 1998 09:14:33 -0700 (Pacific Daylight Time)
Subject: Waveform morphing...
Message-ID: <ISSMTP.1.3(1).19980819091433.4294836231A@Corp.wdc.com>

I have a wavestation AD and don't think you can download new waves to it. 
You can mess with the PCM samples but can't load in your own - say like on
a K2000.  I'm interested in learning of anyone's success in doing this
though through the PCM card port.  You should be able to do it by making
up a dual accessable sram card that your pc could load up.  Same thing
could be done with other members of the Korg line using such a port.  Am I
wrong? Can you do a MIDI sample dump?  I don't think so...

Barry

----------
From: 	MARTIN.CZECH at INTERMETALL.DE
Sent: 	Wednesday, August 19, 1998 4:51 AM
To: 	SYNTH-DIY at MAILHOST.BPA.NL; PLANET4 at SWIPNET.SE
Subject: 	Re: Waveform morphing...

.3. I'm not so shure about a Wavestation A/D, but you should (please
check) be able to interpolate and download your own waves, too.
.m.c.





From ride2619 at ride.ri.net  Wed Aug 19 19:06:46 1998
From: ride2619 at ride.ri.net (Michael J. Barclay de Tolly)
Date: Wed, 19 Aug 1998 13:06:46 -0400
Subject: cancellation of subscription
Message-ID: <008201bdcb93$c00620a0$28e673c6@ride2619.ride.ri.net>

Please cancel my subscription.
Thanks,

Michael J. Barclay de Tolly
ride2619 at ride.ri.net


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From deknow at tiac.net  Wed Aug 19 19:26:04 1998
From: deknow at tiac.net (dean stiglitz)
Date: Wed, 19 Aug 1998 13:26:04 -0400
Subject: studio setup help (patchbays,cables)
Message-ID: <35DB0AAC.47FA6709@tiac.net>

hi all,
well i think i have finally found a new location for my studio, and am
starting to think through what i need to replace, and how i should set
it up.  i've never used a patchbay before, i always set my gear up
facing the middle of the room, but this new space is a little smaller,
and will also be my bedroom :)  it seems like a good idea to use
patchbays and keep everything tight (and against the wall).

can someone recomend something???  i have xlr, balanced and unbalanced
1/4" (and i might even consider something for midi as well).  in my mind
(scary place), i'm thinking it would be most cost effective to get a
patchbay with solder connections on the back, a big spool of wire, and a
bunch of 1/4" and xlr connectors to go to all the inputs and outputs of
the gear (cut the cable to the proper length and solder to the back of
the patchbay).

i've never even looked at patchbays before, so i'm looking for cost
effective units that will add the least ammount of noise (obviosly).
also, what kind of cable should i buy???

deknow




From benny at fcl-us.net  Wed Aug 19 19:42:31 1998
From: benny at fcl-us.net (BennyBlanco)
Date: Wed, 19 Aug 1998 13:42:31 -0400 (EDT)
Subject: studio setup help (patchbays,cables)
In-Reply-To: <35DB0AAC.47FA6709@tiac.net>
Message-ID: <Pine.GSO.3.95q.980819133901.11435A-100000@einstein>

speaking of studio set-up/design. does anyone know where a good place to
purchase a Rack Stand (with or without wheels). I dig some of the QuikLok
designs. I need about 30 Spaces. can somebody direct?


thanks

_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_
benny blanco         /\		blancodisco:	
gamefx, inc.	   /\  /\       http://www.fcl-us.net/~benny/index.html
-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-




From thelab at sprint.ca  Wed Aug 19 20:25:58 1998
From: thelab at sprint.ca (Philip)
Date: Wed, 19 Aug 1998 16:25:58 -0200
Subject: Waveform morphing...
References: <35DAAB2E.6A341134@swipnet.se>
Message-ID: <35DB18B6.43FC@sprint.ca>

Johan Persson wrote:
> 
> Hi all!
> 
> I'm doing some testing on morphing with my computer... The idea is to
> morph between two simple (64 or 128 bytes or similar) waveforms. I know
> this has been discussed before so I though someone would know a bit
> about it. I'm looking for samples or some simple software just to hear
> what it sounds like and if it is worth the work, before I dive into the
> programming bit.
> If things go the way I want, I plan to make two detuned morphing
> oscillators and very limited polyphony... MIDI controlled... That is of
> course just what I want, probably not what I'm able to do :)
> 
> It would also be interesting to hear about similar projects or just any
> ideas whatsoever...
> 
> Johan


Check my web page
http://robotnik.com/the_lab/software/wav2?Wave/wav2?wave.htm 

It is software that morphs two 64 sample .wav files within a Waldorf
Microwave 1/2/xt synth. You can use .wav files (and it will strip off
the header info automaticly) or use any file...ever wonder what
config.sys morphing to autoexec.bat sounded like? ;)  I also added an
additive synthesis tool so that you can use to genererate the start and
end waves solely through additive synthesis. You can also use the
additive synthesis tool to simply add harmonics to an existing wave.
Finally I incorporated two types of digital overloading: clipping and
wrap around. It's lots of fun!!

take care
Philip
-- 
Philip Pilgrim                  The Lab Audio Works
5 Evan's Drive                  - Analog/Digital Recording/Processing
Hammonds Plains                 - Computer/Synth Interfacing
Nova Scotia, Canada             - Hardware/Software Development
B4B 1M8

Phone     +1.902.835.7844
Email      mailto:thelab at sprint.ca

Web Page: http://www.robotnik.com/the_lab



From thudson at cygnus.com  Wed Aug 19 21:41:34 1998
From: thudson at cygnus.com (Thomas Hudson)
Date: Wed, 19 Aug 1998 15:41:34 -0400
Subject: Sequencer Update
In-Reply-To: <9808191434.AA09298@qns1.qns.net>
Message-ID: <000c01bdcba9$5f445ff0$2d90e2cd@thudson1.cygnus.com>



> > I originally
> >> planned on using John Simontons 4-bit convert 
> >> http://www.paia.com/ek7.htm
> >
> >Looks interesting !
> >I just wondered how to build a logic for 16 comparators ...
> >but this might be an alternative! Any drawbacks of
> >this design? John?
> >
> 
> None that I can recall. It's a lot simpler than 16 comparators and the 
> logic of a 16/4 encoder, for sure. It's difficult to make the scheme 
> work for greater than 5 or 6 bits, resistor precision gets to be a 
> problem.
>
In the original article you mentioned it had a top end conversion rate of
under 1kHz. Is this something inherent in the design or because of the
comparators (MC3302P) used?

Thomas




From gray at bright.net  Wed Aug 19 22:12:33 1998
From: gray at bright.net (Steve Hanger)
Date: Wed, 19 Aug 1998 16:12:33 -0400
Subject: No subject
Message-ID: <000a01bdcbad$b37aeb80$8699d4cd@hangs>

remove Steve Hanger



From bnillson at hotmail.com  Wed Aug 19 23:31:16 1998
From: bnillson at hotmail.com (Bjarne Nillson)
Date: Wed, 19 Aug 1998 14:31:16 PDT
Subject: A swedish smorgasboard Cv to Gate tutare!
Message-ID: <19980819213120.929.qmail@hotmail.com>

Are there any interest in a new Midi to Cv gate converter 
for a small amount of money???? On this list???

You can find the MCVD8x8 16ch converter at

http://home2.swipnet.se/~w-21314/

I have 2 MCVD8x8 in my analogue modular
since 5months back...

BJ

PS: the converter may be available as a presoldered PCB
(all components included)without a box, you have to solder the 
appropieate conectors your self etc...

______________________________________________________
Get Your Private, Free Email at http://www.hotmail.com



From jhaible at metronet.de  Thu Aug 20 02:03:33 1998
From: jhaible at metronet.de (jhaible)
Date: Thu, 20 Aug 1998 02:03:33 +0200
Subject: AW: Re: Sequencer Update
Message-ID: <19980820000824.3286.qmail@nuernberg2.pop.metronet.de>

>Hi Juergen. This sounds interesting. I was looking at the Superseque
article 
>the other day. Then I thought about improvements that could be made to it.
One 
>such thing would be to add a switch for changing the length of each step. 
>Thomas Henry suggest using one row of pots to control the frequency of the
VCO 
>that clocks the sequencer. But that means you will have to twek them
carefully 
>to get a consistent rhythm. Maybe it would be better to add a thumbwheel
that 
>selected among the most used rhytmic values. Like 1/4, 1/8, 1/6, dotted
4ths, 
>8th triplets and so on. With variable length you can get away with fewer
steps. 

I'll have CV inputs for clock speed and PWM (= relative gate length).
Personally,
I am no fan of quantized triplets etc. For some reason, a straight beat of
1/8s
sounds right to me, but quantized triplets sound funny ...
Nevertheless, one can use a quantizer for this function (1V/8ve is also a
good
CV scale for clock speed !). Or maybe even a gate bus and proper scaling of
the FM
input is enough to switch between 1/8s and 1/4s, for example.
But this whole talk about time control stuff brings me to one important
point:
It's crucial that I can remove (skip) selected rows from the vertical clock
to have them
ready for timing stuff of filter control.

>Then 8 steps might be enough. Otherwise I think 12 is an absolute minimum.
With 
>8 equal steps it will be difficult to get triplets.
I>s this something you have already thought of?

I'm quite sure now that I will go 4x8.
It's easy to make 1x12 from that with a "reset" at stage 7.


> 1) will you be implementing a "stage select" pulse input (maybe just a
4051 to
> the load inputs of the 4516)?

Something like the touch keyboard of the Serge ?
I don't think so.
While I admire the usefullness of the Serge for both, sequencer and
programmer
(and a few more) applications, I will go purely sequencer here. I consider
a single
analogue CV input + DAC for the preset function, as some of you suggested,
so I can set the preset stage# by a potentiometer or external CV. But even
then, I see it as a voltage controlled *jump* function rather than manual
preset.
("jump", because I'll use the preset input similarly as the reset input)
But if someone really wants individual keys, a simple DAC will do to create
the required CV ...
All in all, I find the preset input even more important for the *vertical*
stuff,
to select one of four different patterns on the fly.

> I didn't know about this circuit when I built my sequencer, and
> used the "brute force" 16 comparator + 2 encoders method for my 4bit
> flash ADC. 

Chris, do you have the circuit for this one at hand? Have spent a few
thoughts about
economic encoding, but haven't come up with anything convincing yet. Are
there
speacial chips for that? (Four LM324s, or LM339s, for the comparators is no
problem.)

>Using the "jam inputs" on the counter like this is so easy and
>adds some neat functionality to the sequencer, I highly recommend it.
>Controlling it with an ADSR or a sawtooth wave for example. OTOH, you
>(Juergen) can probably do all the same tricks with the interpolating
>scanner, and do them better that way!

The I.S. has a clear advantage on creating smooth rather than stepped
waveforms. But this sequencer project will be pure pattern generation;
audio rate operation not intended. And selecting sequences (rows that
is ...) with ADSRs of LFOs is a great idea. So I guess I need a 2bit
ADC for selecting the rows even more necessarily than the 4-bit ADC
for the steps ...


> 2) If you use the vertical clock (and you should ; >),

I am pretty convinced that I should do. That's the grat thing on this diy
list,
that you get much more ideas that you have ever thought of yourself ...

And here's another idea of my own which has to do with vertical clocking.
I'll call it "Event Queue".
I already wrote about a delayed, or synced, action of the sequencer to
manual
inputs. Example: I have 4 sequences set up (4 rows), and the 1st is
currently
running. I press a button to change to sequence #2. But it won't jump to #2
immediately (in the midst of one note), but rather wait for an impulse from

currently running sequence. Most obvious choices would be the end of one
full
sequence, or the end of the currently played note, but I'd take it as far
as
I allow any next pulse from a selected gate bus. Just as you set your skip
or reset points, set a "jump" point. So you press a button to tell the
sequencer
that you want to change the pattern, and the sequencer waits for the next
"jump"
event to carry out this order. Implementation is simple, one D-flipflop.

Now you could repeat this manually triggered action to jump into other
sequences,
but the "Event Queue" idea goes a little farther:
You don't press the manual button once before each jump event, but you can
preprogram several jumps in advance. Simply press the manual button
repeatedly,
and a number of logical "1"s are written into a shift register. Every time
the sequencer
runs across a "jump" point, it carries out this jump operation, and clears
one of these
"1"s in the shift register, until all orders are carried out.
This may be of some (limited) use to cycle thru the rows for a limited
number of times,
and then go on reapeating the last sequence. But the real fun starts when
you have 
several "jump" points in one sequence. Then the sequencer might play notes
1 and 2
from row #1, then notes 2, 3 and 4 from row #2, and continue with note 5 of
row #3.
Mixing the notes of several sequences into completely new patterns.


This is only an idea so far. No soldering today - I spent a beautiful day
in Salzburg
(Austria) with my wife instead. Back to the lab tomorrow (;->).

JH.



From 104065.2340 at compuserve.com  Thu Aug 20 03:39:24 1998
From: 104065.2340 at compuserve.com (terry michaels)
Date: Wed, 19 Aug 1998 21:39:24 -0400
Subject: DIY parts
Message-ID: <199808192139_MC2-56A2-2660@compuserve.com>



-------------Forwarded Message-----------------

From:   terry michaels, 
To:     INTERNET:ijfritz at earthlink.net, INTERNET:ijfritz at earthlink.net
        
Date:   8/19/98  8:48 PM

RE:     Re: DIY parts

Ian - -

The gate capacitance issue is really a minor one, I think in most cases it
can be ignored.  The only time it might require consideration is if you
substitute a FET with a lot of capacitance (50 pf or more), or you want a
really perfect sawtooth.

The design of most FETs creates gate capacitance to the source and drain in
equal amounts.  The KE4859 has about 6 pf from the gate to the source, and
6 pf to the drain.  The fast rising gate pulse couples charge into the
input end of the integrator with the ratio 6pf / 2400pf, which is less than
1% error.  This can be ignored.

A bigger problem is the output impedance of the CA3130, which is at least a
few hundred Ohms, and possibly much more, when dealing with a fast pulse. 
An op amp in a closed loop has an output impedance of a fraction of an Ohm
at low frequencies, but rises to hundreds of Ohms at high frequencies,
because the internal gain of the op amp rolls off as you go up in
frequency, eventually reaching zero.  The result with my circuit is the 12
pf gate capacitance raises both the input and the output of the CA3130
together, creating a 2 volt spike on the top of the sawtooth, lasting 0.2
microseconds.  Again, this probably won't affect any practical use for this
VCO, unless you use a different FET with much greater gate capacitance.

The 2N4392 has about 1/3 the leakage current, and about twice the on
resistance of the KE4859.  I think it should work well enough that you
probably wouldn't see any difference if you substituted it.  At worst, you
might have to increase the value of the 18 pf cap across the LM311 a
little, to allow for more discharge time.  I can copy a data sheet for both
FETs and send it to you by snail mail, if you like. 

BTW, I recently found out my VCO has a low level, high frequency
oscillation in the exponential converter section at certain current levels.
 It can be fixed as follows:
* On the LM308, delete the 68 K resistor from pin 2 to +V.
* Change the 1K resistor from pin 2 to ground, to 1.5M (you can make this
smaller if you want, but no smaller than 100K).
* Add a 10pf cap from pin 2 to pin 6.  Make it 50 - 100 pf if you go with a
100K resistor above.
* Change the 6.8K resistor to 2.7K.

Please pass this on to anyone you know that is using this circuit.  My
apologies for not catching this in the beginning.

Terry



From mamundso at mr.net  Thu Aug 20 03:50:14 1998
From: mamundso at mr.net (Mark Amundson)
Date: Wed, 19 Aug 1998 18:50:14 -0700
Subject: audio driver for more current and dual supply
References: <199808191352.PAA19173@window.intermetall.de>
Message-ID: <35DB80D6.18FF@mr.net>

Martin Czech wrote:
> I need a driver that is able to source 200mA to 500mA at audio
> frequency. E.g. reverb coil driver, magnetic  core driver, little
> speaker driver. I had a look at all these TDA audio amps (for car radio
> etc.) but they all use only a single supply. Does somebody know a
> convenient solution that uses both power rails ?  There is a
> possibility to boost a normal op amp, add npn and pnp in collector
> circuit, the driving and biasing is done by the opamp supply pins and
> two restors attached to these.  Anybody tryed this? Any help appreciated.
> m.c.

Consider using a LM1875 Audio Power Amplifier IC. It is made to run on
split supplies and does about 10 watts at 8 ohms with +/- 15 volt rails.
Will run down to 4 ohm loads as well. It draws about 50mA quiescent and
is in a 5 pin TO-220 package for modest heatsinking. I just built a
professional grade headphone amplifier using a pair of these chips.
Plenty of dynamic range and offer good punch on regulated power
supplies.

Mark Amundson,



From 104065.2340 at compuserve.com  Thu Aug 20 03:55:09 1998
From: 104065.2340 at compuserve.com (terry michaels)
Date: Wed, 19 Aug 1998 21:55:09 -0400
Subject: ASM1 ADSR Idea
Message-ID: <199808192155_MC2-56A2-275F@compuserve.com>

Debby, Gene:

I found your recent discussion on using a CMOS NOR gate input  as a level
detector for resetting the flip flop quite interesting, as I did exactly
the same thing back in the old days.  Very simple, and works well, except,
as you noted, you need to set a trim pot to allow for process variations on
the CMOS gate threshold.

Regarding my Electronotes VCO design, I just posted a suggested change to
solve a potential instability in the exponential convertor.  You may have
already found this problem long ago, but if not, you may want to make this
change.

Terry



From jocke at netcontrol.fi  Thu Aug 20 11:21:44 1998
From: jocke at netcontrol.fi (Joachim Verghese)
Date: Thu, 20 Aug 1998 12:21:44 +0300 (EET DST)
Subject: Maxx VCF-7A ARP 4023 Type
In-Reply-To: <yam7536.1531.121416648@mail.vivid.net>
Message-ID: <Pine.LNX.3.95.980820121442.12355B-100000@home.netcontrol.fi>

Hi,

> The VCF-7A is based on the ARP 4O23 4 pole LM39OO lowpass filter.

Nice simplified circuit!

However, I'd like to point out that the LM3900-based ARP filter is
actually the 4075 (4072 for the 2600). The 4023 is a 2-pole biquad
used in the early Oddies.

Schematics for the 4023 and 4075 can be found at my ARP site at
(which desperately needs to be updated -- I'm ashamed...)

http://www.netcontrol.fi/~jocke/arptech/

BTW, you might want to lower those 4K7 resistors for a wider cut-off
range.

cheers,

-joachim  (the ARP police :-)




From tomg at vivid.net  Thu Aug 20 11:30:30 1998
From: tomg at vivid.net (tomg)
Date: Thu, 20 Aug 1998 04:30:30 -0500
Subject: Maxx VCF-7A ARP 4023 Type
Message-ID: <yam7536.1531.121416648@mail.vivid.net>

The VCF-7A is based on the ARP 4O23 4 pole LM39OO lowpass filter.
I have wanted to do the early Odyssey filter for a long time. Thanks
to marjan for sending it to me. The 4O23  has a quality all it's
own you probibly won't be able to hear it from a 8 bit wave file but
you'll get the general idea. I made a few modifications to the original.

Changed the over all bias radically.
Removed the op-amps.
Changed the exp-converter.
Added a resonance loop.

I didn't match anything all transistors were selected at random.
Haven't done the pcb yet, maybe this weekend. I'm kinda burnt out on
the Mad Mouse pcb right now.

http://www.tomg.vivid.net/maxx/page_034.html  - Page
http://www.tomg.vivid.net/maxx/pics/vcf7a.wav - Wave File

-tg




From jhaible at metronet.de  Thu Aug 20 13:58:01 1998
From: jhaible at metronet.de (jhaible)
Date: Thu, 20 Aug 1998 13:58:01 +0200
Subject: AW: Re: Sequencer Update
Message-ID: <19980820152713.14541.qmail@nuernberg2.pop.metronet.de>

>>Personally, I am no fan of quantized triplets etc. For some reason, a
straight 
>beat 
>>of 1/8s sounds right to me, but quantized triplets sound funny ...
>
>You're not into rock n' roll then?

I like prog rock like Gentle Giant and King Crimson. As a listener, that
is.
No way for me to *play* that stuff myself (;->).

As for triplets, I think (and my knowledge of music theory is quite
limited),
that "triplets" are not exact triplets most of the time, but rather
something
in between straight 1/8s and triplets. At least, that's what I read in the
textbooks,
and when I have tried to program triplets on my old "Twelve" program, it
always did 
sound like a one-man-band's automat and not like a rock group.

>Well, if you use a VCO for clocking, you can have a thumbwheel that
selects 
>different points on a voltage divider. That's how I was thinking of doing
it on 
>the Superseque. But then I started thinking about syncing the sequencer to

>other things. Midi clock for example. 
>If you control step length by changing the clock frequency, then will it
not be 
>impossible to sync it? Wouldn't it be better if you ran the VCO at 24
pulses 
>per quarter note and then used dividers to get the different note lengths?
You 
>could still use a thumbwheel to select between different note lengths. In
this 
>case you just would select between the outputs from different dividers.

You're right. It would be hard to sync it. So the 6 or 12 notes sequence
length
would be the way to go. Speaking of sync, don't expect me to include a Midi
or DIN sync. I'm thinking about an envelope extractor / trigger circuit to
derive
clock pulses from a bass track on the tape machine, for example. I've
patched
something like this on my Modular, from a schmitt trigger and a non
retriggerable
AD envelope generator, and it actually works (for friendly input signals).

>By the way, I didn't quite understand what you meant by 8x4. I thought you

>meant 8 steps and four different voltage pots per step. 

>Another thing I thought about on the Superseque is to have a range switch
for 
>the voltage on the pots. 

Yes, that's important. You can't scale it down later, because of the
quantizer.
It must be built in.

JH.



From Chris.List at sc.siemens.com  Thu Aug 20 15:42:21 1998
From: Chris.List at sc.siemens.com (List, Christopher)
Date: Thu, 20 Aug 1998 09:42:21 -0400
Subject: Sequencer Update
Message-ID: <81A062BC5305D111A9D700805F065968CE94DA@maildepo.sc.siemens.com>

> -----Original Message-----
> From:	jhaible [SMTP:jhaible at metronet.de]
> Sent:	Wednesday, August 19, 1998 8:04 PM
> To:	DIY
> Subject:	AW: Re: Sequencer Update
> 
> > I didn't know about this circuit when I built my sequencer, and
> > used the "brute force" 16 comparator + 2 encoders method for my 4bit
> > flash ADC. 
> 
> Chris, do you have the circuit for this one at hand? Have spent a few
> thoughts about economic encoding, but haven't come up with anything
> convincing yet. Are
> there speacial chips for that? (Four LM324s, or LM339s, for the
> comparators is no
> problem.)
> 
	I went through my files last night to see if I had a protobaord
layout for it, but - like most heavy CMOS logic chip circuits, it didn't
lend itself to protoboard very well, so I just did it all on the fly. I
used a FWR in front of the circuit, then four 339's for the comparators.
A chain of (16) 1K resistors + a 20K trimmer set the reference voltages.
The outputs of the 339s go to a pair of CD4532B 8bit encoders, and these
have to get hooked together in a funky way with a quad AND gate in the
middle (I used a MC14071B). The data sheet for the 4532 shows the hook
up.

	This setup clocks the sequencer pretty well way up into the
10kHz range or so - with the big problems for high speeds coming from
the comparator switching time and the shape of the input waveforms.

	As you said, though, I think just a two bit ADC should do it for
you, or maybe three bit to select from your horizontal - either way your
chip count goes way down!

	Have you planned out the Octave + Semitone quantizer yet?
Unfortunately, there doesn't seem to be anyplace online with the full
catalog of 4000 series datasheets (someone please correct me if I'm
wrong) . Harris requires faxing for those chips, and Fairchild doesn't
have everything listed. I'm curious to hear about your part selection
for this, as it's a cool idea. It'd be great if there were something
like 4017 but with 12 stages - that'd make things very easy! Another
thing that would be cool for this would be if you could latch the
12-step counter value with the latch triggers by any of your quantizer
comparators (I assume you'd have one for each row) and run the result to
another mux driving LED's. You could set up the 12 switches along the
bottom of the module in the shape of a little keyboard with LEDs under
each key and see which notes you're playing with your sequence! Talk
about high parts count for the sake of pretty lights! 

C.List
chris.list at sc.siemens.com





From bnillson at hotmail.com  Thu Aug 20 15:49:07 1998
From: bnillson at hotmail.com (Bjarne Nillson)
Date: Thu, 20 Aug 1998 06:49:07 PDT
Subject: A swedish smorgasboard Cv to Gate tutare!
Message-ID: <19980820134907.10991.qmail@hotmail.com>

>On Wed, 19 Aug 1998, Bjarne Nillson wrote:
>> PS: the converter may be available as a presoldered PCB
>> (all components included)without a box, you have to solder the 
>> appropieate conectors your self etc...
>
> It's great to see more DIY alternatives besides Paia's converter...
> The approximated SEK 2500 would be for a fully assembled and boxed 
unit?
> Since that's a bit too pricey for me (as I'm currently thinking about 
a
> possibility to design a converter of my own) I'd be very interested to
> know how much can you come down with the price in this case, that it's
> sold as a partially completed unit? In my opinion you design is quite 
a
> bit more attractive than it's competitors. So, please could you give 
me
> more info about the pricing of this presoldered version?
>
> PS. I had never visited Ricard Wolf's page before, and since I have 
seen
> much of this diy stuff, it was a big surprice! The MiMi-a looks 
stunning
> and very enticing! (I have never felt this way about a poly-synth 
before
> =) )

The wolf's Programable polyphonic synt, is a hell of a synthesiser
ihave played som tunes on it,its amasing..
Lots of people have asked him to go in production including mee..
But unfourtanetly he say's noo.....

he is a very very good programmer to, the software he does are 
unbelivable steady, (that applyes to the MCVD8x8 too.)
He have done some routines to  his poly synt that i have never seen 
before, strange but very usefull for a musican..

The presoldered would be approx 1500skr if i get my fingers
out off my ass to do it....

I have on that i have bult into a SH101,,,nice...

If any one on the list want the MCVD8x8 manual i can E-mail it. its a 
PDF file small to...


BJ


______________________________________________________
Get Your Private, Free Email at http://www.hotmail.com



From Chris.List at sc.siemens.com  Thu Aug 20 15:57:23 1998
From: Chris.List at sc.siemens.com (List, Christopher)
Date: Thu, 20 Aug 1998 09:57:23 -0400
Subject: FS: Big ol' Tek O-Scope, NYC 
Message-ID: <81A062BC5305D111A9D700805F065968CE94DB@maildepo.sc.siemens.com>

Well I had some focus problems with that used 2215A I picked up a couple
of month ago, but the helpful folks on sci.electronics.equipment told me
to replace (6) 510K resistors that tend to go bad in the focus circuit
and now it works like a charm! (sure enough, two if the resistors
measured 1.5M+

So now that I'm comfortable with it's reliability, I'm selling my old
one, and it's available to whomever wants to come to New York to pick it
up (it weighs about 50lbs).

It's a model 561B storage scope, with the following plug ins;
3B2 Horizontal Sweep - working but uncalibrated
3A3 Dual Differential Vertical Amplifier - only one trace currently
working, and needs calibration.
3L5 Spectrum Analyzer - makes wave shapes, but doesn't seem to be
working quite right.

I have the operation / service manuals for everything, and all the tube
driven sections work, so if you know your transistors you should be able
to get it in 100% shape. As it is, it works just fine as a single trace
scope, and the differential inputs are a really nice feature - though
calibration of the vertical amps would've been nice, I never got around
to it. It can also double as a space heater if you've got a cold dorm
room :).

I figure $50 for the whole package is a fair price.

Email or call me @ 212-258-4110

C.List
chris.list at sc.siemens.com




From b.layer at vikingelectronics.com  Thu Aug 20 16:11:01 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Thu, 20 Aug 1998 09:11:01 -0500
Subject: PC sequencing stuff
Message-ID: <3.0.5.32.19980820091101.007b9670@192.168.210.18>

Hi All,

Well, I've gotten to installing my MIDIman MPU-401 in the PS/2, and I've
run into some 'thingy'.

Anyone know the installation procedure for this aged ISA card, under the
Win95 plug-n-play environment? Obviously, Windows doesn't recognise the new
hardware, and I'm not really sure what the manual installation procedure is.

Is it just as simple as arbitrarily picking open IRQ and memory locations,
then installing drivers in Windows? Too easy...

Since this is OT, private emails would probably be the thing.

Thanks,


Bill Layer
"Quantity has a Quality all of it's own." -JL



From sky36919 at skynet.be  Thu Aug 20 18:48:38 1998
From: sky36919 at skynet.be (Hugo Haesaert)
Date: Thu, 20 Aug 1998 18:48:38 +0200
Subject: Waveform morphing...
In-Reply-To: <ISSMTP.1.3(1).19980819091433.4294836231A@Corp.wdc.com>
Message-ID: <199808201648.SAA03125@papagena.skynet.be>

Hi Barry and List !

I remember that a Dutch outfit produced a rack unit with floppy 
drive, computer connection, maybe hard drive, that connected to the 
pcm slot on the Wavestation .  Very sought after unit, consequently 
very expensive s/h .  About same price as AD unit itself :(  Given up 
looking for one, and now i don't even seem to remember it's name, 
hmmm ... :)

Details, anyone ?

Could'nt the K5000 be programmed to do some serious morphing 
manoeuvres ?

Also, check out :

http://www.wiard.com/TSTech.htm

And lets see what the Pulsar/Scope future brings us :)

FWIW

Keep 'em oscillating :)

Hugo
=



From tomg at vivid.net  Thu Aug 20 20:03:14 1998
From: tomg at vivid.net (tomg)
Date: Thu, 20 Aug 1998 13:03:14 -0500
Subject: Correction  Maxx VCF-7A
In-Reply-To: <yam7536.1531.121416648@mail.vivid.net>
Message-ID: <yam7536.740.120351920@mail.vivid.net>

On 20-Aug-98, tomg wrote:
>The VCF-7A is based on the ARP 4O23 4 pole LM39OO lowpass filter.
>I have wanted to do the early Odyssey filter for a long time. Thanks
>to marjan for sending it to me. The 4O23  has a quality all it's
>own you probibly won't be able to hear it from a 8 bit wave file but
>you'll get the general idea. I made a few modifications to the original.

>Changed the over all bias radically.
>Removed the op-amps.
>Changed the exp-converter.
>Added a resonance loop.

>I didn't match anything all transistors were selected at random.
>Haven't done the pcb yet, maybe this weekend. I'm kinda burnt out on
>the Mad Mouse pcb right now.

>http://www.tomg.vivid.net/maxx/page_034.html  - Page
>http://www.tomg.vivid.net/maxx/pics/vcf7a.wav - Wave File

>-tg

Sorry it was late.. 

"The LM3900-based ARP filter is the 4075. The 4023 is a 2-pole 
biquad used in the early Oddies." 

I got busted by the Arp Police..Thanks joachim.

-tg





From LEG at btinternet.com  Thu Aug 20 20:30:33 1998
From: LEG at btinternet.com (george & lorraine)
Date: Thu, 20 Aug 1998 19:30:33 +0100
Subject: P.E. sequencer
Message-ID: <01bdcc68$9e1e68a0$LocalHost@windows95>

Hi all
Has anybod'y out there built the practical electronic's 16 note seque:
Is it viable or not?.Have downloaded article from somewhere!(one day i will organise these schem's!!)
Any comment's welcome.

Live long and prosper

George Bath,uk 
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From tomg at vivid.net  Thu Aug 20 21:06:28 1998
From: tomg at vivid.net (tomg)
Date: Thu, 20 Aug 1998 14:06:28 -0500
Subject: additive
In-Reply-To: <199808130716.JAA02005@window.intermetall.de>
Message-ID: <yam7536.1403.119340024@mail.vivid.net>


Doesn't subtractive refer to the fact that we limit the
content of the sound by using a simple mix or single
waveform then further limit the content by filtering and
occurrence?

It looks like it should be additive because we add voltages
but it fact limit the sound content therfore subtractive is
more correct.

-tg




From honcho at paia.com  Thu Aug 20 21:33:26 1998
From: honcho at paia.com (honcho at paia.com)
Date: Thu, 20 Aug 98 14:33:26 CDT
Subject: Sequencer Update
Message-ID: <9808201933.AA28930@qns1.qns.net>



On Wed, 19 Aug 1998, "Thomas Hudson" <thudson at cygnus.com> wrote:
>In the original article you mentioned it had a top end conversion 
rate of
>under 1kHz. Is this something inherent in the design or because of 
the
>comparators (MC3302P) used?
>
>Thomas
>>>

I thought about this a little and I have to say I honestly don't 
recall. I think probably it was CYA statement to head off those that 
would think of using it for audio. My gut reservations would be that I 
intended using it for CV kinds of things and took no special 
precautions to optimize settling times of the comparators. Also, the 
lack of a strobe of any kind to indicate valid data would be sorely 
missed at high frequencies. 

On another matter: No one hates letting their ignorance hang out worse 
than I do, but sometimes it's the only way to take care of the basic 
problem. At least ignorace is temporary condition :-) What does AW 
mean in a subject line? Re: is obvious, but what is AW?

-John

---------------------------------------------------------
John Simonton                  PAiA Electronics, Inc
3200 Teakwood Ln.              honcho at paia.com
Edmond OK 73013                http://www.paia.com
405-340-6300                   fax 405-340-6378



From Chad_Gould at Jabil.com  Thu Aug 20 22:06:41 1998
From: Chad_Gould at Jabil.com (Chad Gould)
Date: Thu, 20 Aug 1998 16:06:41 -0400
Subject: [Digital_Hell] Doepfer Regelwerk and neo-analog sequencers
Message-ID: <86E399FF181FD211BFF90000F81EE2790CF47A@STPMSG01>

I own one. It is a cool (buggy but beautiful) box. No ms20 hz/v though.
However, the ARP 2600 shoud have no problem. (: 
Just a warning... no song mode and no programmable rests. It functions
best as a drum trigger / one-shot sample trigger device, since a blank
note actually releases the key. However, if you're doing 8-bar Tangerine
Dream style sequences, it's fine. (: 
____________________________________________________
CHAD GOULD
Jabil Circuit, Inc.

> anyone out there own one yet?
> looks like a cool box....  i wonder if the cv outs do ms20
> hz/vt........  i
> have these visions of running samples thru my ms20 and 2600 and
> sequencing
> the modulation...  they keep me awake at night... 8 sequencable cv
> outs
> into a 2600???  holy fuck......  oh, i think it has some faders too.
> ;)



From Barry.L.Klein at wdc.com  Fri Aug 21 01:01:37 1998
From: Barry.L.Klein at wdc.com (Barry L Klein)
Date: Thu, 20 Aug 1998 16:01:37 -0700 (Pacific Daylight Time)
Subject: Waveform morphing...
Message-ID: <ISSMTP.1.3(1).19980820160137.4294836231G@Corp.wdc.com>

This unit is still being manufactured and can be seen on a web site - but
I too don't remember the name of it.  And you're right, the cost is more
than I paid for my AD.  As the connector pinouts are pretty clear in the
service manuals, hardware design isn't the problem - the memory mapping,
PCM conversion, etc. are the issues.

Barry


----------
From: 	SKY36919 at skynet.be
Sent: 	Thursday, August 20, 1998 9:48 AM
To: 	BARRY.L.KLEIN at WDC.COM
Cc: 	SYNTH-DIY at MAILHOST.BPA.NL
Subject: 	Re: Re: Waveform morphing...
.I remember that a Dutch outfit produced a rack unit with floppy 
drive, computer connection, maybe hard drive, that connected to the 
pcm slot on the Wavestation .  Very sought after unit, consequently 
very expensive s/h .  About same price as AD unit itself :(  Given up 
looking for one, and now i don't even seem to remember it's name, 
hmmm ... :)

Details, anyone ?





From random at montrealnet.net  Fri Aug 21 01:32:26 1998
From: random at montrealnet.net (random)
Date: Thu, 20 Aug 1998 19:32:26 -0400
Subject: additive
References: <yam7536.1403.119340024@mail.vivid.net>
Message-ID: <35DCB20A.9C63D96C@montrealnet.net>



tomg wrote:

> Doesn't subtractive refer to the fact that we limit the
> content of the sound by using a simple mix or single
> waveform then further limit the content by filtering and
> occurrence?
>
> It looks like it should be additive because we add voltages
> but it fact limit the sound content therfore subtractive is
> more correct.
>
> -tg

  It is called substractive synthesis become we removed frequencies from
a give wave form.  Filtering the waveform removes frequencies, i guess
you already know that. And since filtering is the basic part of
substractive. I guess its called substractive for that reason.

Anyways... please correct me if Im wrong.

Jim





From tomg at vivid.net  Fri Aug 21 03:59:36 1998
From: tomg at vivid.net (tomg)
Date: Thu, 20 Aug 1998 20:59:36 -0500
Subject: Arp SN-016
Message-ID: <yam7536.1813.120780544@mail.vivid.net>

I was going throught my old Arp service notes looking 
for modifications for the 39OO filter and found this
one for all units on "Line voltage diviations".

Looks as relevant to all synthezizers now as when it 
was written in Feb. '95. Thought I would share it with 
you...:)

http://www.tomg.vivid.net/misc/pd.zip 56K 

contains a (1meg 3000X2000 aprox) windows bitmap scan.

-tg
 




From tomg at vivid.net  Fri Aug 21 04:04:26 1998
From: tomg at vivid.net (tomg)
Date: Thu, 20 Aug 1998 21:04:26 -0500
Subject: Maxx VCF-7A ARP 4075 Type
In-Reply-To: <Pine.LNX.3.95.980820121442.12355B-100000@home.netcontrol.fi>
Message-ID: <yam7536.1320.120780544@mail.vivid.net>

>BTW, you might want to lower those 4K7 resistors for a wider cut-off
>range.

>cheers,

>-joachim  (the ARP police :-)

Ok changed to 2.2K as per joachim and marjan.. Thanks guys.

-tg






From ijfritz at earthlink.net  Fri Aug 21 04:12:27 1998
From: ijfritz at earthlink.net (Ian Fritz)
Date: Thu, 20 Aug 1998 20:12:27 -0600
Subject: DIY parts
References: <199808192138_MC2-56A2-264D@compuserve.com>
Message-ID: <35DCD78B.1A5D18C4@earthlink.net>

Hi Terry --

Thanks for taking the time to answer the questions about the gate
capacitance. I think I have a better handle on what is going on now. 

I found a good web site for FET info -- belonging to the
Temic/Siliconix/Vishay people -- and they had the spec sheets I was
looking for. I was surprised to see they still have the 2N4859 in their
product list! Looking at the 2N4392 family I noticed that the 2N4391
seems like it might be an alternative to the 2N4859. It has only a bit
more resistance, and much less leakage and faster switching. 

They also have MOSFETs designed for high-speed and glitch-free
switching. If you're interested, check out the SD210DE. They also have
an interesting app note AN301. Their site is www.temic.com

As far as the output impedance of the 3130 ... have you ever thought of
not using an active integrator? I notice that the MOOG schematics I
found on the web have the cap just attached between a voltage reference
and the exponential current source. So the ramp starts at Vref and ramps
down to zero, where a comparitor fires the discharge circuit.  

Best regards,

  Ian



From tomg at vivid.net  Fri Aug 21 07:33:42 1998
From: tomg at vivid.net (tomg)
Date: Fri, 21 Aug 1998 00:33:42 -0500
Subject: Arp SN-016
Message-ID: <yam7537.2116.119687872@mail.vivid.net>

On 20-Aug-98, tomg wrote:
>I was going throught my old Arp service notes looking 
>for modifications for the 39OO filter and found this
>one for all units on "Line voltage diviations".

>Looks as relevant to all synthezizers now as when it 
>was written in Feb. '95. Thought I would share it with 
>you...:)

>http://www.tomg.vivid.net/misc/pd.zip 56K 

>contains a (1meg 3000X2000 aprox) windows bitmap scan.

>-tg
> 

>was written in Feb. '95

...I'm slipping these days..must be the heat... '75





From debus at cityweb.de  Fri Aug 21 08:50:02 1998
From: debus at cityweb.de (Ingo Debus)
Date: Fri, 21 Aug 1998 08:50:02 +0200
Subject: Sequencer Update
References: <81A062BC5305D111A9D700805F065968CE94DA@maildepo.sc.siemens.com>
Message-ID: <35DD1897.2225@cityweb.de>

List, Christopher wrote:
> Unfortunately, there doesn't seem to be anyplace online with the full
> catalog of 4000 series datasheets (someone please correct me if I'm
> wrong)

Did you try Philips?
http://www-us.semiconductors.philips.com/search/

Ingo





From debus at cityweb.de  Fri Aug 21 09:41:43 1998
From: debus at cityweb.de (Ingo Debus)
Date: Fri, 21 Aug 1998 09:41:43 +0200
Subject: filter waveform question
References: <3.0.32.19980818195158.0069e33c@206.99.216.1>
Message-ID: <35DD24B1.4278@cityweb.de>

Toni Jovanovski wrote:
> >On a second-order filter (12dB/oct) it is the Q parameter that
> >determines whether the filter is a Butterworth or Chebysheff or
> >whatever.
> 
> Well,I'm not so sure.I'm must check this

Let's look at it this way (correct me if I'm wrong):
The order of a low pass filter is equal to the number of parameters
which can be varied independently. A first order filter has only one
parameter, the cutoff frequency (Juergen mentioned a 6dB/oct filter with
resonance recently, this cannot be a first order filter then). A second
order filter has two parameters, these can be fc and Q. The terms
"Chebysheff" or "Butterworth" etc. describe how much ripple there is in
the pass band. For a second order filter, the "ripple" consists only of
one peak. The height of the peak is controlled by Q. For instance,
Q=0.58 for Bessel, 0.71 for Butterworth, 0.96 for Chebysheff with 1dB
ripple, 1.30 for Chebysheff with 3dB ripple (numbers from
Tietze-Schenk).
A fourth order filter has four independent parameters, although most
synthesizer 24dB/oct VCFs still only have controls for fc and Q. Any
fourth order filter can be made from two second order filters in series.
Thus you have two fc and two Q parameters. Some synths (e.g Yamaha
SY/TG77) have their 24dB/oct filter implemented this way.

> filter.There is a another class of filters FIR  ( finite impulse response
> )filters.I say this because I wanna show how complex is Filter design.It's
> not just electronics...

But FIR filters cannot be made only of resistors, capacitors, inductors
and amplifiers. You need delay lines. Not necessarily digital, BBDs (or
tape echo machines :-)) can also be used. The difference to a
conventional RLC filter is obvious when a square wave is applied to a
FIR low pass: There's not only overshoot after the rising edge but also
"undershoot" *before* it! This can never be achieved with a RLC filter.

> Yes , of course!!!I forgot to mentiot it.When there isn't resonance ( Q )
> the poles are simple ( real numbers ) and when you put resonance , poles
> become complex-conjugate numbers.Changing the Q factor poles are moving in
> complex-plane!

Yes, and because poles are either single real poles or complex-conjugate
pole pairs the number of poles is the number of parameters which can be
varied independently.

Ingo





From debus at cityweb.de  Fri Aug 21 09:52:40 1998
From: debus at cityweb.de (Ingo Debus)
Date: Fri, 21 Aug 1998 09:52:40 +0200
Subject: TL08x as comparator
References: <19980818171754.8555.qmail@nuernberg2.pop.metronet.de>
Message-ID: <35DD2742.EA9@cityweb.de>

jhaible wrote:
> Should be no problem if you take care of the common mode range,
> i.e. don't go near the negative rails with the inputs.

