Yahoo Groups archive

Cgs synth

Index last updated: 2026-04-28 23:16 UTC

Thread

My first CGS module up and running

My first CGS module up and running

2005-05-01 by Adam Schabtach

It's my first, but it's definitely not my last. I recently completed a
module based on a CGS Digital Noise PC board, in MOTM format. There are some
comments about the project, photos, and demonstration recordings at my web
site. The direct link to the blog entry is:
http://www.studionebula.com/modules.php?op=modload&name=PagEd&file=index&pag
e_id=89

If that doesn't work, just go to www.studionebula.com and look for the
article near the top of the list (currently it's at the top).

Thanks, Ken, it's a fun module!

--Adam

--
Adam Schabtach
www.studionebula.com

Re: My first CGS module up and running

2005-05-07 by Michael

Checked out your build blog and loved the sound samples, the
frequency sweep on the white noise is great, it gets really crunchy,
now I have to build one too! :)

As far as more CGS, you should build a Wave Multipliers, that's my
favorite module so far from Ken.

- Michael nil-x

Show quoted textHide quoted text

--- In cgs_synth@yahoogroups.com, "Adam Schabtach" <adam@s...> wrote:
> It's my first, but it's definitely not my last. I recently
completed a
> module based on a CGS Digital Noise PC board, in MOTM format. There
are some
> comments about the project, photos, and demonstration recordings at
my web
> site. The direct link to the blog entry is:
> http://www.studionebula.com/modules.php?
op=modload&name=PagEd&file=index&pag
> e_id=89
>
> If that doesn't work, just go to www.studionebula.com and look for
the
> article near the top of the list (currently it's at the top).
>
> Thanks, Ken, it's a fun module!
>
> --Adam
>
> --
> Adam Schabtach
> www.studionebula.com

Re: My first CGS module up and running

2005-05-07 by Adam Schabtach

Thanks for dropping by my website. Yes, the Digital Noise does get really
crunchy at low frequencies--it's really fun, and adds a very different
flavor to my system.

The Wave Multiplier is in fact the next CGS module that I will build. I
purchased the PCB at the same time that I bought the board for the Digital
Noise, but I haven't yet started putting it together. If anyone has any
interesting mods or tweaks for the Wave Multiplier, I'd appreciate hearing
about them. (Yes, I'll search the archives, too.)

Yesterday I ordered PCBs for the Steiner filter and the Bi-N-Tic, so those
will come next.

--Adam

Show quoted textHide quoted text

> -----Original Message-----
> From: Michael [mailto:nil@...]
> Sent: Saturday, May 07, 2005 7:38 AM
> To: cgs_synth@yahoogroups.com
> Subject: [cgs_synth] Re: My first CGS module up and running
>
> Checked out your build blog and loved the sound samples, the
> frequency sweep on the white noise is great, it gets really crunchy,
> now I have to build one too! :)
>
> As far as more CGS, you should build a Wave Multipliers, that's my
> favorite module so far from Ken.
>
> - Michael nil-x
>
> --- In cgs_synth@yahoogroups.com, "Adam Schabtach" <adam@s...> wrote:
> > It's my first, but it's definitely not my last. I recently
> completed a
> > module based on a CGS Digital Noise PC board, in MOTM format. There
> are some
> > comments about the project, photos, and demonstration recordings at
> my web
> > site. The direct link to the blog entry is:
> > http://www.studionebula.com/modules.php?
> op=modload&name=PagEd&file=index&pag
> > e_id=89
> >
> > If that doesn't work, just go to www.studionebula.com and look for
> the
> > article near the top of the list (currently it's at the top).
> >
> > Thanks, Ken, it's a fun module!
> >
> > --Adam
> >
> > --
> > Adam Schabtach
> > www.studionebula.com
>
>
>
>
>
> See the following URLS for the CGS Modular Synth home page:
> Main: http://www.cgs.synth.net/
> Secondary: http://otherunicorn.0catch.com/synth/
> Yahoo! Groups Links
>
>
>
>
>
>
>

Re: My first CGS module up and running

2005-05-07 by Richard Brewster

I made the following small mods to my Wave Multiplier:

1. Added a 100pf cap between pins 1 and 2 of IC1 (Grinder) to prevent
parasitic oscillation.

2. Added a 1K resistor to ground at the Grinder output to cut the
amplitude in half. It can swing to +/- 14.5V otherwise. This mod
limits the maximum swing to about +/-7V. You might use two 2K resistors
here to reduce current consumption.

3. Changed to a 33K resistor (from 100K) on the Folds CV input (I have a
pot on this input) for increased sensitivity.

4. Changed to a 100K resistor (from 47K) between pins 1 and 2 on IC4 (I
have a pot on the PWM input) for increased sensitivity.

5. Changed the pulse output (IC4 pin 7) to use a series 3K3 to 1K8 to
ground, as on the CGS56 board, to limit the output to +/-5V.

Be sure to check the archives for information about tweaks to the
Steiner filter. I seem to recall posting my method for matching the
transistors, which is a good idea.

