MOTM

I'd be interested in having a silk screened fron panel for a 
darkstar. I don't yet have a darkstar but plan on getting 
one. Does the panel come with the kit from blacet or should 
I get a blank from Paul? Is it a 2U panel?
Thanks,
Jim

------- Original Copy -------
>Subject: [motm] Kit/module conversions
>Date: 05/19/2000 6:53 AM
>From: "Tentochi" <tentochi@...>
>To: <motm@egroups.com>
>Reply-To: motm@egroups.com

>Well, since there has been a lull in new modules, I thought 
I would work on
>some "compatible" modules and convert them over as much as 
possible to the
>MOTM format.  Obvious things are:
>
>Front Panel
>Pots/Knobs
>Jacks
>
>Difficult things (for me) are:
>
>Converting a 12v module to use the 15v MOTM PSU
>Hooking up power supply connector
>Opamps to replace with higher quality opamps
>Other parts which should be upgraded
>Connecting the PCB to the MOTM front panel
>
>I am currently working on 2 Blacet Dark Star Chaos units.  
Actually these
>boards are easier to stuff--the part numbers are sequential 
and easier to
>read on the PCB.  But the instructions aren't nearly as 
detailed and
>organized.  Thanks Paul!
>
>I am going to have my PCBs custom silk screened.  I found 
an excellent silk
>screener that does a lot of small industrial jobs and is 
very sensitive
>about paint that is already on surface and what is good to 
silk screen on
>top of that.  5 day turnaround.  Price drops dramatically 
for multiple
>parts.  I am waiting until Paul returns to finish up the 
graphics; I want to
>check fonts, dimensions and other details.
>
>Is anyone else interested in having their front panel silk 
screened for the
>Dark Star Chaos?
>
>I will post more details of my experience as it unfolds...
>
>Cheers!
>Shemp
>
>
>-----------------------------------------------------------
-------------
>Remember four years of good friends, bad clothes, explosive 
chemistry
>experiments.
>http://click.egroups.com/1/4051/5/_/529958/_/958737223/
>-----------------------------------------------------------
-------------

>
>
>

Shemp,
	See responses inserted below:

> From: Tentochi <tentochi@...>
> Well, since there has been a lull in new modules,
> I thought I would work on some "compatible" modules
> and convert them over as much as possible to the
> MOTM format.  Obvious things are:
> 
> Front Panel
> Pots/Knobs
> Jacks

I found the Bourns 50K pots to be a good reasonable solution for the 50K
pots in other Blacet kits I converted.  These are like the one's Paul used
in the EG - blue with plastic shaft.  I could not find the 50K Spectrols
with 1/4 inch shafts anywhere anymore.  Here is a source for some of the
MOTM same parts you may want to use:

	Bourns part # 91A1A-B24-B18 \ufffd 50K linear pots
	Allied part # 754-9418, page 717 

Switches can be found at:

	NKK switch # M2102ES1W01 - SPST  on/on toggle switch
	Allied part # 870-8646 - page 274

	NKK switch # M2103ES1W01 - SPST  on/off/on toggle switch
	Allied part # 870-8647 - page 274

Knobs 

	Newark Part number 57F2348  Alco part number PKES-90B-1/4

LEDs:

	RED:  Digikey # = 67-1155-ND      Lumex number = SSI-LXH387ID
	GREEN:  Digikey # = 67-1156-ND      Lumex number = SSI-LXH387GD
	YELLOW: Digikey # = 67-1157-ND      Lumex number = SSI-LXH387YD

 Everyone has the 112A jacks.
 
> Difficult things (for me) are:
> 
> Converting a 12v module to use the 15v MOTM PSU

Oh, John ought to speak to that.  The modules I got from him were 15 volt
compatible.

> Hooking up power supply connector

The Blacet connectors will work.  However, they do not lock the same.  You
can change and use the exact one used by Paul.  They fit the Blacet boards
I made.  They are about 11 cents.

	AMP part # 640445-4 MTA-156 post headers for circuit board mounting
	Allied part # 512-3452, page 476

> Opamps to replace with higher quality opamps

Hmmm... Why?  Isn't a Dark star about Chaos?