It was many years ago when I experienced a TL0* comparator latching up.
I don't recall what that circuit's function exactly was (a peak
indicator or something). Probably the input voltage exceeded the common
mode range, since the input was driven by another IC powered from the
same +/-15V.

But I do recall that once we found that there were problems we swapped
the TLs and those of one manufacturer latched up while those of another
did not (don't remember which manufacturers).

Ingo





From martin.czech at intermetall.de  Fri Aug 21 11:03:48 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Fri, 21 Aug 1998 11:03:48 +0200 (MET DST)
Subject: transfer function order (was Re: filter waveform question)
Message-ID: <199808210903.LAA08858@window.intermetall.de>

> Let's look at it this way (correct me if I'm wrong):
> The order of a low pass filter is equal to the number of parameters
> which can be varied independently. A first order filter has only one

Sorry I cannot resist, forgive my the following math outbreak:

A linear system has a transfer function that can be writen as:

        b(n)*s^(n) + b(n-1)*s^(n-1) + b(n-2)*s^(n-2) + ... + b(0)*s^0
H(s)=  ---------------------------------------------------------------
        a(m)*s^(m) + a(m-1)*s^(m-1) + a(m-2)*s^(m-2) + ... + a(0)*s^0

You have a numerator polynome NP with coefficients b(n), and a denominator
polynome DP with coefficients a(m). s is the complex frequency.

There are complex frequencys where the NP is zero. These points in the complex
plane are called zeros.

There are complex frequencys where the DP is zero. These points in the complex
plane are called poles.

There exists a so called canonical form or realisation, where you find a
chain of m integrators, the b(n) and a(n) are realised by feedback
resistor values. There are many feedback loops.

Now, the order of a linear system is m, ie. the order of the
denominator polynome, or in other terms the number of integrators.

For real systems n<m, ie. all system have a lowpass characteristic (at
least at 100 GHz ;->).  But for our low frequency  stuff n=m is
possible.

Common lowpass filters (bessel,butterworth, chebychev) have a constant
numerator, ie. n=0.  The only difference between them for a given order
and frequency is different pole location.

There are lp filters (Cauer or eliptical) which employ real zeros os
well, ie. there are frequencys where H(s) drops to zero (notches).
These filters are not often used, but it can be shown that they have
the steepest possible slope of all filters.

Highpass filters have n=m, the common types are derived from above
common lp types by transformation, this gives b(n) != 0 only for n=m,
the other b(n) are zero. This means you have n=m real zeros at s=0,
which leads to the fact that hp filters are closed for low frequency.

Allpass filters have the property n=m and every pole matches to a
corresponding zero, eg. p1=x+jy then z1=x-jy. There are conjugate
complex. This property ensures that |H(s)| = 1, as expected for an
allpass.

Our music circuits (filters) use only very little of the possible 
pole/zero arrangements. 
On the other hand it can be shown, that any H(s) can be reproduced
by chaining or parallel use of second order filters (state variable),
and first order sections (simple RC high or lowpass).

m.c.
 




From martin.czech at intermetall.de  Fri Aug 21 11:11:12 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Fri, 21 Aug 1998 11:11:12 +0200 (MET DST)
Subject: Minimoog Vcf
Message-ID: <199808210911.LAA08878@window.intermetall.de>

> Hi:
> 
> The schematic in question is one that I scanned in.  There were some
> components in error on the original schematic (as compared to other
> schematics) which I corrected; I may have typed in a value that is
> incorrect.  I'll look at my other Minimoog VCF schematics, and see where
> the problem might lie.  I'll keep the list posted.
> 
> Sean Costello
> 

Did I miss the final answer?  It would be very interesting to know, why
the famous circuit won't work after above mentioned schematic. Cause
I'm going to build one in the next time.

Does it make a difference if I take other small signal transistors ? I
mean I've got a 1000 box of BC549C.  Will swapping transistor types give
any audible difference ?


m.c.





From scopey at hooked.net  Fri Aug 21 11:17:44 1998
From: scopey at hooked.net (JBaker)
Date: Fri, 21 Aug 1998 09:17:44 +0000
Subject: job opening in audio electronics field
References: <19980821141210.8964.qmail@hyperreal.org>
Message-ID: <35DD3B37.922595BE@hooked.com>

ok, i DON'T do the hiring, but i DO get a bonus if i submit the resume of
someone who gets hired, so here's some specifics:

the company is in the california bay area;  the position would most likely
involve final testing of studio consoles, therefore, working knowledge of
studio gear is a big plus.  also, you'll need some training or experience with
electronics, troubleshooting & reworking skills are also needed.

it's a good place to work; the company offers some great benefits, flextime,
free coffee (oh boy!)

so, if you're interested please reply directly to me, and i'll fill you in on
the details; also, if you're really serious, i can make myself available to
talk with you, proofread resumes, discuss the types of electronic devices you'd
need to know about, etc.

reply to: scopey at hooked.com
thanks for the bandwidth,
jeff




From pae at ar.com.au  Fri Aug 21 11:59:32 1998
From: pae at ar.com.au (Paul Eccles)
Date: Fri, 21 Aug 1998 19:59:32 +1000
Subject: filter waveform question
Message-ID: <01bdccea$6526d820$0f9412cb@pae.ar.com.au>

>The order of a low pass filter is equal to the number of parameters
>which can be varied independently. A first order filter has only one
>parameter, the cutoff frequency (Juergen mentioned a 6dB/oct filter with
>resonance recently, this cannot be a first order filter then). A second
>order filter has two parameters, these can be fc and Q.

If I have two second order filters and whack them in series, what are the
two new parameters I've just scored?

Also, there are second order filters that give you independent control of
more than two parameters. The Tow Thomas biquad is a good example - cut-off,
Q and gain.

Paul.




From planet4 at swipnet.se  Fri Aug 21 13:11:23 1998
From: planet4 at swipnet.se (Johan Persson)
Date: Fri, 21 Aug 1998 13:11:23 +0200
Subject: Arp SN-016
References: <yam7537.2116.119687872@mail.vivid.net>
Message-ID: <35DD55DB.52960AC8@swipnet.se>

> ...I'm slipping these days..must be the heat... '75


Ever considered moving to Sweden? :)





From jhaible at metronet.de  Fri Aug 21 13:47:54 1998
From: jhaible at metronet.de (jhaible)
Date: Fri, 21 Aug 1998 13:47:54 +0200
Subject: AW: Sequencer Update
Message-ID: <19980821220607.8858.qmail@nuernberg2.pop.metronet.de>

> On another matter: No one hates letting their ignorance hang out worse 
> than I do, but sometimes it's the only way to take care of the basic 
> problem. At least ignorace is temporary condition :-) What does AW 
> mean in a subject line? Re: is obvious, but what is AW?

Hi John,

"AW" is what a German mail program will automaticly place in the subject
line when you press the reply button. Most probably an abbreviation
for "Antwort" (=reply).

JH.



From jhaible at metronet.de  Fri Aug 21 14:10:39 1998
From: jhaible at metronet.de (jhaible)
Date: Fri, 21 Aug 1998 14:10:39 +0200
Subject: Sequencer Update
Message-ID: <19980821220609.8858.qmail@nuernberg2.pop.metronet.de>

Hi Chris,

> to a pair of CD4532B 8bit encoders,

Thank you, that's all I needed. Believe it or not, I didn't know (well,
I've never had a reason to ask, so far) waht these "priority encoder"
chips are good for. Now I know (;->).

Yes, it will be easy for me now, as I don't need more than 3 bits for
8 Steps. One single encoder chip.


> 	Have you planned out the Octave + Semitone quantizer yet?

Nothing more than a week ago. I've made a simulation with 2 cascaded
4017 chips, because PSpice aparently doesn't have a model for
the 4067. A few glitches, but it should work.

> Unfortunately, there doesn't seem to be anyplace online with the full
> catalog of 4000 series datasheets (someone please correct me if I'm
> wrong) . Harris requires faxing for those chips, and Fairchild doesn't
> have everything listed. I'm curious to hear about your part selection
> for this, as it's a cool idea.

I think I will use the 4067, plus a binary counter and some reset logic.

I'm on hollidays this week, and I have borrowed a CMOS data book from
work - this is very helpful.
If memory serves, I have downloaded some CMOS data sheets from 
Motorola, but I don't know if thes are complete.

Speaking of manufacturers, I just recognized that I have a lot of 
stupid HC chips in my drawers. I have ordered them as "4000 series
CMOS", and they are marked "HC40xx", with no "74" in front of the
"HC", and they showed strange behaviour on 15V (;->).
Hey, they *did* work, but when I pulled up an input with a 1meg
resistor, the input was clamped to some 6V ... Removed them all.
Strange that it even worked.

Built the core of the vertical count yesterday.
4516 counter, 4052 mux (one half for row selection, one
half for LEDs)

JH.
 



From ride2619 at ride.ri.net  Fri Aug 21 15:24:35 1998
From: ride2619 at ride.ri.net (Michael J. Barclay de Tolly)
Date: Fri, 21 Aug 1998 09:24:35 -0400
Subject: No subject
Message-ID: <00b801bdcd07$0b1c2160$2fe673c6@ride2619.ride.ri.net>

remove Michael J. Barclay de Tolly
Michael J. Barclay de Tolly
ride2619 at ride.ri.net


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From blacet at metro.net  Fri Aug 21 15:57:21 1998
From: blacet at metro.net (John Blacet)
Date: Fri, 21 Aug 1998 13:57:21 +0000
Subject: FREE PCBs
Message-ID: <35DD7CC1.2FBD@metro.net>

Hi DIYers:

We are closing out the Blacet Micro LFO and while supplies last, each of
you can get one FREE PCB! 

This is a very handy VC triangle wave LFO perfect for cramming into
existing synths or for a modular system; you can never have too many
LFOs! Uses very common parts; works on 5 to 15V. More info at our site,
below.

All we need is $3 for shipping and handling (anywhere on earth the
postal system works).

Limit: one free board per customer. (If you want extras, $5 each, but
you can skip the S&H! (You mean I can get TWO boards for $5 TOTAL? 
--YES.)

The complete kit is still $12; but we are offering FREE shipping and
handling for a limited time. NO limit on the number of Kits you can buy!

Print out your mailing address real neat and send it along with your
order to the address below! We can accept cash, check or MO.

Regards.
-------------------------
LFO Offer
Blacet Research 
15210 Orchard Rd
Guerneville CA 95446
-------------------------
blacet at metro.net
http://metro.net/blacet/music.html



From Chris.List at sc.siemens.com  Fri Aug 21 17:44:57 1998
From: Chris.List at sc.siemens.com (List, Christopher)
Date: Fri, 21 Aug 1998 11:44:57 -0400
Subject: Sequencer Update
Message-ID: <81A062BC5305D111A9D700805F065968CE94E7@maildepo.sc.siemens.com>

Yes, Phillips is "the hot ticket" - thanks Ingo!

BTW, when describing the flash ADC I built I said it used a quad "AND"
gate, sorry, that should've been "OR" (4071).

These Phillips datasheets have some interesting chips for sequencers
that I hadn't noticed before - especially for the quantizer we were
discussing...

The 4520B is a dual async binary counter that could handle the counting
for both the octaves and the semitones. You could make a simple
transistor "AND" circuit with inputs from bits 2 and 3 (counting from 0)
of the semitone counter and the output going to the semitone reset and
the octave counter input - and if 8 octaves was enough of a range, you
could just tie bit 3 of the octave counter back to it's reset, or make
another AND circuit for 10 or 12 octaves...

The 4515B is a 16channel multiplexor (line decoder) with built in latch.
This is the perfect thing for that LED-showing-the-note thing I was
talking about, and also for the semitone decoder. They are almost 30%
cheaper than the 4067 - probably because they are not analog muxes, or
maybe because of the smaller package.

Lastly, the 4754B (18 segment LED driver) would be a cool replacement
for the (4) 339's + resistor ladder in the flash ADC circuit, but I
don't know what the price is and none of my current catalogs carry it.

C.List
chris.list at sc.siemens.com

> -----Original Message-----
> From:	Ingo Debus [SMTP:debus at cityweb.de]
> Sent:	Friday, August 21, 1998 2:50 AM
> To:	DIY
> Subject:	Re: Sequencer Update
> 
> List, Christopher wrote:
> > Unfortunately, there doesn't seem to be anyplace online with the
> full
> > catalog of 4000 series datasheets (someone please correct me if I'm
> > wrong)
> 
> Did you try Philips?
> http://www-us.semiconductors.philips.com/search/
> 
> Ingo
> 



From uzs159 at ibm.rhrz.uni-bonn.de  Fri Aug 21 18:55:30 1998
From: uzs159 at ibm.rhrz.uni-bonn.de (uzs159 at ibm.rhrz.uni-bonn.de)
Date: Fri, 21 Aug 1998 18:55:30 +0200
Subject: Temp. compensated VCO
References: <Pine.LNX.3.96.980819110552.2598B-100000@lyseolukio2.kajaani.fi>
Message-ID: <35DDA682.69CC@ibm.rhrz.uni-bonn.de>

Hi Henri, and list,

Henri Kovalainen wrote:
> 
>  The board pic is now available at
> 
>  http://lyseolukio2.kajaani.fi/~dh/compvco.ps

Great work! Cool! Looks very good. 

>  I found out that (at least in my case, it was around 0.5v) the saw
>  amplitude varied quite much. So you might have to twiddle the feedback
>  resistor (470k) on the buffer amp (which also sums the offset trimmer).

In my original schematics this was a 47k resistor, with this you should 
get about 5Vpp saw amplitude.

>  The squarewave is generated with an op-amp comparator, so purists may
>  find it to be too slacky, but it was good enough for me. I haven't had
>  any latching problems with the comparator, but (supposingly) the
>  compensation amp config has latched a couple of times when I have whacked
>  it with a hard negative pulse from a lfo etc. 

This can indeed happen, if you overdrive the tempco-amp, since there is 
the possibility that some of the opamps can go beyond the common mode 
range. But in "normal" operation (with CVs in the range of 0-15V)
it should not happen.

>Also a small negative spike
>  might be present at the bottom of the saw wave, which didn't bother me,
>  and if I ever design a waveshaper board for this one I'll include a
>  clipping amp that will shave these off. The resistors values it the cv
>  summing amp depend on which way you hook the pitch pots. I didn't connect
>  the arrays leftover tranny to the negative rail (this was suggested in
>  Rene's schematics) which hasn't caused any problems that I'm aware of.
I did it this way, and had no problems.

>  Hop, skip and jump with a wire if you want this to be done. I have used
>  IRF530s instead of BUZ20s too, and they all seem to work properly.

I did use BUZ20, BUZ71 and BS108 and all worked fine. If one doesn't
like MOSFETs as switches one can use BJTs as well.


>  Also, I would like to point out that only proper feedback is appreciated,
>  any criticism or flaming is ignored and therefore futile.
>  If you don't like the design, skip it.
Hehe, yeah ;->

Well I should perhaps point out that there is a minor bug in my 
schematic: (I did recently realize this when reading the archives of 95)
The pins 6 and 2 of the 555 should go to the other end of 
the Hi-freq trimmer TP 2 (otherwise this trimmer is useless).
Fortunately one can change it easy on the board. The trace that 
goes to the upmost terminal of T1 should go to the lowest of TP2.

Two other remarks: I do not see why you changed R25 to 47K. The 
555s reset points are 1/3 and 2/3 of supply voltage this gives about 
5Vpp. It worked for me.
And one should include a small resistor into the V+ supply of the 555
to improve the effect of the 680n buffer caps.
This can be done by putting in a 100 Ohms resistor instead of the wire 
bridge that goes away from C7, and replacing the wire bridge from IC5
to another point that has +15V.

Bye
 -Rene



From oakley at enterprise.net  Fri Aug 21 19:14:57 1998
From: oakley at enterprise.net (Tony Allgood)
Date: Fri, 21 Aug 1998 18:14:57 +0100
Subject: Tek 2225 service manual
Message-ID: <001b01bdcd28$137a25c0$dac348c2@default>

Has anyone got a service manual for a Tektronix 2225 they would like to
share with me? I rang up Tektronix in the UK and was told the service manual
was 230UKP, which is absolutely unbelievable. You can buy a S/H scope for
that. I would like to know how to calibrate mine, since it is a bit old and
needs looking at.

Regards,

Tony Allgood, Cumbria, UK

e-mail: oakley at enterprise.net

Rack mounted Moog VCF module, PCBs arriving very soon. Details ...

http://aupe.phys.andrews.edu/diy_archive/schematics/effects/filter.html






From dbalvage at ptdcs2.ra.intel.com  Fri Aug 21 19:34:38 1998
From: dbalvage at ptdcs2.ra.intel.com (Duane R Balvage)
Date: Fri, 21 Aug 1998 10:34:38 -0700
Subject: TL08x as comparator...
Message-ID: <35DDAFAE.C6D@ptdcs2.intel.com>

Hello all...

I have a Question... Someone mentioned that my design using a TL082

as a comparator was "scary", I think mostly in rererence that it was 

capacitively coupled to the voltage it was comparing. Anyone have a 

better idea of how to do it?:


integrator cap pin (4)     |\
CEM 3394        | |        |+\
   >------------| |--------+  \
                | |        |   \
           +5              |    \___________ square out
            |              |    /
            \     +--------+   /
            /     |        |- /
            \<----+        | /
            /              |/
            \
            |
           ---
            -
The reason for the TL part was for HIGH input impedance - I didn't

want to load down the integrating cap. Should I have just used a

large resistor (~1M ohm) instead of the cap?

(sorry, been awhile since op-amps 101 in college....)

			Anyone...?

		TIA!!

				- Duane


   "That boy's got a mouth like a cannon ... Always shootin' it off..."
                                
                             - Foghorn Leghorn
                      ________________________________
                     / o o oo              o ooo o   /\
       -------------/ ////  Duane R. Balvage   //// / /---------
                   /    _________________________  / /
                  / // / // /// // /// // /// / / / /
                 /___ //////////////////////////_/ /
                 \____\________________________\_\/

                     Intel Corporation, RA1-303
                   Portland Technology Development
       =========================================================

              Phone: (503) 613-8055    FAX: (503) 613-8261
                   E-Mail: dbalvage at ptdcs2.intel.com



From Chris.List at sc.siemens.com  Fri Aug 21 19:39:38 1998
From: Chris.List at sc.siemens.com (List, Christopher)
Date: Fri, 21 Aug 1998 13:39:38 -0400
Subject: Tek 2225 service manual
Message-ID: <81A062BC5305D111A9D700805F065968CE94E9@maildepo.sc.siemens.com>

Tony et. al.,

**THE** person to talk to for Tek manuals is a guy by the name of Deane
Kidd in Oregon. He's a retired Tek engineer. He sells original manuals
for $30 + shipping. 
Deane E. Kidd W7TYR
27270 S.W. Ladd Hill Road
Sherwood, OR 97140
Tel: 1-503-625-7363  

...I got mine from him. I found him in the sci.electronics.repair FAQ,
located here;
http://ftp.cised.unina.it/pub/electronics/REPAIR/

Under the heading "Where can I get Schematics / manuals for..."
	
C.List
chris.list at sc.siemens.com

> -----Original Message-----
> From:	Tony Allgood [SMTP:oakley at enterprise.net]
> Sent:	Friday, August 21, 1998 1:15 PM
> To:	synth diy
> Subject:	Tek 2225 service manual
> 
> Has anyone got a service manual for a Tektronix 2225 they would like
> to
> share with me? I rang up Tektronix in the UK and was told the service
> manual
> was 230UKP, which is absolutely unbelievable. You can buy a S/H scope
> for
> that. I would like to know how to calibrate mine, since it is a bit
> old and
> needs looking at.
> 
> Regards,
> 
> Tony Allgood, Cumbria, UK
> 
> e-mail: oakley at enterprise.net
> 
> Rack mounted Moog VCF module, PCBs arriving very soon. Details ...
> 
> http://aupe.phys.andrews.edu/diy_archive/schematics/effects/filter.htm
> l
> 
> 



From Chris.List at sc.siemens.com  Fri Aug 21 20:06:16 1998
From: Chris.List at sc.siemens.com (List, Christopher)
Date: Fri, 21 Aug 1998 14:06:16 -0400
Subject: Sequencer Update
Message-ID: <81A062BC5305D111A9D700805F065968CE94EA@maildepo.sc.siemens.com>

> The 4515B is a 16channel multiplexor (line decoder) with built in
> latch.
> This is the perfect thing for that LED-showing-the-note thing I was
> talking about, and also for the semitone decoder. They are almost 30%
> cheaper than the 4067 - probably because they are not analog muxes, or
> maybe because of the smaller package.
> 
	Ug. Closer inspection reveals this chip to be Active Lo, rather
than Active High, so unless you're running it off of 0 to -15v supply,
it won't work too well :). 
	Oh well. I think I need a break...

	- CL



From jfoster at lucasdigital.com  Fri Aug 21 20:24:14 1998
From: jfoster at lucasdigital.com (Jeff Foster)
Date: Fri, 21 Aug 1998 11:24:14 -0700
Subject: hyperflanger, seeking info
Message-ID: <35DDBB4E.2EF8D4D2@lucasdigital.com>

I received a Paia hyperflanger from a friend.
I am looking for info on:
power voltages
jack and knob assignment ( no markings on the rack panel ). I
think it was built before Paia made a kit from the original article.

perhaps someone has the instruction sheets some where and could provide
the info.

BTW - also got the Paia parmetric and quadrafuzz ( both have factory
panels w/ labeled
controls.)

thx for any info,
Jeff

--
Jeff Foster 415-662-1254
Unix Systems/Networks - Skywalkersound, LucasDigital Ltd.
"State machines are unnatural"





From chrisc at zetnet.co.uk  Fri Aug 21 22:08:13 1998
From: chrisc at zetnet.co.uk (Chris Crosskey)
Date: Fri, 21 Aug 1998 21:08:13 +0100
Subject: Eek**...900 emails.....
Message-ID: <199808212008.VAA19524@irwell.zetnet.co.uk>

Hi Folks, 
just got back from a break enforced by Robot Wars duties to find 899 mails 
waiting for me....this might take a while guys so hold on in there if you're 
waiting for replies...

chrisc



From planet4 at swipnet.se  Fri Aug 21 22:35:25 1998
From: planet4 at swipnet.se (Johan Persson)
Date: Fri, 21 Aug 1998 22:35:25 +0200
Subject: Wavestation stuff (was Waveform morphing...)
References: <ISSMTP.1.3(1).19980820160137.4294836231G@Corp.wdc.com>
Message-ID: <35DDDA0D.1CE3EB96@swipnet.se>

> This unit is still being manufactured and can be seen on a web site - but
> I too don't remember the name of it.  And you're right, the cost is more
> than I paid for my AD.  As the connector pinouts are pretty clear in the
> service manuals, hardware design isn't the problem - the memory mapping,
> PCM conversion, etc. are the issues.
>
> Barry

There was something about this on Music Machines
(manufacturers/korg/wavestation), called the SAM-1... Check it out!

Johan





From buchanan at qualcomm.com  Sat Aug 22 00:07:23 1998
From: buchanan at qualcomm.com (Buck Buchanan)
Date: Fri, 21 Aug 1998 15:07:23 -0700
Subject: DIY'ers at Burning Man?
Message-ID: <3.0.3.32.19980821150723.01647c30@mage.qualcomm.com>

Hi all,

Pelt me with rocks and garbage for this off-topic post but I was just
wondering if there's any DIY'ers from the list going to Burning Man this
year.  I know there are at least several from Analog Haven.

It'd be great to meet and talk "tech talk" as my old girlfriend used to say.

Take it easy,

Buck
Buck Buchanan  AA-436   x84377
RF Eng. Tech  4GP

"If you had a brain you'd take it out and play with it!"  - Mark Busolaki's
mom after we set the lawn mower on fire.... playing with it -



From jhaible at metronet.de  Sat Aug 22 00:33:55 1998
From: jhaible at metronet.de (jhaible)
Date: Sat, 22 Aug 1998 00:33:55 +0200
Subject: filter waveform question
Message-ID: <19980821232705.10157.qmail@nuernberg2.pop.metronet.de>

> A first order filter has only one
> parameter, the cutoff frequency (Juergen mentioned a 6dB/oct filter with
> resonance recently, this cannot be a first order filter then). 

Right. This was a 4-pole filter with a tap after the 1st stage.

JH.




From jhaible at metronet.de  Sat Aug 22 00:46:16 1998
From: jhaible at metronet.de (jhaible)
Date: Sat, 22 Aug 1998 00:46:16 +0200
Subject: transfer function order (was Re: filter waveform question)
Message-ID: <19980821232723.10157.qmail@nuernberg2.pop.metronet.de>

> Sorry I cannot resist, forgive my the following math outbreak:

Great descriptions, both yours and Ingo's.

> Our music circuits (filters) use only very little of the possible 
> pole/zero arrangements. 

The typical N buffered stages + one feedback loop filters can be described
as "polygon filters", because of their special pole locations.

> On the other hand it can be shown, that any H(s) can be reproduced
> by chaining or parallel use of second order filters (state variable),
> and first order sections (simple RC high or lowpass).

This is right for (ideal) linear filters. In the real world, with things
like
nonlinearity, headroom, and so on, they can sound very different.
Just think about two 2-pole sections in series. You will typically have
one high Q and one low Q partial filter. Which one will be the first stage
?
How does the second stage filter the distortion products, when the
first stage is (ever so slightly) overloaded ?

JH.



From eduni at ucsd.edu  Sat Aug 22 01:49:36 1998
From: eduni at ucsd.edu (Ethan Duni)
Date: Fri, 21 Aug 1998 16:49:36 -0700 (PDT)
Subject: additive
Message-ID: <199808212349.QAA27897@smtp.ucsd.edu>


>> Does this remind you of something? It is the Heisenberg theorem applied
>> to music instead of quantum physics (the math is the same in this
>> case):  time resolution rivals with spectral resolution. If you want
>> good spectral resolution, the window has to be very long, thus time
>> resolution suffers and vice versa.

-specifically:

Delta t * Delta f >= 1/4Pi

.. at least i think that was it; i already returned the book to the library.. 

Ethan




From eduni at ucsd.edu  Sat Aug 22 01:51:01 1998
From: eduni at ucsd.edu (Ethan Duni)
Date: Fri, 21 Aug 1998 16:51:01 -0700 (PDT)
Subject: more analogue additive (fwd)
Message-ID: <199808212351.QAA27953@smtp.ucsd.edu>

>It is probably very difficult to get *good sounding* animation with additive 
>synthesis.

-Kawai K5000.

Ethan




From 104065.2340 at compuserve.com  Sat Aug 22 04:29:33 1998
From: 104065.2340 at compuserve.com (terry michaels)
Date: Fri, 21 Aug 1998 22:29:33 -0400
Subject: DIY parts
Message-ID: <199808212230_MC2-56F3-9C1C@compuserve.com>

> Thanks for taking the time to answer the questions about the gate
> capacitance. I think I have a better handle on what is going on now. 

> I found a good web site for FET info -- belonging to the
> Temic/Siliconix/Vishay people -- and they had the spec sheets I was
> looking for. I was surprised to see they still have the 2N4859 in their
> product list! Looking at the 2N4392 family I noticed that the 2N4391
> seems like it might be an alternative to the 2N4859. It has only a bit
> more resistance, and much less leakage and faster switching. 

Hi Ian

Thanks for the info on the Temic FETs, I'll definately check it out..  I
have their data book here, but I completely forgot about it.

One FET I'm going to investigate is the J310.  It has reasonable on
resistance and gate capacitance.   It is commonly used for RF circuits, and
is available from a number of sources.

> As far as the output impedance of the 3130 ... have you ever thought of
> not using an active integrator? I notice that the MOOG schematics I
> found on the web have the cap just attached between a voltage reference
> and the exponential current source. So the ramp starts at Vref and ramps
> down to zero, where a comparitor fires the discharge circuit.  

I chose the integrator type of design for the following reasons.  First,
the input to the integrator is within a few millivolts of ground potential
at all times.  This allows you to run a ground ring around everything on
the input node: the CA3030 pin 2, one end of the timing cap, the source
lead of the FET, and the collector of the exponential transistor in the
CA3046.  The ground ring eliminates leakage from elsewhere on the PCB into
the integrator, and is highly recommended.  Another advantage is the base
to collector of the exponential transistor is within a few millivolts of 0
volts.  This greatly reduces leakage in the transistor.  All of those
things extend the lower range of the oscillator greatly, with no compromise
to the upper range.  Also the sawtooth ramps up from 0 volts.  The ramp is
perfectly straight. 

The disadvanges of the Moog approach are:  The base to collector voltage of
the exponential transistor is never 0, so transistor leakage current is
much greater.  Also, the transistor has a collector inpedance that is less
than infinity, which means the output current, and the current gain of the
transistor, varies at different points of the sawtooth, which results in a
sawtooth that's not perfectly straight.  It's also tricky to get one end of
the sawtooth to reach zero, so greater level shifting is needed. 

Either design gives good performance, neither is a truly perfect design. 
The choice between the two is ultimately a personal one.  This is true for
nearly anything in an analog synth, there are usually many ways of
designing any one module.

Terry



From tadej.bozicko at uni-mb.si  Sat Aug 22 09:36:50 1998
From: tadej.bozicko at uni-mb.si (Tadej Bozicko)
Date: Sat, 22 Aug 1998 09:36:50 +0200
Subject: Again VCO's and exp. converters!
Message-ID: <01bdcd9f$a03405e0$0100007f@localhost>

Hi!
 
I just finished my first VCO on a protoboard and I actually works :)))! It is really a prototype because I haven't decided, which IC I will use for exp. converter. I'm thinking of CA3046 (currently CA3086) with heater, because this is cheap solution. The second option would be LM394/MAT-02. How much is the second design better (for exp. conv)? I've seen that heated CA3046 VCO leave out tempco's. What about heated LM394 (Rick Jensen's design)? Any recommendations will be appreciated! Anyone compared the designs side by side? I would like to choose the most stable design before I begin to work on a PCB. 
The second question is: what exactly does the SOFT SYNC option? Theoretical explanation wanted, not just that it provides more complex waveforms that single oscillator and that it requires two of them (osc's). 
 
Control the voltage!
 
Tadej Bozicko
E-Mail   : tadej.bozicko at uni-mb.si
WWW  : http://imola.uni-mb.si/~bozicko
WWW2: http://www.uni-mb.si/~uelelt68b
 
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From siforte at ix.netcom.com  Sat Aug 22 10:04:01 1998
From: siforte at ix.netcom.com (siforte at ix.netcom.com)
Date: Sat, 22 Aug 1998 03:04:01 -0500 (CDT)
Subject: job opening in audio electronics field
Message-ID: <v02140b00b203c207485f@[204.31.233.69]>

At 9:17 AM 8/21/98, JBaker wrote:
>ok, i DON'T do the hiring, but i DO get a bonus if i submit the resume of
>someone who gets hired, so here's some specifics:
-------
Hi,

Is this Euphonix?

Sanford





From debus at cityweb.de  Sat Aug 22 11:30:22 1998
From: debus at cityweb.de (Ingo Debus)
Date: Sat, 22 Aug 1998 11:30:22 +0200
Subject: TL08x as comparator...
References: <35DDAFAE.C6D@ptdcs2.intel.com>
Message-ID: <35DE8FAA.7DA4@cityweb.de>

Duane R Balvage wrote:
> 
> Hello all...
> I have a Question... Someone mentioned that my design using a TL082
> as a comparator was "scary", I think mostly in rererence that it was
> capacitively coupled to the voltage it was comparing. Anyone have a
> better idea of how to do it?:

Ooops... sorry! I forgot to answer to your first mail.
I thought this was scary, because there could be some DC creeping to the
opamp's input, maybe through some dirt on the PCB or whatever. Since
both the capacitor and the TL's input have really high dc impedance a
parasitic impedance of many megohms can cause severe offsets.
Why not connect the opamp directly to the point you get your signal
from? If the signal is inside the TL's common mode range (as JH
mentioned) you can compensate the DC offset with the voltage applied to
the - input.

> The reason for the TL part was for HIGH input impedance - I didn't
> want to load down the integrating cap.

If it works this way, I'd stay with the TL. Never change a running
system :-)
But do you really need *that* high impedance? The input current of a
LM393 comparator is also pretty low (25nA typ, 250nA max).

Ingo





From jhaible at metronet.de  Sat Aug 22 13:39:08 1998
From: jhaible at metronet.de (jhaible)
Date: Sat, 22 Aug 1998 13:39:08 +0200
Subject: DIY parts
Message-ID: <19980822225730.27934.qmail@nuernberg2.pop.metronet.de>

> I chose the integrator type of design for the following reasons. 

Good reasons indeed, and I won't question them.

But still, a few points to add:
(1)You could use a guard ring without a virtual gnd node, too.
Connect it to the buffer output instead.
(2) You can use an extra transistor for a cascode configuration
if you want to keep the cb voltage of the expo converter's transistor
low. This will also help making a high output impedance.
Korg used an extra FET for this cascode configuration in some of
their VCOs. (Expo converter from dual npn, output drives FET with
base grounded, discharge circuit is a thyristor built from discrete 
npn's and pnp's, and buffer is another FET. 
I do *not* know how good this performs, but I thought I should mention it.

JH.




From urekar.m at EUnet.yu  Sat Aug 22 13:49:00 1998
From: urekar.m at EUnet.yu (<<marjan>>)
Date: Sat, 22 Aug 1998 13:49:00 +0200
Subject: DIY parts
References: <199808212230_MC2-56F3-9C1C@compuserve.com>
Message-ID: <35DEB02C.17EF@eunet.yu>

> I chose the integrator type of design for the following reasons.  First,
> the input to the integrator is within a few millivolts of ground potential
> at all times.  This allows you to run a ground ring around everything on
> the input node: the CA3030 pin 2, one end of the timing cap, the source
> lead of the FET, and the collector of the exponential transistor in the
> CA3046.  The ground ring eliminates leakage from elsewhere on the PCB into
> the integrator, and is highly recommended.  Another advantage is the base
> to collector of the exponential transistor is within a few millivolts of 0
> volts.  This greatly reduces leakage in the transistor.  All of those
> things extend the lower range of the oscillator greatly, with no compromise
> to the upper range.  Also the sawtooth ramps up from 0 volts.  The ramp is
> perfectly straight.


Excuse me for my ignorance, but what circuit is in question as
it seems that I missed something.Is it online ?


marjan



From urekar.m at EUnet.yu  Sat Aug 22 13:49:21 1998
From: urekar.m at EUnet.yu (<<marjan>>)
Date: Sat, 22 Aug 1998 13:49:21 +0200
Subject: Minimoog Vcf
References: <199808210911.LAA08878@window.intermetall.de>
Message-ID: <35DEB041.D22@eunet.yu>

Martin Czech wrote:

> Did I miss the final answer?  It would be very interesting to know, why
> the famous circuit won't work after above mentioned schematic. Cause
> I'm going to build one in the next time.

Well,I found that R20 resistor from Q6 emitter to -10 is 100k not 220k
And +10V should go not to col. of Q6 but to other side 
of R6 47ohm resistor and + node of C9 100uF ? 
Not shure about that last but if you look at moogmodular vcf, it 
looks like that.

> 
> Does it make a difference if I take other small signal transistors ? I
> mean I've got a 1000 box of BC549C.  Will swapping transistor types give
> any audible difference ?

I doubt.


marjan



From debus at cityweb.de  Sat Aug 22 14:05:35 1998
From: debus at cityweb.de (Ingo Debus)
Date: Sat, 22 Aug 1998 14:05:35 +0200
Subject: filter waveform question
References: <01bdccea$6526d820$0f9412cb@pae.ar.com.au>
Message-ID: <35DEB40E.2E80@cityweb.de>

Paul Eccles wrote:
> If I have two second order filters and whack them in series, what are the
> two new parameters I've just scored?

You have two fc and two Q parameters, giving a total of four independent
parameters.

> Also, there are second order filters that give you independent control of
> more than two parameters. The Tow Thomas biquad is a good example - cut-off,
> Q and gain.

Yes, filter gain is another parameter of course. I omitted that because
gain only contributes to the level, not to the waveform. But, if gain is
included, the number of independent parameters is filter order plus 1.

Ingo





From pfperry at melbpc.org.au  Sat Aug 22 14:50:47 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Sat, 22 Aug 1998 22:50:47 +1000 (EST)
Subject: seeking dual linear concentric pots w/knobs
Message-ID: <1.5.4.16.19970114052409.3897d742@popa.melbpc.org.au>

Looking for dual linear pots with concentric knobs
That is, like a balance/vol knob on an old car radio,
not a stereo kind of thing.
I havn't put enough holes in an effect (suprise!)
and I dont want to do something really horrible like
have a knob change mode when half way around....

paul perry melbourne australia




From magnus at analogue.org  Sat Aug 22 15:18:14 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Sat, 22 Aug 1998 15:18:14 +0200
Subject: filter waveform question
In-Reply-To: Your message of "Fri, 21 Aug 1998 09:41:43 +0200"
References: <35DD24B1.4278@cityweb.de>
Message-ID: <199808221318.PAA21755@piraya.electrum.kth.se>

>>>>> "ID" == Ingo Debus <debus at cityweb.de> writes:

Hi!

As there where talk about filters I could not resist to interfear...

 ID> Toni Jovanovski wrote:
 >> >On a second-order filter (12dB/oct) it is the Q parameter that
 >> >determines whether the filter is a Butterworth or Chebysheff or
 >> >whatever.
 >> 
 >> Well,I'm not so sure.I'm must check this

 ID> Let's look at it this way (correct me if I'm wrong):
 ID> The order of a low pass filter is equal to the number of parameters
 ID> which can be varied independently. A first order filter has only one
 ID> parameter, the cutoff frequency (Juergen mentioned a 6dB/oct filter with
 ID> resonance recently, this cannot be a first order filter then). A second
 ID> order filter has two parameters, these can be fc and Q. The terms
 ID> "Chebysheff" or "Butterworth" etc. describe how much ripple there is in
 ID> the pass band. For a second order filter, the "ripple" consists only of
 ID> one peak. The height of the peak is controlled by Q. For instance,
 ID> Q=0.58 for Bessel, 0.71 for Butterworth, 0.96 for Chebysheff with 1dB
 ID> ripple, 1.30 for Chebysheff with 3dB ripple (numbers from
 ID> Tietze-Schenk).
 ID> A fourth order filter has four independent parameters, although most
 ID> synthesizer 24dB/oct VCFs still only have controls for fc and Q. Any
 ID> fourth order filter can be made from two second order filters in series.
 ID> Thus you have two fc and two Q parameters. Some synths (e.g Yamaha
 ID> SY/TG77) have their 24dB/oct filter implemented this way.

The order is strictly connected to the number of poles, not the dB/oct
number not the number of parameters. The number of parameters is
actually greater than the number of poles, it is up to about the
double. The reason for this is that you can have zero's that also can
be varied. One example of this is the fully parametric equalizer which
uses a 2-pole filter but has three variable properties (Frequency,
width and amplification grade). The parametric equalizer use a balance
between the 2 poles and 2 zeros. The poles and zeroes have the same
frequency but their relative distance to eachother controls the
amplification and the distance of them from the jw-axis controls the
width. So, the number of variable parameters is a bad measure.
For larger filters one changes a number of paramters in bulk.

Bessel, Chebychev, Butterworth, Gauss, LaGrange etc. are all diffrent
approximations to the brickwall idealized model of a filter. These
approximations have their respective properties (Butterworth have a
maximum flat frequency response, Besselhave a maximum flat groupdelay
etc).

 >> filter.There is a another class of filters FIR  ( finite impulse response
 >> )filters.I say this because I wanna show how complex is Filter design.It's
 >> not just electronics...

 ID> But FIR filters cannot be made only of resistors, capacitors, inductors
 ID> and amplifiers. You need delay lines. Not necessarily digital, BBDs (or
 ID> tape echo machines :-)) can also be used. The difference to a
 ID> conventional RLC filter is obvious when a square wave is applied to a
 ID> FIR low pass: There's not only overshoot after the rising edge but also
 ID> "undershoot" *before* it! This can never be achieved with a RLC filter.

Well, you *can* make FIR filters which has both pre and post
ringing. The possibilities for preringing is as large for any
filtering concept, they start when the signal enters the filter. The
postringing effect will strictly end at a certain point in time for
FIR filters (thus the name Finite Impulse Responce) where as IIR
(Infinite Impulse Responce) and normal analog filters can
theoretically go on forever (where they in reality would disintegrate
or the signal be swallowed in the noise).

 >> Yes , of course!!!I forgot to mentiot it.When there isn't resonance ( Q )
 >> the poles are simple ( real numbers ) and when you put resonance , poles
 >> become complex-conjugate numbers.Changing the Q factor poles are moving in
 >> complex-plane!

 ID> Yes, and because poles are either single real poles or complex-conjugate
 ID> pole pairs the number of poles is the number of parameters which can be
 ID> varied independently.

Well, no... a pole is allways resonant! The real poles are only
resonant at DC for some exponential change. DC is as much as a
frequency as 440 Hz or 1 kHz in theory.

The resonance (Q) property is the real component of any pole
position. A resonant filter normally has one or two poles near the
jw-axis (and thus appears resonant for stable sines) where as the
others will make more subtle changes in the sound.

There are many measures on filters, many which are more or less
derivate properties on the pole and zero positions of the filter. Some
measures seems like generically correct where they may only hold for a
very tight frequency range for instance. The dB/oct measure is
sometimes a very confusing term where it may be a good term for some
cases, it is a derivate property and not a real direct property.

Cheers,
Magnus



From 104065.2340 at compuserve.com  Sat Aug 22 15:26:23 1998
From: 104065.2340 at compuserve.com (terry michaels)
Date: Sat, 22 Aug 1998 09:26:23 -0400
Subject: DIY parts
Message-ID: <199808220926_MC2-5702-6E96@compuserve.com>



-------------Forwarded Message-----------------

From:	"<<<marjan>>>", INTERNET:urekar.m at EUnet.yu
To:	[unknown], INTERNET:synth-diy at mailhost.bpa.nl
	
Date:	8/22/98  6:56 AM

RE:	Re: DIY parts

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> I chose the integrator type of design for the following reasons.  First,
> the input to the integrator is within a few millivolts of ground potential
> at all times.  This allows you to run a ground ring around everything on
> the input node: the CA3030 pin 2, one end of the timing cap, the source
> lead of the FET, and the collector of the exponential transistor in the
> CA3046.  The ground ring eliminates leakage from elsewhere on the PCB into
> the integrator, and is highly recommended.  Another advantage is the base
> to collector of the exponential transistor is within a few millivolts of 0
> volts.  This greatly reduces leakage in the transistor.  All of those
> things extend the lower range of the oscillator greatly, with no compromise
> to the upper range.  Also the sawtooth ramps up from 0 volts.  The ramp is
> perfectly straight.


Excuse me for my ignorance, but what circuit is in question as
it seems that I missed something.Is it online ?


marjan



From magnus at analogue.org  Sat Aug 22 15:38:44 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Sat, 22 Aug 1998 15:38:44 +0200
Subject: transfer function order (was Re: filter waveform question)
In-Reply-To: Your message of "Fri, 21 Aug 1998 11:03:48 +0200 (MET DST)"
References: <199808210903.LAA08858@window.intermetall.de>
Message-ID: <199808221338.PAA21909@piraya.electrum.kth.se>

>>>>> "MC" == Martin Czech <martin.czech at intermetall.de> writes:

 >> Let's look at it this way (correct me if I'm wrong):
 >> The order of a low pass filter is equal to the number of parameters
 >> which can be varied independently. A first order filter has only one

 MC> Sorry I cannot resist, forgive my the following math outbreak:

You to... ah well :)

 MC> A linear system has a transfer function that can be writen as:

 MC>         b(n)*s^(n) + b(n-1)*s^(n-1) + b(n-2)*s^(n-2) + ... + b(0)*s^0
 MC> H(s)=  ---------------------------------------------------------------
 MC>         a(m)*s^(m) + a(m-1)*s^(m-1) + a(m-2)*s^(m-2) + ... + a(0)*s^0

 MC> You have a numerator polynome NP with coefficients b(n), and a denominator
 MC> polynome DP with coefficients a(m). s is the complex frequency.