-Richard Brewster

Adam Schabtach wrote:

Show quoted textHide quoted text

>Thanks for dropping by my website. Yes, the Digital Noise does get really
>crunchy at low frequencies--it's really fun, and adds a very different
>flavor to my system.
>
>The Wave Multiplier is in fact the next CGS module that I will build. I
>purchased the PCB at the same time that I bought the board for the Digital
>Noise, but I haven't yet started putting it together. If anyone has any
>interesting mods or tweaks for the Wave Multiplier, I'd appreciate hearing
>about them. (Yes, I'll search the archives, too.)
>
>Yesterday I ordered PCBs for the Steiner filter and the Bi-N-Tic, so those
>will come next.
>
>--Adam
>
>
>

Re: My first CGS module up and running

2005-05-07 by Adam Schabtach

Thanks for the summary, Richard. I did find some of your postings in the
archives. I think that you mentioned that you were going to try other ICs
also. Did you ever do that experiment? Was there anything to be gained by
changing op-amps?

Thanks--
--Adam

Show quoted textHide quoted text

> -----Original Message-----
> From: Richard Brewster [mailto:pugix@...]
> Sent: Saturday, May 07, 2005 10:42 AM
> To: cgs_synth@yahoogroups.com
> Subject: Re: [cgs_synth] Re: My first CGS module up and running
>
> I made the following small mods to my Wave Multiplier:
>
> 1. Added a 100pf cap between pins 1 and 2 of IC1 (Grinder) to prevent
> parasitic oscillation.
>
> 2. Added a 1K resistor to ground at the Grinder output to cut the
> amplitude in half. It can swing to +/- 14.5V otherwise. This mod
> limits the maximum swing to about +/-7V. You might use two 2K resistors
> here to reduce current consumption.
>
> 3. Changed to a 33K resistor (from 100K) on the Folds CV input (I have a
> pot on this input) for increased sensitivity.
>
> 4. Changed to a 100K resistor (from 47K) between pins 1 and 2 on IC4 (I
> have a pot on the PWM input) for increased sensitivity.
>
> 5. Changed the pulse output (IC4 pin 7) to use a series 3K3 to 1K8 to
> ground, as on the CGS56 board, to limit the output to +/-5V.
>
> Be sure to check the archives for information about tweaks to the
> Steiner filter. I seem to recall posting my method for matching the
> transistors, which is a good idea.
>
> -Richard Brewster
>
> Adam Schabtach wrote:
>
> >Thanks for dropping by my website. Yes, the Digital Noise does get really
> >crunchy at low frequencies--it's really fun, and adds a very different
> >flavor to my system.
> >
> >The Wave Multiplier is in fact the next CGS module that I will build. I
> >purchased the PCB at the same time that I bought the board for the
> Digital
> >Noise, but I haven't yet started putting it together. If anyone has any
> >interesting mods or tweaks for the Wave Multiplier, I'd appreciate
> hearing
> >about them. (Yes, I'll search the archives, too.)
> >
> >Yesterday I ordered PCBs for the Steiner filter and the Bi-N-Tic, so
> those
> >will come next.
> >
> >--Adam
> >
> >
> >
>
>
>
>
>
> See the following URLS for the CGS Modular Synth home page:
> Main: http://www.cgs.synth.net/
> Secondary: http://otherunicorn.0catch.com/synth/
> Yahoo! Groups Links
>
>
>
>
>
>
>

Re: My first CGS module up and running

2005-05-08 by Richard Brewster

I think I preferred the LM358 for the Grinder, as recommended by Ken.
Dang, it has been too long ago. Truth is that I assembled the board and
ran it on my bench, but I still have to build it into its Stooge panel.
I've had several months hiatus on module building due to moving to
another house. But I am about to start catching up, especially now that
I have a new cabinet, the double high slant cabinet from synthesizers.com.

-Richard

Adam Schabtach wrote:

Show quoted textHide quoted text

>Thanks for the summary, Richard. I did find some of your postings in the
>archives. I think that you mentioned that you were going to try other ICs
>also. Did you ever do that experiment? Was there anything to be gained by
>changing op-amps?
>
>Thanks--
>--Adam
>
>
>
>>-----Original Message-----
>>From: Richard Brewster [mailto:pugix@...]
>>Sent: Saturday, May 07, 2005 10:42 AM
>>To: cgs_synth@yahoogroups.com
>>Subject: Re: [cgs_synth] Re: My first CGS module up and running
>>
>>I made the following small mods to my Wave Multiplier:
>>
>>1. Added a 100pf cap between pins 1 and 2 of IC1 (Grinder) to prevent
>>parasitic oscillation.
>>
>>2. Added a 1K resistor to ground at the Grinder output to cut the
>>amplitude in half. It can swing to +/- 14.5V otherwise. This mod
>>limits the maximum swing to about +/-7V. You might use two 2K resistors
>>here to reduce current consumption.
>>
>>3. Changed to a 33K resistor (from 100K) on the Folds CV input (I have a
>>pot on this input) for increased sensitivity.
>>
>>4. Changed to a 100K resistor (from 47K) between pins 1 and 2 on IC4 (I
>>have a pot on the PWM input) for increased sensitivity.
>>
>>5. Changed the pulse output (IC4 pin 7) to use a series 3K3 to 1K8 to
>>ground, as on the CGS56 board, to limit the output to +/-5V.
>>
>>Be sure to check the archives for information about tweaks to the
>>Steiner filter. I seem to recall posting my method for matching the
>>transistors, which is a good idea.
>>
>>-Richard Brewster
>>
>>
>>