SynthModules

For some of my programs I really need a +/- 5 volt input or output so 
I just finished building a 1U MOTM-sized set of level shifters.  It 
has four +/- 5 volt to 0 to 10 volt shifters and another four 0 to 10 
volt to +/- 5 volt shifters.  It's also useful with some of my older 
ARP gear that is 0 to 10 volts as well.  I uploaded some images in
the photo section.  Now I can say that my PSIM hardware is complete.

Dave

Is there any production module out there that has this functionality? That would be a highly useful module for "frankensynth" types.
 
Cheers,
Rob A.


djbrow54 <davebr@earthlink.net> wrote:

For some of my programs I really need a +/- 5 volt input or output so 
I just finished building a 1U MOTM-sized set of level shifters. It 
has four +/- 5 volt to 0 to 10 volt shifters and another four 0 to 10 
volt to +/- 5 volt shifters. It's also useful with some of my older 
ARP gear that is 0 to 10 volts as well. I uploaded some images in
the photo section. Now I can say that my PSIM hardware is complete.

Dave 




Be sure to check out the primary Web site at:
http://www.SynthModules.com

Yahoo! Groups Links








		
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Rob

Check out the 'Signal Processor' from Synth.Com:
http://www.synthesizers.com/q125.html

While it is not 10 channels at once, it is fully adjustable and is
really, REALLY handy!!

Larry

--- In SynthModules@yahoogroups.com, Rob Adams <wiard300@y...> wrote:
> Is there any production module out there that has this
functionality? That would be a highly useful module for "frankensynth"
types.

>  
> Cheers,
> Rob A.

Dave,

Have the schematics for these level shifters been posted anywhere?

Scott

djbrow54 wrote:

> For some of my programs I really need a +/- 5 volt input or output so 
> I just finished building a 1U MOTM-sized set of level shifters.  It 
> has four +/- 5 volt to 0 to 10 volt shifters and another four 0 to 10 
> volt to +/- 5 volt shifters.  It's also useful with some of my older 
> ARP gear that is 0 to 10 volts as well.  I uploaded some images in
> the photo section.  Now I can say that my PSIM hardware is complete.
> 
> Dave 
> 
> 
> 
> 
> Be sure to check out the primary Web site at:
> http://www.SynthModules.com
>   
> Yahoo! Groups Links
> 
> 
> 
>  
> 
> 
> 
> 

-- 
"If the American people ever allow private banks to control the issue of 
their currency first by inflation and then by deflation, the banks and 
corporations that will grow up around them will deprive the people of 
all property until their children will wake up homeless on the continent 
their fathers conquered". -Thomas Jefferson in 1802 in a letter to then 
Secretary of the Treasury, Albert Gallatin

"The regional Federal Reserve banks are not government agencies. ...but 
are independent, privately owned and locally controlled corporations." 
-- Lewis vs. United States, 680 F. 2d 1239 9th Circuit 1982

No, I didn't even draw them out.  I used two inverting op amps in 
series.  The first is configured as an adder.  Signal at gain=-1 and
15 volts at gain=-1/3.  The second is configured as an inverter.  I
used TL074 op amps.  I figured out the resistor pattern for a Radio
Shack perf board and then built 8 identical stages.  1/2 of the
circuits connected to the +15 volts for a shift up and the other
half connected to the -15 for a shift down.  I used resistors from
the positive input to grounds to minimize offset.  My worst output
was offset by 7 mV so they are reasonably accurate.

There is a photo of just the perf board in the photos section under 
DJB photos.  You can see the 8 identical circuit patterns.  Let me 
know if you really want a schematic and I will draw one up. I did
for all my other boards.

Dave


--- In SynthModules@yahoogroups.com, "Scott E." <yahudinyhwh@s...> 
wrote:

> Dave,
> 
> Have the schematics for these level shifters been posted anywhere?
> 
> Scott
>

I scanned, and uploaded a schematic to the photos section in
the DJB PSIM-1 folder. - Dave

--- In SynthModules@yahoogroups.com, "Scott E." <yahudinyhwh@s...> 
wrote:

> Dave,
> 
> Have the schematics for these level shifters been posted anywhere?
> 
> Scott

Thanks, Dave.