 MC> There are complex frequencys where the NP is zero. These points in the complex
 MC> plane are called zeros.

 MC> There are complex frequencys where the DP is zero. These points in the complex
 MC> plane are called poles.

All this is very true...

 MC> There exists a so called canonical form or realisation, where you find a
 MC> chain of m integrators, the b(n) and a(n) are realised by feedback
 MC> resistor values. There are many feedback loops.

 MC> Now, the order of a linear system is m, ie. the order of the
 MC> denominator polynome, or in other terms the number of integrators.

 MC> For real systems n<m, ie. all system have a lowpass characteristic (at
 MC> least at 100 GHz ;->).  But for our low frequency  stuff n=m is
 MC> possible.

In a way we should be happy that our hearing is so frequency limited
(20Hz-20kHz) since this allows many tricks that simply is not
available to designers working with GHz and above. The higher
frequency you use the more you learn about how the real aspects of
physical laws starts kicking in.

 MC> There are lp filters (Cauer or eliptical) which employ real zeros os
 MC> well, ie. there are frequencys where H(s) drops to zero (notches).
 MC> These filters are not often used, but it can be shown that they have
 MC> the steepest possible slope of all filters.

However, in musical cursuits we see a diffrent form of these filters,
they apear in EQs, phasers, flangers, choruses etc. They all use a
combination of poles and zeros to achieve their effect.

 MC> Allpass filters have the property n=m and every pole matches to a
 MC> corresponding zero, eg. p1=x+jy then z1=x-jy. There are conjugate
 MC> complex. This property ensures that |H(s)| = 1, as expected for an
 MC> allpass.

The allpass property is in reality a lowfrequency or bandwidth limited
property which we can fake efficiently good in audio. The property is
also only valid for stable sines where as sines with changine
amplitude will not experience a flat frequency responce.

 MC> Our music circuits (filters) use only very little of the possible 
 MC> pole/zero arrangements. 
 MC> On the other hand it can be shown, that any H(s) can be reproduced
 MC> by chaining or parallel use of second order filters (state variable),
 MC> and first order sections (simple RC high or lowpass).

I agree that music circuits use a very little part of the possible
solutionspace of pole/zero arrangements. One limiting factor for
making large and complex filters is it's noise property and stability
in pole/zero positions. Such analysis will be a major effort for any
larger H(s) realization, more complex structures may be used for
optimal performance (The standard Sallen-Key is not cutting it very
well).

Cheers,
Magnus






From magnus at analogue.org  Sat Aug 22 16:29:18 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Sat, 22 Aug 1998 16:29:18 +0200
Subject: Sequencer Update
In-Reply-To: Your message of "Fri, 21 Aug 1998 14:10:39 +0200"
References: <19980821220609.8858.qmail@nuernberg2.pop.metronet.de>
Message-ID: <199808221429.QAA22151@piraya.electrum.kth.se>

>>>>> "j" == jhaible  <jhaible at metronet.de> writes:

 j> Nothing more than a week ago. I've made a simulation with 2 cascaded
 j> 4017 chips, because PSpice aparently doesn't have a model for
 j> the 4067. A few glitches, but it should work.

Some very small glitches is to be expected anyways, a simple lowpass
filter could remove these glitches without greatly interfering with
the function. 

 >> Unfortunately, there doesn't seem to be anyplace online with the full
 >> catalog of 4000 series datasheets (someone please correct me if I'm
 >> wrong) . Harris requires faxing for those chips, and Fairchild doesn't
 >> have everything listed. I'm curious to hear about your part selection
 >> for this, as it's a cool idea.

Check out Philips, and you should get them from Motorola as well.
I also think National has them...

 j> I think I will use the 4067, plus a binary counter and some reset logic.

 j> I'm on hollidays this week, and I have borrowed a CMOS data book from
 j> work - this is very helpful.

I don't know how I would survive without my RCA CMOS databook from
early 80thies.

Cheers,
Magnus



From ka4hjh at gte.net  Sat Aug 22 18:12:49 1998
From: ka4hjh at gte.net (KA4HJH)
Date: Sat, 22 Aug 1998 12:12:49 -0400
Subject: Tek 2225 service manual
In-Reply-To:  <81A062BC5305D111A9D700805F065968CE94E9@maildepo.sc.siemens.com>
Message-ID: <v04011700b2049ddf0570@[153.37.233.75]>

>Tony et. al.,
>
>**THE** person to talk to for Tek manuals is a guy by the name of Deane
>Kidd in Oregon. He's a retired Tek engineer. He sells original manuals
>for $30 + shipping.
>Deane E. Kidd W7TYR

Note the suffix. Don't they have hamfests in the UK? 230UKP is highway robbery.

Terry Bowman, KA4HJH
"The Mac Doctor"



From dave at mail.kc.net  Sat Aug 22 18:53:51 1998
From: dave at mail.kc.net (Dave)
Date: Sat, 22 Aug 1998 11:53:51 -0500
Subject: hyperflanger, seeking info
In-Reply-To: <35DDBB4E.2EF8D4D2@lucasdigital.com>
Message-ID: <3.0.1.32.19980822115351.00b7c718@mail.kc.net>

I assume you've been to www.paia.com, and/or emailed John Simonton?

That's probably your best bet.  :-)  

Dave

At 11:24 AM 8/21/98 -0700, Jeff Foster wrote:
>I received a Paia hyperflanger from a friend.
>I am looking for info on:
>power voltages
>jack and knob assignment ( no markings on the rack panel ). I
>think it was built before Paia made a kit from the original article.
>
>perhaps someone has the instruction sheets some where and could provide
>the info.
>
>BTW - also got the Paia parmetric and quadrafuzz ( both have factory
>panels w/ labeled
>controls.)
>
>thx for any info,
>Jeff
>
>--
>Jeff Foster 415-662-1254
>Unix Systems/Networks - Skywalkersound, LucasDigital Ltd.
>"State machines are unnatural"
>
>
>
Dave in KCMO USA
dave at o2.net
http://www.o2.net/~dave/




From LEG at btinternet.com  Sat Aug 22 22:59:25 1998
From: LEG at btinternet.com (george & lorraine)
Date: Sat, 22 Aug 1998 21:59:25 +0100
Subject: seeking dual linear concentric pots w/knobs
Message-ID: <01bdce0f$bee434e0$LocalHost@windows95>


-----Original Message-----
From: Paul Perry <pfperry at melbpc.org.au>
To: synth-diy at mailhost.bpa.nl <synth-diy at mailhost.bpa.nl>
Date: 22 August 1998 15:16
Subject: seeking dual linear concentric pots w/knobs


>Looking for dual linear pots with concentric knobs
>That is, like a balance/vol knob on an old car radio,
>not a stereo kind of thing.
>I havn't put enough holes in an effect (suprise!)
>and I dont want to do something really horrible like
>have a knob change mode when half way around....
>
>paul perry melbourne australia
>
Hi Paul
Now that's a DAMM good question.I have been looking for a source for these
thing's for a while (i use a lot of test kit ,scopes,psu's)with these types
of pot's and figured they would be cool for a sequencer layout(16 pot's in 8
holes!!!).I even took a dual psu half to bit's one lunchtime,at work,to
gleem some info but no joy!
We may be enlightened!!!

Live long and prosper

George,Bath,uk





From cmacdon at ix.netcom.com  Sat Aug 22 23:37:12 1998
From: cmacdon at ix.netcom.com (Christopher MacDonald)
Date: Sat, 22 Aug 1998 14:37:12 -0700
Subject: ASM-1 VCF breadboarded using +/-12 volts
Message-ID: <35DF3A08.4720@ix.netcom.com>

Hi all,

I wanted to take a break from the diode filter for a while so I decided
to try breadboarding an ASM-1 state variable filter.  After some
struggle (fried a 3080 somehow) I have it fairly well tamed.  In order
to make it work with a +/- 12 volt supply I had to change R21 and R26 to
1k as well as making R23  and R28 10k.  These values were arrived at
empirically so I can't vouch for their theoretical correctness.

The only problem I am having now is that, with moderate resonance
settings, I can't put more than about a 0.4 volt peak-to-peak wave
through the filter without some fairly ugly distortion.  Does anyone
know if this is typical or is there some other modification I need to
make?

If it is normal, I am considering increasing the input resistor value
and giving the output op-amp buffers some amplification.

Any advice would be appreciated.  I would really like to complete a new
module sometime soon!  :-)

-Chris MacDonald



From jhaible at metronet.de  Sun Aug 23 01:08:58 1998
From: jhaible at metronet.de (jhaible)
Date: Sun, 23 Aug 1998 01:08:58 +0200
Subject: seeking dual linear concentric pots w/knobs
Message-ID: <19980822232801.28616.qmail@nuernberg2.pop.metronet.de>

> I havn't put enough holes in an effect (suprise!)
> and I dont want to do something really horrible like
> have a knob change mode when half way around....

Don't want to talk you into something, but using a knob
for different functions cw and ccw from 12 o clock position
is not *that* bad. I used it on my JH-4 Polysynth all the time.
It was very importsnt for me to have many functions from a restricted
number of knobs, as I will have a full set of knobs for each voice
(like OB Four Voice). The only problem was to find functions
that are unlikely to be activated at the same time ...

JH.



From ijfritz at earthlink.net  Sun Aug 23 06:15:49 1998
From: ijfritz at earthlink.net (Ian Fritz)
Date: Sat, 22 Aug 1998 22:15:49 -0600
Subject: DIY parts
References: <19980822225730.27934.qmail@nuernberg2.pop.metronet.de>
Message-ID: <35DF9775.FC911E93@earthlink.net>

Jeurgen --

Are the Korg schematics up anywhere? I don't recall running into them.
Thanks.

  Ian

jhaible wrote:

> (2) You can use an extra transistor for a cascode configuration
> if you want to keep the cb voltage of the expo converter's transistor
> low. This will also help making a high output impedance.
> Korg used an extra FET for this cascode configuration in some of
> their VCOs. (Expo converter from dual npn, output drives FET with
> base grounded, discharge circuit is a thyristor built from discrete
> npn's and pnp's, and buffer is another FET.
> I do *not* know how good this performs, but I thought I should mention it.



From ijfritz at earthlink.net  Sun Aug 23 06:21:45 1998
From: ijfritz at earthlink.net (Ian Fritz)
Date: Sat, 22 Aug 1998 22:21:45 -0600
Subject: DIY parts
References: <199808212230_MC2-56F3-9C1C@compuserve.com>
Message-ID: <35DF98D9.710C8B8A@earthlink.net>

Terry --

So do you think you'll be staying with the 3130? I haven't come across
many other good high speed, low offset, low bias devices. Maybe the
Burr-Brown OPA132?

  Ian

terry michaels wrote:

> I chose the integrator type of design for the following reasons...



From pfperry at melbpc.org.au  Sun Aug 23 08:24:18 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Sun, 23 Aug 1998 16:24:18 +1000 (EST)
Subject: seeking dual linear concentric pots w/knobs
Message-ID: <1.5.4.16.19970114225738.3077f8f0@popa.melbpc.org.au>

At 01:08 AM 23/08/98 +0200, you wrote:

>Don't want to talk you into something, but using a knob
>for different functions cw and ccw from 12 o clock position
>is not *that* bad. 

....well I agree, it's just the added ckt complexity!

paul perry melb aust




From gur-m at internet-zahav.net  Sun Aug 23 07:04:31 1998
From: gur-m at internet-zahav.net (Gur Milstein)
Date: Sun, 23 Aug 1998 07:04:31
Subject: analog seq pot's
Message-ID: <3.0.2.16.19980823070431.2b07c252@mail.internet-zahav.net>

hi guy's.
as i'm gone fenish my analog seq i would like to know
which kind of pots are most recomended for it.
cermet,carbon,conductive plastic ?
the seq is 4/16 so ther are lots of pots and if i go Spectrol
that well be lots of $,but if i go carbon i think that drift
well be a problem,so what you guy's say ?

thanx
Gur Milstein



From gur-m at internet-zahav.net  Sun Aug 23 07:04:42 1998
From: gur-m at internet-zahav.net (Gur Milstein)
Date: Sun, 23 Aug 1998 07:04:42
Subject: tempco
Message-ID: <3.0.2.16.19980823070442.2b07498a@mail.internet-zahav.net>

hi guy's.
i'm thinking of buying a large contete of KRL tempco
for my use and for sale to you guy's that need them
for the ASM-1 and other stuff,i would like to know
how many of you need them ?
please reply privetly.

thanx
Gur Milstein



From gur-m at internet-zahav.net  Sun Aug 23 07:04:50 1998
From: gur-m at internet-zahav.net (Gur Milstein)
Date: Sun, 23 Aug 1998 07:04:50
Subject: quantizer pcb
Message-ID: <3.0.2.16.19980823070450.2a0f1632@mail.internet-zahav.net>

do any body know if ther is any pcb layout for a quantizer,
did any body did one ?

thanx
Gur Milstein



From yoh212 at lulu.acns.nwu.edu  Sun Aug 23 10:44:04 1998
From: yoh212 at lulu.acns.nwu.edu (Yoshiki Ohmura (Yoshi))
Date: Sun, 23 Aug 1998 03:44:04 -0500 (CDT)
Subject: LFO -> trigger
Message-ID: <Pine.HPP.3.93.980823034305.9153A-100000@lulu.acns.nwu.edu>

What kind of circuit do I have to build to convert the LFO signal into a
trigger/gate signal?  Are there any schemtics out there?

Thanks

Yoshi





From debus at cityweb.de  Sun Aug 23 11:05:29 1998
From: debus at cityweb.de (Ingo Debus)
Date: Sun, 23 Aug 1998 11:05:29 +0200
Subject: filter waveform question
References: <35DD24B1.4278@cityweb.de> <199808221318.PAA21755@piraya.electrum.kth.se>
Message-ID: <35DFDB54.24C3@cityweb.de>

Magnus Danielson wrote:
> >>>>> "ID" == Ingo Debus <debus at cityweb.de> writes:
[...]
>  ID> The order of a low pass filter is equal to the number of parameters
>  ID> which can be varied independently. A first order filter has only one
[...]
> The order is strictly connected to the number of poles, not the dB/oct
> number not the number of parameters. The number of parameters is
> actually greater than the number of poles, it is up to about the
> double. The reason for this is that you can have zero's that also can
> be varied.

Sorry, I've mixed things up. I wrote "low pass filter" but I actually
meant "filter with no zeros". Of course a low pass filter can have zeros
too.

Ingo




From massann at tin.it  Sun Aug 23 11:41:29 1998
From: massann at tin.it (Massimo Sanna)
Date: Sun, 23 Aug 1998 10:41:29 +0100
Subject: Looking for exciter  schematics
Message-ID: <yam7539.1477.119067728@mail.tin.it>

Hi to all you on the list,
I am interested in building an exciter, like Aphex' Aural Exciter :  can
anyone help me finding schematics, URLs or even articles?

Thank you in advance

 
         Massimo Sanna

    email:   massann at tin.it
http://space.tin.it/arte/massanna




From magnus at analogue.org  Sun Aug 23 13:19:41 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Sun, 23 Aug 1998 13:19:41 +0200
Subject: filter waveform question
In-Reply-To: Your message of "Sat, 22 Aug 1998 14:05:35 +0200"
References: <35DEB40E.2E80@cityweb.de>
Message-ID: <199808231119.NAA00606@piraya.electrum.kth.se>

>>>>> "ID" == Ingo Debus <debus at cityweb.de> writes:

 >> Also, there are second order filters that give you independent control of
 >> more than two parameters. The Tow Thomas biquad is a good example - cut-off,
 >> Q and gain.

 ID> Yes, filter gain is another parameter of course. I omitted that because
 ID> gain only contributes to the level, not to the waveform. But, if gain is
 ID> included, the number of independent parameters is filter order plus 1.

All the gain values will multiply with each other to become the total
gain. This fact may be used to allow for individual gain at each stage
for best overall dynamics.

Cheers,
Magnus






From pfperry at melbpc.org.au  Sun Aug 23 14:17:18 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Sun, 23 Aug 1998 22:17:18 +1000 (EST)
Subject: LFO -> trigger
Message-ID: <1.5.4.16.19970115045049.37078254@popa.melbpc.org.au>

At 03:44 AM 23/08/98 -0500, Yoshiki Ohmura (Yoshi) wrote:
>What kind of circuit do I have to build to convert the LFO signal into a
>trigger/gate signal?  Are there any schemtics out there?
>
What sort of LFO have you got?
An easy thing to do is just run the lfo to a comparator.
When the lfo voltage is above the comparator set point, it is ON,
and off when it is below.
This will be enough to trigger whatever you have, the only problem
being that the 'trigger' might not be at the right point of the lfo cycle.

Indeed, you could make a "window comparator" and then you can choose the
part of the
lfo cycle that it is on.... but, there is the second unwanted output on the
downside 
of the lfo.... but, if you run the output into a flip flop arranged as a
divide by
two ckt then you can throw away every second one (or, for that matter, every
odd one,
which gives full ability to select where on the lfo the trigger comes from).

There is a 'window discriminator' ckt on p669 of the 2nd edition of Horowitz
and Hill
"The Art of Electronics"

paul perry melb aust




From ride2619 at ride.ri.net  Sun Aug 23 15:18:58 1998
From: ride2619 at ride.ri.net (Michael J. Barclay de Tolly)
Date: Sun, 23 Aug 1998 09:18:58 -0400
Subject: Fw: 
Message-ID: <001001bdce98$ccc734c0$2de673c6@ride2619.ride.ri.net>


-----Original Message-----
From: Michael J. Barclay de Tolly <ride2619 at ride.ri.net>
To: synth-diy at mailhost.bpa.nl <synth-diy at mailhost.bpa.nl>
Date: Friday, August 21, 1998 11:18 AM


remove Michael J. Barclay de Tolly
Michael J. Barclay de Tolly
ride2619 at ride.ri.net
 

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From jhaible at metronet.de  Sun Aug 23 19:49:16 1998
From: jhaible at metronet.de (jhaible)
Date: Sun, 23 Aug 1998 19:49:16 +0200
Subject: seeking dual linear concentric pots w/knobs
Message-ID: <19980823224621.17188.qmail@nuernberg2.pop.metronet.de>

> >Don't want to talk you into something, but using a knob
> >for different functions cw and ccw from 12 o clock position
> >is not *that* bad. 
> 
> ....well I agree, it's just the added ckt complexity!

Depends on the complexity of your original circuit.
If you use the pot directly as attenuator, you're right.
If you use the pot to control a VCA (because you want
voltage contol, or for some other reason), the additional
ckt is next to zero. You need a single pnp transistor to
control a 3080 with a positive-only CV anyway, and it's just
a matter of biasing two transistors to make one work from
a certain voltage (coresponding to 12 o clock position) 
upward, and the other obe downward.

JH.



From jhaible at metronet.de  Sun Aug 23 19:53:34 1998
From: jhaible at metronet.de (jhaible)
Date: Sun, 23 Aug 1998 19:53:34 +0200
Subject: DIY parts
Message-ID: <19980823224625.17188.qmail@nuernberg2.pop.metronet.de>


> Hmm... do you have any schematics of this? I know that you have
> mentioned a couple of diffrent ways to make better VCOs but I lack
> schematics for these cases.

I think the MS-20 does this. I think the shemos are online somewhere (?).
Not that the MS-20 is such a good reference for "the best VCO ever",
though ...

JH.



From urekar.m at EUnet.yu  Sun Aug 23 21:16:04 1998
From: urekar.m at EUnet.yu (<<marjan>>)
Date: Sun, 23 Aug 1998 21:16:04 +0200
Subject: DIY parts
References: <199808212230_MC2-56F3-9C1C@compuserve.com> <35DEB02C.17EF@eunet.yu> <35DEE2DB.DFA2A3ED@earthlink.net>
Message-ID: <35E06A74.114B@eunet.yu>

> 
> It's Terry's 1973 Electronotes VCO. Still the best VCO I've seen

thanks all for clarification...


How about already mentioned 4007 for switching instead FET ?
Don't have data sheet handy ,I belive it's not perfect
(gate cap,parasite diodes etc.) but you can run 3 vcos from
the same chip.I saw it at tomg's site and somewhere else.


marjan



From synth1 at airmail.net  Sun Aug 23 22:22:15 1998
From: synth1 at airmail.net (Paul Schreiber)
Date: Sun, 23 Aug 1998 20:22:15 -0000
Subject: Synthtech 800 #
Message-ID: <01BDCED4.13B72440@dal18-09.ppp.iadfw.net>

I now have a "800" toll-free (for you!) number
for phone & fax:

1-888-818-MOTM

Paul Schreiber
Synthesis Technology




From ijfritz at earthlink.net  Sun Aug 23 22:48:45 1998
From: ijfritz at earthlink.net (Ian Fritz)
Date: Sun, 23 Aug 1998 14:48:45 -0600
Subject: DIY parts
References: <199808212230_MC2-56F3-9C1C@compuserve.com> <35DEB02C.17EF@eunet.yu> <35DEE2DB.DFA2A3ED@earthlink.net> <35E06A74.114B@eunet.yu>
Message-ID: <35E0802D.13F31CE7@earthlink.net>

Marjan --

That would work, but the On resistance is quite high.

BTW, Terry's original design has a 20 million-to-one frequency range --
.003Hz to 60kHz -- and very little high-end droop. What we're after here
is the best way to redo the design with readily available modern
components.

  Ian


<<>> wrote:

> How about already mentioned 4007 for switching instead FET ?
> Don't have data sheet handy ,I belive it's not perfect
> (gate cap,parasite diodes etc.) but you can run 3 vcos from
> the same chip.I saw it at tomg's site and somewhere else.
> 
> marjan



From jhaible at metronet.de  Mon Aug 24 00:41:03 1998
From: jhaible at metronet.de (jhaible)
Date: Mon, 24 Aug 1998 00:41:03 +0200
Subject: Quantizer again
Message-ID: <19980823224627.17188.qmail@nuernberg2.pop.metronet.de>

Just another idea.
If I already have 12 switches for the semitones, I might
as well have 12 LEDs. Each time the comparator triggers
the S&H for the quantized output, it can also trigger a latch
and thus turn on the coresponding semitone LED. This
would combine the advantages of analogue sequencer and
software sequencers: Turn a knob for fast control, and see the
quantized result indicated by the respective LED. One would
arrange the LEDs and switches in a 1-octave keyboard layout
on the frontpanel, of course ...
I am pretty sure that I will implement this. Not so sure about
the next step further, however: replace the semitone switches
with pushbuttons. Like these Shadow keys that include a LED.
Problem is that I need one additional D-Flipflop and an extra
CMOS switch for each semitone.
This is all just theory so far. At the moment I'm soldering stupid
input / output / debounce logic.

JH.



From jhaible at metronet.de  Mon Aug 24 00:46:46 1998
From: jhaible at metronet.de (jhaible)
Date: Mon, 24 Aug 1998 00:46:46 +0200
Subject: 4007 (was: Re: DIY parts)
Message-ID: <19980823225749.17334.qmail@nuernberg2.pop.metronet.de>


> How about already mentioned 4007 for switching instead FET ?
> Don't have data sheet handy ,I belive it's not perfect
> (gate cap,parasite diodes etc.) but you can run 3 vcos from
> the same chip.I saw it at tomg's site and somewhere else.

It's no good idea to have the discharge circuitry of several
VCOs too close together. Your always fighting "interlock",
i.e. a limited minimum beat rate between VCOs, before they
are syncronized (soft sync'ed) thru parasitic coupling.

JH.



From sasami at blaze.net.au  Mon Aug 24 02:36:51 1998
From: sasami at blaze.net.au (Ken Stone)
Date: Mon, 24 Aug 1998 02:36:51 +0200 (MET DST)
Subject: seeking dual linear concentric pots w/knobs
Message-ID: <199808240036.CAA03588@mailhost.bpa.nl>

I actually use these dual pots in my sequencer, using the outer for coarse
and the inner for fine tuning. The ones I have are fairly easy to move, so
if you aren't careful, adjusting one, you can mess up the other (stray
finger or whatever). The real problem with these is knobs - I don't have
any. The inner shaft uses 6mm splined, but the outer is just at tube with a
couple of slits (as per car radios).

Ken


>>Looking for dual linear pots with concentric knobs
>>That is, like a balance/vol knob on an old car radio,
>>not a stereo kind of thing.
>>I havn't put enough holes in an effect (suprise!)
>>and I dont want to do something really horrible like
>>have a knob change mode when half way around....
>>
>>paul perry melbourne australia
>>
>Hi Paul
>Now that's a DAMM good question.I have been looking for a source for these
>thing's for a while (i use a lot of test kit ,scopes,psu's)with these types
>of pot's and figured they would be cool for a sequencer layout(16 pot's in 8
>holes!!!).I even took a dual psu half to bit's one lunchtime,at work,to
>gleem some info but no joy!
>We may be enlightened!!!
>
>Live long and prosper
>
>George,Bath,uk
>
>
>
_____________________________________________________________

                Ken Stone  sasami at blaze.net.au
                   ** Catgirl Paradise **
               <http://www.anime.net/~kens/>
         ** Australian Miniature Horses and ponies **
             <http://www.blaze.net.au/~sasami/>
_____________________________________________________________





From 104065.2340 at compuserve.com  Mon Aug 24 04:10:23 1998
From: 104065.2340 at compuserve.com (terry michaels)
Date: Sun, 23 Aug 1998 22:10:23 -0400
Subject: DIY parts
Message-ID: <199808232210_MC2-5725-CAD6@compuserve.com>



-------------Forwarded Message-----------------

From:   terry michaels, 
To:     INTERNET:jhaible at metronet.de, INTERNET:jhaible at metronet.de
        
Date:   8/23/98  8:57 PM

RE:     Re: DIY parts

Message text written by INTERNET:jhaible at metronet.de
> But still, a few points to add:
> (1)You could use a guard ring without a virtual gnd node, too.
> Connect it to the buffer output instead.
>(2) You can use an extra transistor for a cascode configuration
> if you want to keep the cb voltage of the expo converter's transistor
> low. This will also help making a high output impedance.
> Korg used an extra FET for this cascode configuration in some of
> their VCOs. (Expo converter from dual npn, output drives FET with
> base grounded, discharge circuit is a thyristor built from discrete 
> npn's and pnp's, and buffer is another FET. 
> I do *not* know how good this performs, but I thought I should mention
it.

Hi Jeurgen:

You're absolutely right, of course.  Havn't seen the Korg stuff, but I'm
not surprised about the cascode idea. That is a clever approach. 

There has been a lot of VCO designs in the last 30+ years, I think almost
everything has been tried by now.

Terry



From gerryd at ntx-tech.com  Mon Aug 24 06:32:58 1998
From: gerryd at ntx-tech.com (Gerry Dahl)
Date: Sun, 23 Aug 1998 23:32:58 -0500
Subject: WTB: Broken /non-working MemoryMoog
Message-ID: <35E0ECFA.1B26@ntx-tech.com>

Hi Everyone,
Looking for a broken MemoryMoog or a broken Moog Source.

Thanks.
Gerry Dahl

P.S. Will trade my 60mhz scope for a memorymoog.



From digiboy at erols.com  Mon Aug 24 07:58:25 1998
From: digiboy at erols.com (mike(digiboy))
Date: Mon, 24 Aug 1998 00:58:25 -0500
Subject: FT: EML400/401  16stage  analog sequencer
Message-ID: <l03130303b206af106891@[207.172.114.117]>

I have a fully operational EML Electrocomp 400/401 synthesizer with a
single 16 stage x 3 voltage rows sequencer panel complete with manual(copy)
in excellent condition.  I will trade the whole unit, synth and sequencer,
for a working 32 (double 16 x 3) stage  EML sequencer panel alone. Details
and scan available if interested








From aschrock at cs.brandeis.edu  Mon Aug 24 08:06:15 1998
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Mon, 24 Aug 1998 02:06:15 -0400 (EDT)
Subject: WTB: Broken /non-working MemoryMoog
In-Reply-To: <35E0ECFA.1B26@ntx-tech.com>
Message-ID: <Pine.HPP.3.95.980824020507.12887A-100000@bay.cs.brandeis.edu>

Hmm... www.ebay.com had one last time I checked. Bidding was at $450 or
so, and it was 90% operational or something. 

I also put this to the list just as a general FYI in case anybody was
interested. 

Andrew

| Andrew Schrock							|
| Network Programmer, Synthesizer and electronic music enthusiast	|
| aschrock at cs.brandeis.edu						|

On Sun, 23 Aug 1998, Gerry Dahl wrote:

> Hi Everyone,
> Looking for a broken MemoryMoog or a broken Moog Source.
> 
> Thanks.
> Gerry Dahl
> 
> P.S. Will trade my 60mhz scope for a memorymoog.
> 




From martin.czech at intermetall.de  Mon Aug 24 10:00:53 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Mon, 24 Aug 1998 10:00:53 +0200 (MET DST)
Subject: Minimoog Vcf
Message-ID: <199808240800.KAA00601@window.intermetall.de>


> Well,I found that R20 resistor from Q6 emitter to -10 is 100k not 220k
> And +10V should go not to col. of Q6 but to other side 
> of R6 47ohm resistor and + node of C9 100uF ? 
> Not shure about that last but if you look at moogmodular vcf, it 
> looks like that.
> 
This makes sense. It is a kind of emitter follower (darlington).
In this case the emitter resistors should be equal.
And it is a differential to single ended converter. Again symmetry
is required.

Can any of the moog godnesses confirm ?

m.c. 




From ryckebu at subasehp.san.mrms.navy.mil  Mon Aug 24 11:17:22 1998
From: ryckebu at subasehp.san.mrms.navy.mil (Jules Ryckebusch)
Date: Mon, 24 Aug 1998 09:17:22 +0000
Subject: Looking for exciter  schematics
In-Reply-To: <000501bdcf6a$9d869d90$2d90e2cd@thudson1.cygnus.com>
References: <yam7539.1477.119067728@mail.tin.it>
Message-ID: <199808241619.JAA29294@subasehp.san.mrms.navy.mil>

I wrote that article. If you need the schematic, send me your snail 
mail address and I'll send you a copy. I believe Jamie does have the 
schematic on line

> From:          "Thomas Hudson" 
<thudson at cygnus.com>
> To:            "Massimo Sanna" <massann at tin.it>, <synth-diy at mailhost.bpa.nl>
> Subject:       RE: Looking for exciter  schematics
> Date:          Mon, 24 Aug 1998 10:22:25 -0400
> Importance:    Normal

> 
> I remember seeing a DIY article about selectively distorting
> high frequency bands, I believe called a Harmonic Sweetener.
> I don't know where the article is from but I believe you can
> find the schematics at Jamie Helmans site:
> 
> http://www.wcug.wwu.edu/~jamie/schems.html
> 
> > -----Original Message-----
> > From: owner-synth-diy at mailhost.bpa.nl
> > [mailto:owner-synth-diy at mailhost.bpa.nl]On Behalf Of Massimo Sanna
> > Sent: Sunday, August 23, 1998 5:41 AM
> > To: synth-diy at mailhost.bpa.nl
> > Subject: Looking for exciter schematics
> > 
> > 
> > Hi to all you on the list,
> > I am interested in building an exciter, like Aphex' Aural Exciter :  can
> > anyone help me finding schematics, URLs or even articles?
> > 
> > Thank you in advance
> > 
> >  
> >          Massimo Sanna
> > 
> >     email:   massann at tin.it
> > http://space.tin.it/arte/massanna
> > 
> > 
> 
> 



From oakley at enterprise.net  Mon Aug 24 11:24:45 1998
From: oakley at enterprise.net (Tony Allgood)
Date: Mon, 24 Aug 1998 10:24:45 +0100
Subject: 4007 (was: Re: DIY parts)
Message-ID: <001401bdcf74$ac2b0b60$70c348c2@default>

JH said:

It's no good idea to have the discharge circuitry of several
VCOs too close together. Your always fighting "interlock",
i.e. a limited minimum beat rate between VCOs, before they
are syncronized (soft sync'ed) thru parasitic coupling.



This is so true. But this weekend I found another example of this sort of
thing in a high level circuit. I had a schmitt trigger CMOS chip squaring
the ramp output of a CEM3340 to give me a square wave. But I could hear it
clicking at the beat frequency with the other VCO. I traced it to the
another gate within the same CMOS chip. This gate was being fired from the
pulse output from the second VCO. Gate to gate crosstalk, and bad enough to
delay the change of state in one of the gates. The problem was solved by
using the gates on opposite quarters of the same chip.

Regards,

Tony Allgood, Cumbria, UK

e-mail: oakley at enterprise.net

Rack mounted Moog VCF module. PCBs have been ordered.

http://aupe.phys.andrews.edu/diy_archive/schematics/effects/filter.html







From PhilC at Core-Design.com  Mon Aug 24 12:07:07 1998
From: PhilC at Core-Design.com (Phil Callaghan  (Core Design Ltd.))
Date: Mon, 24 Aug 1998 11:07:07 +0100
Subject: Home-made Modular Synth teething trouble
Message-ID: <815A4DA1B7DAD111957800805F65E8E8033073@mailsvr.core-design.com>

I have built a simple modular analogue synth from designs in R.A.
Penfold's book "Electronic Synthesizer Construction" with a few modules
of my own.

I get problems when interconnecting the modules, and I can't figure out
what is wrong due to my limited knowledge of electronics.

Most of the modules seem in interact in ways which are not acceptable.
For example, I connect a noise generator to a op-amp amplifier and the
noise cuts off above a certain volume. I thought that maybe it was
necessary to put a buffer between the noise and amp, but this made no
difference. Then I tried to smooth the power supply rails using
capacitors, but this didn't work either. Another such problem is the VCO
starts to oscillate when I connect an LFO to the S&H.

I have been reading books on electronics, but none of them shed any
light on this interconnection problem. I think this must be a basic
modular problem and wondered if anyone here could point me in the right
direction.

Phil Callaghan




From tomg at vivid.net  Mon Aug 24 12:34:46 1998
From: tomg at vivid.net (tomg)
Date: Mon, 24 Aug 1998 05:34:46 -0500
Subject: Maxx Additions
Message-ID: <yam7540.2305.119792624@mail.vivid.net>

Added pcb for BLG-1A Boolean Logic Module

www.tomg.vivid.net/maxx/pics/blogic_4.gif

Added pcb for DTG-1A Dual Transit Generator

www.tomg.vivid.net/maxx/pics/pics/dtg_7.gif
www.tomg.vivid.net/maxx/pics/pics/dtg_8.gif
www.tomg.vivid.net/maxx/pics/pics/dtg_9.gif

pcb layouts are untested. maybe this week? 
I am going to build the Mad Mouse hopefully
tuesday.

The pcb for the VCF-7A 39OO filter is ready.
as well as the MM pcb. I'll get 'em up 
later today.

I have found a way to get my Amiga cad drawings
into Corel so exact size ps and cdr pcb versions 
will start to appear. I got email from a guy
last week who said he'd done most of the Maxx
stuff in a pro-pcb program and as soon as they
are tested he'll send them to me in ps to post 
on the site. This could be very cool to produce
art from. We shall see...

-tg
 




From tomg at vivid.net  Mon Aug 24 12:38:58 1998
From: tomg at vivid.net (tomg)
Date: Mon, 24 Aug 1998 05:38:58 -0500
Subject: 4007 (was: Re: DIY parts)
In-Reply-To: <19980823225749.17334.qmail@nuernberg2.pop.metronet.de>
Message-ID: <yam7540.2939.119792624@mail.vivid.net>

On 23-Aug-98, jhaible wrote:


>It's no good idea to have the discharge circuitry of several
>VCOs too close together. Your always fighting "interlock",
>i.e. a limited minimum beat rate between VCOs, before they
>are syncronized (soft sync'ed) thru parasitic coupling.

>JH.

I agree. I haven't had any problems but for some reason I
just don't like it and plan on removing that version from
the page. It seems to work ok and no lock up but I feel
uneasy about it.

-tg






From martin.czech at intermetall.de  Mon Aug 24 12:52:05 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Mon, 24 Aug 1998 12:52:05 +0200 (MET DST)
Subject: transfer function order (was Re: filter waveform question)
Message-ID: <199808241052.MAA01223@window.intermetall.de>

> > On the other hand it can be shown, that any H(s) can be reproduced
> > by chaining or parallel use of second order filters (state variable),
> > and first order sections (simple RC high or lowpass).
> 
> This is right for (ideal) linear filters. In the real world, with things
> like
> nonlinearity, headroom, and so on, they can sound very different.
> Just think about two 2-pole sections in series. You will typically have
> one high Q and one low Q partial filter. Which one will be the first stage
> ?
> How does the second stage filter the distortion products, when the
> first stage is (ever so slightly) overloaded ?
> 
Serious questions, but I mean this was a theoretical answer.
A transfer function is a (quite succesfull) way to 
describe reality, it assumes ideal behaviour.

But nevertheless, I wonder what will happen if you take
a four stage filter (e.g. cascade) and add the voltages
from every stage together. This should introduce some zeros.

It is not quite the same as using integrators, have to
figure out what will happen in this case.

m.c. 




From Hcabnivek at aol.com  Mon Aug 24 13:39:57 1998
From: Hcabnivek at aol.com (Hcabnivek at aol.com)
Date: Mon, 24 Aug 1998 07:39:57 EDT
Subject: 76477 Super Controller PCB???
Message-ID: <586dc583.35e1510e@aol.com>

In a message dated 98-08-24 01:04:00 EDT, you write:

>  received my 76477 chips from John Blacet and am gearing up
>  to build the "Super Contoller Module" from the Thomas Henry
>  book "Build A Better Music Synthesizer".  Does anyone have a
>  printed circuit board print on that circuit? 

Jimmy,
I got about 3/4 done with my layout of this in easytrax and them got side
tracked, so not much help to you there. I decided that I wanted to work out VC
on the lfo rate before I build it. Be aware that there is a resistor value
missing on the shematic.  It's the very bottom componant on the left hand side
and should be 100k.
Hope this little piece of info helps.
Kevin




From ms6gpm at bath.ac.uk  Mon Aug 24 13:59:26 1998
From: ms6gpm at bath.ac.uk (Gez.)
Date: Mon, 24 Aug 1998 12:59:26 +0100 (BST)
Subject: Resonant filters?
In-Reply-To: <yam7540.2305.119792624@mail.vivid.net>
Message-ID: <Pine.SOL.3.93.980824125731.21487C-100000@midge.bath.ac.uk>



  Is there any way to produce filters (H,L & B) with control over
  cutoff ferquency and resonance without DSP?




From Juergen.Haible at nbgm.siemens.de  Mon Aug 24 15:32:42 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Mon, 24 Aug 1998 15:32:42 +0200
Subject: AW: VP-330 (analog speech synthesis)
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D582A08868@nbgm336a.nbgm.siemens.de>

	>BTW, I seem to recall that the main internal differences between
the
	>two VP-330 versions were in the choir section. Does anyone know
what
	>those differences were? I've only got the service manual for the
	>later version (the one with momentary LED buttons instead of rocker
	>switches).

Hi Joachim,

I have looked at the service manuals, and the component values
in the filters seem to be the same. 

JH.



From jocke at netcontrol.fi  Mon Aug 24 15:55:47 1998
From: jocke at netcontrol.fi (Joachim Verghese)
Date: Mon, 24 Aug 1998 16:55:47 +0300 (EET DST)
Subject: VP-330
In-Reply-To: <1BF5E20E0C4DD111BBAB00805FE2D582A08868@nbgm336a.nbgm.siemens.de>
Message-ID: <Pine.LNX.3.95.980824164319.1394A-100000@home.netcontrol.fi>

Hi!

> I have looked at the service manuals, and the component values
> in the filters seem to be the same. 

Yes, I also realised that (got the Mk I schemos). The only difference
I found was that the FET switches of the later version are "single
ended" (as opposed to change-over) and therefore do not ground the
input of the corresponding signal summing line. Probably doesn't affect
the overall sound much.

-joachim





From thudson at cygnus.com  Mon Aug 24 16:22:25 1998
From: thudson at cygnus.com (Thomas Hudson)
Date: Mon, 24 Aug 1998 10:22:25 -0400
Subject: Looking for exciter  schematics
In-Reply-To: <yam7539.1477.119067728@mail.tin.it>
Message-ID: <000501bdcf6a$9d869d90$2d90e2cd@thudson1.cygnus.com>


I remember seeing a DIY article about selectively distorting
high frequency bands, I believe called a Harmonic Sweetener.
I don't know where the article is from but I believe you can
find the schematics at Jamie Helmans site:

http://www.wcug.wwu.edu/~jamie/schems.html

> -----Original Message-----
> From: owner-synth-diy at mailhost.bpa.nl
> [mailto:owner-synth-diy at mailhost.bpa.nl]On Behalf Of Massimo Sanna
> Sent: Sunday, August 23, 1998 5:41 AM
> To: synth-diy at mailhost.bpa.nl
> Subject: Looking for exciter schematics
> 
> 
> Hi to all you on the list,
> I am interested in building an exciter, like Aphex' Aural Exciter :  can
> anyone help me finding schematics, URLs or even articles?
> 
> Thank you in advance
> 
>  
>          Massimo Sanna
> 
>     email:   massann at tin.it
> http://space.tin.it/arte/massanna
> 
> 



From pfperry at melbpc.org.au  Mon Aug 24 16:57:58 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Tue, 25 Aug 1998 00:57:58 +1000 (EST)
Subject: Resonant filters?
Message-ID: <1.5.4.16.19970116073122.282fe5ac@popa.melbpc.org.au>

At 12:59 PM 24/08/98 +0100, "Gez." wrote:

>  Is there any way to produce filters (H,L & B) with control over
>  cutoff ferquency and resonance without DSP?
>
.....er, what do you mean?
There are plenty of H.L & B filters with control voltages adjusting
cutoff freq and resonance, made from standard discrete components..

A more interesting question is, Is there any way to produce filters 
(H,L & B) with control over cutoff ferquency and resonance **WITH** DSP,
 and have them behave in a satisfactory way for musical
applications? The solution is neither simple nor obvious....

paul perry melbourne australia




From mmcintos at ball.com  Mon Aug 24 16:58:11 1998
From: mmcintos at ball.com (McIntosh, Malcolm)
Date: Mon, 24 Aug 1998 08:58:11 -0600
Subject: seeking dual linear concentric pots w/knobs
Message-ID: <09DB74475204D1119C8200805F19D0032D12D1@aeromsg1.ball.com>

I saw some of these types of concentric pots (and a good selection of
sliders) in the catalogs from the following distributors:

A/D Electronics, Inc.
10421 Burnham Drive N.M., Building 4
Gig Harbor, Wa   98332
USA
Voice: 253/851-8005
Fax: 253/851-8090
http://www.adelectronics.com/


Vimex International Corporation
1623 N. Barclay Boulevard
Buffalo Grove, IL   60089
USA
Voice: 800/227-0075
Fax: 847/808-7687
http://www.vimex.com/


Mechatronic Elektronisce Bauelemente GmbH + Co
Eschenbr?nnlestra?e 16
71065 Sindelfingen
Germany?
Telefon: 0 70 31 /79 70-0
Fax: 0 70 31 /7970 70
http://www.kk.net/mechatronic/


Noble U.S.A., Inc
5450 Meadowbrook Industrial Court
Rolling Meadows, IL 60008 U.S.A.
USA
Voice: 847/364-6038
Fax: 847-364-6045
http://nobleusa.com/


I have actually gotten some sliders for my Moog Opus 3 from Vimex.

