SynthModules

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