Scott
===============================
djbrow54 wrote:

> I scanned, and uploaded a schematic to the photos section in
> the DJB PSIM-1 folder. - Dave
> 
> --- In SynthModules@yahoogroups.com, "Scott E." <yahudinyhwh@s...> 
> wrote:
>

The trick with the perfboard was to get the resistor pattern down
so there were no wires.  Then it was pretty easy to duplicate since
there were eight identical sections.

Having said that, I would appreciate  a PCB that was setup with a 
number of duplicate op amp circuits that would handle the basic stuff 
with extra breadboard areas for the more exotic stuff.  I've probably 
wired up 6 to 7 modules that could have been easily handled this way.
 
Ken Stone's CGS-23 comes close although there are only 4 op amps in a 
configuration that is difficult to change, and there are no bias 
resistors or extra breadboard area.  Paul's MOTM-000 breadboard is a 
bit too basic although I have used several of those as well.  The 
biggest issue is the power connector since they're not on 0.100 grid 
and you need the filters, etc.

Is there any interest in a better breadboard pcb?

Dave

--- In SynthModules@yahoogroups.com, Larry Hendry <hendrysr@y...> 
wrote:

> If you would like a premade PCB to make up some circuits like this,
> you can use the DB-320 from Scott Juskiw.  It is a TL074
> constructucted into 4 separate inverting op amps.  The resistors
> from amp + to ground are included to provide the best offset as
> Dave suggested.  You would have to add one resistor each for the
> inverting summing amps to provide the offset from the power
> supply.  They could easily be tacked on the bottom of the PCB since
> VCC is available for the chip power supply. near the pin (-)
> required to attach the offset
> bias.  Two of the amps could be constructed like this and the other
> two as simple unity gain inverting amps to invert the signal back to
> normal. You end up with two complete circuits on one PCB.
> 
> This might be a bunch easier that using perfboard.
> Larry H
> 
> http://www.tellun.com/motm/diy/db320/DB-320.html

If you would like a premade PCB to make up some circuits like this,
you can use the DB-320 from Scott Juskiw.  It is a TL074
constructucted into 4 separate inverting op amps.  The resistors from
amp + to ground are included to provide the best offset as Dave
suggested.  You would have to add one resistor each for the inverting
summing amps to provide the offset from the power supply.  Tehy coudl
easily be tacked on the bottom of the PCB since VCC is available for
the chip power supply. near the pin (-) required to attach the offset
bias.  Two of the amps could be constructed like this and the other
two as simple unity gain inverting amps to invert the signal back to
normal. You end up with two complete circuits on one PCB.

This might be a bunch easier that using perfboard.
Larry H

http://www.tellun.com/motm/diy/db320/DB-320.html


--- "Scott E." <yahudinyhwh@sbcglobal.net> wrote:

> Thanks, Dave.
> 
> Scott
> ===============================
> djbrow54 wrote:
> 
> > I scanned, and uploaded a schematic to the photos section in
> > the DJB PSIM-1 folder. - Dave
> > 



	
		
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----- Original Message ----- 

From: "djbrow54" <davebr@earthlink.net>
>
> Having said that, I would appreciate  a PCB that was setup with a
> number of duplicate op amp circuits that would handle the basic stuff
> with extra breadboard areas for the more exotic stuff.  I've probably
> wired up 6 to 7 modules that could have been easily handled this way.
[snip]
> Is there any interest in a better breadboard pcb?

In a word, "yes!" I'm just getting started in Synth DIY, but I've already
seen that op amps are everywhere, serving as input mixers, inverters, level
shifters, buffers, and more. I had the same idea as you when I saw those
generic little perfboards with the IC patterns on them. I made a mental note
to compare a bunch of circuits to find some commonality.

I'm glad you're around, Dave, because I'm just following in your wake. You
invent what I want before I realize that I want it! :-)
--
john

On Wed, 18 Aug 2004, djbrow54 wrote:

> Is there any interest in a better breadboard pcb?

Absolutely! Though cost could be an influence, though.

- Colin Hinz
  Toronto, Canada