Hope this helps

Malcolm


> -----Original Message-----
> From:	sasami at blaze.net.au [SMTP:sasami at blaze.net.au]
> Sent:	Sunday, August 23, 1998 5:37 PM
> To:	synth-diy at mailhost.bpa.nl
> Subject:	Re: seeking dual linear concentric pots w/knobs
> 
> I actually use these dual pots in my sequencer, using the outer for
> coarse
> and the inner for fine tuning. The ones I have are fairly easy to
> move, so
> if you aren't careful, adjusting one, you can mess up the other (stray
> finger or whatever). The real problem with these is knobs - I don't
> have
> any. The inner shaft uses 6mm splined, but the outer is just at tube
> with a
> couple of slits (as per car radios).
> 
> Ken
> 
> 
> >>Looking for dual linear pots with concentric knobs
> >>That is, like a balance/vol knob on an old car radio,
> >>not a stereo kind of thing.
> >>I havn't put enough holes in an effect (suprise!)
> >>and I dont want to do something really horrible like
> >>have a knob change mode when half way around....
> >>
> >>paul perry melbourne australia
> >>
> >Hi Paul
> >Now that's a DAMM good question.I have been looking for a source for
> these
> >thing's for a while (i use a lot of test kit ,scopes,psu's)with these
> types
> >of pot's and figured they would be cool for a sequencer layout(16
> pot's in 8
> >holes!!!).I even took a dual psu half to bit's one lunchtime,at
> work,to
> >gleem some info but no joy!
> >We may be enlightened!!!
> >
> >Live long and prosper
> >
> >George,Bath,uk
> >
> >
> >
> _____________________________________________________________
> 
>                 Ken Stone  sasami at blaze.net.au
>                    ** Catgirl Paradise **
>                <http://www.anime.net/~kens/>
>          ** Australian Miniature Horses and ponies **
>              <http://www.blaze.net.au/~sasami/>
> _____________________________________________________________
> 



From oakley at enterprise.net  Mon Aug 24 17:33:09 1998
From: oakley at enterprise.net (Tony Allgood)
Date: Mon, 24 Aug 1998 16:33:09 +0100
Subject: Fw: Tek 2225 service manual
Message-ID: <001601bdcf74$adf03b00$70c348c2@default>

George told me about Mauritron in the UK to supply manuals for scopes. They
didn't have the one I wanted but they seem to do many others.

http://dialspace.dial.pipex.com/mauritron/


Regards,

Tony Allgood, Cumbria, UK

e-mail: oakley at enterprise.net

Rack mounted Moog VCF module. PCBs being ordered today.

http://aupe.phys.andrews.edu/diy_archive/schematics/effects/filter.html









From magnus at analouge.org  Mon Aug 24 20:48:32 1998
From: magnus at analouge.org (Magnus Danielson)
Date: Mon, 24 Aug 1998 20:48:32 +0200
Subject: filter waveform question
In-Reply-To: Your message of "Sun, 23 Aug 1998 11:05:29 +0200"
References: <35DFDB54.24C3@cityweb.de>
Message-ID: <199808241848.UAA23475@piraya.electrum.kth.se>

>>>>> "ID" == Ingo Debus <debus at cityweb.de> writes:

Hi Ingo!

 ID> Magnus Danielson wrote:
 >> >>>>> "ID" == Ingo Debus <debus at cityweb.de> writes:
 ID> [...]
 ID> The order of a low pass filter is equal to the number of parameters
 ID> which can be varied independently. A first order filter has only one
 ID> [...]
 >> The order is strictly connected to the number of poles, not the dB/oct
 >> number not the number of parameters. The number of parameters is
 >> actually greater than the number of poles, it is up to about the
 >> double. The reason for this is that you can have zero's that also can
 >> be varied.

 ID> Sorry, I've mixed things up. I wrote "low pass filter" but I actually
 ID> meant "filter with no zeros". Of course a low pass filter can have zeros
 ID> too.

This just shows that keeping a strict definition of the vocabulary can
help avoiding stupid misstakes.

The reason that I say "about the double" above is since the frequency
independent gain comes in, an phenomenes like clipping and noise (as
we touched the subject before) limits the dynamic range.

Now, how many cats does it take to keep a Gnome happy?

Cheers,
Magnus





From b.layer at vikingelectronics.com  Mon Aug 24 20:53:00 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Mon, 24 Aug 1998 13:53:00 -0500
Subject: MIDI devices
Message-ID: <3.0.5.32.19980824135300.007ada50@192.168.210.18>

Hi All,

Thanks to everyone who helped with my unknown MIDI devices; I've got the
situation well under control.

Apparently, the Roland MPU-IPC is a two-part system, and I've only got the
external box. If anyone can supply me with a PC (or C64...) internal card,
I'd be much obliged. BTW does anyone know why they used a 25-PIN parallel
printer connector on the MPU-IPC box? Seems like WAY to many lines... (The
MIDIman only needs 9!)

They didn't make a version that connects to the parallel port, did they?
That would expalin the connector at least.

The MIDIman interface is now installed, and controlling my Fatman/EML
combo. The folks at MIDIman were very helpful to this end. Interestingly
enough, they dissuaded me from using their own driver, in favor of that
which is part of the Cakewalk system; they said Cakewalk's is better! Now
how's that for honesty? 

Thanks again,
 
Bill Layer
"Quantity has a Quality all of it's own." -JL



From bnillson at hotmail.com  Mon Aug 24 21:41:24 1998
From: bnillson at hotmail.com (Bjarne Nillson)
Date: Mon, 24 Aug 1998 12:41:24 PDT
Subject: Home-made Modular Synth teething trouble
Message-ID: <19980824194124.16413.qmail@hotmail.com>


>I have built a simple modular analogue synth from designs in R.A.
>Penfold's book "Electronic Synthesizer Construction" with a few modules
>of my own.
>
>I get problems when interconnecting the modules, and I can't figure out
>what is wrong due to my limited knowledge of electronics.
>
>Most of the modules seem in interact in ways which are not acceptable.
>For example, I connect a noise generator to a op-amp amplifier and the
>noise cuts off above a certain volume. I thought that maybe it was
>necessary to put a buffer between the noise and amp, but this made no
>difference. Then I tried to smooth the power supply rails using
>capacitors, but this didn't work either. Another such problem is the 
VCO
>starts to oscillate when I connect an LFO to the S&H.
>
>I have been reading books on electronics, but none of them shed any
>light on this interconnection problem. I think this must be a basic
>modular problem and wondered if anyone here could point me in the right
>direction.
>
>Phil Callaghan

The problem is, you have build a nonworking synt due to the
fact that you have used a RA Penfold book!!!
The answer is that its lot of non working designs in those books...

regards
BJ



______________________________________________________
Get Your Private, Free Email at http://www.hotmail.com



From magnus at analogue.org  Mon Aug 24 21:43:20 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Mon, 24 Aug 1998 21:43:20 +0200
Subject: 4007 (was: Re: DIY parts)
In-Reply-To: Your message of "Mon, 24 Aug 1998 05:38:58 -0500"
References: <yam7540.2939.119792624@mail.vivid.net>
Message-ID: <199808241943.VAA23849@piraya.electrum.kth.se>

>>>>> "t" == tomg  <tomg at vivid.net> writes:

Hi!

 t> On 23-Aug-98, jhaible wrote:
 >> It's no good idea to have the discharge circuitry of several
 >> VCOs too close together. Your always fighting "interlock",
 >> i.e. a limited minimum beat rate between VCOs, before they
 >> are syncronized (soft sync'ed) thru parasitic coupling.

This is touching a subject that we have been discussing before, both
for the Minimoog and Oberheim SEM if I recall things right.
I also think that some of what I am about to say I have said before,
but none the less:

When squeeking my ASM-1 VCO upto 116 kHz I started to notice various
wavedistorsions around the reset-period of the wave. I used a
4-channel 500 MHz (2 Gs/s and channel) Techtronix oscilloscope with
350 MHz probes for my analysis and framedgrabbed the measurements.

Well, as the reset-cursuit turned off the reset FET I saw a distinct
ringing which had a lowest frequency of about 2.2 MHz. It was stable
as a rock and didn't change abit due to frequency adjustments. When
looking at one of my waveforms I suddenly discovered that the output
of the LM311 was swinging 15V in something like 25 ns and thus was
suddenly pulling a lot of current. This will together with the
inductance of the PCB strips and capacitor longer away from a slightly
resonant curcuit. This is well known trouble in the EMC field and any
experienced and thinking analog and digital designer working above 10
MHz should know about these things.

I could also clearly see how this impulse would eat itself into the
signalpath in various ways. Carefull examination of an unsoldered
laminate also showed that these power-rails where passing the LM311
and feed further to the CA3140 (used as the integrator of the
oscillator). Power decoupling caps where miles/mils away and thus not
very effective.

So, when people talk about intermodulation like this I can certainly
beleive it. Altought being an "analog" curcuit it suffers problems
which is "digital" (and these same problem is being viewed as analog
for those people, talk about irony). The frequency of these things is
way above what the curcuit is supposed to operate at, but it may still
make a noticable effect.

So, keeping such cursuits abit of the normal powerlines with
highfrequency caps closeby would certainly help to remove such
problems. It is standard procedure for digital cursuits, just apply it
to analog.

For anyone that is really into viewing things, peek in at this
unfinished page to see my picture:
http://www.it.kth.se/~e93_mda/synths/friends/stopp/asm1vco.html

I will make some further measurements and try out propper decoupling
to help out ASM-1 owners as well as others to get a clue on this thing.

Cheers,
Magnus



From WeAreAs1 at aol.com  Mon Aug 24 22:19:54 1998
From: WeAreAs1 at aol.com (WeAreAs1 at aol.com)
Date: Mon, 24 Aug 1998 16:19:54 EDT
Subject: MIDI devices
Message-ID: <726003b2.35e1caec@aol.com>


In a message dated 8/24/98 11:00:07 AM, you wrote:

<<BTW does anyone know why they used a 25-PIN parallel
printer connector on the MPU-IPC box? Seems like WAY to many lines... (The
MIDIman only needs 9!)
>>

It's because the MPU-IPC system also includes some extras (besides MIDI) such
as FSK Tape Sync In/Out and an audio Click signal (some other stuff, too - I
can't remeber at this moment, though)

<<They didn't make a version that connects to the parallel port, did they?
That would expalin the connector at least.>>

No, they didn't.

Michael Bacich



From tomg at vivid.net  Mon Aug 24 22:50:59 1998
From: tomg at vivid.net (tomg)
Date: Mon, 24 Aug 1998 15:50:59 -0500
Subject: BLM  additions?
Message-ID: <yam7540.2966.119953344@mail.vivid.net>

Has anyone else been playing with 39OO logic?
I think I can do a rs-latch and a 1 of 2 d-mux
without using a gross of lm39OOs. I think this
would complete the set. The blm-1b would contain.

2 buffers
2 inverters
1 and
1 nand
1 or
1 nor
1 xor
1 rs latch
1 1 of 2 de-multiplexer

Can anybody suggest anything else within reason?
Think about it before suggesting something that
would take 3O nortons.

-tg





From sasami at blaze.net.au  Tue Aug 25 00:06:00 1998
From: sasami at blaze.net.au (Ken Stone)
Date: Tue, 25 Aug 1998 00:06:00 +0200 (MET DST)
Subject: 4007 (was: Re: DIY parts)
Message-ID: <199808242206.AAA23828@mailhost.bpa.nl>

Gate to gate coupling within chips is not uncommon. In a commercial design I
did years ago I was having this problem with either a CMOS chip or a quad
comparator (I forget which). In this case I was able to solve the problem by
using a 1uf capacitor (not an electro) across the power rails close to the
chip. Nowdays, I always decouple all of my CMOS chips with 100nF capacitors.

>JH said:
>
>It's no good idea to have the discharge circuitry of several
>VCOs too close together. Your always fighting "interlock",
>i.e. a limited minimum beat rate between VCOs, before they
>are syncronized (soft sync'ed) thru parasitic coupling.
>
>
>
>This is so true. But this weekend I found another example of this sort of
>thing in a high level circuit. I had a schmitt trigger CMOS chip squaring
>the ramp output of a CEM3340 to give me a square wave. But I could hear it
>clicking at the beat frequency with the other VCO. I traced it to the
>another gate within the same CMOS chip. This gate was being fired from the
>pulse output from the second VCO. Gate to gate crosstalk, and bad enough to
>delay the change of state in one of the gates. The problem was solved by
>using the gates on opposite quarters of the same chip.
>
>Regards,
>
>Tony Allgood, Cumbria, UK
>
>e-mail: oakley at enterprise.net
>
>Rack mounted Moog VCF module. PCBs have been ordered.
>
>http://aupe.phys.andrews.edu/diy_archive/schematics/effects/filter.html
>
>
>
>
>
_____________________________________________________________

                Ken Stone  sasami at blaze.net.au
                   ** Catgirl Paradise **
               <http://www.anime.net/~kens/>
         ** Australian Miniature Horses and ponies **
             <http://www.blaze.net.au/~sasami/>
_____________________________________________________________





From tomg at vivid.net  Tue Aug 25 00:22:22 1998
From: tomg at vivid.net (tomg)
Date: Mon, 24 Aug 1998 17:22:22 -0500
Subject: Mad Mouse Update
Message-ID: <yam7540.1138.120717800@mail.vivid.net>

The more I look at this the less it looks like a 
beginners project. Maybe I need to do something
with a CEM3394.....


Mad Mouse Schematics
http://www.tomg.vivid.net/madm/page_002.html

Mad Mouse PCB
http://www.tomg.vivid.net/madm/page_003.html

-tg




From jkjelec at tiac.net  Tue Aug 25 01:09:59 1998
From: jkjelec at tiac.net (Kyle Jarger)
Date: Mon, 24 Aug 1998 23:09:59 +0000
Subject: Again VCO's and exp. converters!
Message-ID: <199808250249.WAA23684@mailnfs0.tiac.net>

Tadej Bozicko <tadej.bozicko at uni-mb.si> wrote:

> The second question is: what exactly does the SOFT SYNC option? =
> Theoretical explanation wanted, not just that it provides more complex =
> waveforms that single oscillator and that it requires two of them =
> (osc's).

I think that soft sync is when the second oscillator resets only if 
it's instantaneous voltage is near the point where it would have 
reset, anyway.  Therefore, the 2ns osac only syncs to the first at 
certain osc2/osc1 frequency ratios, not _always_, as in hard sync.

Regards,
Kyle Jarger
jkjelec at tiac.net
JKJ Electronics
Visit our MIDI/CV converters website 
http://www.tiac.net/users/jkjelec



From massann at tin.it  Tue Aug 25 01:55:08 1998
From: massann at tin.it (Massimo Sanna)
Date: Tue, 25 Aug 1998 00:55:08 +0100
Subject: Looking for exciter schematics
Message-ID: <yam7541.408.119075216@mail.tin.it>

I would thank all the people who helped me in my  search:  
I think this is a special list  ;-)

Greetings


         Massimo Sanna

    email:   massann at tin.it
http://space.tin.it/arte/massanna




From costello at seanet.com  Tue Aug 25 02:34:32 1998
From: costello at seanet.com (Sean Costello)
Date: Mon, 24 Aug 1998 17:34:32 -0700
Subject: New Phaser schematic online
Message-ID: <35E20698.B494C533@seanet.com>

Hi everyone:

I just put a new phaser schematic up on my website
(http://www.seanet.com/~costello).  The schematic is for the Compact
Phasing "A," a German design which was manufactured by Gerd Schulte
Audio Electronika in the 1970's.  The Compact Phasing "A" was used by
Tangerine Dream, Ash Ra Tempel, Klaus Schulze and others.  It uses two
lamps driven by an LFO; each lamp drives four photocells which act as
the variable resistors in the usual op-amp phase shifting circuit.

Now that I think about it, I have a lot of designs on my page that were
used by German bands.  The VCS3 filter, the Moog filter, the Moog 960
sequencer, and now this phaser.  I need to get these things built (Tom
G's diode ladder filter is on a breadboard currently), & buy a Farfisa
to run through them, & get that Mellotron sample CD...

Anyway, if anyone has any comments on the phaser design, please let me
know, and I'll put them up on my page.  Also, please feel free to put
any of the schematics on my site (i.e. under my domain - not the ones I
link to) up on other sites, as I am really running out of room.

Thanks,

Sean Costello

P.S.  Speaking of Moogs, Farfisas, and German bands, the new album by
Jessamine should be out tomorrow.  Jessamine is a band from Portland,
Oregon (formerly from Seattle, Washington) that uses guitar, bass,
drums, Micromoog, Farfisa, and about a million old pedals to generate
some very nice moody spacey music.  If you like early Pink Floyd, Can,
Cluster, etc., you should check out Jessamine.  Available on the Kranky
record label.



From pfperry at melbpc.org.au  Tue Aug 25 03:29:02 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Tue, 25 Aug 1998 11:29:02 +1000 (EST)
Subject: UHF techniques (was: Re: 4007)
Message-ID: <1.5.4.16.19970116180221.30979462@popa.melbpc.org.au>

At 09:43 PM 24/08/98 +0200, Magnus Danielson  wrote:

>When squeeking my ASM-1 VCO upto 116 kHz I started to notice various

.......er, I doubt that Gene intended to run it beyond the dogs & bats range!
Perhaps decoupling caps could be placed on top of the chip and soldered 
directly to the power pins... (saved my ass a few times)

I used to be insanely jealous of anyone with a cro that went above 20MHz,
but now
I can see that ignorance is (sometimes) bliss....

paul perry melbourne australia




From tomg at vivid.net  Tue Aug 25 04:04:31 1998
From: tomg at vivid.net (tomg)
Date: Mon, 24 Aug 1998 21:04:31 -0500
Subject: Maxx vcf7a update
Message-ID: <yam7540.1559.120998016@mail.vivid.net>

This would be the vcf7a pcb. Still untested...

http://www.tomg.vivid.net/maxx/page_034.html

http://www.tomg.vivid.net/maxx/pics/vcf7a_3.gif
http://www.tomg.vivid.net/maxx/pics/vcf7a_4.gif
http://www.tomg.vivid.net/maxx/pics/vcf7a_5.gif

-tg






From batzman at all-electric.com  Tue Aug 25 05:48:53 1998
From: batzman at all-electric.com (The Dark force of dance)
Date: Tue, 25 Aug 1998 12:48:53 +0900
Subject: Looking for exciter  schematics
Message-ID: <3.0.32.19980825124347.006e1dfc@mail.chariot.net.au>

Y-ellow Y'all.
	I had been following this thread with some interest. I have a need to
replace my Aphex Anal Explorer. Oops I mean Aural Exciter and build
something of a clone. It's a back-burner project at the moment but I had
been looking for a schematic for it for some years.

I tried to trace out the circuit some years ago but I couldn't make sense
of it then. It makes more sense now but I have in no-way had time to get
back to tracing the circus. It's a bugger of a job.

Having said that, I know that it works entirely differently to the Circuit
by Jules Ryckebusch. What it appears to do is selectively filter out the
top end, then re-modulate that with it self. It uses an OTA. A 13600.
Actually not a real 13600 but a second source part. I forget the part
number but it amounts to the same thing. The control current input (Iabc)
is fed from the signal source it self. This seems to be a fixed amount but
the source is through the filter. The output of this circuit is mixed back
with the dry signal through the mix pot. I say "Seems to" because I'm not
entirely sure that's exactly how it works.

As best as I can figure it, the audio in the selected frequency band 2
quadrant multiplies with the original signal causing harmonic spikes. The
irony of this is that this should, in theory, provide similar enhancement
properties you can get with a good valve pre-amp. (Note here Eric. I said
"Similar" not the same.)

But. Clipping within the band and re-mixing it is certainly an interesting
concept.

I noted recently also that Vesta made an almost identical clone to the
Aphex type C box. The principal is probably well established now. I just
wish I could find an actual circus to the Aphex type from which I could
work. If anyone has such a circuit kicking round in their archive, I'll
swap you three chickens and a goat for it.

Thanks in advance.

Be absolutely Icebox.

 _ __        _                              
| "_ \      | |         batzman at all-electric.com / aek at all-electric.com
| |_)/  __ _| |_ ____           ALL ELECTRIC KITCHEN               
|  _ \ / _` | __|___ |  The new AEK CD, Elementary Urban sanity    
| |_) | (_| | |_  / /   is out now on Transmission Communications from
|_,__/ \__,_|\__|/ /    http://brisbane.dialix.com.au:80/~com11
                / ,__   and check out http://www.all-electric.com
Goodfortune    |_____|       Let your SANITY wear thin.




From ka4hjh at gte.net  Tue Aug 25 07:32:56 1998
From: ka4hjh at gte.net (KA4HJH)
Date: Tue, 25 Aug 1998 01:32:56 -0400
Subject: Looking for exciter  schematics
In-Reply-To: <3.0.32.19980825124347.006e1dfc@mail.chariot.net.au>
Message-ID: <v04011701b207fbeb4efa@[208.255.152.91]>

>I noted recently also that Vesta made an almost identical clone to the
>Aphex type C box. The principal is probably well established now. I just
>wish I could find an actual circus to the Aphex type from which I could
>work. If anyone has such a circuit kicking round in their archive, I'll
>swap you three chickens and a goat for it.

There was an exciter-like device in Electronic Musician years ago which was
a fairly straightforward distort-and-EQ-it-type circuit. Somebody from
Aphex wrote in to "remind" everyone that their design was patented, blah
blah blah. So the question is--was the design too close, or was Aphex just
blowing smoke?

Terry Bowman, KA4HJH
"The Mac Doctor"



From ryckebu at subasehp.san.mrms.navy.mil  Tue Aug 25 12:28:15 1998
From: ryckebu at subasehp.san.mrms.navy.mil (Jules Ryckebusch)
Date: Tue, 25 Aug 1998 10:28:15 +0000
Subject: Looking for exciter  schematics
In-Reply-To: <yam7541.2925.119070912@mail.tin.it>
References: <199808241619.JAA29294@subasehp.san.mrms.navy.mil>
Message-ID: <199808251730.KAA03865@subasehp.san.mrms.navy.mil>

Based on the response to this thread, I will re-draw the schematic 
in a postable format and do it that way. As a side note, it really 
does sound like the Aphex device. I believe Aphex came up with 
varitaions, including the cross modulation of the high frequencies 
with a multiplier AND the distortion method I used (which is in one 
of their patents, alebiet probably "bustable") Give me a couple days 
ont this and I'll post it. I always wanted to use a tube section for 
the distortion end of the circuit... Maybe now would be a good time. 
One final note, the Aphex patent using distortion expired in 1997.

Jules

> From:          Massimo Sanna 
<massann at tin.it>
> To:            Jules Ryckebusch <ryckebu at subasehp.san.mrms.navy.mil>
> Date:          Tue, 25 Aug 1998 00:16:58 +0100
> Subject:       RE: Looking for exciter  schematics

> Hi Jules,
> I am interested in knowing as much as possible about this kind of devices:
> well, I like audio devices in general, but something of exciter's behaviour
> has impressed me in past.
>  If you really can  send me the schematic, here it is my address:
> 
>   Massimo Sanna
>   Piazza degli Alpini, 6
>   09134    Cagliari
>   Italy
> 
> 
>  I am proud to be on this list.   Thanks a lot for your help, it is
> invaluable.
> 
> 
>          Massimo Sanna
> 
>      Q-Indie Techno Project
>     member of S.U.I.F. group
>     email:   massann at tin.it
> http://space.tin.it/arte/massanna
> 
> 
> 



From martin.czech at intermetall.de  Tue Aug 25 12:34:48 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Tue, 25 Aug 1998 12:34:48 +0200 (MET DST)
Subject: some app. notes
Message-ID: <199808251034.MAA10233@window.intermetall.de>

I asked about boosting op amp output current (and voltage).
The answers were LT1010 and (after digging) National App. Note
272.

Further I found this quite usefull (well, a bit dust is on
there, but never the less)

I came across App. Note 31. This is a collection of op amp
circuits. A bit outdated, but may be inspiring.

App. Note 242 shows a current meter 100pA-3mA.

App. Note 182 deals with power supply reliability.

m.c.




From ryckebu at subasehp.san.mrms.navy.mil  Tue Aug 25 14:58:27 1998
From: ryckebu at subasehp.san.mrms.navy.mil (Jules Ryckebusch)
Date: Tue, 25 Aug 1998 12:58:27 +0000
Subject: My 10$ Harmonic Sweetner and Aphex
In-Reply-To: <19980825181249.21396.qmail@nuernberg2.pop.metronet.de>
Message-ID: <199808252001.NAA07418@subasehp.san.mrms.navy.mil>

O.K here is the final dope on my $10 harmonic sweetner. See Aphex's 
original patent of 17 April 1979 at:
http://www.patents.ibm.com/details?&patent_number=4150253
It is interesting reading. They use a single diode clipper for 
harmonic generation claiming both even and odd harmonics generated. 
They first run the signal through a high pass filter (3-4K0 then the 
clipper then another high pass filter at 6Khz. the patent is 
interesting reading actually, they cover the bases of electronically 
mixing the two signals or acoustically via separate amp and speakers 
for the original and harmonics. Based on the date and adding 17 years 
I can commercially use my circuit as of April 17th 1996, so I was off 
a couple years. My article description in the sept 1987 Electronic 
Musician reads very close to thier patent description but I didn't 
read that until today! Cool.

Jules Ryckebusch



From debus at cityweb.de  Tue Aug 25 15:37:01 1998
From: debus at cityweb.de (Ingo Debus)
Date: Tue, 25 Aug 1998 15:37:01 +0200
Subject: Resonant filters?
References: <1.5.4.16.19970116073122.282fe5ac@popa.melbpc.org.au>
Message-ID: <35E2BDF9.6E8F@cityweb.de>

Paul Perry wrote:
> A more interesting question is, Is there any way to produce filters
> (H,L & B) with control over cutoff ferquency and resonance **WITH** DSP,
>  and have them behave in a satisfactory way for musical
> applications? The solution is neither simple nor obvious....

Ever heard how the (digital) filter of a Roland sampler (S-330,
S-760...) sounds? I once compared it to a CEM3320 filter, both with high
resonance and with the same input singal. There was no big difference.

But resonance cannot be controlled by MIDI controllers :-(

Ingo




From b.layer at vikingelectronics.com  Tue Aug 25 16:39:08 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Tue, 25 Aug 1998 09:39:08 -0500
Subject: Looking for exciter  schematics
In-Reply-To: <3.0.32.19980825124347.006e1dfc@mail.chariot.net.au>
Message-ID: <3.0.5.32.19980825093908.007c2100@192.168.210.18>

Hi 
>
>As best as I can figure it, the audio in the selected frequency band 2
>quadrant multiplies with the original signal causing harmonic spikes. The
>irony of this is that this should, in theory, provide similar enhancement
>properties you can get with a good valve pre-amp. (Note here Eric. I said
>"Similar" not the same.)
>
(Bill climbs atop the soapbox, obviously requiring some effort..)

Interesting thought, but any valve preamp that 'enhances' the sound by
adding harmonics is not a very good preamp. It is important (for sake of
our purposes) that we dispell the notion that tubes are inherently
euphonic. A more correct approach would be to agree that when operated for
intended distortion, tubes are much more inherently musical than SS devices.

Remember these things:

1) If they say their tube amp is 'sweet' they mean a signle-ended section
producing even-order harmonics  

2) If they it has that 'all-out tube sound', they mean it's a push-pull
section (likely AB1) producing odd-order distortion.

I guess what I'm getting at is: Don't believe the hype! (both can't be
right) Tubes can be sweet, agressive or quite transparent; take your pick.

 
Bill Layer
"Quantity has a Quality all of it's own." -JL



From semh9228 at oberlin.edu  Tue Aug 25 17:34:16 1998
From: semh9228 at oberlin.edu (Silence)
Date: Tue, 25 Aug 1998 11:34:16 -0400 (EDT)
Subject: Exciter
Message-ID: <Pine.OSF.3.96.980825112529.10369B-100000@mercury.cc.oberlin.edu>

As I understand it,
The exciter filters out everything below a certain frequency, let's say,
5Khz.  It then distorts these frequency bands, and then mixes the original
signal with the modified signal.  The output then sounds 'brighter'
because it actually adds harmonics that weren't originally present in the
signal.  It was really a novelty at the time.  Speaking of tubes, the
original was accidentally created when one of the design guys at Aphex
incorrectly assembled a tube amp.  The result was what is
considered to be the first 'psycho-acoustic' enhancer.  The first design
was so secret that they wrapped the entire circuit in epoxy, and only made
the unit available for rental, it could not be purchased.  You can see why
they might write into EM with copyright complaints.  I have never seen the
schematic for the original, but I think that other circuits sound just as
good.  Just split a signal, send half through a hipass filter and the
distortion circuit of your choice, and then mix the two signals back
together.  There you go.  I have heard most of this second hand so please
correct misinformation.  Thanks.

				Eli

					




From hdan at charybdis.com  Tue Aug 25 17:47:10 1998
From: hdan at charybdis.com (Dan Higdon)
Date: Tue, 25 Aug 1998 10:47:10 -0500
Subject: MOTM VCA overdrive
Message-ID: <01bdd03f$9eb94160$352ccfcf@ares.charybdis.com>

I (finally) got my PAiA MIDI->CV controller finished, and was able
to take Wally from the realms of sci-fi noise maker to real musical
instrument.  (No more drones for him!  :-)

At any rate, this gave me a lot of extra freedom to play Wally like
a "real" synth, and I made one interesting discovery about my
MOTM VCA module.  Aside from being dead-clean (from a 
noise perspective), this little guy can overdrive like a demon!
I don't know if it was designed that way, but if I hit it with a bit
too much control voltage, it starts to clip in a *very* sweet way.

This sort of thing might be old news to the rest of you, but
for me it was a revelation, and it sounds MUCH nicer than
overdriving my Mackie or StudioQUAD ins.  :-)  In fairness, I
haven't tried pumping the signal through my tubefuzz (Anderton
 style), and I don't own any real tube-gear (yet), so maybe I could
get better distortion sounds.  (I've played with distortion effects
on my digitals, but their effect is largely uninspiring to my ear.)
This distortion sounds more like a "blasting" brass instrument
than a guitar amp, but that may be a function of the waves I'm
feeding it more than the circuit.

At any rate, to sum up:  MOTM VCAs may be quiet, but you can
goose them into a less polite personality.  I can't wait for the
preamp/env follower/moog filter!

(The MOTM line has convinced me to switch my existing modules
away from banana jacks to 1/4".  It just gets too annoying trying to
mix the two.  <sigh>  It won't be cheap or easy, but I think it's the
right thing to do for me.)

----------------------------------------
hdan at charybdis.com
"Trust not the monkey, nor his clever schemes" - hdan




From dbalvage at ptdcs2.ra.intel.com  Tue Aug 25 18:21:57 1998
From: dbalvage at ptdcs2.ra.intel.com (Duane R Balvage)
Date: Tue, 25 Aug 1998 09:21:57 -0700
Subject: Exciter
Message-ID: <35E2E4A5.5648@ptdcs2.intel.com>

Hello all -

I believe that Silence's description was fairly accurate, but it was 

incomplete. When you "clip" a signal, it tends to "hard limit" it

or at least compress it.

 So, after the HPF and clipping ckt. (back to back green

LED's in a feedback loop is my personal favorite - all even *and* odd

harmonics represented...), an envelope follower & VCA mix the "clipped"

signal back into the "clean" signal. That way the harmonic content 

"follows" the music volume like it should. I also have the feeling that 

the HPF loosely "tracks" the input signal's cutoff frequency - that way,

the more muffled the original, the more "enhancement" it gets....


Just my 0.02 worth, an edumucated guess at best....



					- Duane
-- 
   "That boy's got a mouth like a cannon ... Always shootin' it off..."
                                
                             - Foghorn Leghorn
                      ________________________________
                     / o o oo              o ooo o   /\
       -------------/ ////  Duane R. Balvage   //// / /---------
                   /    _________________________  / /
                  / // / // /// // /// // /// / / / /
                 /___ //////////////////////////_/ /
                 \____\________________________\_\/

                     Intel Corporation, RA1-303
                   Portland Technology Development
       =========================================================

              Phone: (503) 613-8055    FAX: (503) 613-8261
                   E-Mail: dbalvage at ptdcs2.intel.com



From don at till.com  Tue Aug 25 18:30:12 1998
From: don at till.com (Don Tillman)
Date: Tue, 25 Aug 1998 09:30:12 -0700 (PDT)
Subject: VCA chips
Message-ID: <199808251630.JAA13339@shell9.ba.best.com>

Hiya.

JH's interpolating scanner work inspired me to come up with some
designs of my own, and I'm writing up an article about them that I'll
be posting soon.

And so... I've been looking at the VCA issue.  JH uses SSM2024's,
clearly a good choice for hifi reasons, but it appears from the Analog
Devices web site (http://www.analog.com) that these are no longer in
production and a newer chip called the SSM2164 is the one to use.
Okay fine; and look, the data sheet for the SSM2164 mentions that you
they're designed to replace the SSM2024 with minimal circuit changes.
Cool...

Except they fail to mention that the polarity of the control input is
inverted.  

Before I phone Analog Devices, does anybody have any insight
recommendations on this?  Any experience with the 2164?

  -- Don









From costello at seanet.com  Tue Aug 25 18:44:08 1998
From: costello at seanet.com (Sean Costello)
Date: Tue, 25 Aug 1998 09:44:08 -0700
Subject: Looking for exciter  schematics
References: <3.0.32.19980825124347.006e1dfc@mail.chariot.net.au>
Message-ID: <35E2E9D8.3C0A4D83@seanet.com>

The Dark force of dance wrote:

> As best as I can figure it, the audio in the selected frequency band 2
> quadrant multiplies with the original signal causing harmonic spikes. The
> irony of this is that this should, in theory, provide similar enhancement
> properties you can get with a good valve pre-amp. (Note here Eric. I said
> "Similar" not the same.)

Are you sure it is using amplitude modulation?  With the 13600 circuit
you describe, maybe it is controlling a lowpass or allpass filter with
the input frequency.  FMing an allpass filter would seem to be a great
way to produce lots of harmonics.

> I noted recently also that Vesta made an almost identical clone to the
> Aphex type C box. The principal is probably well established now. I just
> wish I could find an actual circus to the Aphex type from which I could
> work. If anyone has such a circuit kicking round in their archive, I'll
> swap you three chickens and a goat for it.

If the circuit was patented after 1974 or so, you should be able to find
it at http://www.patents.ibm.com.  I did a search for "Aphex" last
night, but all of the patents seemed too recent.  Did Aphex have a
different corporate name in the past?

Sean Costello



From a-davidh at microsoft.com  Tue Aug 25 19:35:25 1998
From: a-davidh at microsoft.com (David Halliday (Volt Computer))
Date: Tue, 25 Aug 1998 10:35:25 -0700
Subject: Exciter
Message-ID: <C35556591D34D111BB5600805F1961B906183FE4@RED-MSG-47>

I went to the IBM Patent server ( http://www.patents.ibm.com/ibm.html );
put "Aphex" in the search line and come up with the following 13 citations:

Functional control block for voltage regulator with dual servo loops
Concentric servo voltage regulator utilizing an inner servo loop and an
outer servo loop 
Wave dependent compressor
Peak accelerated compressor
Reflected plate amplifier
Transient discriminate harmonics generator
Frequency discriminate leveler
Audio bass frequency enhancement
Logic enhanced noise gate
Discrete parallel path modulation multiplexer
High frequency expander device
Impulse detection circuit
Split-band clipper 


All of these patents are available for viewing on this web site.





-----Original Message-----
From: Silence [mailto:semh9228 at oberlin.edu]
Sent: Tuesday, August 25, 1998 8:34 AM
To: synth-diy at mailhost.bpa.nl
Subject: Exciter


As I understand it,
The exciter filters out everything below a certain frequency, let's say,
5Khz.  It then distorts these frequency bands, and then mixes the original
signal with the modified signal.  The output then sounds 'brighter'
because it actually adds harmonics that weren't originally present in the
signal.  It was really a novelty at the time.  Speaking of tubes, the
original was accidentally created when one of the design guys at Aphex
incorrectly assembled a tube amp.  The result was what is
considered to be the first 'psycho-acoustic' enhancer.  The first design
was so secret that they wrapped the entire circuit in epoxy, and only made
the unit available for rental, it could not be purchased.  You can see why
they might write into EM with copyright complaints.  I have never seen the
schematic for the original, but I think that other circuits sound just as
good.  Just split a signal, send half through a hipass filter and the
distortion circuit of your choice, and then mix the two signals back
together.  There you go.  I have heard most of this second hand so please
correct misinformation.  Thanks.

				Eli

					



From Chris.List at sc.siemens.com  Tue Aug 25 19:55:47 1998
From: Chris.List at sc.siemens.com (List, Christopher)
Date: Tue, 25 Aug 1998 13:55:47 -0400
Subject: VCA chips
Message-ID: <81A062BC5305D111A9D700805F065968CE94EF@maildepo.sc.siemens.com>

Hi Don - 

Yes, I've played with the 2164, and it is a nice chip, but it is
significantly different from the 2024. The biggest difference being the
fact that it is controlled exponentially by a voltage rather than
linearly by a current. Far from a "drop in replacement". 

Other than that, I'm not sure what kind of info you're looking for...

Last time I checked, Newark was still selling 2024's, so I picked up
about 10 of 'em for safe keeping...

C.List
chris.list at sc.siemens.com

> -----Original Message-----
> From:	Don Tillman [SMTP:don at till.com]
> Sent:	Tuesday, August 25, 1998 12:30 PM
> To:	synth-diy at mailhost.bpa.nl; jhaible at metronet.de
> Subject:	VCA chips
> 
> Hiya.
> 
> JH's interpolating scanner work inspired me to come up with some
> designs of my own, and I'm writing up an article about them that I'll
> be posting soon.
> 
> And so... I've been looking at the VCA issue.  JH uses SSM2024's,
> clearly a good choice for hifi reasons, but it appears from the Analog
> Devices web site (http://www.analog.com) that these are no longer in
> production and a newer chip called the SSM2164 is the one to use.
> Okay fine; and look, the data sheet for the SSM2164 mentions that you
> they're designed to replace the SSM2024 with minimal circuit changes.
> Cool...
> 
> Except they fail to mention that the polarity of the control input is
> inverted.  
> 
> Before I phone Analog Devices, does anybody have any insight
> recommendations on this?  Any experience with the 2164?
> 
>   -- Don
> 
> 
> 
> 
> 



From jhaible at metronet.de  Tue Aug 25 20:08:46 1998
From: jhaible at metronet.de (jhaible)
Date: Tue, 25 Aug 1998 20:08:46 +0200
Subject: AW: New Phaser schematic online
Message-ID: <19980825181249.21396.qmail@nuernberg2.pop.metronet.de>

Sean, this is great news !
Do you know how long I wanted to see these schemos ??
And where on earth did you get them ??

Comments on the design later - I've just downloaded it, and
wanted to share my joy immediately.

JH.




From jhaible at metronet.de  Tue Aug 25 20:24:04 1998
From: jhaible at metronet.de (jhaible)
Date: Tue, 25 Aug 1998 20:24:04 +0200
Subject: VCA chips
Message-ID: <19980825221030.25497.qmail@nuernberg2.pop.metronet.de>

> JH's interpolating scanner work inspired me to come up with some
> designs of my own, and I'm writing up an article about them that I'll
> be posting soon.

Sounds interesting !

> And so... I've been looking at the VCA issue.  JH uses SSM2024's,
> clearly a good choice for hifi reasons, but it appears from the Analog
> Devices web site (http://www.analog.com) that these are no longer in
> production and a newer chip called the SSM2164 is the one to use.

I noticed the same thing some time ago, and asked AD about the 2024's.
Back then (about 1/2 year ago), they said they were still in production,
but they recommend the 2164 instead. So it's a good idea to ask them again
about the 2024's current state.

> Okay fine; and look, the data sheet for the SSM2164 mentions that you
> they're designed to replace the SSM2024 with minimal circuit changes.
> Cool...
> Except they fail to mention that the polarity of the control input is
> inverted.  

Doesn't the 2164 has exponential control inputs ? I don't remember that
exactly,
but in that case it would be hard to use in the Scanner.

I haven't done this myself, but I highly recommend that someone tries the
CA3280 (no typo) for the scanner. It can handle much higher Iabc currents,
so one could insert the LEDs directly in the Iabc control path. (with ne
calculated
threshold voltages, of course).

JH.




From b.layer at vikingelectronics.com  Tue Aug 25 21:13:27 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Tue, 25 Aug 1998 14:13:27 -0500
Subject: Analog voice processing
Message-ID: <3.0.5.32.19980825141327.007c5210@192.168.210.18>

Hi All,

(Please indulge me in a silly question)

Does anyone know what effect was used for the voices of the Ceylons in
Battlestar Galactica? It had a nasty metal-on-metal type sound. My initial
guess is that this was done with a vocoder and synth. 

I've heard versions of this effect at several different times, and I'm
interested in emulating it.

Thanks,



Bill Layer
"Quantity has a Quality all of it's own." -JL



From tomg at vivid.net  Tue Aug 25 22:18:10 1998
From: tomg at vivid.net (tomg)
Date: Tue, 25 Aug 1998 15:18:10 -0500
Subject: Maxx VCF-8A KLM type
Message-ID: <yam7541.522.120970120@mail.vivid.net>

The VCF-8A is based on the KLM filter. The filter can be configured
high or low. Build two and put 'em in series high-pass/low-pass.
It was in that last batch of stuff marjan sent me. He said it sounded 
really good so I gave it a shot. I REALLY like this filter! I will do 
a dual LM136OO version! It falls somewhere between the OBX type and
the ms5O type, the best of both. Breaks into self-osc. about 75% on 
the res pot DANGER! it's LOUD.  

Modifications.

 used 2X 3O8O/O72 instead of 136OO
 changed the exp-conv.
 changed a few res loop values.
 added hi/low select switch.

PCB is untested.

page-

http://www.tomg.vivid.net/maxx/page_035.html

vcf8a.wav file 67K-

http://www.tomg.vivid.net/maxx/pics/vcf8a.wav

-tg




From magnus at analogue.org  Tue Aug 25 23:54:00 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Tue, 25 Aug 1998 23:54:00 +0200
Subject: MIDI devices
In-Reply-To: Your message of "Mon, 24 Aug 1998 16:19:54 EDT"
References: <726003b2.35e1caec@aol.com>
Message-ID: <199808252154.XAA16967@piraya.electrum.kth.se>

>>>>> "W" == WeAreAs1  <WeAreAs1 at aol.com> writes:

Hi!

 W> In a message dated 8/24/98 11:00:07 AM, you wrote:

 W> <<BTW does anyone know why they used a 25-PIN parallel
 W> printer connector on the MPU-IPC box? Seems like WAY to many lines... (The
 W> MIDIman only needs 9!)
 >>> 

 W> It's because the MPU-IPC system also includes some extras (besides MIDI) such
 W> as FSK Tape Sync In/Out and an audio Click signal (some other stuff, too - I
 W> can't remeber at this moment, though)

>From Chapter 2 of MPU-401 Midi Processing Unit Technical Reference
Manual Version 1.5 5/29/85 (that is, blitzing new :) comes the
following pinassignments:

Signal	Pin #	Direction
D0	1	I/O
D1	14	I/O
D2	2	I/O
D3	15	I/O
D4	3	I/O
D5	16	I/O
D6	4	I/O
D7	17	I/O
A0	5	I
A1	18	I
A2	6	I
RD*	9	I
WR*	22	I
CS*	10	I
DSR*	23	O
RES*	11	I
+5Vdc	12&24	I
GND	13&25	I

Signals with * are active low.

