Modular Synth Panels

Hey Mike,

I haven't gotten to mine yet, but here's the plan:

Use dual 100k or dual 50k lin pots.
You'll need two CV Mixer PCBs.

The different divisions from the PCB go first to the pots. Use a 
system, like "higher division goes to upper lugs of pot". All those 
pots are attenuators.
Let's do an example Alt Group of pots. You'll have six of these groups.
The Alt Group A, A/2, A/4, A/8 is wired together via 47k resistors to 
the bottom lug of that Alt Switch, so when you throw the switch up, you 
will get this Alt Group (the upper group) of divisions.
Alt Group A/6, A/16, A/32, A/64 is wired the same way to the top lug of 
the Alt Switch.
The middle lug of the switch goes to any pad on the mixer (there are 
three mixers -- two external and one on the SubOsc PCB) at pin 2 of the 
TL072 (past the summing resistors, which we used up on the panel.)
This is cool, because it allows up to switch between useful audio 
divisions and control/ clock divisions for each channel, independently.

The inversion of each group on the external mixers is from pin 1 of the 
TL072, via a 1k resistor, just like it's done on the mixer of the 
SubOsc PCB.

Mixer one is just channel A.
Mixer two is just channel B.
Mixer three is the multiplications and such.
The Mix switches are easy -- For Mix A, just take the output of channel 
A to the outside lug, and the middle lug to the summing node for the 
Mixed channel Mixer. Do the same for the Mix B switch.
Those switches make the Mix Output more versatile. With both switches 
off, you just get the multiplication on the Mix Out. But if you're 
going for super-super tone hugeness of the universe, turn it all on! : 
)

Does that make sense? I know it's confusing. If you want, I can start 
building mine now too and take some pics.
It's a very cool module, though. I added all the things I wish my 
original had.

Cheers,
Scott Deyo
The Bridechamber
contact@...
http://www.bridechamber.com


On Apr 1, 2008, at 3:41 PM, clickmrmike wrote:

> So Scott, exactly how have you wired your version of the CGS SubOsc?
>  The panel is cool, but I don't completely grok the switched pot 
> layout.
>
>  Thanks,
>  mrmike
>
>  
>