> Other parts which should be upgraded

Can't think of any.

> Connecting the PCB to the MOTM front panel

I used a MOTM bracket (purchased from Paul).  I drilled holes in my Blacet
PCBs in locations not offensive to the circuitry and the drilled holes in
the bracket to match.  I used very nice looking black hex head bolts to
connect the bracket to holes through the front panel.

> I am currently working on 2 Blacet Dark Star Chaos units.  Actually these
> boards are easier to stuff--the part numbers are sequential and easier to
> read on the PCB.  But the instructions aren't nearly as detailed and
> organized.  Thanks Paul!

With no offense intended to ANYone.  NOBODY writes instructions as detailed
and easy to follow as Paul.  I have built kits from PAiA, Blacet, and Big
Briar.  While all instructions were at least adequate (and some better than
others), Paul's were clearly the best.

Stooge (these opinions belong only to the stooge that lives inside of me
and do not always reflect the views and ideas of the host body, and no I
don't have a personality problem) Larry

> I found the Bourns 50K pots to be a good reasonable solution for the 50K
> pots in other Blacet kits I converted.  These are like the one's Paul used
> in the EG - blue with plastic shaft.  I could not find the 50K Spectrols
> with 1/4 inch shafts anywhere anymore.  Here is a source for some of the
> MOTM same parts you may want to use:
>
> 	Bourns part # 91A1A-B24-B18 \ufffd 50K linear pots
> 	Allied part # 754-9418, page 717
>

With regards to the DarkStar specifically, I have it from John that the pot
values are not critical, since they are all basically voltage dividers. So
if you have an easier time finding 100K, for instance - no problem.

Dave Bradley
Principal Software Engineer
Engineering Animation, Inc.
daveb@...

Hello Shemp!

I am intersted in a front panel for the dark star if the quality is the same 
as MOTM. Count me in

Thomas White

PS. I am planning to make a small set of classic Curtis (CEM) chip modules 
for the fun of it. Does anybody have any experience in this area or basic 
information to make a reversible attenuators for say...

all of the inputs on a VC ADSR

Or is this way too complicated to be simplified this way? Thanks
DJTW


>Is anyone else interested in having their front panel silk screened for the
>Dark Star Chaos?
>
>I will post more details of my experience as it unfolds...
>
>Cheers!
>Shemp
>

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In a message dated 5/19/2000 6:06:28 PM, djthomaswhite@... writes:

>PS. I am planning to make a small set of classic Curtis (CEM) chip modules
>for the fun of it. Does anybody have any experience in this area or basic
>information to make a reversible attenuators for say...
>all of the inputs on a VC ADSR
>
>Or is this way too complicated to be simplified this way? Thanks
>DJTW

Hi Thomas,

I have (at least) one of each of the classic CEM modules working now. They 
are all modified PAiA EKx series modules -- I've got a bunch more awaiting a 
finished enclosure. I'm so enamored of my idea of a reversing attenuator on a 
few inputs of a VCEG as I described a few months ago (and stooge approved 
too!), that I've changed all my graphics to accommodate my idea. 
Unfortunately, I haven't figured out a good way to limit the CV inputs to 
those required (I think it's 0V to 5V) by the CEM 3310 -- you wouldn't want 
to damage the IC by allowing a negative or too positive voltage at the CV 
inputs to the chip. I don't know how to do this, especially while maintaining 
the CV accuracy. If anyone has any thoughts, I'd love to hear them.

JB

> I haven't figured out a good way to limit the CV inputs to
> those required (I think it's 0V to 5V) by the CEM 3310 -- you
> wouldn't want
> to damage the IC by allowing a negative or too positive voltage at the CV
> inputs to the chip. I don't know how to do this, especially while
> maintaining
> the CV accuracy.

Put a 5.1V Zener diode at the output of the summing amp, to clamp it to that
maximum value.

Dave Bradley
Principal Software Engineer
Engineering Animation, Inc.
daveb@...