DSR* (Data Set Ready) output is Open Collector and is usually
connected to the host system interrupt system.

The ISA card will buffer the signals (A0, A1, A2, RD*, WR*, RES*) from
the bus and the data buss will be sent through a bidirectional
transciever. A 74LS244 and a 74LS245 will perform thise task well.
I assume that the ISA signals IORD* and IOWR* can be directly
used. The 245 will have it's direction default as being out from the
bus and only when CS* and IORD* gets active simultaniously will it be
reversed. The CS* will then be connected to the OE* (pin 19) of the
245 where as the IORD* is connected to the DIR input (pin 1). For this
to work will the ISA bus be connected to the A-side (pin 2-9) and the
contact to the MPU-401 to the B-side (pin 18-11). We still want the
CS* to be generated. This is done with a 74LS688 which compares the
address A9-A3 and the ANDed result of IORD* and IOWR* with the fixed
pattern 11000000 giving the CS* on pin 19. We would also like to
isolate the DSR* signal, this can be done by using a 74LS09 AND gate,
another is being used for ANDing the IORD* and IOWR* for the CS*
generation. The buffered DSR* signal is being hooked to the IRQ2 line.

Let's see, the chipcount is now:
1	74LS244
1	74LS245
1	74LS688
1	74LS09

Add to this:
Some resistors (pullup for the Open Collector input as well as
standard input protection).
Some capacitors (power decoupling and input protection).
25-pin D-sub connector.

And you have replaced the missing card to make that MPU-401 running
with all kinds of software on your PC. Who ever said that ISA was complex?

 W> <<They didn't make a version that connects to the parallel port, did they?
 W> That would expalin the connector at least.>>

 W> No, they didn't.

Giving up on compability with exsisting code you could probably get it
working with many bidirectional and almost bindirectional parallel
ports. Even the original parallel port where a wire away from being
directional and rumours says that they intended it to bethat but they
withdraw this very late in the design and hardwired it to
unidirectional (the LS245 was there and a spare pin on a register was
left hanging loose, just a wire would be needed to control the DIR pin).

MAybe not very analog and originally not intended to be DIY but now we
at least got the later in on this thread ;)

PS. Bill, send that MPU-401 my way ;)

Cheers,
Magnus



From magnus at analogue.org  Wed Aug 26 00:06:25 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Wed, 26 Aug 1998 00:06:25 +0200
Subject: UHF techniques (was: Re: 4007)
In-Reply-To: Your message of "Tue, 25 Aug 1998 11:29:02 +1000 (EST)"
References: <1.5.4.16.19970116180221.30979462@popa.melbpc.org.au>
Message-ID: <199808252206.AAA17061@piraya.electrum.kth.se>

>>>>> "PP" == Paul Perry <pfperry at melbpc.org.au> writes:

 PP> At 09:43 PM 24/08/98 +0200, Magnus Danielson  wrote:
 >> When squeeking my ASM-1 VCO upto 116 kHz I started to notice various

 PP> .......er, I doubt that Gene intended to run it beyond the dogs & bats range!
 PP> Perhaps decoupling caps could be placed on top of the chip and soldered 
 PP> directly to the power pins... (saved my ass a few times)

Well, I wanted to get a feeling about upper and lower limits, over a
19.7 octave range I had pretty good tracking. The thing was that I
only noticed these things as I got up there, but later I could find
them when looking for them at any frequency.

 PP> I used to be insanely jealous of anyone with a cro that went above 20MHz,
 PP> but now
 PP> I can see that ignorance is (sometimes) bliss....

Well, one learn to apprechiate these features the more one uses
them. The scope was bought to troubleshoot more or less digital
curcuits but this is what I use it for during the weekends ;)

Cheers,
Magnus





From jhaible at metronet.de  Wed Aug 26 00:35:13 1998
From: jhaible at metronet.de (jhaible)
Date: Wed, 26 Aug 1998 00:35:13 +0200
Subject: Just another Phaser ...
Message-ID: <19980825224342.26014.qmail@nuernberg2.pop.metronet.de>

> 
> Hey, I'm glad that someone appreciates this!  I know that this phaser is
> responsible for some of my favorite sounds out there. 

Yes, that's the reason for me, too.

> Let me know what this phaser inspires for you.  

Well, the modulation circuit is rather strange. Will have to look at this
closer. The rest is rather standard, similar to the Mutron. Notable: The
feedback loop only goes around 2 stages. I have to do some simulations
of this circuit ...

> I'd love to see a modern
> design that can produce these sounds.  

I have just published the description and schematics of my "Neptune"
optoelectronic phaser. It's at 
<http://www.synthfool.com/diy/hj_neptune.html>
(Thanks, Kevin !). It is more based on the Univibe rather than the Mutron
design (phase splitter and non-grounded photocells), but it shows the
typical
slow and smoothed modulation that comes from the LDR's response time.

>I am
> repairing my Mutron Phasor II right now, which has a weird metal "can"
> with 10 legs - I presume this is an LED surrounded by 4 photocells.

Phasor II - is this the same as the Biphase ? The Biphase has 6 LDRs + LED
packed together (x2).

JH.



From ka4hjh at gte.net  Wed Aug 26 06:02:01 1998
From: ka4hjh at gte.net (KA4HJH)
Date: Wed, 26 Aug 1998 00:02:01 -0400
Subject: My 10$ Harmonic Sweetner and Aphex
In-Reply-To: <199808252001.NAA07418@subasehp.san.mrms.navy.mil>
References: <19980825181249.21396.qmail@nuernberg2.pop.metronet.de>
Message-ID: <v04011700b20938e08187@[208.255.152.3]>

>My article description in the sept 1987 Electronic
>Musician reads very close to thier patent description but I didn't
>read that until today! Cool.

Amazing. I guess eleven years was worth the wait. Isn't the Internet wonderful?

Terry Bowman, KA4HJH
"The Mac Doctor"



From batzman at all-electric.com  Wed Aug 26 08:32:48 1998
From: batzman at all-electric.com (The Dark force of dance)
Date: Wed, 26 Aug 1998 15:32:48 +0900
Subject: Looking for exciter  schematics
Message-ID: <3.0.32.19980826151923.006abc44@mail.chariot.net.au>

Y-ellow Jules 'n' y'all.

At 10:28 AM 08/25/98 +0000, Jules Ryckebusch wrote:
>Based on the response to this thread, I will re-draw the schematic 
>in a postable format and do it that way. As a side note, it really 
>does sound like the Aphex device. I believe Aphex came up with 
>varitaions, including the cross modulation of the high frequencies 
>with a multiplier AND the distortion method I used (which is in one 
>of their patents, alebiet probably "bustable") Give me a couple days 
>ont this and I'll post it. I always wanted to use a tube section for 
>the distortion end of the circuit... Maybe now would be a good time. 
>One final note, the Aphex patent using distortion expired in 1997.

This all sounds more plausible. At the time I tried to reverse engineer the
box I had no clue as to how these things work. Which always makes things
harder to understand. The thing that stumped me was that the amplitude
control of the 13600, IE: Iabc, was derived directly through a resistor
from it's input. At which point I threw my hands up and said. "Nar this is
too weird." Upon reflection though it could have been simply trying to use
the OTA for distortion. I don't know if anyone has noticed but an LM13600
in just the _Wrong_ configuration makes one wicked distortion unit.

I don't know exactly but it could also stand to reason that it provides
some sort of cross modulation circuit. Unfortunately all these things crop
up at just the wrong time for me. Bogged down as I am at the moment in a
VGA system that won't. But I've downloaded some of the patent information
and will chew threw it at my earliest possible time. I also want to look
into how they do their bass enhancement as well.

Thanks y'all and I look forward to your re-drawn enhancer circuit Jules.

Be Absolutely Icebox.

 _ __        _                              
| "_ \      | |         batzman at all-electric.com / aek at all-electric.com
| |_)/  __ _| |_ ____           ALL ELECTRIC KITCHEN               
|  _ \ / _` | __|___ |  The new AEK CD, Elementary Urban sanity    
| |_) | (_| | |_  / /   is out now on Transmission Communications from
|_,__/ \__,_|\__|/ /    http://brisbane.dialix.com.au:80/~com11
                / ,__   and check out http://www.all-electric.com
Goodfortune    |_____|       Let your SANITY wear thin.




From martin.czech at intermetall.de  Wed Aug 26 09:21:12 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Wed, 26 Aug 1998 09:21:12 +0200 (MET DST)
Subject: VCA chips
Message-ID: <199808260721.JAA20316@window.intermetall.de>

> Yes, I've played with the 2164, and it is a nice chip, but it is
> significantly different from the 2024. The biggest difference being the
> fact that it is controlled exponentially by a voltage rather than
> linearly by a current. Far from a "drop in replacement". 

This was also my impression.
It seems that all linear control VCAs are gone.

Would it be possible to make a VCA with CA3280 in the following manner:
The two otas should match. I can use the linearising diodes,
no need for input attenuator (how much noise comes from the diodes?).
If I set them up in differential mode, ie. one with the signal
at + , the other at - and subtract the output currents, will this
give improoved control feedthrough rejection?
However, the CA3280 data sheet claims lower noise and feedthrough
(then 3080) anyway. Hope I can test this in September.

m.c. 




From martin.czech at intermetall.de  Wed Aug 26 09:49:35 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Wed, 26 Aug 1998 09:49:35 +0200 (MET DST)
Subject: Analog voice processing
Message-ID: <199808260749.JAA20386@window.intermetall.de>

> Hi All,
> 
> (Please indulge me in a silly question)
> 
> Does anyone know what effect was used for the voices of the Ceylons in
> Battlestar Galactica? It had a nasty metal-on-metal type sound. My initial
> guess is that this was done with a vocoder and synth. 
> 
I think it is pitch shifting with lfo controlling the pitch shift ,
fast and deep. This can be done by a chorus with very deep modulation.
The Peavy Profex II has such a sound as preset.

Aiaiaiat leeaeaest ieieit suouounnndssss tououo meieiei thaiaiat waiaiay.

m.c.




From martin.czech at intermetall.de  Wed Aug 26 09:52:22 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Wed, 26 Aug 1998 09:52:22 +0200 (MET DST)
Subject: VCA chips (2)
Message-ID: <199808260752.JAA20394@window.intermetall.de>

Sorry a stupid mistake.
This way no enhancemet will be possible.

It must read:

If I set them up in differential mode, ie. one with the signal at + ,
the other WIRTH AN INVERTED SIGNAL ALSO at + and subtract the output
currents, will this give improoved control feedthrough rejection?
However, the CA3280 data sheet claims lower noise and feedthrough (then
3080) anyway. Hope I can test this in September.

m.c.




From tomg at vivid.net  Wed Aug 26 10:08:50 1998
From: tomg at vivid.net (tomg)
Date: Wed, 26 Aug 1998 03:08:50 -0500
Subject: Maxx Arm-1A Audio Ring Mod.
Message-ID: <yam7542.2520.120887024@mail.vivid.net>

The ARM-1A Audio Ring Modulator was taken from a Sept.'79 Radio
Electronics series by James J. Barbarello on "Electronic Percussion
Synthesizers". It is a simple 3O8O vca thats modulated by a audio 
frequency oscillator. It sounds a lot like a ring modulator but isn't 
one. It's more like a tremelo and can be used as one ,just modulate 
it at a lower frequency. The on-board oscillator can be omitted if 
you have a source osc. already. Build 2, modulate at different 
frequencys then mix, for a pretty good Cylon. Maybe pre mix phase 
shift 1 of them..reverb?...bbuuyy yyoouurr lleeaavveee..

Bill's VoC question reminided me I had this.

-tg








From tomg at vivid.net  Wed Aug 26 10:13:47 1998
From: tomg at vivid.net (tomg)
Date: Wed, 26 Aug 1998 03:13:47 -0500
Subject: Maxx Arm-1A update
Message-ID: <yam7542.2353.120887024@mail.vivid.net>

uuh thats ....

http://www.tomg.vivid.net/maxx/page_036.html

cya

-tg




From bluebear at enterprise.net  Wed Aug 26 12:07:42 1998
From: bluebear at enterprise.net (Jeremy Brookes)
Date: Wed, 26 Aug 1998 11:07:42 +0100
Subject: Analog voice processing
Message-ID: <01BDD0E1.E97ACC80@AARDVARK>

>Does anyone know what effect was used for the voices of the Ceylons in
>Battlestar Galactica? It had a nasty metal-on-metal type sound. My initial
>guess is that this was done with a vocoder and synth. 
>
>I've heard versions of this effect at several different times, and I'm
>interested in emulating it.

>From what I can recall reading on this somewhere and from memory of what it sounded like, I believe it was done with Ring Modulation. I may be wrong of course...




From uzs159 at ibm.rhrz.uni-bonn.de  Wed Aug 26 13:48:47 1998
From: uzs159 at ibm.rhrz.uni-bonn.de (uzs159 at ibm.rhrz.uni-bonn.de)
Date: Wed, 26 Aug 1998 13:48:47 +0200
Subject: Minimoog Vcf
In-Reply-To: <199808240800.KAA00601@window.intermetall.de>
Message-ID: <3.0.5.32.19980826134847.007a39d0@ibm.rhrz.uni-bonn.de>

At 10:00 24.08.98 +0200, you wrote:
>
>> Well,I found that R20 resistor from Q6 emitter to -10 is 100k not 220k
>> And +10V should go not to col. of Q6 but to other side
>> of R6 47ohm resistor and + node of C9 100uF ?
>> Not shure about that last but if you look at moogmodular vcf, it
>> looks like that.
>>
>This makes sense. It is a kind of emitter follower (darlington).
>In this case the emitter resistors should be equal.
>And it is a differential to single ended converter. Again symmetry
>is required.
>
>Can any of the moog godnesses confirm ?
>
>m.c.
>

I'm by no means a moog godness, (merely a seeker of wisdom :)
it makes sense to me, but then if you look at the schem 
the R24 at Q7 at the opposite leg of the diffamp is 220k 
and not 100k. 
Wouldn't it make sense to make both legs totally symmetrical,
that would be R20=R24 and R3+R6=R7?
In my incarnation of the mini filter the problem seems to be 
that Q7 and Q5 have different temperatures due to the different 
currents. I have to either cool Q5 or heat Q7. 
When I power the unit up, it oscillates at maximum Q setting, 
but as soon as the components raise their temperatures the 
oscillation dies.
Connecting +10V to the other side of R6 didnt't help.

I changed the R20 from 220k to 100k and now the unit oscillates.
(Well only above a certain frequency but thats maybe due to my 
different cap values)

To me it looks like follows, one should thermocouple Q5 and Q7
(and maybe match them, the schem doesn't say anything here)
Or maybe I'll even use a trimmer for offset correction in the diffamp.

BTW does anyone know what value the CV summing resistors have ?

Bye
 -Rene









From Juergen.Haible at nbgm.siemens.de  Wed Aug 26 15:09:47 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Wed, 26 Aug 1998 15:09:47 +0200
Subject: AW: Minimoog Vcf
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D582A22E2B@nbgm336a.nbgm.siemens.de>

	>> Well,I found that R20 resistor from Q6 emitter to -10 is 100k not
220k
	>> And +10V should go not to col. of Q6 but to other side 
	>> of R6 47ohm resistor and + node of C9 100uF ? 
	>> Not shure about that last but if you look at moogmodular vcf, it 
	>> looks like that.
	>> 
	>This makes sense. It is a kind of emitter follower (darlington).
	>In this case the emitter resistors should be equal.
	>And it is a differential to single ended converter. Again symmetry
	>is required.
	>
	>Can any of the moog godnesses confirm ?

Well, I'm not from the Moog Olymp, but I have built my MidiMini
from the original Minimoog schemos (the VCF part, that is),
and it works.
There is good reason the R6, C9 filter for the left side of the
differential amp, because the filter output signal is related to the
positive supply, and not to GND. The right part of the differential
amp has no output, so connecting it directly to the dirty +10V
is ok. Therefore I think the schemos are right.

Just my opinion - never looked into a real Minimoog.

JH.



From Juergen.Haible at nbgm.siemens.de  Wed Aug 26 15:13:13 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Wed, 26 Aug 1998 15:13:13 +0200
Subject: AW(2): Minimoog Vcf
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D582A22E3B@nbgm336a.nbgm.siemens.de>

	> To me it looks like follows, one should thermocouple Q5 and Q7
	> (and maybe match them, the schem doesn't say anything here)

In my clone I matched the transistors (I thought the manual said so ?),
but did not thermocouple them.

JH.





From deknow at tiac.net  Wed Aug 26 17:20:49 1998
From: deknow at tiac.net (dean stiglitz)
Date: Wed, 26 Aug 1998 11:20:49 -0400
Subject: solinoids
Message-ID: <35E427D0.55AE9C32@tiac.net>

does anyone know of a source for small solinoids (about the size needed
to actuate keys on a sk-1 :)???

deknow




From steve at babcom.u-net.com  Wed Aug 26 19:54:47 1998
From: steve at babcom.u-net.com (Steven Cook)
Date: Wed, 26 Aug 1998 18:54:47 +0100
Subject: Dome Filter Question
Message-ID: <35E44BE8.51554419@babcom.u-net.com>

Hi,

I wonder if anyone can tell me if is possible to replace the presets in the
Bode Dome Filter with fixed resistors and if so what values should be used?

Also, would it be better to replace the transistors with opamp stages?

Available from:
http://aupe.phys.andrews.edu/diy_archive/manuals/moog/mod_50.gif

Thanks in advance.

Steve Cook.




From boldman at interplanet.it  Wed Aug 26 20:07:58 1998
From: boldman at interplanet.it (boldman at interplanet.it)
Date: Wed, 26 Aug 1998 19:07:58 +0100
Subject: AW: Minimoog Vcf
In-Reply-To:  <1BF5E20E0C4DD111BBAB00805FE2D582A22E2B@nbgm336a.nbgm.siemens.de>
Message-ID: <l03102806b209fdd88c0c@[192.106.97.17]>


>Well, I'm not from the Moog Olymp, but I have built my MidiMini
>from the original Minimoog schemos (the VCF part, that is),
>and it works.
>There is good reason the R6, C9 filter for the left side of the
>differential amp, because the filter output signal is related to the
>positive supply, and not to GND. The right part of the differential
>amp has no output, so connecting it directly to the dirty +10V
>is ok. Therefore I think the schemos are right.
>
>Just my opinion - never looked into a real Minimoog.
>
>JH.

Hi, riccardo here.
I am not into the olympus too, but I also have built a minimoog copying the
original boards (it was not really only me, I just did the research on the
components and do the wiring and solderings).
A question, how did you solve the problem with the C type pot?
(if I understand well it is an inverted logarithmic, I only found linear
or logarithmic pots. I did it with a stereo logarithmic pot using a so
strange wiring that I cannot remember right now. It works correclty but
does not reproduce the original sensitivity of the control, wich in a
certain way
is not too bad)

ciao
riccardo





From ka4hjh at gte.net  Wed Aug 26 20:39:58 1998
From: ka4hjh at gte.net (KA4HJH)
Date: Wed, 26 Aug 1998 14:39:58 -0400
Subject: VCA chips (2)
In-Reply-To: <199808260752.JAA20394@window.intermetall.de>
Message-ID: <v04011700b20a06ad75d6@[208.255.152.3]>

>However, the CA3280 data sheet claims lower noise and feedthrough (then
>3080) anyway. Hope I can test this in September.

Does anyone still make the 3280? I haven't seen one listed in a catalog for
years. Always heard it was superior to the 3080.

Terry Bowman, KA4HJH
"The Mac Doctor"



From TPaddock at eldec.com  Wed Aug 26 20:44:19 1998
From: TPaddock at eldec.com (Paddock, Toby)
Date: Wed, 26 Aug 1998 11:44:19 -0700
Subject: Looking for exciter  schematics
Message-ID: <508EAFE25C84D11182F00060973193E2854F13@BDC003NT>

I have a Rocktron exciter/imager and was wondering HOW it works.  
The manual seems to be a little light on the details.  
I can sort of understand the _phase_ mode, but am missing something with
the _frequency_ mode.
US patents 4647876 and 4696044 are listed, but look like just the noise
reduction part.

The following is from the instruction manual:


EXCITER/IMAGER/HUSH II
INSTRUCTION MANUAL

 OPERATION
Each channel of the RX20 is divided into four sections: Process,
Frequency/Phase, Mix, and Hush II.  
Let's look at each section individually.

PROCESS
The Process Module is basically a gain control feeding the dynamic
filter/excitercircuit.  
Two things happen as we increase the level of Process: 
1) the Dynamic Filter is opened more resulting in processing of a wider
bandwidth of program; i.e. the more the process, the higher the
frequency allowed to pass to the Exciter. 
2) the higher the level going to the detection circuit is set.  
The Led readout can be used to determine the extent of the bandwidth
being enhanced.  
The more Leds that are lit, the higher the frequencies that are being
excited.  
Try setting the Process control so the first three Leds are lit most of
the time and the fourth one (red) comes on only in load passages.  
This is one of a multitude of settings possible, but is a good starting
point.

FREQUENCY/PHASE
Two modes of operation are selectable in this module.  Frequency and
Phase.  

In Frequency mode we dial in the desired cut off point of the signal
feeding the Exciter circuit.  
With the control completely counter clockwise the lowest frequency sent
to the Exciter will be 50OHz (fig. 1).  
As we turn the control clockwise we raise the cut off frequency to as
high as 5kHz.  
In any event the only thing we are changing is the lower limit of
bandwidth, and the Exciter is always receiving frequencies up to 2OkHz.

   (fig 1:  a generic high pass filter graph with 2 cutoff frequencies
and an arrow pointing up in freq)

In Phase mode (button pushed in), there is a notch created in the filter
which we can move between 50OHz (knob turned to right) and 4kHz (konb
turned to left) or a frequency in between (fig. 2). 
The depth of this notch is directly related to the level at the input to
the dynamic filter circuit.
As the level increases the notch depth increase and the enhancement of
frequencies above the notch point are accentuated.

   (fig 2:  a generic notch filter graph with notch at 4k and an arrow
pointing down in freq)

MIX
The Mix Module simply controls the ratio of enhanced signal to that of
the uneffected signal.
As we turn the Mix control clockwise we increase the amount of enhanced
signal sent to the summing amp.  
With the Mix control turned completely clockwise, we will have the
highest level of enhancement at the output of the RX20.

HUSH II
The Hush II Module is the single ended noise reduction circuit in the
RX20.  
Before exploring the controls, we need a basic understanding of how this
Module works.
The circuit is comprised of two parts: the Expander and the Dynamically
Controlled Low Pass Filter.

(and so on about noise reduction...)


Hoping this finds you,
Toby Paddock
- -- -  - -- -  - -- -  - -- -  - -- -
http://www.seanet.com/~tpaddock
Pronteon Approved, 98% content-free




From ka4hjh at gte.net  Wed Aug 26 20:48:20 1998
From: ka4hjh at gte.net (KA4HJH)
Date: Wed, 26 Aug 1998 14:48:20 -0400
Subject: solinoids
In-Reply-To: <35E427D0.55AE9C32@tiac.net>
Message-ID: <v04011702b20a08bcf1ce@[208.255.152.3]>

>does anyone know of a source for small solinoids (about the size needed
>to actuate keys on a sk-1 :)???

Have you thought of using "muscle wire" (shape memory alloy)?

Terry Bowman, KA4HJH
"The Mac Doctor"



From ka4hjh at gte.net  Wed Aug 26 20:48:36 1998
From: ka4hjh at gte.net (KA4HJH)
Date: Wed, 26 Aug 1998 14:48:36 -0400
Subject: Analog voice processing
In-Reply-To: <3.0.5.32.19980825141327.007c5210@192.168.210.18>
Message-ID: <v04011701b20a07489a37@[208.255.152.3]>

>Does anyone know what effect was used for the voices of the Ceylons in
>Battlestar Galactica? It had a nasty metal-on-metal type sound. My initial
>guess is that this was done with a vocoder and synth.

Your initial guess is correct. Listen to the vocoder used in Kraftwerk's
"Radio Activity" and you'll hear something very similar--only in German. An
almost identical match can be heard in Cabaret Voltaire's song "Seconds Too
Late" (admittedly much more obscure). Vocoders are very sneaky if they'r
used right. It took me years to figure out how the Pink Floyd did the dogs
in, uh, "Dogs".

Terry Bowman, KA4HJH
"The Mac Doctor"



From tomg at vivid.net  Wed Aug 26 21:33:06 1998
From: tomg at vivid.net (tomg)
Date: Wed, 26 Aug 1998 14:33:06 -0500
Subject: Maxx VCF-6A EMS type Update
Message-ID: <yam7542.341.119272472@mail.vivid.net>

If the diff-pair lock up they could draw excessive current
and cook themselves. Not that this is likeley but it's a
possibility. 

It's a good idea to break the direct connection from the
emitters to the collector of the npn with a 1K-1.5K current 
limiting resistor. 

This is the way the Moog filter and original EMS are 
constructed. Shouldn't have a big affect on the cutoff and
could save a diff-pair+? .

Thanks to Dr. Steve Granger for pointing this out. The 6A 
page will be changed to reflect this update.

-tg




From oakley at enterprise.net  Wed Aug 26 23:51:35 1998
From: oakley at enterprise.net (Tony Allgood)
Date: Wed, 26 Aug 1998 22:51:35 +0100
Subject: A good chip....
Message-ID: <000f01bdd13b$d6c2acc0$37c448c2@default>

Hi All,

Several projects on the boil at the moment; the main one is having the PCBs
made for the rack mounted VCF. Thanks to Steve R and Paul P for making me
find another supplier to get those prices really low. Present costs could be
20UKP inclusive of P&P, but I will keep you posted on that.

But the reason I write is to tell you about the SSM2000 ic. This is single
ended noise reduction unit that anyone can buy... no licenses here. It looks
great for keeping BBD stuff clean, although how much better than companding
systems I will have to find out. It has two VCAs and two VCFs per chip, and
you can use it for stereo compression... not true stereo because it has only
one control chain. Price is 9UKP from Maplin. Might be good for a twin VCA.

Data is probably available at the AD website. I got mine from the Maplin
data CD, so if someone needs it I can give it to them.

Regards,

Tony Allgood, Cumbria, UK

e-mail: oakley at enterprise.net

Rack mounted Moog VCF module. Details to be found at...

http://aupe.phys.andrews.edu/diy_archive/schematics/effects/filter.html








From lavaud at pratique.fr  Thu Aug 27 00:58:26 1998
From: lavaud at pratique.fr (Denis Lavaud)
Date: Thu, 27 Aug 1998 00:58:26 +0200
Subject: Rumours about Elektor schematics re-edition
Message-ID: <199808262300.BAA19376@absinthe.pratique.fr>

Hello !

Some people told me that Elektor Netherlands are going
to restart publishing the Elektor synth (Formant,
Vocoder, etc.) schematics, updated with modern ICs...

True or False ???

I would like it to be true ! :)


			Denis Lavaud





From tomg at vivid.net  Thu Aug 27 03:25:02 1998
From: tomg at vivid.net (tomg)
Date: Wed, 26 Aug 1998 20:25:02 -0500
Subject: Cylon or Ceylon?
Message-ID: <yam7542.121.119868184@mail.vivid.net>

I went ahead and fixed it up so you can just
plug a mic in and garbble. Added a mic preamp,
envelope follower, and a vca.

It there is enough interest I'll do a board.

www.tomg.vivid.net/misc/cylon.wav
www.tomg.vivid.net/misc/cylon.gif

-tg







From dave at mail.kc.net  Thu Aug 27 03:43:35 1998
From: dave at mail.kc.net (Dave)
Date: Wed, 26 Aug 1998 20:43:35 -0500
Subject: My 10$ Harmonic Sweetner and Aphex
In-Reply-To: <199808252001.NAA07418@subasehp.san.mrms.navy.mil>
References: <19980825181249.21396.qmail@nuernberg2.pop.metronet.de>
Message-ID: <3.0.1.32.19980826204335.00b9eea8@mail.kc.net>

At 12:58 PM 8/25/98 +0000, you wrote:
>O.K here is the final dope on my $10 harmonic sweetner. 
(snip...)
>My article description in the sept 1987 Electronic 
>Musician reads very close to thier patent description but I didn't 
>read that until today! Cool.

I had a lot of fun with that circuit.  If I remember correctly, Aphex was
-very- defensive about the article, stating that their circuit was far more
advanced; that it didn't generate third-order harmonics like yours did.  

I suppose it -was- necessary for them to attempt justify the extra $289...
;-)

Dave in KCMO USA
dave at o2.net
http://www.o2.net/~dave/




From 104065.2340 at compuserve.com  Thu Aug 27 04:08:56 1998
From: 104065.2340 at compuserve.com (terry michaels)
Date: Wed, 26 Aug 1998 22:08:56 -0400
Subject: Looking for exciter  schematics
Message-ID: <199808262209_MC2-5781-8BEA@compuserve.com>

Message text written by "The Dark force of dance"
>This all sounds more plausible. At the time I tried to reverse engineer
the
>box I had no clue as to how these things work. Which always makes things
>harder to understand. The thing that stumped me was that the amplitude
>control of the 13600, IE: Iabc, was derived directly through a resistor
>from it's input. At which point I threw my hands up and said. "Nar this is
>the OTA for distortion. I don't know if anyone has noticed but an LM13600
>in just the _Wrong_ configuration makes one wicked distortion unit.

>I don't know exactly but it could also stand to reason that it provides
>some sort of cross modulation circuit. Unfortunately all these things crop
>up at just the wrong time for me. Bogged down as I am at the moment in a
>VGA system that won't. But I've downloaded some of the patent information
>and will chew threw it at my earliest possible time. I also want to look
>into how they do their bass enhancement as well.

>Thanks y'all and I look forward to your re-drawn enhancer circuit Jules.

Batz:

If Iabc is connected to its input, the LM13600 is multiplying the input by
itself, and is acting as a squaring circuit.  Squaring a sine wave doubles
its frequency.   Maybe this is the underlying principle behind the
"Exciter".

Terry




From nighthawk at mci2000.com  Thu Aug 27 06:25:04 1998
From: nighthawk at mci2000.com (nighthawk)
Date: Wed, 26 Aug 1998 21:25:04 -0700 (PDT)
Subject: Greetings
Message-ID: <MAPI.Id.0016.00696768746861773030303930303039@MAPI.to.RFC822>

Hi,

My name is Jimmy Williams.  I have made a couple of posts to this list,
each with positive responses and am finally signed on for the list.  I am a
repair tech for Music Loft, in Winston-Salem, NC,  where my wife and I 
call home.  I am currently working on the keyboard interface from the
Mini-3, and am indebted to Tom for his help on that.

After getting the keyboard going, I plan to experiment with some VCOs, 
particularly modeling after the Korg MS-10, with the 1458 used for just
about everything.  I am also gathering info on the SN76477 "Super
Controller Module" from Thomas Henry's book as per my previous post.
Once more, if any of you know of a PC Board layout for that circuit, it 
would save me much hair loss!

Please feel free to drop me a line and introduce yourselves.  I look
forward to contributing when I can, although I am not the engineer some 
of you seem to be.  I will be on vacation next week, so am trying to get
as much done as possible before, therefore, if you contact me, forgive
me if it is after Labor Day before I get back to you.  If I could only get
around this wasteful need for sleep...

Jimmy Williams




From martin.czech at intermetall.de  Thu Aug 27 07:53:02 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Thu, 27 Aug 1998 07:53:02 +0200 (MET DST)
Subject: Dome Filter Question
Message-ID: <199808270553.HAA00632@window.intermetall.de>

> Hi,
> 
> I wonder if anyone can tell me if is possible to replace the presets in the
> Bode Dome Filter with fixed resistors and if so what values should be used?
> 
> Also, would it be better to replace the transistors with opamp stages?
> 
> Available from:
> http://aupe.phys.andrews.edu/diy_archive/manuals/moog/mod_50.gif
> 
> Thanks in advance.
> 
> Steve Cook.
> 
I wonder if there is no better circuit...
As far as I understand, the "dome filter" is two allpass which have a
allmost constant phase shift of 90 deg between them, in order to get
large bandwidth quadrature.

I found such a filter in an old amateur radio book, they need SSB as
well. It is a passive RC ladder with four signal ways. You need a trafo
or op amp phase splitter in the front end (180 deg). I can remember
that a simulation showed < 0.5 deg error for a capacitor ratio of 1.6.
That is a lot of capacitors, and you need 4 matching for each stage.
OTOH, the more stages, the less matching is needed.
I know somebody who made his SSB reciever with this "polyphase" method.
If someone is interested, I could dig this out. It would
even be better if you could provide some web space as well...

m.c.




From Juergen.Haible at nbgm.siemens.de  Thu Aug 27 10:02:49 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Thu, 27 Aug 1998 10:02:49 +0200
Subject: AW: AW: Minimoog Vcf
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D582A299AA@nbgm336a.nbgm.siemens.de>

	> A question, how did you solve the problem with the C type pot?

I *used* a C-type pot (;->).
I did only get one by chance, back then, but it's not so bad
anymore today. Last time I looked Farnell had a few in
their catalogue.

	>(if I understand well it is an inverted logarithmic, I only found
linear
	>or logarithmic pots. I did it with a stereo logarithmic pot using a
so
	>strange wiring that I cannot remember right now. It works correclty
but
	>does not reproduce the original sensitivity of the control, wich in
a
	>certain way
	>is not too bad)

I'm not a fan of this method. You will improove the behaviour for a
small region, but no way to get a smooth action for
the full range.
Better methods, if you don't have a reverse log pot:
(1) use a log slider pot and turn it upside down.
(2) use an ordinary log pot and connect it backward (ccw end
      position is max resonance). Relabel it as "damping" ...
(3) use an exponential VCA and a linear pot
(4) try to fif a shaft at the back of a log pot (reportedly works
      with the cheap plastic Piher types)

JH.



From Juergen.Haible at nbgm.siemens.de  Thu Aug 27 10:07:03 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Thu, 27 Aug 1998 10:07:03 +0200
Subject: AW: Analog voice processing
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D582A2B7EA@nbgm336a.nbgm.siemens.de>


	>Vocoders are very sneaky if they'r
	>used right. It took me years to figure out how the Pink Floyd did
the dogs
	>in, uh, "Dogs".

One of the best vocoder parts ever, IMO. Love that song!
Now do tell us the secrets ! 

JH.



From Juergen.Haible at nbgm.siemens.de  Thu Aug 27 10:15:54 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Thu, 27 Aug 1998 10:15:54 +0200
Subject: AW: A good chip....
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D582A2B801@nbgm336a.nbgm.siemens.de>

	>But the reason I write is to tell you about the SSM2000 ic. This is
single
	>ended noise reduction unit that anyone can buy... no licenses here.
It looks
	>great for keeping BBD stuff clean, although how much better than
companding
	>systems I will have to find out.

Nothing against the 2000 (how could I say anything against an SSM chip ...),
but why should a single ended NR be better than a good compander system ?
IMO, the only problem with BBD companders is that they all use the slow
attack NE571 chips.
The Roland VP330 shows how to build a much better  compander from cheap
standard circuits. Well, an obsolete japanese VCA there, but I have used
an LM13700 instead, and it works fine. See my Frequency Shifter schemos
for details. And remember this is a cheap and dirty circuit; you can even
improove
it by using high quality VCAs.

JH.
>  



From tomg at vivid.net  Thu Aug 27 10:59:22 1998
From: tomg at vivid.net (tomg)
Date: Thu, 27 Aug 1998 03:59:22 -0500
Subject: ARM & Cylon
In-Reply-To: <yam7542.121.119868184@mail.vivid.net>
Message-ID: <yam7543.1113.120694696@mail.vivid.net>

On 26-Aug-98, tomg wrote:
>I went ahead and fixed it up so you can just
>plug a mic in and garbble. Added a mic preamp,
>envelope follower, and a vca.

>It there is enough interest I'll do a board.

>www.tomg.vivid.net/misc/cylon.wav
>www.tomg.vivid.net/misc/cylon.gif

>-tg

Heiko reports an error on the ARM schemo
3O8O pin 7 is +V not pin 8.

The ARM was taken almost verbatum from the RE
series. I modified it a little today to fix a
few problems. If it didn't work the first time
try again. Sorry.

It's Cylon. I looked it up on the net...:)
I copied the cylon files to the arm page
for the time being. 

-tg









From batzman at all-electric.com  Thu Aug 27 12:25:52 1998
From: batzman at all-electric.com (The Dark force of dance)
Date: Thu, 27 Aug 1998 19:25:52 +0900
Subject: Looking for exciter  schematics
Message-ID: <3.0.32.19980827191641.0068501c@mail.chariot.net.au>

Y-ellow y'all.
	So many people have written to me about this both privately and publicly.
It's pretty scary really considering how peripheral this all is at the
moment. But it has got me thinking.

terry michaels pointed out thusly.

>If Iabc is connected to its input, the LM13600 is multiplying the input by
>itself, and is acting as a squaring circuit.  Squaring a sine wave doubles
>its frequency.   Maybe this is the underlying principle behind the
>"Exciter".

Yup. This sounds about right. As Paul Perry mentioned, an integration
function. Or at least to a certain extent. It would stand to reason. I wish
I had time (And space) to get back inside my anal explorer type C box and
have a poke around. From memory this sounds a vary plausible explanation.
And probably why Aphex say. "Our distortion is better than yours anyway so
nerrr." Followed by. "And if you don't watch out I'll go tell mummy."

Stiff cheddar. I just wanna know what it is that's so special. I could do
with an exciter clone but I'm never satisfied with what some manufacturer
tells me is the limits of my creativity. I wanna mess with this stuff. But
first I wanna know what I'm messing with.

Paul Perry mentioned a friend who had successfully modeled an exciter in
software on a DSP. The thing is that on my last CD I messed with this
process where by I would take the signal, distort it, make a 2 quadrant
wave out of it and then re-modulate the original signal with it. And I was
getting these amazingly analogue sounding recordings even though it was
entirely digital. I was actually trying to go some way to model the
behavior of a "bad" valve stage transient but in hind sight, what I
probably ended up doing was re-creating an aural exciter. But I maintain
that the process is similar.

A long time ago in a list far away we had this discussion about. "Why
exactly do valves sound better if indeed they actually do." What we came
down to was a term we coined called. "Micro-non-linearities". We know the
mechanism by which these random non-linearities occurs and further research
showed me that it was the very thing that designers of vacuum tubes try to
overcome that is the probable cause of these "warming" effects. I've been
trying to get round to building some valve stages ever since. I'll get
there eventually Eric Promise. :) But! I postulated at the time, a very
elaborate scheme by which you could model the process with a transistor
stage as a joke. But it's all suddenly dawned on me that an aural exciter
really just an emulation of the kinds of harmonic distortions (And I use
that term loosely) that a valve stage _can_ introduce without too much
trouble. And I should just make a side mention that if you've ever looked
at the behavior of a 13600 going into clipping, it certainly looks like a
valve does. In that it soft-clips like a class A valve stage.

I guess I should, for the sake of succinctness sum up thusly. We use to use
valves because it was _Thee_ technology. Now we use them because they
somehow "Sound better." Though few of us have a clue to exactly why. So why
is it that we need an Anal explorer? To make things sound better... Bottom
line.

Curious don't you think?

I'm making no value judgements here. I still want to mess with valve stages
a real lot when I get the chance. I've got a bunch of really interesting
glow fets here (thanks Eric) just itching to be messed with. It's just that
it crossed my mind that if all this is the case, then both a valve preamp
and an anal explorer would be playing in the same ball park. Which is
better who knows and who cares, just that it would seem that the inventors
of the anal explorer may have simply stumbled onto the same process,
(different mechanics) as that of a vacuum tube stage. Now if that could
have been proven in the 70s, wouldn't that have blown their little patent
right out of the water. :)

Be absolutely icebox.

 _ __        _                              
| "_ \      | |         batzman at all-electric.com / aek at all-electric.com
| |_)/  __ _| |_ ____           ALL ELECTRIC KITCHEN               
|  _ \ / _` | __|___ |  The new AEK CD, Elementary Urban sanity    
| |_) | (_| | |_  / /   is out now on Transmission Communications from
|_,__/ \__,_|\__|/ /    http://brisbane.dialix.com.au:80/~com11
                / ,__   and check out http://www.all-electric.com
Goodfortune    |_____|       Let your SANITY wear thin.




From synth1 at airmail.net  Thu Aug 27 14:38:46 1998
From: synth1 at airmail.net (Paul Schreiber)
Date: Thu, 27 Aug 1998 12:38:46 -0000
Subject: Source of good VCA chips
Message-ID: <01BDD1B7.A3AEBC80@dal18-28.ppp.iadfw.net>

The CEM3381 (now called a PA381) is a dual VCA, low noise, 1/100th of the
CV feedthrough of a 3080. 20dB better noise and SNR specs. 
This part is STILL in production. Very simple to use. 

See www.synthtech.com for data sheets.

Paul Schreiber




From smart at nn.com  Thu Aug 27 15:29:52 1998
From: smart at nn.com (Mark Smart)
Date: Thu, 27 Aug 1998 08:29:52 -0500 (CDT)
Subject: FS: Refurbished ARP Omni 2 - $400
Message-ID: <199808271329.IAA09585@medusa.nn.com>

I am a professional electronics guy who just finished overhauling this
synth. It is now electronically in much BETTER shape than when it left the
factory. Here's a list of what I did:

1. Replaced all blown IC's capacitors, broken keys, etc.

2. Power supply mod.
   As many people know, these synths have a reputation for unreliability.
   The reason for this is that the power supply was misdesigned such that
   it generates power spikes every time you turn the synth on or off. Over
   time, this fries chips and capacitors. In response to this problem, ARP
   designed a modification which was to be performed on all Omni's which
   came in for repair. It involved soldering some caps and transient
   supressors to the power supply and changing a resistor to lower the
power
   supply voltage to +/- 13 volts. I have performed this mod on this synth.
   Basically this means that this synth is in all likelihood immune from
   the problems which do (or will) plague any non-modified Omni 2 you can
   find.

3. I also performed the well-known filter modification which raises the
   cutoff
   frequency to what it was originally designed. This makes a very
   noticeable and positive difference in the sound of the "synthesizer"
   section. This mod has been discussed a lot on this list, and is also
   discussed in the book "Vintage Synthesizers" in the chapter about the
   ARP 2600 (some of the 2600's, as well as Odysseys, etc, used the same
   filter module as the Omni.) It sounds great.

4. Omni's frequently develop a "stuck notes" problem. This is from
   capacitors which blow up due to the aforementioned power supply problem.
   I replaced ALL these caps, even the ones which weren't misbehaving, just
   to prevent future potential problems.

5. I replaced ALL the 10 uF tantalum bypass caps for the same reason. They
   also frequently are victims of the un-modified power supply.

6. Of course, I cleaned up all the pots so they slide easily and do not
   crackle.

It is in good cosmetic condition with a few blemishes: there are some
scratches on the top where other stuff was set on top. They keyboard looks
great from playing position, but one key has a chunk missing from it which
you can only see if you look at the keyboard from underneath. All slider
caps are present.

Included with the synth is a really nice Calzone flight case.

I have reduced the price (again) to $400 + shipping.

A whole lot of work, care, and (dare I say it) LOVE went into this synth,
and I am quite proud of the results. It sounds fantastic!

I can provide a reference if necessary (another guy I sold a repaired
Omni I to)


************************************************
*     Mark Smart                               *
*     Electronics Engineer                     *
*     NovaNET Learning, Inc.                   *
*     smart at medusa.nn.com                      *
************************************************



From thudson at cygnus.com  Thu Aug 27 15:32:28 1998
From: thudson at cygnus.com (Thomas Hudson)
Date: Thu, 27 Aug 1998 09:32:28 -0400
Subject: Greetings
In-Reply-To: <MAPI.Id.0016.00696768746861773030303930303039@MAPI.to.RFC822>
Message-ID: <000301bdd1bf$22b7c6f0$2d90e2cd@thudson1.cygnus.com>

> I am also gathering info on the SN76477 "Super
> Controller Module" from Thomas Henry's book as per my previous post.
> Once more, if any of you know of a PC Board layout for that circuit, it 
> would save me much hair loss!
>
Tom wrote an article for the Super Controller in Polyphony and
included a PC board layout. You can get a reprint of all of his
articles from Midwest Analog Products:

http://Prairie.Lakes.com/~map/books.html

I have this but the PC layout suffers from copying.
You may be able to get the original Polyphony issue
(Sept/Oct 1981) from Paia (http://www.paia.com)

Thomas





From b.layer at vikingelectronics.com  Thu Aug 27 15:35:53 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Thu, 27 Aug 1998 08:35:53 -0500
Subject: Cylon or Ceylon?
In-Reply-To: <yam7542.121.119868184@mail.vivid.net>
Message-ID: <3.0.5.32.19980827083553.007ac490@192.168.210.18>

 Hi Tom/All,

You know, the people of Ceylon. The were the first island nation to develop
interstellar drive capability, as well as a violent dislike for Loren
Green, after he dumped that load of Alpo while escaping an Imperial
Battlecruiser..

Ok, Cylons.

-b  


Bill Layer
Sales Technician
<b.layer at vikingelectronics.com>

----------------------------------
Viking Electronics, Inc.
Hudson, WI. U.S.A
715.386.8861 (ext. 210)
<http://www.vikingelectronics.com>
----------------------------------

"Telecommunications Solutions for the 21st Century"



From halmans at globalxs.nl  Thu Aug 27 15:43:39 1998
From: halmans at globalxs.nl (Maarten Halmans)
Date: Thu, 27 Aug 1998 15:43:39 +0200
Subject: Bit one schematic
Message-ID: <35E5628B.E564CAC5@globalxs.nl>

Hi All,

I am looking for a Crumar Bit One schematic.
Can anyone help me out?

Thanks,

Maarten Halmans






From moxie at idonex.se  Thu Aug 27 16:47:47 1998
From: moxie at idonex.se (Johan Gustavsson)
Date: Thu, 27 Aug 1998 16:47:47 +0200 (MET DST)
Subject: Tomgs excellent adventure
Message-ID: <199808271447.QAA06639@jolt.idonex.se>

Took a look at Toms new modules - Looks nice! Only one thing...What is
a KLM type filter? I mean, I thought I'd mastered the synth TLAs by
now, when out of the blue a new one appears. I'm stunned.

On another note, does anyone have a lead on an external input module
schemo? I'd like a space with external input, mic preamp, envelope
follower and trigger/gate generator. I've got the schematic and PCB of
Paias 2700-series envelope follower, but I seem to remember that that
one runs off strange voltages or something...
/Moxie (Contemplating keyboard designs)




From don at till.com  Thu Aug 27 17:10:28 1998
From: don at till.com (Don Tillman)
Date: Thu, 27 Aug 1998 08:10:28 -0700 (PDT)
Subject: VCA chips
In-Reply-To: <19980825221030.25497.qmail@nuernberg2.pop.metronet.de>
	(jhaible@metronet.de)
Message-ID: <199808271510.IAA24229@shell9.ba.best.com>

   From: "jhaible" <jhaible at metronet.de>
   Date: Tue, 25 Aug 1998 20:24:04 +0200

   I noticed the same thing some time ago, and asked AD about the 2024's.
   Back then (about 1/2 year ago), they said they were still in production,
   but they recommend the 2164 instead. So it's a good idea to ask them again
   about the 2024's current state.

I phoned Analog Devices.  They said, as I suspected, that the SSM2024
is still in production but the SSM2164 is recommended for new VCA
designs.  And they left the SSM2024 off their web site because they
are not recommending it for new VCA designs.

   Doesn't the 2164 has exponential control inputs?  I don't remember that
   exactly,but in that case it would be hard to use in the Scanner.

True, and that would defeat one of the goals of my design.  Though it
might be an interesting variation...

   I haven't done this myself, but I highly recommend that someone tries the
   CA3280 (no typo) for the scanner. It can handle much higher Iabc currents,
   so one could insert the LEDs directly in the Iabc control path. 

Hmmmm....  The data sheet says it'll take an Iabc of 10mA without
exploding, but no curve is plotted for more than 1mA in the data
sheet.  It makes me a little suspicious.  It's certainly an area to
explore.

The CA3280 also has the advantage of a wide output voltage swing, so
you're not forced to follow it with a virtual ground current input
stage (like an inverting opamp circuit).  And the CA3280 has both
positive and negative inputs, so you don't need an additional
inverting stage on top of that if care about polarity.

  -- Don



From don at till.com  Thu Aug 27 17:11:50 1998
From: don at till.com (Don Tillman)
Date: Thu, 27 Aug 1998 08:11:50 -0700 (PDT)
Subject: VCA chips
In-Reply-To: <199808260721.JAA20316@window.intermetall.de> (message from
	Martin Czech on Wed, 26 Aug 1998 09:21:12 +0200 (MET DST))
Message-ID: <199808271511.IAA24520@shell9.ba.best.com>

   From: Martin Czech <martin.czech at intermetall.de>
   Date: Wed, 26 Aug 1998 09:21:12 +0200 (MET DST)

   It seems that all linear control VCAs are gone.

Huh?  The CA3080 and it's buddies (the CA3060, CA3094, CA3280, and
LM13600) are all linear control when you feed them a control current,
or exponential control when you feed them a voltage and add a little
circuitry.

The SSM2024 is linear control with a current and SSM2164 is exponential
control with a voltage or current.  

And those are all in full production.  I think.

   Would it be possible to make a VCA with CA3280 in the following
   manner: 

I think the CA3280 has pretty low feedthrough as it stands.  Is that
the issue?

  -- Don





From jfoster at lucasdigital.com  Thu Aug 27 17:23:12 1998
From: jfoster at lucasdigital.com (Jeff Foster)
Date: Thu, 27 Aug 1998 08:23:12 -0700
Subject: thank you Blacet Research
Message-ID: <35E579E0.B228F3C4@lucasdigital.com>

Just want to say thanks to Blacet Research.
I sent in my request for a Free LFO board ( really a 2 kits and 2
blanks) on
Monday Aug. 24th. I dropped the mail in the box at about 8:30 AM.

Come Wednesday, Aug. 26 5 PM, I had  a package waiting for me at home
from Blacet
Amazing turn around time - thanks BR!! (also the US post did a fine job
as well)

Jeff

--
Jeff Foster 415-662-1254
Unix Systems/Networks - Skywalkersound, LucasDigital Ltd.
"State machines are unnatural"





From don at till.com  Thu Aug 27 17:31:16 1998
From: don at till.com (Don Tillman)
Date: Thu, 27 Aug 1998 08:31:16 -0700 (PDT)
Subject: VCA chips (2)
In-Reply-To: <v04011700b20a06ad75d6@[208.255.152.3]> (message from KA4HJH on
	Wed, 26 Aug 1998 14:39:58 -0400)
Message-ID: <199808271531.IAA29261@shell9.ba.best.com>

   Date: Wed, 26 Aug 1998 14:39:58 -0400
   From: KA4HJH <ka4hjh at gte.net>

   Does anyone still make the 3280? I haven't seen one listed in a catalog for
   years. Always heard it was superior to the 3080.

Harris makes it nowadays.  (How did it go?  It was originally an RCA
chip and I *think* what happened was that RCA was owned by NBC, NBC
was bought by GE, the linear line was taken over by Siliconix which
was also bought by GE previously, then the linear line was sold to
Harris.  Is that right?)

You can get data sheets and all at:
http://www.harris.com

Yeah, the CA3280 was designed to be a superior CA3080.  Linearizing
diodes to compensate for the diffamp transfer curve and low noise (the
3080 doesn't actually have a noise spec).  The LM13600 (National
Semiconductor) is basically the same thing but with an emitter
follower stage you can choose to use or not.

  -- Don




From costello at seanet.com  Thu Aug 27 17:48:29 1998
From: costello at seanet.com (Sean Costello)
Date: Thu, 27 Aug 1998 08:48:29 -0700
Subject: Tomgs excellent adventure
References: <199808271447.QAA06639@jolt.idonex.se>
Message-ID: <35E57FCD.ADCBF2A3@seanet.com>

Johan Gustavsson wrote:
> 
> Took a look at Toms new modules - Looks nice! Only one thing...What is
> a KLM type filter? I mean, I thought I'd mastered the synth TLAs by
> now, when out of the blue a new one appears. I'm stunned.

I think it refers to the KLM-307, which is the little daughterboard used
in the Korg MS-20 synth for the filter section (that is, in the later
revision of the synth).  The filters in question are actually Sallen-Key
filters.  The MS-20 has two Sallen-Key filters, a highpass followed by a
lowpass.

Sean Costello



From thudson at cygnus.com  Thu Aug 27 17:52:02 1998
From: thudson at cygnus.com (Thomas Hudson)
Date: Thu, 27 Aug 1998 11:52:02 -0400
Subject: Tomgs excellent adventure
In-Reply-To: <199808271447.QAA06639@jolt.idonex.se>
Message-ID: <000c01bdd1d2$a21e8b50$2d90e2cd@thudson1.cygnus.com>


I've been looking at a Thomas Henry design for an envelope
follower that uses the NE570. It rectifies the input signal
twice allowing a smaller filtering cap for better response
times. I believe this technique is also discussed in 
Electronotes. The NE570 design is in "Making Music with the
NE570 Compander" see 
http://Prairie.Lakes.com/~map/books.html#ne570

Thomas

> -----Original Message-----
> From: owner-synth-diy at mailhost.bpa.nl
> [mailto:owner-synth-diy at mailhost.bpa.nl]On Behalf Of Johan Gustavsson
> Sent: Thursday, August 27, 1998 10:48 AM
> To: synth-diy at mailhost.bpa.nl
> Subject: Tomgs excellent adventure
> 
> 
> Took a look at Toms new modules - Looks nice! Only one thing...What is
> a KLM type filter? I mean, I thought I'd mastered the synth TLAs by
> now, when out of the blue a new one appears. I'm stunned.
> 
> On another note, does anyone have a lead on an external input module
> schemo? I'd like a space with external input, mic preamp, envelope
> follower and trigger/gate generator. I've got the schematic and PCB of
> Paias 2700-series envelope follower, but I seem to remember that that
> one runs off strange voltages or something...
> /Moxie (Contemplating keyboard designs)
> 
> 



From jfoster at lucasdigital.com  Thu Aug 27 17:53:39 1998
From: jfoster at lucasdigital.com (Jeff Foster)
Date: Thu, 27 Aug 1998 08:53:39 -0700
Subject: CEM 3371, question
Message-ID: <35E58103.74A52D27@lucasdigital.com>

Hi all,
Anyone built anything with the CEM 3371 waveform generator?
Can you share any details of this adventure?

thx,
Jeff

--
Jeff Foster 415-662-1254
Unix Systems/Networks - Skywalkersound, LucasDigital Ltd.
"State machines are unnatural"





From costello at seanet.com  Thu Aug 27 18:24:49 1998
From: costello at seanet.com (Sean Costello)
Date: Thu, 27 Aug 1998 09:24:49 -0700
Subject: Minimoog Vcf
References: <199808210911.LAA08878@window.intermetall.de>
Message-ID: <35E58851.E0C05ED6@seanet.com>

Martin Czech wrote:
> 
> > Hi:
> >
> > The schematic in question is one that I scanned in.  There were some
> > components in error on the original schematic (as compared to other
> > schematics) which I corrected; I may have typed in a value that is
> > incorrect.  I'll look at my other Minimoog VCF schematics, and see where
> > the problem might lie.  I'll keep the list posted.
> >
> > Sean Costello
> >
> 
> Did I miss the final answer?  It would be very interesting to know, why
> the famous circuit won't work after above mentioned schematic. Cause
> I'm going to build one in the next time.

I have just looked at the 3 schematics I have - the one scanned in from
the Minimoog service manual, the drawing of the filter alone from an
earlier version of the manual, and a hand-drawn version by Gene Stopp. 
All of them have the positive power supply connected to the collector of
Q6 (in the output differential amplifier).  Two of them show R20 and R24
to be equal in value (220K); as the version I scanned in had a different
value for R20, I assumed it was a typo, and changed it to be equal to
R24.  I haven't found any other errors in the schematic I posted.  This
is in no way saying that the schematic is accurate, just that it
corresponds with the other Minimoog filter schematics that I have.

Sean Costello



From martin.czech at intermetall.de  Thu Aug 27 18:45:38 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Thu, 27 Aug 1998 18:45:38 +0200 (MET DST)
Subject: VCA chips (2)
Message-ID: <199808271645.SAA06826@window.intermetall.de>

> Yeah, the CA3280 was designed to be a superior CA3080.  Linearizing
> diodes to compensate for the diffamp transfer curve and low noise (the
> 3080 doesn't actually have a noise spec).  The LM13600 (National
> Semiconductor) is basically the same thing but with an emitter
> follower stage you can choose to use or not.

I think the 3280 claims matched gm.
There is a chip photo which makes this resonable.
Does the 13700 also ? I don't know.
By the way, what's the difference 13600 13700?
Better output darlington? I think for new designs 13700 is recommended.

m.c.




From urekar.m at EUnet.yu  Thu Aug 27 20:20:34 1998
From: urekar.m at EUnet.yu (<<marjan>>)
Date: Thu, 27 Aug 1998 20:20:34 +0200
Subject: Minimoog Vcf
References: <199808210911.LAA08878@window.intermetall.de> <35E58851.E0C05ED6@seanet.com>
Message-ID: <35E5A372.5D60@eunet.yu>

> I have just looked at the 3 schematics I have - the one scanned in from
> the Minimoog service manual, the drawing of the filter alone from an
> earlier version of the manual, and a hand-drawn version by Gene Stopp.
> All of them have the positive power supply connected to the collector of
> Q6 (in the output differential amplifier).  Two of them show R20 and R24
> to be equal in value (220K); as the version I scanned in had a different
> value for R20, I assumed it was a typo, and changed it to be equal to
> R24.  I haven't found any other errors in the schematic I posted.  This
> is in no way saying that the schematic is accurate, just that it
> corresponds with the other Minimoog filter schematics that I have.

while at it,can you tell me the values for pots in envelope section

and why in the old vco board rev CV summing 741s are connected to gnd
instead to +10 on pin 7  ?


marjan



From jhaible at metronet.de  Thu Aug 27 21:55:07 1998
From: jhaible at metronet.de (jhaible)
Date: Thu, 27 Aug 1998 21:55:07 +0200
Subject: VCA chips
Message-ID: <19980827204539.2034.qmail@nuernberg2.pop.metronet.de>

> I phoned Analog Devices.  They said, as I suspected, that the SSM2024
> is still in production but the SSM2164 is recommended for new VCA
> designs.  And they left the SSM2024 off their web site because they
> are not recommending it for new VCA designs.

Yes, that's more or less the same answer I got.
Isn't it sad - if they hush up the chip, it is going to die sooner or later
..

> Hmmmm....  The data sheet says it'll take an Iabc of 10mA without
> exploding, but no curve is plotted for more than 1mA in the data
> sheet.  It makes me a little suspicious.  It's certainly an area to
> explore.

I think the Prophet 5 uses them with rather high control currents. I
remember
thinking these low resistor values were typos, until I saw that the 3280
allows
that high control currents. But the Prophet 5 might not be the best
reference
for the ultimate analogue design (with all repect to its brilliant
concept).

2 questions left:

What do you think about high control currents for discrete transistor pairs
?
Any drawbacks ? Do the transistor pairs unbalance themselves due to self
heating at higher currents ?

Availabillity of the CA3280 - I know it's hard to get in Germany. But is it
still manufactured or not ? I have a few left, but I hesitate to use them
if
I can't get them in the future ...

JH.




From chrisc at zetnet.co.uk  Thu Aug 27 23:01:16 1998
From: chrisc at zetnet.co.uk (Chris Crosskey)
Date: Thu, 27 Aug 1998 22:01:16 +0100
Subject: Rumours about Elektor schematics re-edition
Message-ID: <199808272101.WAA32285@irwell.zetnet.co.uk>

We live in hope I suppose, but they'd better update the construction techniques, 
I'm damned if I'm going to do any more of that flying-wire to the front panel 
that they were so fond of, but I could live with teh <ARP2600> style 
semi-pre-patching I suppose.....my Formant (never finished) didn't have this as 
I couold never fiond any 41617 connectors of the right size....

chrisc
>
>Some people told me that Elektor Netherlands are going
>to restart publishing the Elektor synth (Formant,
>Vocoder, etc.) schematics, updated with modern ICs...
>
>True or False ???
>
>I would like it to be true ! :)



From jpiper at jrihealth.org  Thu Aug 27 23:51:59 1998
From: jpiper at jrihealth.org (Jessica Piper)
Date: Thu, 27 Aug 1998 17:51:59 -0400
Subject: AW: Minimoog Vcf
In-Reply-To: <l03102806b209fdd88c0c@[192.106.97.17]>
References: < <1BF5E20E0C4DD111BBAB00805FE2D582A22E2B@nbgm336a.nbgm.siemens.de>
Message-ID: <3.0.5.32.19980827175159.007a3e00@jrihealth.org>

>A question, how did you solve the problem with the C type pot?
>(if I understand well it is an inverted logarithmic, I only found linear
>or logarithmic pots. I did it with a stereo logarithmic pot using a so
>strange wiring that I cannot remember right now. It works correclty but
>does not reproduce the original sensitivity of the control, wich in a
>certain way
>is not too bad)
>
>ciao
>riccardo
>

I believe Digi-key caries C-taper pots.  They can be reached at
1(800)digi-key, or www.digikey.com.  They have a really good selection in
general, though they are pricey.  As an online data source, however, they
cannot be beat.  All semiconductor listings have links directly to the
manufacturer's data sheet, when available.  (This is intended as an answer
to clist's cmos data sheet collection as well.)  I never order from them,
but I use their web site all the time.

jessica





From pfperry at melbpc.org.au  Thu Aug 27 23:54:17 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Fri, 28 Aug 1998 07:54:17 +1000 (EST)
Subject: env folower
Message-ID: <1.5.4.16.19970119142727.39079a5c@popa.melbpc.org.au>

At 04:47 PM 27/08/98 +0200, Johan Gustavsson <moxie wrote:

>On another note, does anyone have a lead on an external input module
>schemo? I'd like a space with external input, mic preamp, envelope
>follower 

how smooth you want the env follower depends on what you want to do 
with it. 
The common approaches are:
1. precision rectifier folowed by  3rd order40Hz low pass filter

2. peak detector with a zero-crossing reset.

Both these ckts are (or were) on the net somewhere.....

paul perry melb aust
BTW I built #1 using ckts from Jung's "Op Amp Cookbook".
Worked OK for me (enveloped controlled tekkno filter)




From mpulver at midiwall.com  Fri Aug 28 00:23:30 1998
From: mpulver at midiwall.com (Mark Pulver)
Date: Thu, 27 Aug 1998 17:23:30 -0500
Subject: Used Gear Price List
Message-ID: <199808272223.RAA29993@mw.3com.com>


***
*** This message is cross-posted to many lists. PLEASE watch any
*** replies that you may choose to make.
***


I've been spending some time on the Used Gear Price List ("UGPL")...


For those that missed the announcement the other day, first and most
importantly, the UGPL is FULLY back online and active. I am now updating it
a couple of times a day.

Next, I've been doing some work on the display format and such. Things to
note should be smaller fonts on the pages, faster access time, a simple
average of the pricing, and (finally!) All dates are real!!!

And... for those that like to sit on the couch and browse paper... The list
is once again available as a single text file. You can download the zipped
file from the link on the main page.


                    http://www.midiwall.com/usedgear/


Thanks all for your patience in the last 6 months!

Mark
_________________________________________________________________________
Mark Pulver - Home of the "MIDI 2nd Bedroom Featuring the Modular Closet"
 http://www.midiwall.com - Nord Mod: http://www.midiwall.com/nordmodular



From gosd at lankaster.com  Fri Aug 28 01:09:02 1998
From: gosd at lankaster.com (crystal)
Date: Thu, 27 Aug 1998 16:09:02 -0700
Subject: 8secdigdelmod?
Message-ID: <35E5E70E.7CC8@lankaster.com>

hello all,
anyone know the exact process to turn a digitech RDS4000 4 second dig
delay/sampler into an 8 second dd? i think it's a matter of swapping
DRAMS and a jumper or two on the pcb.





From jhaible at metronet.de  Fri Aug 28 02:39:13 1998
From: jhaible at metronet.de (jhaible)
Date: Fri, 28 Aug 1998 02:39:13 +0200
Subject: VCA chips (2)
Message-ID: <19980828143402.16129.qmail@nuernberg2.pop.metronet.de>

> I think the 3280 claims matched gm.
> Does the 13700 also ? I don't know.

The 13600 / 13700, too. 3dB tracking, if memory serves.
That's the major (if not only) advantage over two 3080's:
You can just short pins 1 and 16 together in stereo vca
or SVF VCF applications.

> By the way, what's the difference 13600 13700?
> Better output darlington? I think for new designs 13700 is recommended.

Not better. Different.

The 13600 gets the Iabc of the OTA mirrored into the emitter of the first
transistor of the darlington buffer. This decreases input impedance of the
buffer,
but makes the impedance track to the gm of the OTA. Good for VCF stuff.
Extremely bad for vocoders, because you get crosstalk from the analysis to
the
synthesis section.

The 13700 has a plain darlington. Constant high impedance. Still not high
enough
for VCOs that shall also be used as LFOs, or for VCADSRS. You will often
find
the recommendation to use an opamp buffer instead. Personally, I go for a
discrete
FET in front of the darlington buffer when it is possible.

BTW, CA3280 and LM13700 are more different than one might think. The
13700's
linearization diodes are crap, because without real current sources you are
far
from linearizing the input stage. You can slightly improove this by using
resistors
to the negative supply instead of the resistors to GND (Keep in mind that
these are
not used to divide down the input voltage anymore ! They rather act as
return path for
diode bias current, and an impedance of 500R to 1k is quite ridiculous for
a current
source ...)
The 3280 is much closer to the ideal "Gilbert" case.

JH





From batzman at all-electric.com  Fri Aug 28 07:11:16 1998
From: batzman at all-electric.com (The Dark force of dance)
Date: Fri, 28 Aug 1998 14:11:16 +0900
Subject: OT: solution to PC systems problem??
Message-ID: <3.0.32.19980828140725.006adcd8@mail.chariot.net.au>

Y-ellow Y'all.
	I'm sure some people are going to find this off topic but there's a method
in my madness.

I need to find a way to share a mouse and keyboard between two computers.
They are mounted in my _Live_ rack and the second machine is, for the most
part, a turn-key system. I've successfully managed to switch the video
through one monitor. I used a pair of relays which can be remote controlled
from a switch at the terminal, (Mouse/monitor/keyboard) which is on a
single extension cable and can be located up to 1.8 metres from the rack it
self. But switching, or faking the keyboard and mouse is another matter
entirely. The keyboard and mouse talk back to the system.

The other thing I need to be able to do is power the systems down reliably
with out necessarily using a keyboard command. I don't know if there's some
kind of hardware or software hook I can use to do it. Ideally so that I can
give one command to shut down from one computer and they will both shut
down in sequence. Otherwise if I just shut the first one down, the second
one will get killed in the processes.

If anyone has any clues on where I might find information on this stuff I
would really appreciate it. I'm after the simplest solution. One that won't
take me weeks of R&D to perfect.

Any help would be greatly appreciated.

Be absolutely Icebox.

 _ __        _                              
| "_ \      | |         batzman at all-electric.com / aek at all-electric.com
| |_)/  __ _| |_ ____           ALL ELECTRIC KITCHEN               
|  _ \ / _` | __|___ |  The new AEK CD, Elementary Urban sanity    
| |_) | (_| | |_  / /   is out now on Transmission Communications from
|_,__/ \__,_|\__|/ /    http://brisbane.dialix.com.au:80/~com11
                / ,__   and check out http://www.all-electric.com
Goodfortune    |_____|       Let your SANITY wear thin.




From martin.czech at intermetall.de  Fri Aug 28 08:29:36 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Fri, 28 Aug 1998 08:29:36 +0200 (MET DST)
Subject: Source of good VCA chips
Message-ID: <199808280629.IAA12294@window.intermetall.de>

> The CEM3381 (now called a PA381) is a dual VCA, low noise, 1/100th of the
> CV feedthrough of a 3080. 20dB better noise and SNR specs. 
> This part is STILL in production. Very simple to use. 
> 
I have the data sheet.
But something was strange with these bugs.
I think due to reduced pincount (DIL8) they had
some limitations, was it strange input bias needs or
something. However, I remember the two vca on the chip beeing
different, one could use only one of them and thus
avoid the difficulties.

m.c.




From pfperry at melbpc.org.au  Fri Aug 28 09:09:13 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Fri, 28 Aug 1998 17:09:13 +1000 (EST)
Subject: VCA chips
Message-ID: <1.5.4.16.19970119234221.0d9f4b60@popa.melbpc.org.au>

At 09:55 PM 27/08/98 +0200, jhaible wrote:

>Any drawbacks ? Do the transistor pairs unbalance themselves due to self
>heating at higher currents ?
>
>Availabillity of the CA3280 - I know it's hard to get in Germany. But is it
>still manufactured or not ? I have a few left, but I hesitate to use them
>if>I can't get them in the future ...
>
good attitude JH, I'm sick of cancelled chips.
With a 'balanced' pair, wouldn't you only need 2 pots to line up
any arbitrary pair of transistors? Have I missed something?

paul perry melb aust




From martin.czech at intermetall.de  Fri Aug 28 09:49:02 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Fri, 28 Aug 1998 09:49:02 +0200 (MET DST)
Subject: OT: solution to PC systems problem??
Message-ID: <199808280749.JAA12481@window.intermetall.de>

> 
> I need to find a way to share a mouse and keyboard between two computers.
> They are mounted in my _Live_ rack and the second machine is, for the most
> part, a turn-key system. I've successfully managed to switch the video
> through one monitor. I used a pair of relays which can be remote controlled
> from a switch at the terminal, (Mouse/monitor/keyboard) which is on a
> single extension cable and can be located up to 1.8 metres from the rack it
> self. But switching, or faking the keyboard and mouse is another matter
> entirely. The keyboard and mouse talk back to the system.

Maybe one can find out what happens on the pins of keyboard and mouse
plug if they don't move. I suspect: nothing.  Some computers notice if
you plug out and give an error message, but IBM-compatibles ? They
don't even notice.  So the hope is that you only need a multi throw,
two pole switch for each computer, switching between real device and
fake device, ie.  pullup or pulldown resistor. Maybe a couple of 4066
switches do the job.

Isn't this a shame? I mean : it is 1998, we could fly to the mars if we
had the money, but still Windooze is to dumb to allow remote login from
another machine and remote terminal and remote graphics.

Maybe there is software that allows remote login, perhaps via RS232?

At work I've a Sparc 10 (maybe upgrade to Ultra).  I always remote
login for compute jobs, even if they have graphics.  The job runs on
the server, and the server sends X-commands to my sparc, where the data
is displayed. You don't evben feel that it is remote.
When I return home and sit in front of my pentium , I feel
like getting from ferrari to a childrens toy-car. No shell,
no real multitasking, oh boy, that's progress.

m.c.




From schmitz at patho.bonn.com  Fri Aug 28 11:00:27 1998
From: schmitz at patho.bonn.com (=?iso-8859-1?Q?Dr=2E_J=F6rg_Schmitz?=)
Date: Fri, 28 Aug 1998 11:00:27 +0200
Subject: No subject
Message-ID: <814F53AC8CEDD111A274004F4902BAE6B781@bnpc1.patho.bonn.com>

Is there anyone who knows one (or more) internet pages
with patches for modular synths ?
For example : The Jean Michel Jarre Thunderstorm.
I have patched the rain, but this growling deep wonderful thunder
is a secret for me.
I tried it whith PinkNoise->LPFilterCV(highly resonant). Works, but not
satisfiying at all.

Another way : is there someone in DIY who has enough space in his
homepage to
include a list of modular patches ? For example, it would be possible to
save the files in the NordModular Format, the NordModular editor 
is downloadable in the net.

J?rg

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From martin.czech at intermetall.de  Fri Aug 28 11:32:13 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Fri, 28 Aug 1998 11:32:13 +0200 (MET DST)
Subject: thunder and patches
Message-ID: <199808280932.LAA13394@window.intermetall.de>

> Is there anyone who knows one (or more) internet pages
> with patches for modular synths ?
> 
> Another way : is there someone in DIY who has enough space in his
> homepage to
> include a list of modular patches ? For example, it would be possible to
> save the files in the NordModular Format, the NordModular editor 
> is downloadable in the net.

Some simple patches are in the formant books.

I've got three startup books at home which also show simple
patches.

> For example : The Jean Michel Jarre Thunderstorm.
> I have patched the rain, but this growling deep wonderful thunder
> is a secret for me.
> I tried it whith PinkNoise->LPFilterCV(highly resonant). Works, but not
> satisfiying at all.

If you use high reso, you'll get more and more an instable sine wave.
Very narrow bandwidth.
Sounds like whistling at higher freq.
No wonder that this doesn't sound like th\under.

A broad band bandpass (LP and HP chained) could work better.
Just an idea.

m.c.




From H.J.vanderlinden at stud.far.ruu.nl  Fri Aug 28 13:58:01 1998
From: H.J.vanderlinden at stud.far.ruu.nl (Heiko van der Linden)
Date: Fri, 28 Aug 1998 13:58:01 +0200
Subject: midi to cv converter
Message-ID: <35E69B49.BCDB27AD@stud.far.ruu.nl>

Hi,
Is there anyone out there who now a site where I can find the schems and
the software for a midi to cv converter. I'm planning on building one
myself one of these days.
Thanks




From rsowa at WizjaTV.pl  Fri Aug 28 14:50:29 1998
From: rsowa at WizjaTV.pl (Roman Sowa)
Date: Fri, 28 Aug 1998 14:50:29 +0200
Subject: ODP: VCA chips
Message-ID: <2BF6F749A4A3D11185AD00A0C94CF67A0FBC26@demon>

1. That's what balanced pairs are made for - two (or more)
transistors in one piece of sillicon are at (almost) the same
temperature no matter what. That's why they stay
balanced with temperature changes...
But balanced transistor isn't enough for precise exp converter.
Exponential argument of Ube to Ic equation changes with temperature,
and that affects everything.

2. Don't they have it at Harris?
http://www.harris.com

Roman

	Paul Perry wrote>  

> 2 questions left:
> 
> What do you think about high control currents for discrete transistor
> pairs
> ?
> Any drawbacks ? Do the transistor pairs unbalance themselves due to
> self
> heating at higher currents ?
> 
> Availabillity of the CA3280 - I know it's hard to get in Germany. But
> is it
> still manufactured or not ? I have a few left, but I hesitate to use
> them
> if
> I can't get them in the future ...
> 
> JH.



From thudson at cygnus.com  Fri Aug 28 15:42:40 1998
From: thudson at cygnus.com (Thomas Hudson)
Date: Fri, 28 Aug 1998 09:42:40 -0400
Subject: No subject
In-Reply-To: <814F53AC8CEDD111A274004F4902BAE6B781@bnpc1.patho.bonn.com>
Message-ID: <000901bdd289$b9dcf4e0$2d90e2cd@thudson1.cygnus.com>


A patch repository sounds like a great idea. As far as thunder
goes, the best simulation I ever achieved came from a patch
by John Simonton. Instead of using a noise source, tune several
(I used three) VCOs to a subsonic range running the mix into a VCA
controlled by an ADSR, and make sure each VCO
is detuned from the others. The beat frequencies actually produce
a very convincing low rumble. Of course, it helps to have a few
18 inch Cerwin-Vega's...

Thomas


> -----Original Message-----
> From:	owner-synth-diy at mailhost.bpa.nl
> [mailto:owner-synth-diy at mailhost.bpa.nl] On Behalf Of Dr. J?rg Schmitz
> Sent:	Friday, August 28, 1998 5:00 AM
> To:	'synth-diy at mailhost.bpa.nl'
> Subject:
>
> Is there anyone who knows one (or more) internet pages
> with patches for modular synths ?
> For example : The Jean Michel Jarre Thunderstorm.
> I have patched the rain, but this growling deep wonderful thunder
> is a secret for me.
> I tried it whith PinkNoise->LPFilterCV(highly resonant). Works, but not
> satisfiying at all.
>
> Another way : is there someone in DIY who has enough space in his
> homepage to
> include a list of modular patches ? For example, it would be possible to
> save the files in the NordModular Format, the NordModular editor
> is downloadable in the net.
>
> J?rg
>
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From hdan at charybdis.com  Fri Aug 28 16:58:20 1998
From: hdan at charybdis.com (Dan Higdon)
Date: Fri, 28 Aug 1998 09:58:20 -0500
Subject: OT: solution to PC systems problem??
Message-ID: <01bdd294$4c124360$352ccfcf@ares.charybdis.com>

If you don't mind a pre-built solution, go down to just about any computer
store and just buy one.  We even have a box in the office that can switch
kb/mouse/monitor between up to 8 computers with a single button push.

They do make them smaller and cheaper, of course.  :-)

----------------------------------------
hdan at charybdis.com
"Trust not the monkey, nor his clever schemes" - hdan





From stephen at electromusic.com  Fri Aug 28 17:09:29 1998
From: stephen at electromusic.com (Stephen Machnowski)
Date: Fri, 28 Aug 1998 11:09:29 -0400
Subject: thunder and patches
In-Reply-To: <199808280932.LAA13394@window.intermetall.de>
Message-ID: <3.0.2.32.19980828110929.00704710@pop.inch.com>

At 11:32 AM 8/28/98 +0200, you wrote:
>> Is there anyone who knows one (or more) internet pages
>> with patches for modular synths ?

There is this book I read a couple years ago that they have at a library uptown I'll have to get and do some scans from. It is called something unbelievable like:

Advanced Modular Synthesizer Patches

I'll try to get it next week and get back.

Stephen


the------electro.music.specialist
--d--i--y--modular-----&--records
electroNYC http://www.electromusic.com



From b.layer at vikingelectronics.com  Fri Aug 28 17:56:11 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Fri, 28 Aug 1998 10:56:11 -0500
Subject: Wave file archive
Message-ID: <3.0.5.32.19980828105611.007cb2b0@192.168.210.18>

Hi All,

Hey, guess what? 

In the recent past, there has been talk on the list about an online archive
for wave files. Thanks to the kindness of Mark Gilmore at ASOG, I have
secured 100MB of space on the ASOG (Atma-Sphere Owner's Group) server for
use as a synth-DIY .wav file archive.

Is the interest strong enough to support the efforts required? Please let
me know; I hope to get a bare-bones site up this weekend. Of course, I'll
need some .wav files... When submitting, please include some documentation,
a brief description perhaps, of how the sound was created, and what your
goals were.

Also, how should the site be organized? If one or more individuals
contribute multiple files, I may go ahead and give seperate pages to the
more prolific contributors. Alternately, the site could be organized
alpanumeric or something else boring like that.



Your thoughts please...


Bill Layer
"Quantity has a Quality all of it's own." -JL



From b.layer at vikingelectronics.com  Fri Aug 28 18:01:18 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Fri, 28 Aug 1998 11:01:18 -0500
Subject: No subject
In-Reply-To: <000901bdd289$b9dcf4e0$2d90e2cd@thudson1.cygnus.com>
References: <814F53AC8CEDD111A274004F4902BAE6B781@bnpc1.patho.bonn.com>
Message-ID: <3.0.5.32.19980828110118.007e9d20@192.168.210.18>

Hi Thomas,

See my post re: wave file archive. I could host the patch archive as well,
it would seem to make a perfect companion... See the patch, hear the sound!

This could be pretty cool.


Bill Layer
Sales Technician
<b.layer at vikingelectronics.com>

----------------------------------
Viking Electronics, Inc.
Hudson, WI. U.S.A
715.386.8861 (ext. 210)
<http://www.vikingelectronics.com>
----------------------------------

"Telecommunications Solutions for the 21st Century"



From johns at oei.com  Fri Aug 28 18:07:19 1998
From: johns at oei.com (John Speth)
Date: Fri, 28 Aug 1998 09:07:19 -0700
Subject: AW: Minimoog Vcf
In-Reply-To: <3.0.5.32.19980827175159.007a3e00@jrihealth.org>
Message-ID: <000a01bdd29d$ef019a40$2c15d7d0@johns.oei.com>

To help me reduce my ignorance, What exactly is a C-type pot?

John Speth
Object Engineering, Inc
mailto:johns at oei.com
 

> -----Original Message-----
> From: owner-synth-diy at mailhost.bpa.nl
> [mailto:owner-synth-diy at mailhost.bpa.nl]On Behalf Of Jessica Piper
> Sent: Thursday, August 27, 1998 2:52 PM
> To: boldman at interplanet.it
> Cc: synth-diy at mailhost.bpa.nl
> Subject: Re: AW: Minimoog Vcf
> 
> 
> >A question, how did you solve the problem with the C type pot?





From costello at seanet.com  Fri Aug 28 18:08:43 1998
From: costello at seanet.com (Sean Costello)
Date: Fri, 28 Aug 1998 09:08:43 -0700
Subject: No subject
References: <814F53AC8CEDD111A274004F4902BAE6B781@bnpc1.patho.bonn.com>
Message-ID: <35E6D60B.3FF57289@seanet.com>

Dr. J?rg Schmitz wrote:

> Another way : is there someone in DIY who has enough space in his
> homepage to
> include a list of modular patches ? For example, it would be possible to
> save the files in the NordModular Format, the NordModular editor
> is downloadable in the net.

Using the Nord Modular editor is a great idea.  That way, very
complicated visual files can be downloaded as simple text files...

Hmmm.  I just had a thought.  Since the Nord Modular editor outputs
simple text files (that are then sent to the Modular via MIDI), I wonder
how hard it would be to write a program that converted the text files
into a format that CSound could use?  That way, any patch on the Nord
Modular could be heard for FREE, assuming that modules that were similar
to the Nord algorithms could be programmed in CSound.  Also, it would be
a GREAT editor for creating CSound patches!  Anyone have any input?

A program that converted Nord Modular files into Extended CSound would
be even cooler, as Extended CSound might be able to run the Nord patches
in real time, depending on the power of the SHARC chip.  

As far as space for a patch database, well, I am going to be getting A
LOT more space very soon...I'll keep the list posted...

Sean Costello



From jamos at technotoys.com  Fri Aug 28 18:29:14 1998
From: jamos at technotoys.com (Jim Johnson)
Date: Fri, 28 Aug 1998 09:29:14 -0700
Subject: thunder and patches
In-Reply-To: <3.0.2.32.19980828110929.00704710@pop.inch.com>
References: <3.0.2.32.19980828110929.00704710@pop.inch.com>
Message-ID: <199808280929140700.04CE1DB8@mail.proaxis.com>

>
>There is this book I read a couple years ago that they have at a library
uptown I'll have to get and do some scans from. It is called something
unbelievable like:
>
>Advanced Modular Synthesizer Patches
>
>I'll try to get it next week and get back.
>

Wow. Instead of just copying the book, how about providing us with the
publisher information so we can track it down and maybe buy it? I'd love to
have a copy of that book - I have never seen anything published on modular
synths of this nature.

TIA

Jim Johnson 
Metaphoric Software
-------------------
Makers of Techno Toys
Software for Electronic Music
http://www.technotoys.com
info at technotoys.com




From oakley at enterprise.net  Fri Aug 28 19:29:03 1998
From: oakley at enterprise.net (Tony Allgood)
Date: Fri, 28 Aug 1998 18:29:03 +0100
Subject: AW: Minimoog Vcf
Message-ID: <000801bdd2a9$8e2160a0$02c548c2@default>

JH said:
>Better methods, if you don't have a reverse log pot:
(1) use a log slider pot and turn it upside down.
(2) use an ordinary log pot and connect it backward (ccw end
      position is max resonance). Relabel it as "damping" ...
(3) use an exponential VCA and a linear pot
(4) try to fif a shaft at the back of a log pot (reportedly works
      with the cheap plastic Piher types)



Are we talking about the emphasis pot here? Another way to get a really good
law is to use a 10K log pot as a potential divider. i.e.. the high Q end
(CW) to the ac coupled output of the diff amp and the low Q end (CCW) to
ground. The wiper is taken via another cap to the base of the bottom pair.
AND then connect the high Q end of the pot to the wiper via a 3K9 resistor.
This last addition gives a really smooooth change from no res to full
oscillation. Only one drawback is that control breakthrough gets worse...
but this is no problem if the VCF is pre-VCA.

Regards,

Tony Allgood, Cumbria, UK

e-mail: oakley at enterprise.net

Rack mounted Moog VCF module. Details to be found at...

http://aupe.phys.andrews.edu/diy_archive/schematics/effects/filter.html






From b.layer at vikingelectronics.com  Fri Aug 28 19:41:17 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Fri, 28 Aug 1998 12:41:17 -0500
Subject: Wave file archive
Message-ID: <3.0.5.32.19980828124117.007a3b10@192.168.210.18>

(This is send #2; I didn't get an echo of the first attempt...)

Hi All,

Hey, guess what? 

In the recent past, there has been talk on the list about an online archive
for wave files. Thanks to the kindness of Mark Gilmore at ASOG, I have
secured 100MB of space on the ASOG (Atma-Sphere Owner's Group) server for
use as a synth-DIY .wav file archive.

Is the interest strong enough to support the efforts required? Please let
me know; I hope to get a bare-bones site up this weekend. Of course, I'll
need some .wav files... When submitting, please include some documentation,
a brief description perhaps, of how the sound was created, and what your
goals were.

Also, how should the site be organized? If one or more individuals
contribute multiple files, I may go ahead and give seperate pages to the
more prolific contributors. Alternately, the site could be organized
alpanumeric or something else boring like that.



Your thoughts please...


Bill Layer
"Quantity has a Quality all of it's own." -JL



From jmik at rci.rutgers.edu  Fri Aug 28 21:23:18 1998
From: jmik at rci.rutgers.edu (Joe Miklojcik)
Date: Fri, 28 Aug 1998 14:23:18 -0500
Subject: No subject
References: <814F53AC8CEDD111A274004F4902BAE6B781@bnpc1.patho.bonn.com> <35E6D60B.3FF57289@seanet.com>
Message-ID: <35E703A5.5EE734AF@rci.rutgers.edu>

When I wrote Clavia about writing a Nord Modular editor for Linux, they
essentiallly told me that the sysex protocol between the editor and the
hardware was so hairy that they couldn't document it.  Now I learn of a Nord
Modular editor outputs simple text files?  Somebody clue me... I may have
some new hardware to buy and some new software to write in the *very* near
future...

Sean Costello wrote:

> Dr. J?rg Schmitz wrote:
>
> > Another way : is there someone in DIY who has enough space in his
> > homepage to
> > include a list of modular patches ? For example, it would be possible to
> > save the files in the NordModular Format, the NordModular editor
> > is downloadable in the net.
>
> Using the Nord Modular editor is a great idea.  That way, very
> complicated visual files can be downloaded as simple text files...
>
> Hmmm.  I just had a thought.  Since the Nord Modular editor outputs
> simple text files (that are then sent to the Modular via MIDI), I wonder
> how hard it would be to write a program that converted the text files
> into a format that CSound could use?  That way, any patch on the Nord
> Modular could be heard for FREE, assuming that modules that were similar
> to the Nord algorithms could be programmed in CSound.  Also, it would be
> a GREAT editor for creating CSound patches!  Anyone have any input?
>
> A program that converted Nord Modular files into Extended CSound would
> be even cooler, as Extended CSound might be able to run the Nord patches
> in real time, depending on the power of the SHARC chip.
>
> As far as space for a patch database, well, I am going to be getting A
> LOT more space very soon...I'll keep the list posted...
>
> Sean Costello






From b.layer at vikingelectronics.com  Fri Aug 28 21:25:27 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Fri, 28 Aug 1998 14:25:27 -0500
Subject: Wave file archive
In-Reply-To: <2E12619580C0D1118C6400805F9F4C95DB249D@nj7460exch001u.ho.l
 ucent.com>
Message-ID: <3.0.5.32.19980828142527.007cd8b0@192.168.210.18>

Hi Steve, 

At 03:02 PM 8/28/98 -0400, you wrote:
>Sounds great!  Would 100mb really be enough, though? 

In a word, yes.

 Should we be limited
>to a certain size?  I've got some 10 and 20 mb files of complete pieces I
>could submit, but could also cut this down.  This would be very useful to me
>because the provider of my web site doesn't have space to put music files
>and also has an objection to posting music on the web because it frequently
>has to be downsampled to 11k mono for reasonable download times.
 
 Size limitation will have much to do with this. I have no intention
whatsoever of posting full-length pieces; that level of exposure is not my
intention. However, 'samples' linked to a full-length piece elsewhere would
be fine. My intention is to provide a 'sound index', with associated
technical information (patches, equipment used, recording technique etc.)

Any suggestions on a max filesize or length? I was thinking 250K initially...


Bill Layer
Sales Technician
<b.layer at vikingelectronics.com>

----------------------------------
Viking Electronics, Inc.
Hudson, WI. U.S.A
715.386.8861 (ext. 210)
<http://www.vikingelectronics.com>
----------------------------------

"Telecommunications Solutions for the 21st Century"



From Hcabnivek at aol.com  Fri Aug 28 22:05:13 1998
From: Hcabnivek at aol.com (Hcabnivek at aol.com)
Date: Fri, 28 Aug 1998 16:05:13 EDT
Subject: Test - Please igonre
Message-ID: <96714d09.35e70d79@aol.com>>

Test - Please igonre



From yoh212 at lulu.acns.nwu.edu  Fri Aug 28 22:52:57 1998
From: yoh212 at lulu.acns.nwu.edu (Yoshiki Ohmura (Yoshi))
Date: Fri, 28 Aug 1998 15:52:57 -0500 (CDT)
Subject: VCA chips
In-Reply-To: <19980827204539.2034.qmail@nuernberg2.pop.metronet.de>
Message-ID: <Pine.HPP.3.93.980828155119.10826B-100000@lulu.acns.nwu.edu>

On Thu, 27 Aug 1998, jhaible wrote:

> > I phoned Analog Devices.  They said, as I suspected, that the SSM2024
> > is still in production but the SSM2164 is recommended for new VCA
> > designs.  And they left the SSM2024 off their web site because they
> > are not recommending it for new VCA designs.
> 
> Yes, that's more or less the same answer I got.
> Isn't it sad - if they hush up the chip, it is going to die sooner or later
> ..

WHere can I order these VCA chips?  I checked mouser and newark, and
neither had it.

Thanks

Yoshi

PS if your girlfriend/wife complains that you spend to much time with this
DIY stuff, tell heryou'll order her a "High Speed CMOS Logic Dual
Monostable Multivibrator with Reset" ;)




From pab210 at is8.nyu.edu  Fri Aug 28 22:57:53 1998
From: pab210 at is8.nyu.edu (Plinio Andres Barraza)
Date: Fri, 28 Aug 1998 16:57:53 -0400 (EDT)
Subject: My Wurlie drives me crazy ! 
In-Reply-To: <35CBF15B.7CA4@stad.dsl.nl>
Message-ID: <Pine.OSF.3.95.980828163741.16780A-100000@is8.nyu.edu>



Who is looking for the Wurlitzer reeds?  I have ordered them a few times
before and I thought I had the address of the company that suplies them in
my files.  Just now I didn't find the address but they are called
Morelock's Organ Parts they are in Rienzi, Mississippi (not in the
vecinity of the Netherlands but I'm sure they'l ship the reeds) try
calling them: (601) 462-7618.

I just returned from a three week vacation so this message is in response
to an older message.  

I hope this helps

Plinio Barraza




From costello at seanet.com  Fri Aug 28 23:31:55 1998
From: costello at seanet.com (Sean Costello)
Date: Fri, 28 Aug 1998 14:31:55 -0700
Subject: 8secdigdelmod?
References: <35E5E70E.7CC8@lankaster.com>
Message-ID: <35E721CB.39271432@seanet.com>

crystal wrote:
> 
> hello all,
> anyone know the exact process to turn a digitech RDS4000 4 second dig
> delay/sampler into an 8 second dd? i think it's a matter of swapping
> DRAMS and a jumper or two on the pcb.

Whoa. I have a busted 2-second Digitech delay pedal, that would make a
nice 8-second delay (unbusted, of course).  If anyone has any advice,
I'd love to do this.

Thanks,

Sean COstello



From guist at pucsp.br  Sat Aug 29 01:44:28 1998
From: guist at pucsp.br (Guilherme dos Santos Tsubota)
Date: Fri, 28 Aug 1998 20:44:28 -0300 (GMT-0300)
Subject: No subject
Message-ID: <Pine.LNX.4.02.9808282044050.10736-100000@nucc.pucsp.br>

Is there any brazilian???

Tem algum brasileiro????
[]s

                                  GUILHERME  DOS  SANTOS  TSUBOTA  
 do-re-music_____________________________________________________
 Pontificia Universidade Catolica de Sao Paulo - RIMA/PROEM

   Email : guist at pucsp.br                      www.pucsp.br
   URL   : www.nucc.pucsp.br/~guist           rima.pucsp.br
           www.do-re-music.com               proem.pucsp.br       
   tel   : (+55 11) 256-1622 R.214          ICQ   : 8162203




From 104065.2340 at compuserve.com  Sat Aug 29 04:11:41 1998
From: 104065.2340 at compuserve.com (terry michaels)
Date: Fri, 28 Aug 1998 22:11:41 -0400
Subject: DIY parts
Message-ID: <199808282212_MC2-57B6-3907@compuserve.com>

Message text written by INTERNET:ijfritz at earthlink.net
>Terry --

>So do you think you'll be staying with the 3130? I haven't come across
>many other good high speed, low offset, low bias devices. Maybe the
>Burr-Brown OPA132?

>  Ian


Ian:

Thanks for the suggestion on the OPA132.  The common mode input range does
not include the negative supply, so it can't be operated with a single
supply like the CA3130.  Other than that, it might work well, I'll fully
evaluate it in the near future.

Terry




From pfperry at melbpc.org.au  Sat Aug 29 04:22:55 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Sat, 29 Aug 1998 12:22:55 +1000 (EST)
Subject: Nord Modular editor for Linux
Message-ID: <1.5.4.16.19970120185602.3157b23a@popa.melbpc.org.au>

At 02:23 PM 28/08/98 -0500, Joe Miklojcik wrote:
>When I wrote Clavia about writing a Nord Modular editor for Linux, they
>essentiallly told me that the sysex protocol between the editor and the
>hardware was so hairy that they couldn't document it.  Now I learn of a Nord
>Modular editor outputs simple text files?  Somebody clue me... 

"we can't document it" is corporate speak for 
1. We don't know what we are doing.
or, 2. We don't want you to know what we are doing.
or, (usually) BOTH of the above.
In any case, it is one of the deadly warning flags..

paul perry melbourne australia
Some are born great.
Some achieve greatness.
Some, like Paula Yates, have greatness thrust into them.


>




From batzman at all-electric.com  Sat Aug 29 06:08:51 1998
From: batzman at all-electric.com (The Dark force of dance)
Date: Sat, 29 Aug 1998 13:08:51 +0900
Subject: OT: solution to PC systems problem??
Message-ID: <3.0.32.19980829130818.006daebc@mail.chariot.net.au>

Y-ellow Y'all.
	And thanks to the many suggestions. I've managed to find a great deal of
the information I needed.

To all that suggested those commercially available switch boxes. Thanks but
they aren't a very elegant solution in this case. There's nowhere to put
one and they aren't remote-controllable. They also generally don't deal
with multiple formats. IE: PS/2

To sum up. (In case anyone else needs to do this kinda thing)
The keyboard is relatively easy to do. An old keyboard on the end of a
cross over switch. In this case a set of relay contacts. Just the board
from the keyboard module will do. You don't actually need the keys. As long
as both it (the dummy) and the real keyboard are powered up, it's possible
to swap between them without the PC noticing. Just as long as you're not
sending data at the time you switch over. This shouldn't be too much of a
problem.

So when both machines boot, they will see a keyboard on the end of the
system and receive the necessary ACKs back from it. After that it doesn't
much matter. There may be a problem with the status LED information but in
this case it's not a problem because the master keyboard (as it were) has
no LEDs. It's an IR keyboard. (Thanks Philip) :)

The mouse is another problem all together. I'm not entirely sure if the
same approach will work. However a Serial mouse and a PS/2 mouse are
entirely different entities. What I realized I can in fact do is use a
serial mouse. I don't _have_to_ use a PS/2 Mouse. The PS/2 mouse is
virtually hooked directly across a UART. It's powered by 5 volts and not 12
as in a serial mouse. It's data signal is also 5 volts as opposed to +/-12
in a serial mouse. And of course that means it's signal is positive logic
instead of being inverted. In short, it would be a really big job to
convert the PS/2 Mouse up to Serial. Not impossible but impractical. But as
I said, I shouldn't have to.

What I still don't know is from where the serial mouse actually takes it's
power. I assume that what it does is get power from one of the signals on
the serial port. Since an RS232 port supplys no power as such. One or two
of the lines must be taken high/low and the mouse get's it's power from
that. The mouse being CMOS should draw only a small amount of current and
can get away with it. But I can't work out how this is done exactly.
Obviously time for some raw science here to find out.

Anyway, thanks for all the pointers. I appreciate it.

Be absolutely Icebox.

 _ __        _                              
| "_ \      | |         batzman at all-electric.com / aek at all-electric.com
| |_)/  __ _| |_ ____           ALL ELECTRIC KITCHEN               
|  _ \ / _` | __|___ |  The Elementary Urban sanity CD
| |_) | (_| | |_  / /   out now on Transmission Communications
|_,__/ \__,_|\__|/ /    
                / ,__   http://www.all-electric.com
Goodfortune    |_____|       



From the_hex at relay-1.ziplink.net  Sat Aug 29 06:35:23 1998
From: the_hex at relay-1.ziplink.net (Chris ('the Hex'))
Date: Sat, 29 Aug 1998 00:35:23 -0400
Subject: (nord modular tech stuff)
Message-ID: <1.5.4.32.19980829043523.00679fd8@pop3.ziplink.net>

The patch definitions files (*.PCH) which the PC editor uses for storing and
loading patches are formatted as simple text files.  I checked it out
myself, and it's true!  They're formatted pretty much like .INI files,
though the parameters and settings are a bit cryptic.  The interface that
the editor and the hardware use to talk to each other once the patches are
loaded, on the other hand, is another barrel of worms.  This was was Clavia
must have been talking about when they discussed their complex sysex standards.

Now, the cool thing about text-readable patches (to rephrase what Sean said)
is that a clever programmer with the appropriate knowlege to interpret what
the heck they mean would be able to write a hack to convert between Nord's
patch files and other popular modular sound-definition languages (CSound
specifically).  This would allow you to convert stuff back and forth between
CSound and the Modular.  Better still, it would allow you to use the
kick-ass Nord Modular editor (which Clavia distributes free) as an interface
to CSound.  Plus it would give people a way to audition (via CSound) what
their Modular patches might sound like *if* they bought the Modular, without
making the initial investment right away.

Taking this to yet *another* level, I can imagine someone putting together
some software to convert back and forth between .PCH files and the MP4
format, which, I understand, is largely based on CSound's standards.

So what about it?  Any ambitious hackers in the house tonight?! :)  My copy
of Visual C++ is rarin' to go but unfortunately I don't own a Modular and
couldn't check the results.  (Yup, I downloaded the editor awhile ago just
to drool over it and don't have the liquid cash to buy the thing...I know
I'm not the only one out there in this boat either...)

Cheers,
Chris (the Hex)

At 02:23 PM 8/28/98 -0500, Joe Miklojcik wrote:
>Now I learn of a Nord
>Modular editor outputs simple text files?  Somebody clue me... I may have
>some new hardware to buy and some new software to write in the *very* near
>future...

>Sean Costello wrote (among other things):
...
>> Hmmm.  I just had a thought.  Since the Nord Modular editor outputs
>> simple text files (that are then sent to the Modular via MIDI), I wonder
>> how hard it would be to write a program that converted the text files
>> into a format that CSound could use?




From borg0 at jps.net  Sat Aug 29 08:21:52 1998
From: borg0 at jps.net (Debby and Gene Stopp)
Date: Fri, 28 Aug 1998 23:21:52 -0700
Subject: No subject
Message-ID: <029501bdd317$c728f2a0$c8c4edd0@oemcomputer>

The best thunder patch I've come up with does not use noise either. I did it
on an OB-8, with all 16 oscillators in unison mode, at the lowest possible
frequency, pulse wave outputs, and PWM by sample and hold. The oscillators
initial pulse width is such that they go silent occaisionally (not all at
once, however). They crackle in and out against each other. The VCF is set
for a long release so that the sound goes from crisp to muffled after
several seconds.

This patch is so realistic that it sounds like a sampler playing a thunder
sample. Freaks people out, especially other synthesists.:) To me, noise
through a filter sounds like wind perhaps, but *never* thunder.

And my 18-inchers are Peaveys. :)

- Gene

-----Original Message-----
From: Thomas Hudson <thudson at cygnus.com>
To: Dr. J?rg Schmitz <schmitz at patho.bonn.com>; synth-diy at mailhost.bpa.nl
<synth-diy at mailhost.bpa.nl>
Date: Friday, August 28, 1998 8:31 AM
Subject: RE:


>
>A patch repository sounds like a great idea. As far as thunder
>goes, the best simulation I ever achieved came from a patch
>by John Simonton. Instead of using a noise source, tune several
>(I used three) VCOs to a subsonic range running the mix into a VCA
>controlled by an ADSR, and make sure each VCO
>is detuned from the others. The beat frequencies actually produce
>a very convincing low rumble. Of course, it helps to have a few
>18 inch Cerwin-Vega's...
>
>Thomas
>
>
>> -----Original Message-----
>> From: owner-synth-diy at mailhost.bpa.nl
>> [mailto:owner-synth-diy at mailhost.bpa.nl] On Behalf Of Dr. J?rg Schmitz
>> Sent: Friday, August 28, 1998 5:00 AM
>> To: 'synth-diy at mailhost.bpa.nl'
>> Subject:
>>
>> Is there anyone who knows one (or more) internet pages
>> with patches for modular synths ?
>> For example : The Jean Michel Jarre Thunderstorm.
>> I have patched the rain, but this growling deep wonderful thunder
>> is a secret for me.
>> I tried it whith PinkNoise->LPFilterCV(highly resonant). Works, but not
>> satisfiying at all.
>>
>> Another way : is there someone in DIY who has enough space in his
>> homepage to
>> include a list of modular patches ? For example, it would be possible to
>> save the files in the NordModular Format, the NordModular editor
>> is downloadable in the net.
>>
>> J?rg
>>
>




From borg0 at jps.net  Sat Aug 29 08:38:46 1998
From: borg0 at jps.net (Debby and Gene Stopp)
Date: Fri, 28 Aug 1998 23:38:46 -0700
Subject: OT: solution to PC systems problem??
Message-ID: <029601bdd317$c878a420$c8c4edd0@oemcomputer>

Watch out if you're using Win95 - any interruption in the mouse connection
will cause 95 to loose it and never find it again, requiring you to tab your
way over to shutdown and starting over. NT doesn't do this - apparently it
polls for the mouse and if it gets unplugged and then plugged in later,
cursor control will resume after about ten seconds. NT is quite a tolerant
OS. 98 I haven't tried, even though I'm staring at it right now...

The missing keyboard at boot time is easy to get around - if there isn't a
"halt on no errors" option in the BIOS, then there's probably a "quick boot"
option in the BIOS (the latter on many of the newer AGP 100-meg Super 7 ATX
mainboards). Once booted, both 95 and NT will tolerate a disconnected
keyboard that gets reconnected later, no problem.

I've had good luck with the Linksys active switch, which works seamlessly
with both NT and 95, and uses momentary front panel switches that you could
probably easily remote. One drawback is cost, about $200 for a 4-port
keyboard/mouse/monitor switch. But it's cheaper than 4 monitors and takes up
less room. And last but not least, it's not nearly as fun as hacking up a
bunch of old keyboards!

- Gene


-----Original Message-----
From: The Dark force of dance <batzman at all-electric.com>
To: 'DIY' <synth-diy at mailhost.bpa.nl>
Date: Friday, August 28, 1998 9:55 PM
Subject: RE:OT: solution to PC systems problem??


>Y-ellow Y'all.
> And thanks to the many suggestions. I've managed to find a great deal of
>the information I needed.
>
>To all that suggested those commercially available switch boxes. Thanks but
>they aren't a very elegant solution in this case. There's nowhere to put
>one and they aren't remote-controllable. They also generally don't deal
>with multiple formats. IE: PS/2
>
>To sum up. (In case anyone else needs to do this kinda thing)
>The keyboard is relatively easy to do. An old keyboard on the end of a
>cross over switch. In this case a set of relay contacts. Just the board
>from the keyboard module will do. You don't actually need the keys. As long
>as both it (the dummy) and the real keyboard are powered up, it's possible
>to swap between them without the PC noticing. Just as long as you're not
>sending data at the time you switch over. This shouldn't be too much of a
>problem.
>
>So when both machines boot, they will see a keyboard on the end of the
>system and receive the necessary ACKs back from it. After that it doesn't
>much matter. There may be a problem with the status LED information but in
>this case it's not a problem because the master keyboard (as it were) has
>no LEDs. It's an IR keyboard. (Thanks Philip) :)
>
>The mouse is another problem all together. I'm not entirely sure if the
>same approach will work. However a Serial mouse and a PS/2 mouse are
>entirely different entities. What I realized I can in fact do is use a
>serial mouse. I don't _have_to_ use a PS/2 Mouse. The PS/2 mouse is
>virtually hooked directly across a UART. It's powered by 5 volts and not 12
>as in a serial mouse. It's data signal is also 5 volts as opposed to +/-12
>in a serial mouse. And of course that means it's signal is positive logic
>instead of being inverted. In short, it would be a really big job to
>convert the PS/2 Mouse up to Serial. Not impossible but impractical. But as
>I said, I shouldn't have to.
>
>What I still don't know is from where the serial mouse actually takes it's
>power. I assume that what it does is get power from one of the signals on
>the serial port. Since an RS232 port supplys no power as such. One or two
>of the lines must be taken high/low and the mouse get's it's power from
>that. The mouse being CMOS should draw only a small amount of current and
>can get away with it. But I can't work out how this is done exactly.
>Obviously time for some raw science here to find out.
>
>Anyway, thanks for all the pointers. I appreciate it.
>





From tadej.bozicko at uni-mb.si  Sat Aug 29 09:41:13 1998
From: tadej.bozicko at uni-mb.si (Tadej Bozicko)
Date: Sat, 29 Aug 1998 09:41:13 +0200
Subject: SSM2164 as exp. converter for VCO's
Message-ID: <01bdd320$65bde580$0100007f@localhost>

Hi there!

I just checked Analog Devices chip SSM2164 which is quad VCA and I got an idea to use it as an exponential converter for VCO. Since SSM2164 has exponential control (voltage) of a current trough the single VCA, exp. converter for VCO would be fairly easy to implement. The only question is whether the log. conformance of the SSM2164 is adequate for quality VCO, or is the standard CA3046 design (heated) better and what about temperature stability? Suggestions, comments....


Tadej Bozicko
E-Mail   : tadej.bozicko at uni-mb.si
WWW  : http://imola.uni-mb.si/~bozicko
WWW2: http://www.uni-mb.si/~uelelt68b

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From don at till.com  Sat Aug 29 10:48:15 1998
From: don at till.com (Don Tillman)
Date: Sat, 29 Aug 1998 01:48:15 -0700 (PDT)
Subject: VCA chips
In-Reply-To: <Pine.HPP.3.93.980828155119.10826B-100000@lulu.acns.nwu.edu>
	(yoh212@lulu.acns.nwu.edu)
Message-ID: <199808290848.BAA04714@shell9.ba.best.com>

   Date: Fri, 28 Aug 1998 15:52:57 -0500 (CDT)
   From: "Yoshiki Ohmura (Yoshi)" <yoh212 at lulu.acns.nwu.edu>

   On Thu, 27 Aug 1998, jhaible wrote:

   > > I phoned Analog Devices.  They said, as I suspected, that the SSM2024
   > > is still in production but the SSM2164 is recommended for new VCA
   > > designs. 

   > Yes, that's more or less the same answer I got.
   > Isn't it sad - if they hush up the chip, it is going to die
   > sooner or later 

True, but the fact that the SSM2164 is a recent chip should suggest
that there's some interesting work going on in the VCA market.

   WHere can I order these VCA chips?  I checked mouser and newark, and
   neither had it.

The Analog Devices web page(http://www.analog.com/) lists their
distibutors:  Allied, Newark, etc.

  -- Don


 



From rsowa at WizjaTV.pl  Sat Aug 29 13:40:15 1998
From: rsowa at WizjaTV.pl (Roman Sowa)
Date: Sat, 29 Aug 1998 13:40:15 +0200
Subject: ODP: Is there any brazilian???
Message-ID: <2BF6F749A4A3D11185AD00A0C94CF67A0FBC2A@demon>

Don't know about that,
but for sure there's a polish guy, who also thinks that
he's the only DIY freak in whole country.
That's me, of course

Roman

> -----Oryginalna wiadomo??-----
> Od:	Guilherme dos Santos Tsubota [SMTP:guist at pucsp.br]
> Wys?ano:	29 sierpnia 1998 01:44
> Do:	synth-diy at mailhost.bpa.nl
> Temat:	
> 
> Is there any brazilian???
> 
> Tem algum brasileiro????
> []s
> 
>                                   GUILHERME  DOS  SANTOS  TSUBOTA  
>  do-re-music_____________________________________________________
>  Pontificia Universidade Catolica de Sao Paulo - RIMA/PROEM
> 
>    Email : guist at pucsp.br                      www.pucsp.br
>    URL   : www.nucc.pucsp.br/~guist           rima.pucsp.br
>            www.do-re-music.com               proem.pucsp.br       
>    tel   : (+55 11) 256-1622 R.214          ICQ   : 8162203



From Hcabnivek at aol.com  Sat Aug 29 13:41:56 1998
From: Hcabnivek at aol.com (Hcabnivek at aol.com)
Date: Sat, 29 Aug 1998 07:41:56 EDT
Subject: posting problem
Message-ID: <38d4bf85.35e7e904@aol.com>>

I've attempted to post something twice now without it being mailed back to me
by the listserver or without bouncing back to me.  Has the list been working
correctly? 
I'm going to try once more, if you see the same post from me show up three
times in short order, please let me know.
Kevin



From rsowa at WizjaTV.pl  Sat Aug 29 14:06:23 1998
From: rsowa at WizjaTV.pl (Roman Sowa)
Date: Sat, 29 Aug 1998 14:06:23 +0200
Subject: ODP: SSM2164 as exp. converter for VCO's
Message-ID: <2BF6F749A4A3D11185AD00A0C94CF67A0FBC2B@demon>

Hi,

I got a whole lot of ideas for SSM2164 (VCO too), and I can't wait till
9th September when my AD distributor will have those chips.
Ordered 3 just to play with them and see if they are any good.

When I'm done maybe will write sth about that.

Roman

> -----Oryginalna wiadomo??-----
> Od:	Tadej Bozicko [SMTP:tadej.bozicko at uni-mb.si]
> Wys?ano:	29 sierpnia 1998 09:41
> Do:	Synth DIY
> Temat:	SSM2164 as exp. converter for VCO's
> 
> Hi there!
> ?
> I just checked Analog Devices chip SSM2164 which is quad VCA and I got
> an idea to use it as an exponential converter for VCO. Since SSM2164
> has exponential control (voltage) of a current trough the single VCA,
> exp. converter for VCO would be fairly easy to implement. The only
> question is whether the log. conformance of the SSM2164 is adequate
> for quality VCO, or is the standard CA3046 design (heated) better and
> what about temperature stability? Suggestions, comments....
> ?
> ?
> Tadej Bozicko
> E-Mail?? : tadej.bozicko at uni-mb.si <mailto:tadej.bozicko at uni-mb.si>
> WWW? : <http://imola.uni-mb.si/~bozicko>
> WWW2: <http://www.uni-mb.si/~uelelt68b>
> ?



From cyborg0 at GlobalEyes.net  Sat Aug 29 19:57:40 1998
From: cyborg0 at GlobalEyes.net (cyborg0 at GlobalEyes.net)
Date: Sat, 29 Aug 1998 12:57:40 -0500
Subject: studio 440 powersupply probs
Message-ID: <35E84114.7E832279@globaleyes.net>

Ok, heres the deal..
the studio 440 outputs +/- 15v, +/- 5v...

Both are too low.. 4.85 volts and 14.8 volts...
The chips run HOT as hell in this machine..My first guess is that the
powersupply rails are rippled.. The reset on the uP has trouble booting
the system.. I fixed a jupiter6 with this problem, as well as a prophet
5 with uP reset problems.. it ended up being PS ripple from caps going
bad..

But, for SOME reason, Sequential WILL NOT give out the schematics for
the powersupply, NOR will they work on a powersupply!
Why not? I think this is somewhat ignorant of them to let soo many of
these beautiful machines go down the tubes due to a powersupply!
I want to ressurrect this unit, but can anyone think of any caveats?
Perhaps the unit is some weird switch mode PS? I just dont get it..why
all the mystery about this power supply?
Any tips?

Robert




From bnillson at hotmail.com  Sat Aug 29 20:34:10 1998
From: bnillson at hotmail.com (Bjarne Nillson)
Date: Sat, 29 Aug 1998 11:34:10 PDT
Subject: Nord Modular editor for Linux
Message-ID: <19980829183410.20518.qmail@hotmail.com>



>At 02:23 PM 28/08/98 -0500, Joe Miklojcik wrote:
>>When I wrote Clavia about writing a Nord Modular editor for Linux, 
they
>>essentiallly told me that the sysex protocol between the editor and 
the
>>hardware was so hairy that they couldn't document it.  Now I learn of 
a Nord
>>Modular editor outputs simple text files?  Somebody clue me... 
>
>"we can't document it" is corporate speak for 
>1. We don't know what we are doing.
>or, 2. We don't want you to know what we are doing.
>or, (usually) BOTH of the above.
>In any case, it is one of the deadly warning flags..
>
>paul perry melbourne australia
>Some are born great.
>Some achieve greatness.
>Some, like Paula Yates, have greatness thrust into them.

Paul you are onto something here, for my own experience, "Hans"
the dude who are the owner and Hardware designer at Clavia
i have met him twice at some ocations, he is a "strange" person

For example the reason they built the NordLead was:
"we wanted one ourself"
at the same time the dude who does the
assembling at clavia  went out to by a P5,,,because they felt
it was better..????

They are strange people at Clavia..

According to some people there are plenty of consults at Clavia
doing somthing ,,, whatthey do, we dont know...

BJ

 


______________________________________________________
Get Your Private, Free Email at http://www.hotmail.com



From yoh212 at lulu.acns.nwu.edu  Sat Aug 29 21:11:16 1998
From: yoh212 at lulu.acns.nwu.edu (Yoshiki Ohmura (Yoshi))
Date: Sat, 29 Aug 1998 14:11:16 -0500 (CDT)
Subject: anything bigger then a decade counter?
Message-ID: <Pine.HPP.3.93.980829141004.7974A-100000@lulu.acns.nwu.edu>


Are there any counters/dividers that can count higher then 10 (a la CMOS
4017)? 

THanks

Yoshi





From jhaible at metronet.de  Sat Aug 29 21:54:19 1998
From: jhaible at metronet.de (jhaible)
Date: Sat, 29 Aug 1998 21:54:19 +0200
Subject: Phasers - if you don't have enough already
Message-ID: <19980829195924.9451.qmail@nuernberg2.pop.metronet.de>

Ok - phasers once more.

With all this talk about the SSM 2024 and the SSM2164 im coming back
to an all pass stage that I've proposed a long time ago on synth-diy.

You're all familiar with the OTA all pass stage as found in the EH Small
Stone,
Moog 12 Stage, and probably many other phase shifters. All these circuits
work
fine with 3080-type OTAs which allow a large output voltage swing, but they
fail to work with the above mentioned SSM VCAs that need a virtual GND node
at their outputs.

The problem can be solved with a little more components: One OTA + 2 OpAmps
for each all pass stage. The idea is to split the all pass function into a
low pass (LP)
function and a second, auxiliary function. The maths go like this:

What we want is:  AP(s) = (1-s) / (1+s).

What we can easily build with a 2024-type ota abd an opamp integrator
is an inverting low pass: LP(s) = -1 / (1+s)

Now we do some calculations:
 
AP(s) = ( -2 + 1 + s) / (1+s) 
         = -( 2 * ( -1 / (1+s) ) + 1 ) 
         = - ( 2 * LP(s) + 1)

This is a function we can easily implement: Build a LP from ota and opamp
1,
and build an inverting adder from opamp 2, with 2 inputs weighted 2:1.

I have not really used this circuit so far, because of the additional opamp
that is required.
But now I have found two new arguments for this method:

(1) You probably know the switchable all pass / low pass circuit from
Electronotes.
     It allows mixed configurations of low pass and all pass stages, which
result in
     some very "musical" transfer functions. The method there (and like
I've implemented
     it in my filter /phaser, too) is switching a capacitor from input (all
pass) to gnd
     (low pass). This requires shielded cables, and if you want to swich
electronically,
     the resistance of CMOS switches might cause non ideal behaviour.
     With my new method, you have the low pass function separate to the all
pass
     function, and you can switch between two buffered opamp outputs. I
think the
     extra opamps are better than shielded cables for sensitive signals.

(2) I am even thinking about an all CMOS phaser solution. Don Tillman
showed us how
     to use a 4069 as a hex VC resistor, and built a phaser from that and
some opamps. (?)
     But what if we want to replace the opamps with 4069's, too ? Similar
problem as
     with the SSM chips. You can build nice inverting linear amplifiers
from the unbuffered
     gates, but the second (positive) input of a real opamp is missing.
     But a similar trick as shown above will work. Build a passive CR high
pass this time,
     with the R going to GND and being part of a 4069 without VCC
connected. Then 
     invert the HP output with one normally powered 4069 gate, and build a
weighted
     adder with another 4069 gate.

I have tested this stuff with PSpice simulation, but haven't built anything
yet. (Sequencer
has priority. (;->) ) IMO, the method could be highly useful for (1).
Number (2) might be
more of a fun project only, but somehow I like the idea of an "all digital
chip purely
analogue" FX device.

What do you think ?

JH.

PS.: I hope the description was fairly understandable. I've also drawn a
little picture, but
I won't publish it on my web page in its current, untested state. Mail me
if you want a
copy.



From magnus at analogue.org  Sat Aug 29 22:32:59 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Sat, 29 Aug 1998 22:32:59 +0200
Subject: Nord Modular editor for Linux
In-Reply-To: Your message of "Sat, 29 Aug 1998 12:22:55 +1000 (EST)"
References: <1.5.4.16.19970120185602.3157b23a@popa.melbpc.org.au>
Message-ID: <199808292032.WAA20443@piraya.electrum.kth.se>

>>>>> "PP" == Paul Perry <pfperry at melbpc.org.au> writes:

 PP> At 02:23 PM 28/08/98 -0500, Joe Miklojcik wrote:
 >> When I wrote Clavia about writing a Nord Modular editor for Linux, they
 >> essentiallly told me that the sysex protocol between the editor and the
 >> hardware was so hairy that they couldn't document it.  Now I learn of a Nord
 >> Modular editor outputs simple text files?  Somebody clue me... 

 PP> "we can't document it" is corporate speak for 
 PP> 1. We don't know what we are doing.
 PP> or, 2. We don't want you to know what we are doing.
 PP> or, (usually) BOTH of the above.
 PP> In any case, it is one of the deadly warning flags..

In my experience there is usually many cases of obscure protocols with
sometimes hairy and not well understood features that is being cocked
up all over simply due to lack of understanding about the mechanisms
involved. So, if they say that it is so hairy that they could not
document it I would not be supprising at all.

On the other hand I would not be supprised if they would try to keep
it to themselfs independently of how good it is or not.

How much would you like to document your latest hastywork that just
about got together but seems to work out in the field? And now this
stranger comes up and wants to examine your work, are you really ready
to let him in? I think not. So, it can be a true engineering story, or
just a feasable excuse.

Cheers,
Magnus (chief protocol maniac :)
Currently validating one of my protocols to ensure stability and
expected function ;)




From thelab at sprint.ca  Sat Aug 29 22:38:14 1998
From: thelab at sprint.ca (Philip)
Date: Sat, 29 Aug 1998 18:38:14 -0200
Subject: Transistor C557C???
Message-ID: <35E866B6.4C1A@sprint.ca>

Is a C557C pnp or npn?
What is the pin out as held in fingers, looking at flat side, pins down?
CEB...EBC..etc?

Philip

-- 
Philip Pilgrim                  The Lab Audio Works
5 Evan's Drive                  - Analog/Digital Recording/Processing
Hammonds Plains                 - Computer/Synth Interfacing
Nova Scotia, Canada             - Hardware/Software Development
B4B 1M8

Phone     +1.902.835.7844
Email      mailto:thelab at sprint.ca

Web Page: http://www.robotnik.com/the_lab



From cyborg0 at GlobalEyes.net  Sat Aug 29 23:50:17 1998
From: cyborg0 at GlobalEyes.net (cyborg0 at GlobalEyes.net)
Date: Sat, 29 Aug 1998 16:50:17 -0500
Subject: anything bigger then a decade counter?
References: <Pine.HPP.3.93.980829141004.7974A-100000@lulu.acns.nwu.edu>
Message-ID: <35E87798.26701E10@globaleyes.net>

yeah, you could just use a carry enable configuration and chain two 10 count
dividers. When one is done counting, it hands off the count to a second BCD
counter, which finishes the counting. It really depends on what you wanna do
with it.

OR, you could go with a binary counter, that would take you up to 16.
Depends on what you are doing with it..
If you are driving a decimal display, then you would be better off with the
BCD (10) counters set up in a msb/lsb configuration.
But, if all you are doing is counting, its up to you.
Rob
ps, if your feeling rather spry,  go to barnes and noble and get the
ttl/cmos cookbook.. it is the best, they explain stuff in depth. Some of
those circuit encyclopaedias are really interesting too, along with the
Forrest Mims books at radio shack. $1.99 for a book about circuits cant be
beat..


Yoshiki Ohmura (Yoshi) wrote:

> Are there any counters/dividers that can count higher then 10 (a la CMOS
> 4017)?
>
> THanks
>
> Yoshi






From magnus at analogue.org  Sun Aug 30 01:00:27 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Sun, 30 Aug 1998 01:00:27 +0200
Subject: Nord Modular editor for Linux
In-Reply-To: Your message of "Sat, 29 Aug 1998 11:34:10 PDT"
References: <19980829183410.20518.qmail@hotmail.com>
Message-ID: <199808292300.BAA21364@piraya.electrum.kth.se>

>>>>> "BN" == Bjarne Nillson <bnillson at hotmail.com> writes:

Hej BJ!

 BN> Paul you are onto something here, for my own experience, "Hans"
 BN> the dude who are the owner and Hardware designer at Clavia
 BN> i have met him twice at some ocations, he is a "strange" person

>From my experience there are more strange people in that family...

Also, doesn't this come with the territory? ;)

 BN> For example the reason they built the NordLead was:
 BN> "we wanted one ourself"
 BN> at the same time the dude who does the
 BN> assembling at clavia  went out to by a P5,,,because they felt
 BN> it was better..????

In a way it would be hard to make a good product if you where not
beleiving in it (or being a good mental prostitute). If you where not
trying to make a synth that you would like to have yourself, how would
you get it right? Well, you could now the trade well, but it doesn't
work well in the long run.

 BN> They are strange people at Clavia..

Strange people make some strange and unique things.

 BN> According to some people there are plenty of consults at Clavia
 BN> doing somthing ,,, whatthey do, we dont know...

There are about zillions things they could be doing. Like help out
writting software etc.

Hmm... wounder if I could do some extra work for them ;)

Cheers,
Magnus



From batzman at all-electric.com  Sun Aug 30 06:02:09 1998
From: batzman at all-electric.com (The Dark force of dance)
Date: Sun, 30 Aug 1998 13:02:09 +0900
Subject: Power Gloov
Message-ID: <3.0.32.19980830130006.006b8998@mail.chariot.net.au>

Y-ellow Y'all.
	A long time ago in a list server far away, we talked about interfacing the
matel/nintendo power glove. I found this hURL that might be useful.

http://www.cms.dmu.ac.uk/~cph/menelli.html

Ok so it's HC11 based but it might be OK.

Be absolutelY Icebox.



 _ __        _                              
| "_ \      | |         batzman at all-electric.com / aek at all-electric.com
| |_)/  __ _| |_ ____           ALL ELECTRIC KITCHEN               
|  _ \ / _` | __|___ |  The Elementary Urban sanity CD
| |_) | (_| | |_  / /   out now on Transmission Communications
|_,__/ \__,_|\__|/ /    
                / ,__   http://www.all-electric.com
Goodfortune    |_____|       



From batzman at all-electric.com  Sun Aug 30 06:39:11 1998
From: batzman at all-electric.com (The Dark force of dance)
Date: Sun, 30 Aug 1998 13:39:11 +0900
Subject: Sample Rate conversion
Message-ID: <3.0.32.19980830133755.006bb664@mail.chariot.net.au>

Y-ellow Y'all.
	I'm hot today. :) Some time back people were talking about Sample Rate
conversion. Here is a project to do just that. Also included is how to
convert S/PDIF to AES/EBU Which was something else someone mentioned.

http://exodo.upr.clu.edu/~hunt/src.htm

Hope this helps.

Be absoluely Icebox.

 _ __        _                              
| "_ \      | |         batzman at all-electric.com / aek at all-electric.com
| |_)/  __ _| |_ ____           ALL ELECTRIC KITCHEN               
|  _ \ / _` | __|___ |  The Elementary Urban sanity CD
| |_) | (_| | |_  / /   out now on Transmission Communications
|_,__/ \__,_|\__|/ /    
                / ,__   http://www.all-electric.com
Goodfortune    |_____|       



From verbos at on-q.com  Sun Aug 30 06:48:46 1998
From: verbos at on-q.com (mark verbos)
Date: Sat, 29 Aug 1998 22:48:46 -0600
Subject: quantizer question
Message-ID: <35E8D9AC.EEA2D3DD@on-q.com>

sooo...


In looking at Chris list's ARP style quantizer, I can't help but
ask if one could get away with using a cheeper 8 bit D to A
converter. One that is like $3 insted of like $23? Since only 7
bits are used anyway.

is there a good reason why not?


--
mark verbos

"I think the future of analog modulars is to build them
yourself."

verbos at on-q.com
http://www.on-q.com/verbos
massive magazine... http://www.massivemag.com
current release...
 "Logic Circuits" as CMOS on Shokoy, Germany





From don at till.com  Sun Aug 30 06:53:02 1998
From: don at till.com (Don Tillman)
Date: Sat, 29 Aug 1998 21:53:02 -0700 (PDT)
Subject: Phasers - if you don't have enough already
In-Reply-To: <19980829195924.9451.qmail@nuernberg2.pop.metronet.de>
	(jhaible@metronet.de)
Message-ID: <199808300453.VAA22158@shell9.ba.best.com>

   From: "jhaible" <jhaible at metronet.de>
   Date: Sat, 29 Aug 1998 21:54:19 +0200

   Ok - phasers once more.

   I am even thinking about an all CMOS phaser solution. Don Tillman
   showed us how to use a 4069 as a hex VC resistor, and built a
   phaser from that and some opamps.

Yep.  Though someone else pointed out that an Electro Harmonix product
might have done this independently.

   But what if we want to replace the opamps with 4069's, too? 

Note that 4069 FETs are noisey when used as linear amplifiers.
(When they're voltage controlled resistors it's not a problem.)  


  -- Don



From costello at seanet.com  Sun Aug 30 08:16:27 1998
From: costello at seanet.com (Sean Costello)
Date: Sat, 29 Aug 1998 23:16:27 -0700
Subject: Phasers - if you don't have enough already
References: <199808300453.VAA22158@shell9.ba.best.com>
Message-ID: <35E8EE3B.7A15281B@seanet.com>

Don Tillman wrote:

>    I am even thinking about an all CMOS phaser solution. Don Tillman
>    showed us how to use a 4069 as a hex VC resistor, and built a
>    phaser from that and some opamps.
> 
> Yep.  Though someone else pointed out that an Electro Harmonix product
> might have done this independently.

I just saw this - someone posted a Badstone schematic, which seems to
use a 4049 for its FETs.  Still a very cool idea, that I want to
experiment with.

BTW, how much of a difference do the VCR's make in a phaser design? Will
a design that uses FETs sound noticably different than a design that
uses photoresistors?  How about OTA-based phasers?  Can anyone describe
the sonic differences between these phasers, in a way that makes sense?

Thanks,

Sean Costello (owner of a Maestro Phaser, a Mutron Phasor II, a
weak-sonding Ibanez Soundtank Phaser, and the Boss SE-50 which does a
nice job of phasing in the digital domain)




From dave.halliday at greymatter.com  Sun Aug 30 08:32:06 1998
From: dave.halliday at greymatter.com (Dave Halliday)
Date: Sun, 30 Aug 1998 06:32:06 GMT
Subject: anything bigger then a decade counter?
Message-ID: <980829234440204@greymatter.com>

>      
>     Are there any counters/dividers that can count higher then 10 (a la 
>     CMOS 4017)? 
>      


How high do you want to count and what sort of range do you need.

There are a bunch of 16 counters out there.  There are also some 
counters that are designed to be chained together to get as many 
decades of counting as you need.  There are also counters that let you 
pre-load a number into them and they start counting from that number ( 
rather than zero ) and there are also up/down counters of several 
sorts.









--- Via Silver Xpress V4.4 [Reg]



From gjalass at snafu.de  Sun Aug 30 09:04:47 1998
From: gjalass at snafu.de (Gert Jalass)
Date: Sun, 30 Aug 1998 07:04:47 GMT
Subject: quantizer question
In-Reply-To: <35E8D9AC.EEA2D3DD@on-q.com>
References: <35E8D9AC.EEA2D3DD@on-q.com>
Message-ID: <35e9f89a.177433565@berlin.snafu.de>

On Sat, 29 Aug 1998 22:48:46 -0600, you wrote:

>sooo...
>
>
>In looking at Chris list's ARP style quantizer, I can't help but
>ask if one could get away with using a cheeper 8 bit D to A
>converter. One that is like $3 insted of like $23? Since only 7
>bits are used anyway.
>
>is there a good reason why not?

Mark,

please keep in mind that DAC's do have tolerances ( e.g. 1 LSB - Least
Significant Bit ). Since it's required to quantize to e.g. semitones
You do need a very "good" DAC to keep audible errors to a minimum.
Therefore only the MSB's of the 12-Bit DAC are used.

Gert



From torbjorn.hornfeldt at abc.se  Sun Aug 30 10:44:41 1998
From: torbjorn.hornfeldt at abc.se (Torbjorn Hornfeldt)
Date: Sun, 30 Aug 1998 10:44:41 +0200
Subject: VCA chips
Message-ID: <3.0.3.32.19980830104441.00a93650@mail.abc.se>

Anyone got any experience with the Mitsubishi M 5283 Dual Hi-Fi VCA chip?

Some specs are:
0-5V CV, 95 dB range, plus/minus 0,1 dB matching between channels.
Plus/minus 7 to 16 V supply.

Torbj?rn,
Solna, Sweden





From jhaible at metronet.de  Sun Aug 30 10:54:21 1998
From: jhaible at metronet.de (jhaible)
Date: Sun, 30 Aug 1998 10:54:21 +0200
Subject: Phasers - if you don't have enough already
Message-ID: <19980830115119.21538.qmail@nuernberg2.pop.metronet.de>

>    But what if we want to replace the opamps with 4069's, too? 
> 
> Note that 4069 FETs are noisey when used as linear amplifiers.
> (When they're voltage controlled resistors it's not a problem.)  

Good point.
It was not that much an issue in the Wasp Filter - it *is* as little
noisy, but not that bad. But I can see that it could be worse with
the phaser, because of the limited voltage across the FETs that
work as resistors. What was maximum voltage for decent
distortion ? And did you feed part of the audio signal to the gate
to linearize the FETs, or was it a strictly low number of components
device ?

JH.



From gur-m at internet-zahav.net  Sun Aug 30 11:09:55 1998
From: gur-m at internet-zahav.net (Gur Milstein)
Date: Sun, 30 Aug 1998 11:09:55
Subject: book
Message-ID: <3.0.2.16.19980830110955.563781b0@mail.internet-zahav.net>

hi guy's.
had any body read/have the book "the development and practice of electronic
music" ?
it should contian lot of info about seq automation in it .

i want to buy one but it cost 120$ US second hand,
so dos it worth the mony ?

thanx
Gur Milstein



From synth1 at airmail.net  Sun Aug 30 14:49:21 1998
From: synth1 at airmail.net (Paul Schreiber)
Date: Sun, 30 Aug 1998 12:49:21 -0000
Subject: dbx  VCA
Message-ID: <01BDD42B.10CA0840@dal11-04.ppp.iadfw.net>

Because dbx (at least in the US, throught T.H.A.T. Corp.) requires a 
$2000 minimum order.

Paul Schreiber
Synthesis Technology


----------
From: 	papareil[SMTP:papareil at netsud.fr]
Sent: 	Sunday, August 30, 1998 4:04 PM
To: 	synth-diy at mailhost.bpa.nl
Subject: 	dbx  VCA

Hi list ppl ! 

Anyone  know the dbx2150 series(2155,2151,2180...) and SSM2018 (ex
SSM2013/2014) - those ics are greats VCAs for audio, i have used some
for  building compressors ,noise gate,....with succes and good results!
Why nobody use them in synth VCA ?

Don't they fit with synth VCA performances ? (i doubt)

Are they too much clean for this application ? 

Marc Bareille






From edusilva at bahianet.com.br  Sun Aug 30 15:46:20 1998
From: edusilva at bahianet.com.br (Eduardo Silva)
Date: Sun, 30 Aug 1998 10:46:20 -0300
Subject: Is there any brazilian?
Message-ID: <199808301405.LAA10739@unix2.bahianet.com.br>

Yes: It's me!
Anyone else?
______________________
Eduardo Silva
ES2 Audio
edusilva at bahianet.com.br
+55 71 245 8942
Brazil

----------
> De: Guilherme dos Santos Tsubota <guist at pucsp.br>
> Para: synth-diy at mailhost.bpa.nl
> Assunto: 
> Data: Sexta-feira, 28 de Agosto de 1998 20:44
> 
> Is there any brazilian???
> 
> Tem algum brasileiro????
> []s
> 
>                                   GUILHERME  DOS  SANTOS  TSUBOTA  
>  do-re-music_____________________________________________________
>  Pontificia Universidade Catolica de Sao Paulo - RIMA/PROEM
> 
>    Email : guist at pucsp.br                      www.pucsp.br
>    URL   : www.nucc.pucsp.br/~guist           rima.pucsp.br
>            www.do-re-music.com               proem.pucsp.br       
>    tel   : (+55 11) 256-1622 R.214          ICQ   : 8162203



From DCMagnuson at aol.com  Sun Aug 30 15:49:31 1998
From: DCMagnuson at aol.com (DCMagnuson at aol.com)
Date: Sun, 30 Aug 1998 09:49:31 EDT
Subject: Good books still in print?
Message-ID: <8bd5f792.35e9586b@aol.com>>

Hi everyone, I just began building my first modular, and have now finished my
4th module (yeah, I've got a LONG way to go).  Anyways, I'm wondering if there
are any good analog synth design/theory books that are still in print.   I've
been scrounging schematics off the web, but I'd like to have a little theory
to go along with these designs...  Plus, I'd like to design my own circuits
rather than ripping off all the old Moog and ARP circuits.

Thanks in advance

Dave Magnuson



From rsowa at WizjaTV.pl  Sun Aug 30 15:54:40 1998
From: rsowa at WizjaTV.pl (Roman Sowa)
Date: Sun, 30 Aug 1998 15:54:40 +0200
Subject: ODP: Transistor C557C???
Message-ID: <2BF6F749A4A3D11185AD00A0C94CF67A0FBC2C@demon>

PNP, CBE

> -----Oryginalna wiadomo??-----
> Od:	Philip [SMTP:thelab at sprint.ca]
> Wys?ano:	29 sierpnia 1998 22:38
> Do:	synth-diy at mailhost.bpa.nl
> Temat:	Transistor C557C???
> 
> Is a C557C pnp or npn?
> What is the pin out as held in fingers, looking at flat side, pins
> down?
> CEB...EBC..etc?
> 
> Philip
> 



From don at till.com  Sun Aug 30 17:33:05 1998
From: don at till.com (Don Tillman)
Date: Sun, 30 Aug 1998 08:33:05 -0700 (PDT)
Subject: Phasers - if you don't have enough already
In-Reply-To: <19980830115119.21538.qmail@nuernberg2.pop.metronet.de>
	(jhaible@metronet.de)
Message-ID: <199808301533.IAA25179@shell9.ba.best.com>

   From: "jhaible" <jhaible at metronet.de>
   Date: Sun, 30 Aug 1998 10:54:21 +0200

   >    But what if we want to replace the opamps with 4069's, too? 
   > 
   > Note that 4069 FETs are noisey when used as linear amplifiers.
   > (When they're voltage controlled resistors it's not a problem.)  

   Good point.
   It was not that much an issue in the Wasp Filter - it *is* as little
   noisy, but not that bad. But I can see that it could be worse with
   the phaser, because of the limited voltage across the FETs that
   work as resistors. What was maximum voltage for decent
   distortion ? 

Guitar levels, about a volt or so. (Depending on your tolerance for
distortion of course.) 

   And did you feed part of the audio signal to the gate to linearize
   the FETs, or was it a strictly low number of components device ?

I should have fed 1/2 the audio signal into the gates to linearize the
FETs, but I didn't know about that then.  Hey, I was only about 17
years old at the time!

Hmmm, I don't think any of the other FET-based phase shifters
linearized their FETs either.  The MXR Phase 90 certainly didn't.

  -- Don





From rsowa at WizjaTV.pl  Sun Aug 30 17:43:19 1998
From: rsowa at WizjaTV.pl (Roman Sowa)
Date: Sun, 30 Aug 1998 17:43:19 +0200
Subject: ODP: Good books still in print?
Message-ID: <2BF6F749A4A3D11185AD00A0C94CF67A0FBC2F@demon>

If you've built 4 modules already, then you know the theory.

I'd recommend to review synths' service and user's manuals - you can get
them on the web. http://surf.to/analogue

And i like the idea of designing by yourself - same with me.
How do you think - did R. Moog use internet to get schematics for his
modulars?
Maybe you will invent something too...

Roman

> -----Oryginalna wiadomo??-----
> Od:	DCMagnuson at aol.com [SMTP:DCMagnuson at aol.com]
> Wys?ano:	30 sierpnia 1998 15:50
> Do:	synth-diy at mailhost.bpa.nl
> Temat:	Good books still in print?
> 
> Hi everyone, I just began building my first modular, and have now
> finished my
> 4th module (yeah, I've got a LONG way to go).  Anyways, I'm wondering
> if there
> are any good analog synth design/theory books that are still in print.
> I've
> been scrounging schematics off the web, but I'd like to have a little
> theory
> to go along with these designs...  Plus, I'd like to design my own
> circuits
> rather than ripping off all the old Moog and ARP circuits.
> 
> Thanks in advance
> 
> Dave Magnuson



From papareil at netsud.fr  Sun Aug 30 18:04:14 1998
From: papareil at netsud.fr (papareil)
Date: Sun, 30 Aug 1998 18:04:14 +0200
Subject: dbx  VCA
Message-ID: <35E977FE.3BAB@netsud.fr>

Hi list ppl ! 

Anyone  know the dbx2150 series(2155,2151,2180...) and SSM2018 (ex
SSM2013/2014) - those ics are greats VCAs for audio, i have used some
for  building compressors ,noise gate,....with succes and good results!
Why nobody use them in synth VCA ?

Don't they fit with synth VCA performances ? (i doubt)

Are they too much clean for this application ? 

Marc Bareille



From thelab at sprint.ca  Sun Aug 30 19:13:45 1998
From: thelab at sprint.ca (|[| Philip Pilgrim |]|)
Date: Sun, 30 Aug 1998 14:13:45 -0300
Subject: Transistor C557C???
References: <2BF6F749A4A3D11185AD00A0C94CF67A0FBC2C@demon>
Message-ID: <35E98849.C4B@sprint.ca>

1. according to my reading of my NTE book, it's npn, EBC.

2. PNP, CBE

3. BC557 is pnp CBE if you look that way

 ---
0 0 0
-----

E B C   bottom view


4. 2sc557c npn, sili, connections cbe 
    bc557, then pnp, to92 case , ebc connections ,flat towards you
    .pins held up .....


I guess it is PNP CBE. It's from a MAM VF-11 tran says only C557C in
text. Don't know if B or SC prefex. It's part of the Envelope follower
circuit. Still trying to understand how it works? 


Thanks everyone!!!

Philip
-- 
Philip Pilgrim          	The Lab 
5 Evan's Drive          	- Analog/Digital Recording/Processing
Hammonds Plains       		- Computer/Synth Interfacing
Nova Scotia, Canada   		- Hardware/Software Development
B4B 1M8                   

   <<<<< Home of SH-101 NovaMod and UP Midi Programmer
>>>>>                     

Phone     +1.902.835.7844
Email     mailto:thelab at sprint.ca
Web Page: http://www.robotnik.com/the_lab/



From synth1 at airmail.net  Sun Aug 30 19:28:28 1998
From: synth1 at airmail.net (Paul Schreiber)
Date: Sun, 30 Aug 1998 17:28:28 -0000
Subject: 3340 Auction #1 has begun!
Message-ID: <01BDD43B.9B3458E0@dal11-04.ppp.iadfw.net>

20pcs of 3340 VCO are available for bidding until Thursday Sept. 3rd. Limit
of 2pcs per person. Send bids to synth1 at airmail.net. You can buy 1.
Shipping is $3 in US and $7 foreign per order.

This is a Dutch auction. The top bids get the chips, at the bid price. For
example, if 2 items are for sale, and the bids are $1, $2, $4, and $10, the
items go for $4 and $10. THe $10 bid does NOT get the $4 price.

UNLESS you state otherwise, I will assume the bids are FOR ONE CHIP.

If you have questions, call me at 888-818-MOTM.

Paul Schreiber
Synthesis Technology




From synth1 at airmail.net  Sun Aug 30 19:36:03 1998
From: synth1 at airmail.net (Paul Schreiber)
Date: Sun, 30 Aug 1998 17:36:03 -0000
Subject: 3340 Auction...Part 2
Message-ID: <01BDD43F.CC96B960@dal11-04.ppp.iadfw.net>

1) Min. bid is $18/chip.

2) I will post on Wed the current top 10 bids.

3) You can bid as many times as you want.

Paul S.




From jhaible at metronet.de  Sun Aug 30 20:26:26 1998
From: jhaible at metronet.de (jhaible)
Date: Sun, 30 Aug 1998 20:26:26 +0200
Subject: dbx  VCA
Message-ID: <19980831224845.20221.qmail@nuernberg2.pop.metronet.de>

> Anyone  know the dbx2150 series(2155,2151,2180...) and SSM2018 (ex
> SSM2013/2014) - those ics are greats VCAs for audio, i have used some
> for  building compressors ,noise gate,....with succes and good results!
> Why nobody use them in synth VCA ?
> 
> Don't they fit with synth VCA performances ? (i doubt)
> 
> Are they too much clean for this application ? 

Two other questions:

(1) Are they inexpensive ? 
(2) Are there second sources to buy them ?

The second one is most important. Large companies won't use chips
that are built from at least two manufacturers, for good reason.
If you rely on one source, you'll get in trouble. Just think about
EH and the MN BBD chips.
For DIY builders, I'd say it's a good rule of thump to have a second
source *distributor*, regardless of how many manufacturers there are
for one chip.
The best circuits from DIY perspective are those built from standard
transistors and opamps.

JH.





From lheckman at juno.com  Sun Aug 30 21:05:13 1998
From: lheckman at juno.com (Lucas A Heckman)
Date: Sun, 30 Aug 1998 14:05:13 -0500
Subject: PCB Kits?
References: <TCPSMTP.18.8.29.-13.31.54.900.16149@clubmet.metrobbs.com>
Message-ID: <19980830.140513.6702.0.lheckman@juno.com>

Hello,
I plan to hand-design a few VCO, VCF, and ADSR circuits for a modular
synthesizer.  For the sake of convenience and reliability, I want to
have a decent circuit board.  In most cases, I'll need only one 
circuit board for each unit; I do not plan to make 7 identical VCOs, for
instance.  A few questions:

1) Which modules will perform reliably using point-to-point wiring?
Reliable tracking is unimportant, but I do not want to sacrifice much
sound quality.  (I plan to have VCOs, VCFs, VCAs, ring mod, LFOs, 
ADSRs)

2) Can you recommend a PCB kit for me?  I've seen one in Mouser, and a
cheaper one in Jameco that uses a negative film process.  Are these 
any
good?

3) How does "direct etch" work?  Is this what I need?  Do I need a kit
to direct etch, or can I just buy a few supplies?

Thanks for your help.
Lucas

_____________________________________________________________________
You don't need to buy Internet access to use free Internet e-mail.
Get completely free e-mail from Juno at http://www.juno.com
Or call Juno at (800) 654-JUNO [654-5866]



From oakley at enterprise.net  Sun Aug 30 22:33:16 1998
From: oakley at enterprise.net (Tony Allgood)
Date: Sun, 30 Aug 1998 21:33:16 +0100
Subject: Frequency multiplication
Message-ID: <002b01bdd456$e2038780$14c648c2@default>

Hi all,

I want to make a high frequency VCO, 32 times the normal frequency, to use
as a driver osc for a walsh bank. There are several options:
1. Use a HF VCO... like a CEM3340 with a smaller than usual cap. I've tried
this before, it worked sort of...
2. Use an ordinary pitched VCO's triangle output and FWR and level shift it
5 times over. Never tried this but it could work... but will it track fast
enough?
3. Use an ordinary VCO's sawtooth output and have a load of comparators to
generate a pulse train as the sawtooth drops in voltage over one time
period.
4. I'm open to any other ideas.

Regards,

Tony Allgood, Cumbria, UK

e-mail: oakley at enterprise.net

Rack mounted Moog VCF module. Details to be found at...

http://aupe.phys.andrews.edu/diy_archive/schematics/effects/filter.html







From oakley at enterprise.net  Sun Aug 30 22:33:35 1998
From: oakley at enterprise.net (Tony Allgood)
Date: Sun, 30 Aug 1998 21:33:35 +0100
Subject: dbx  VCA
Message-ID: <002c01bdd456$e2f624e0$14c648c2@default>

Marc brought up the idea of using dbx2155 et al. as VCAs in synths. I've
used these and yes they do sound good even if they distort the input a tad.
0.05% THD ha, ha. But I found the real problem with these was control
breakthrough. You always had to slug the CV otherwise it would thump
something horrid. I cannot remember the rise times I used with the 2155 but
I bet it was a lot slower than a good ADSR. However, they are very good for
panning and things... but at a fiver a go (sterling that is), they are a bit
too pricey for most people. The SSM parts are cheaper and better I think.
However, THAT corp have come out with better VCAs of late, and of these I
cannot comment. Mind you I haven't found a source of these who is willing to
sell me any in small numbers.

Regards,

Tony Allgood, Cumbria, UK

e-mail: oakley at enterprise.net

Rack mounted Moog VCF module. Details to be found at...

http://aupe.phys.andrews.edu/diy_archive/schematics/effects/filter.html







From Hcabnivek at aol.com  Mon Aug 31 00:48:44 1998
From: Hcabnivek at aol.com (Hcabnivek at aol.com)
Date: Sun, 30 Aug 1998 18:48:44 EDT
Subject: Posting problems
Message-ID: <e0bb1be.35e9d6cc@aol.com>>

Hi Folks,
I tried to send the same post to synth diy 5 times on friday and saturday with
no luck, but my post about the appearant problem went through just fine.  I
have no idea why.  None of the five bounced back to me.  I'm sure that they
will post to the list a decade from now.  I'm going to send the origional
again right after I send this, maybe it will work now.
thanks
Kevin



From DCMagnuson at aol.com  Mon Aug 31 01:03:27 1998
From: DCMagnuson at aol.com (DCMagnuson at aol.com)
Date: Sun, 30 Aug 1998 19:03:27 EDT
Subject: PCB Kits?
Message-ID: <867c05b9.35e9da3f@aol.com>>

In a message dated 8/30/98 4:27:29 PM Eastern Daylight Time, lheckman at juno.com
writes:

> 2) Can you recommend a PCB kit for me?  I've seen one in Mouser, and a
>  cheaper one in Jameco that uses a negative film process.  Are these 
>  any
>  good?

I haven't used either of the two you've mentioned above, but I've had good
luck using the supplies from my local Radio Shack.  All told, the kit and
supplies are very cheap, and very straight forward to use. 

>  
>  3) How does "direct etch" work?  Is this what I need?  Do I need a kit
>  to direct etch, or can I just buy a few supplies?

The RS kit is simply a copper clad board (1 sided), a bottle of etchant
solution and an etch resistant marker (Sharpie).  You just color in the areas
you want traces, dunk it in the etcher (1/4" deep or so in a container) and in
30-45 minutes, you'll have a PCB.  

I remember seeing the Mouser kit, and I believe it came with a heater, etc...
the RS kit is much more simple, but also less than $20.  I think the heater
only speeds up the process.  

If you only plan to etch a handful of boards, the simple kit will probably be
fine, but if you plan on doing a lot of boards, the more advanced set up may
be prefered.
  
Dave Magnuson



From papareil at netsud.fr  Mon Aug 31 02:11:12 1998
From: papareil at netsud.fr (Marc Bareille)
Date: Mon, 31 Aug 1998 02:11:12 +0200
Subject: dbx  VCA
References: <002c01bdd456$e2f624e0$14c648c2@default>
Message-ID: <35E9EA20.7AE4@netsud.fr>

Thank for all the  answers! This is a Great List :)

Tony Allgood wrote:
> 
> Marc brought up the idea of using dbx2155 et al. as VCAs in synths. I've
> used these and yes they do sound good even if they distort the input a tad.
> 0.05% THD ha, ha.

Yes there are not perfect! But if you dont use them for HiFi but for
sono and instruments 
(well as dynamic processing mainly ) they are quite good and efficients.
Have build some for friends  and they are still in use!

> But I found the real problem with these was control
> breakthrough. You always had to slug the CV otherwise it would thump
> something horrid. 

Yes again , you're rigth !  I experiment the same pb when i try to build
a fast side chain for driving 
the dbx vca... or give to the attack/realese time of my compressor a to
small value 

>I cannot remember the rise times I used with the 2155 but
>I bet it was a lot slower than a good ADSR

I think a synth VCA need to have a very fast attack rate ... dbx vca
will probably  make problem on this side
and it's rigth that they need good trimming to give good sound as well ! 

> The SSM parts are cheaper and better I think.

I will probably try the SSM2018... (i have some never used samples
somewhere... :) 

>Mind you I haven't found a source of these who is willing to
> sell me any in small numbers.

I know two sources in France for those ics :
 
the first is a retailer and have only the 2150A and the 2252 RMS
detector for 73FF each (about 7.3? or $14)
but you can order only 1 if you want... http://wwww.selectronic.fr

the second one is the official importator :SCV audio - they have all the
collection of THAT ics...
but the prices are heavy if you buy only one. Prices are very degressive
with qte ...
For people who just want few ics they provide packages with different
combinations 
(ie: 3*2150 +3*2252 for about 400FF -40?- 80$) 

you can contact them here : http://www.scv.fr
they have an E-mail: scv at scv.fr    


thanx  
Marc Bareille



From cyborg0 at GlobalEyes.net  Mon Aug 31 02:34:35 1998
From: cyborg0 at GlobalEyes.net (cyborg0 at GlobalEyes.net)
Date: Sun, 30 Aug 1998 19:34:35 -0500
Subject: solinoids
References: <v04011702b20a08bcf1ce@[208.255.152.3]>
Message-ID: <35E9EF9B.A82CC45F@globaleyes.net>

from what I have seen, it _seems_ that the muscle wire wouldnt be able to
contract quickly enough for certain applications, although nitinol would be
neat to be able to use..BTW, doesnt that stuff need a pretty high dc pulsed
voltage to contract?
rob

KA4HJH wrote:

> >does anyone know of a source for small solinoids (about the size needed
> >to actuate keys on a sk-1 :)???
>
> Have you thought of using "muscle wire" (shape memory alloy)?
>
> Terry Bowman, KA4HJH
> "The Mac Doctor"






From 8brain at spiritone.com  Mon Aug 31 03:48:49 1998
From: 8brain at spiritone.com (R.Fahl)
Date: Sun, 30 Aug 1998 17:48:49 -0800
Subject: Mislabelled Regulators
Message-ID: <v02130500b20fb059482d@[205.139.109.16]>

Just built another power supply to test some new modules.  Measured the
output voltages: positive supply 15.11 volts DC Negative -18.3 vDC.  Didn't
make sense to me, so I ended up swapping regulators.  Same result.  This
made me suspicious.  Replaced the negative regulator again, but this time
from a different manufacturer.  This time the negative rail was -15 volts
(close enuff).  Looks like someone sold me a batch of mislabelled 7918s.  I
take it someone in Malaysia was feeling underpaid.





From Cary.Roberts at usa.net  Mon Aug 31 04:55:48 1998
From: Cary.Roberts at usa.net (Cary Roberts)
Date: Sun, 30 Aug 1998 21:55:48 -0500
Subject: Solenoids for an SK-1???
Message-ID: <35EA10B4.1B3837F@usa.net>

I'm not sure of the original post, but there was a clip in there about
SK-1 keys.  If you want to control an SK-1, your best bet is Paul
Messick's SK-1 MIDI retrofit.  It can be found at: 

http://www.maxmidi.com/diy/sk1/index.html

-Cary



From pfperry at melbpc.org.au  Mon Aug 31 07:31:52 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Mon, 31 Aug 1998 15:31:52 +1000 (EST)
Subject: Phasers - if you don't have enough already
Message-ID: <1.5.4.16.19970122220452.2e7fa9fe@popa.melbpc.org.au>

At 11:16 PM 29/08/98 -0700, Sean Costello  wrote:

>uses photoresistors?  How about OTA-based phasers?  Can anyone describe
>the sonic differences between these phasers, in a way that makes sense?
>
the modualting waveform (which I know isn't what is being asked about here)
prob makes as much or more diff than the actual phaser config...
and, a function of LED/LDR systems is to smooth out the modulating signal,
as the LDR had a longish 'recovery' time after illumination (and even more so
for systems based on incandescant bulbs).
There has been a lot of discussion on phasers on the AMPAGE tech-Talk bbs,
apparently one successful waveform rectified a sine wave to give a bumpy 
sort of modulator which was good.

paul perry melbourne australia




From pfperry at melbpc.org.au  Mon Aug 31 07:54:37 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Mon, 31 Aug 1998 15:54:37 +1000 (EST)
Subject: Good books still in print?
Message-ID: <1.5.4.16.19970122222739.36af5732@popa.melbpc.org.au>

Hi everyone, I just began building my first modular, and have now finished my
4th module (yeah, I've got a LONG way to go).  Anyways, I'm wondering if there
are any good analog synth design/theory books that are still in print.   I've
been scrounging schematics off the web, but I'd like to have a little theory
to go along with these designs...  Plus, I'd like to design my own circuits
rather than ripping off all the old Moog and ARP circuits.

Thanks in advance

Dave Magnuson





From gur-m at internet-zahav.net  Mon Aug 31 07:02:19 1998
From: gur-m at internet-zahav.net (Gur Milstein)
Date: Mon, 31 Aug 1998 07:02:19
Subject: serge knobs
Message-ID: <3.0.2.16.19980831070219.2217aa74@mail.internet-zahav.net>

hi guy's.
any body know the size of the knobs used in the serge modular ?
allso where i can get them and are they chipe ?

thanx
Gur Milstein



From cmacdon at ix.netcom.com  Mon Aug 31 09:14:46 1998
From: cmacdon at ix.netcom.com (Christopher MacDonald)
Date: Mon, 31 Aug 1998 00:14:46 -0700
Subject: serge knobs
Message-ID: <35EA4D66.749B@ix.netcom.com>

Here are the dimensions of a knob from a recent panel:

15mm tall
12mm diameter

There is a 3 letter logo which looks like "HIO" to me and possible a
part number of 900P.  No guarantees here, just my guesses based on
looking at a knob.

Sorry I don't know where these knobs can be purchased.  If you find out,
I would like to know too as I like them quite a bit.

-Chris MacDonald



From bryantrv at totcon.com  Mon Aug 31 08:28:03 1998
From: bryantrv at totcon.com (bryantrv)
Date: Mon, 31 Aug 1998 08:28:03
Subject: Mislabelled Regulators
In-Reply-To: <v02130500b20fb059482d@[205.139.109.16]>
Message-ID: <3.0.5.16.19980831082803.3d3f41e6@mail.totcon.com>

Pardon the stupid question, but isn't the 7918 a -18v regulator? Would it
not be a 7915 for -15v?

Chris Bryant, Tech Head Wanabe, DeLand, Forida


>Just built another power supply to test some new modules.  Measured the
>output voltages: positive supply 15.11 volts DC Negative -18.3 vDC.  Didn't
>make sense to me, so I ended up swapping regulators.  Same result.  This
>made me suspicious.  Replaced the negative regulator again, but this time
>from a different manufacturer.  This time the negative rail was -15 volts
>(close enuff).  Looks like someone sold me a batch of mislabelled 7918s.  I
>take it someone in Malaysia was feeling underpaid.
>
>
>



From tomg at vivid.net  Mon Aug 31 10:51:57 1998
From: tomg at vivid.net (tomg)
Date: Mon, 31 Aug 1998 03:51:57 -0500
Subject: Mad Mouse 3.5 - LM136OO VCO
Message-ID: <yam7547.2885.120297888@mail.vivid.net>


I'm still playing with designs for the MM. The latest
bunch and details are on my page. I know I said no OTAs.
You'll just have to take a look.

LM136OO - CV-VCA
LM136OO - VCF
LM136OO - VCA
LM136OO - DUAL VCO

http://www.tomg.vivid.net/madm/page_004.html

-tg





From Colin.Fraser at scottishpower.plc.uk  Mon Aug 31 11:19:22 1998
From: Colin.Fraser at scottishpower.plc.uk (Fraser, Colin J)
Date: Mon, 31 Aug 1998 10:19:22 +0100
Subject: quantizer question
Message-ID: <81880CC73125D211BC6800805F0D83070C70@catsprntp01.cat.scottishpower.plc.uk>

> -----Original Message-----
> From: gjalass at snafu.de [mailto:gjalass at snafu.de]
> Sent: 30 August 1998 08:05
> To: mark verbos
> Cc: Synth-DIY
> Subject: Re: quantizer question
> 
> 
> On Sat, 29 Aug 1998 22:48:46 -0600, you wrote:
> 
> >In looking at Chris list's ARP style quantizer, I can't help but
> >ask if one could get away with using a cheeper 8 bit D to A
> >converter. One that is like $3 insted of like $23? Since only 7
> >bits are used anyway.
> >
> >is there a good reason why not?
> 
> please keep in mind that DAC's do have tolerances ( e.g. 1 LSB - Least
> Significant Bit ). Since it's required to quantize to e.g. semitones
> You do need a very "good" DAC to keep audible errors to a minimum.
> Therefore only the MSB's of the 12-Bit DAC are used.

I have used various 8 bit DACs (ZN428, ZN558) to output CVs in various
units and never had any problem with 'tolerance'.
You just have to apply a bit of gain to the output of the DAC so that a
1 bit step = 1 semitone (83.3mV for 1v/oct).

A 12 bit DAC allows 3 or 4 octaves of Hz/V type output if you use all
the bits (and a lookup table).

The average error in a quantised *continuous* signal will be at least
1/2 LSB - maybe this is where people get the idea that an 8 bit DAC has
poor tolerance.


Colin f



From Juergen.Haible at nbgm.siemens.de  Mon Aug 31 12:12:52 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Mon, 31 Aug 1998 12:12:52 +0200
Subject: AW: Phasers - if you don't have enough already
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D582A48BB3@nbgm336a.nbgm.siemens.de>

	Hi Sean, 

	>I just saw this - someone posted a Badstone schematic, which seems
to
	>use a 4049 for its FETs.  

I have the schemos. So this "E" device is actually a 4049 ?

> BTW, how much of a difference do the VCR's make in a phaser design?
> 
The modulation waveform smoothing of LDRs was already mentioned.
Distortion character is another important point. I have a very cheap
phaser (don't remember the name, but it's the same which Maplin
sell, only that Maplin is much more expensive) that uses FETs. Very
noisy, but unbeaten as an extra distortion device for my Korg CX-3
organ. My 13700-based phaser has a rather ugly distortion when
the input level is too high, especially in stereo mode when one channel
is clean and the other one is distorted. My "Neptune" Phaser (opto)
has a very nice sound, but I am a little disapointed by its distortion
at overdrive. The ARP ladder is embedded into a compander system
(with CD4007 as VC resistors !), and this shows the best behaviour for 
overdrive. This might have to do with the resonance. If resonance breaks
into oscillation on a phaser, it sounds much worse than with a LPF filter, 
for example. With the whole phaser inside a compander, it won't 
"scream" at high reso settings, but has a very strong resonance effect 
nevertheless.

JH.




From Juergen.Haible at nbgm.siemens.de  Mon Aug 31 12:16:10 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Mon, 31 Aug 1998 12:16:10 +0200
Subject: AW: Mislabelled Regulators
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D582A48BBC@nbgm336a.nbgm.siemens.de>


	>Just built another power supply to test some new modules.  Measured
the
	>output voltages: positive supply 15.11 volts DC Negative -18.3 vDC.
Didn't
	>make sense to me, so I ended up swapping regulators.  Same result.
This
	>made me suspicious.  Replaced the negative regulator again, but
this time
	>from a different manufacturer.  This time the negative rail was -15
volts
	>(close enuff).  Looks like someone sold me a batch of mislabelled
7918s.  I
	>take it someone in Malaysia was feeling underpaid.

Probably not mislabelled, but just more sensitive to oscillation ??

JH.





From rsowa at WizjaTV.pl  Mon Aug 31 15:07:39 1998
From: rsowa at WizjaTV.pl (Roman Sowa)
Date: Mon, 31 Aug 1998 15:07:39 +0200
Subject: ODP: quantizer question
Message-ID: <2BF6F749A4A3D11185AD00A0C94CF67A0FBC35@demon>

8 bit DACs DO have poor tolerance, as every other converter.
But ussually it is limited to the few LSBs. So, the wider DAC input,
the better linearity within MSB range.

1/2 LSB quantization noise mentioned by Colin has nothing to do with
DAC linearity. They're made just as precise as needed to maintain
differential error less than 1LSB (the code higher by 1LSB gives
output voltage no less than with code smaller by 1LSB). And that's not
even a rule for higher resolution DACs (14 bits and more).
That's what makes'em 8-bitters cheeper.

If you had no problem with 8 bit DACs, then maybe you were lucky
and got a better piece, or used it as a 6 or 5 bit converter.

I was lucky too - i bought 12bit AD7548 in radio shack for about
$1.50 a piece.

Now, with new IC prices falling down (at least few of them) it's easy
to find affordable, yet well performing DAC

Roman

> -----Oryginalna wiadomo??-----
> Od:	Fraser, Colin J [SMTP:Colin.Fraser at scottishpower.plc.uk]
> Wys?ano:	31 sierpnia 1998 11:19
> Do:	Synth-DIY
> Temat:	RE: quantizer question
> 
> > >In looking at Chris list's ARP style quantizer, I can't help but
> > >ask if one could get away with using a cheeper 8 bit D to A
> > >converter. One that is like $3 insted of like $23? Since only 7
> > >bits are used anyway.
> 
> I have used various 8 bit DACs (ZN428, ZN558) to output CVs in various
> units and never had any problem with 'tolerance'.
> You just have to apply a bit of gain to the output of the DAC so that
> a
> 1 bit step = 1 semitone (83.3mV for 1v/oct).
> 
> A 12 bit DAC allows 3 or 4 octaves of Hz/V type output if you use all
> the bits (and a lookup table).
> 
> The average error in a quantised *continuous* signal will be at least
> 1/2 LSB - maybe this is where people get the idea that an 8 bit DAC
> has
> poor tolerance.
> 
> 
> Colin f



From MHELIN at tne01.ntc.nokia.com  Mon Aug 31 17:08:15 1998
From: MHELIN at tne01.ntc.nokia.com (Mikko Helin)
Date: Mon, 31 Aug 1998 18:08:15 +0300
Subject: Sample Rate Conversion, PCB making tips
Message-ID: <980831180815.20417181@tnclus.ntc.nokia.com>

I got finally my Ensoniq AudioPCI (ES1370) sound card to read S/PDIF 
data. I'll update my web page at http://www.uta.fi/~helin/digital.htm
later with schematics. I just wired CS8412 to output data in
I2S format, and connected the thing into AudioPCI's MPEG/DVD input. 
Now I've grabbed 100's of megabytes data from sample CD's. 

Now the tip how to make PCB's. I haven't actually tried this,
but I was just reading sfnet.harrastus.elektroniikka newsgroup
(don't try it unless you've got some training in Finnish language).
There was one guy who had tried everything, and he found that
self-adhesive adressing label sheets, or actually the slippery
paper on the back, gave the best results, much better than TEC100
or PnP blue, almost as good as photocopied pcb's. Got to try
find some sheets and test this method.

-Mikko


Batz wrote:
>Y-ellow Y'all.
>	I'm hot today. :) Some time back people were talking about Sample Rate
>conversion. Here is a project to do just that. Also included is how to
>convert S/PDIF to AES/EBU Which was something else someone mentioned.
>
>http://exodo.upr.clu.edu/~hunt/src.htm
>
>Hope this helps.
>
>Be absoluely Icebox.
>
> _ __        _                              
>| "_ \      | |         batzman at all-electric.com / aek at all-electric.com
>| |_)/  __ _| |_ ____           ALL ELECTRIC KITCHEN               
>|  _ \ / _` | __|___ |  The Elementary Urban sanity CD
>| |_) | (_| | |_  / /   out now on Transmission Communications
>|_,__/ \__,_|\__|/ /    
>                / ,__   http://www.all-electric.com
>Goodfortune    |_____|       



From Colin.Fraser at scottishpower.plc.uk  Mon Aug 31 17:28:47 1998
From: Colin.Fraser at scottishpower.plc.uk (Fraser, Colin J)
Date: Mon, 31 Aug 1998 16:28:47 +0100
Subject: quantizer question
Message-ID: <81880CC73125D211BC6800805F0D83070C79@catsprntp01.cat.scottishpower.plc.uk>

> -----Original Message-----
> From: Roman Sowa [mailto:rsowa at WizjaTV.pl]
> Sent: 31 August 1998 14:08
> To: Synth-DIY
> Subject: ODP: quantizer question
> 
> 
> 8 bit DACs DO have poor tolerance, as every other converter.
> But ussually it is limited to the few LSBs. So, the wider DAC input,
> the better linearity within MSB range.
>
> 1/2 LSB quantization noise mentioned by Colin has nothing to do with
> DAC linearity. They're made just as precise as needed to maintain
> differential error less than 1LSB (the code higher by 1LSB gives
> output voltage no less than with code smaller by 1LSB). And that's not
> even a rule for higher resolution DACs (14 bits and more).
> That's what makes'em 8-bitters cheeper.

If the tolerance is a design decision, maybe the devices I used are
built to be accurate even at the LSB end ...
I don't see how a R-2R network can't be fabricated on a chip with close
tolerance resistances, regardless of how many bits there are.
Obviously as you increase the number of bits for a given supply voltage,
the voltage level of the lower bits will get lost in noise.
 
> If you had no problem with 8 bit DACs, then maybe you were lucky
> and got a better piece, or used it as a 6 or 5 bit converter.

I've used half a dozen 8 bit dacs in these applications, some with 7
bits used, some with 8, and never had any problem with tuning of
oscillators driven by them.

What order of error would you suggest I should be getting ?


Colin f



From Chris.List at sc.siemens.com  Mon Aug 31 18:40:47 1998
From: Chris.List at sc.siemens.com (List, Christopher)
Date: Mon, 31 Aug 1998 12:40:47 -0400
Subject: quantizer question
Message-ID: <81A062BC5305D111A9D700805F065968CE94FA@maildepo.sc.siemens.com>

On Sunday, August 30, 1998 12:49 AM, mark verbos [SMTP:verbos at on-q.com]
wrote:
> 	sooo...
> In looking at Chris list's ARP style quantizer, I can't help but
> ask if one could get away with using a cheeper 8 bit D to A
> converter. One that is like $3 insted of like $23? Since only 7
> bits are used anyway.
> 
> is there a good reason why not?
> mark verbos

As mentioned, you get the added benefit of higher tolerance with those
DACs, but the only real reason I choose them was because I have the
databook from analog devices, and they were the first +15v, parallel
output flash DAC that I came across. I never did too much research on
it, or looked too much at other companies products. 

If someone would like to suggest suitable replacements, that'd be cool.

- CList



From keen at austin.ibm.com  Mon Aug 31 21:07:50 1998
From: keen at austin.ibm.com (R.G. Keen)
Date: Mon, 31 Aug 98 14:07:50 -0500
Subject: PCB making tips 
In-Reply-To: (Your message of Mon, 31 Aug 98 18:08:15 +0300.)
             <980831180815.20417181@tnclus.ntc.nokia.com>
Message-ID: <199808311907.OAA28402@keen.austin.ibm.com>


>Now the tip how to make PCB's. I haven't actually tried this,
>but I was just reading sfnet.harrastus.elektroniikka newsgroup
>(don't try it unless you've got some training in Finnish language).
>There was one guy who had tried everything, and he found that
>self-adhesive adressing label sheets, or actually the slippery
>paper on the back, gave the best results, much better than TEC100
>or PnP blue, almost as good as photocopied pcb's. Got to try
>find some sheets and test this method.
These do work, as the siliconized surface holds the toner only
tenuously. However, the hold of the toner to the sheet is so slight
that you essentially have to process the PCB as soon as you print the
sheet. Anything else and some parts of the toner rub off the sheet with
handling. You have to be more careful as the lines get finer and the
handling longer. 

The PNP blue is far preferable to TEC100, and is much tougher than 
the addressing label sheet, as the toner will not rub off as easily. 
I have made PCB's with PNP blue sheets that have been in a file folder 
for six months or more and had excellent results. 


I'll reproduce here the biggest tip of all in making PCB's - make
yourself a drill microscope. Drilling is by far worse than imaging and
etching.

Get a Dremel Moto-tool ($40), carbide PCB bits ($5), a Dremel drill
press accessory ($40), a Tasco 7x20 rifle scope, 1/2" plywood, and 
a 3x or 5x plastic jeweler's loupe. 

Make a small stand of about 12" by 12" out of plywood or chipboard. 

Screw the bottom plate of the drill press accessory to
the top surface of the plywood, mark where the back post and center
hole rest over the plywood, then remove the plate. Drill out clearance
holes for the post and the drill end of the moto-tool in the plywood.

Screw the plate back on top of the plywood, then insert the back post 
through the plate and plywood so there is enough post on the bottom of
the plywood to attach the Moto-tool holder under the plywood pointing
up through the center hole in the plywood and plate. 

Using some 1/2"
plywood and automotive type hose clamps, make a holder to attach the
rifle scope to the portion of the back post that protrudes on top,
positioning the scope so the crosshairs can be adjusted to look down
through the center of the center hole at the drill bit. Tape the
jeweler's loupe to the objective end of the scope to correct the focus
to about 2".

Now put a drill bit in the Moto-tool, align the scope to point directly
into the center of the bit. Tighten everything down so it doesn't move. 

You can now put an etched PCB on the plate, center up a pad in the
crosshairs, and drill UP FROM THE BOTTOM in the exact center. 

This is a lot of trouble, granted, but once you do this once, you'll
never drill a PCB the ordinary way again. 0.028" holes are easy, and
you don't break carbide bits - which now last for throusands of holes.



From moxie at idonex.se  Mon Aug 31 21:47:25 1998
From: moxie at idonex.se (Johan Gustavsson)
Date: Mon, 31 Aug 1998 21:47:25 +0200 (MET DST)
Subject: Mad Mouse 3.5 - LM136OO VCO
In-Reply-To: <yam7547.2885.120297888@mail.vivid.net> (message from tomg on
	Mon, 31 Aug 1998 03:51:57 -0500)
Message-ID: <199808311947.VAA10893@jolt.idonex.se>

> I'm still playing with designs for the MM. The latest
> bunch and details are on my page. I know I said no OTAs.
> You'll just have to take a look.

Hmm...well, there's no harm in publishing two versions of a same-ish
thing, is there? The mad mouse and the mad rat :-) The MMv2 is still a
whole lot less complex than the MIDI4cv, so...if the new design is
simpler than that, but more complex than the mini-theremin, then Bob's
your close relative, aye?

I suppose the new one doesn't sound as good, or something, but still,
the DIY ladder looks real nice: First build this, then for something
slightly better build the mouse, then build the M4cv or go straight
for the Maxx...:-)

So, keep the new one simple and straightforward, and keep them both on
page, methinks.

/Moxie (Daily visitor to EFM)




From tomg at vivid.net  Mon Aug 31 23:14:03 1998
From: tomg at vivid.net (tomg)
Date: Mon, 31 Aug 1998 16:14:03 -0500
Subject: Funny!
Message-ID: <yam7547.175.118939712@mail.vivid.net>

I just got off the phone with Mouser, getting some of
those cheep 136OO. Anyway after giving my order I asked
for a total and was told "these computers don't add".

After I picked myself up off the floor. Between fits of
laffter I said "I'm sorry ma'm adding is the only thing
your computer actually does".

I know she thought I was crazy! I'm still giggling....

-tg





