Cgs synth

hi all,
Well I am getting my bandpass filters mounted up and runinng.
I have rev1 boards. The freq pots works as expected, but the Q
or bandwitdh pot seems to have little effect. I read on the list
that you can drop the 4k7 res. inline to 2k2 or1k...anyone done
that? I am looking for more of an "effect" from the res pot.

also - any suggestion for a simple summer, passive or active for
the combined output of the 3 bpf? I could use an op amp summer, but
can I do the same with a transistor and just fly the leads n
the jack?

the saw pahsar/mangle is next ont he beach to build, after I clean up
a bit....

oh, using the plfo modulating a filter feed by a tri wave and a
little echo I got a very nice digderidoo type sound. added a little
wave multiplier on a slooow sweep to get a growl in there too.
meditation....

Jeff

>Well I am getting my bandpass filters mounted up and runinng.
>I have rev1 boards. The freq pots works as expected, but the Q
>or bandwitdh pot seems to have little effect. I read on the list
>that you can drop the 4k7 res. inline to 2k2 or1k...anyone done
>that? I am looking for more of an "effect" from the res pot.

Yes, and it can be made to "scream". You may even need to go a little under 1k.

>also - any suggestion for a simple summer, passive or active for
>the combined output of the 3 bpf? I could use an op amp summer, but
>can I do the same with a transistor and just fly the leads n
>the jack?

Use an op-amp summer, such as that in the CGS04 DC mixer. I'm building a
module with 5 of the BPF in parallel right now, and have added such a summer
myself.

Ken
_______________________________________________________________________
Ken Stone sasami@...
Modular Synth PCBs for sale <http://www.blaze.net.au/~sasami/synth/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>

> Use an op-amp summer, such as that in the CGS04 DC mixer.

thanks!
ok, sounds right


I'm building a

> module with 5 of the BPF in parallel right now, and have added such

a summer

> myself.

I tried 4 but could not fit them on the small frack rac
size panels :-(
hmm, are you using 5 boards or a new nodule for CGS ?

>
> Ken

______________________________________________________________________
_

> Ken Stone sasami@h...
> Modular Synth PCBs for sale <http://www.blaze.net.au/~sasami/synth/>
> Australian Miniature Horses & Ponies

<http://www.blaze.net.au/~sasami/>

> I'm building a
>> module with 5 of the BPF in parallel right now, and have added such
>a summer
>> myself.
>I tried 4 but could not fit them on the small frack rac
>size panels :-(
>hmm, are you using 5 boards or a new nodule for CGS ?

I'm using 5 boards. They are actually designed to stack one above the other,
with common bus wires running between them. When I'm done, I'll update the
web page.

Ken
_______________________________________________________________________
Ken Stone sasami@...
Modular Synth PCBs for sale <http://www.blaze.net.au/~sasami/synth/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>

> I'm using 5 boards. They are actually designed to stack one above

the other,

> with common bus wires running between them. When I'm done, I'll

update the

> web page.
>
> Ken

commom bus wire for power?
doppelganger

I am using buss wire too and little bits of teflon tubes as
seperators between borads. will use long bolts with
spacers to attach the mess
to a frame behind panel.

I dropped the 4k7 R on the res pot to 1k and this
provides enoght color for my taste. thanks for the suggestion.

no the build the summer.

>

______________________________________________________________________
_

> Ken Stone sasami@h...
> Modular Synth PCBs for sale <http://www.blaze.net.au/~sasami/synth/>
> Australian Miniature Horses & Ponies

<http://www.blaze.net.au/~sasami/>

>
>commom bus wire for power?

Yes.

Also I run a common bus wire between the "OUT2" terminals. This then
connects directly to the summing node of a summer/mixer, for the mixed output.


Ken
_______________________________________________________________________
Ken Stone sasami@...
Modular Synth PCBs for sale <http://www.blaze.net.au/~sasami/synth/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>

>
> Also I run a common bus wire between the "OUT2" terminals. This then
> connects directly to the summing node of a summer/mixer, for the

mixed output.

should not there be a resistor for each output before the summer?
maybe there is one on the pcb...did not look ....?

smart design.

tata
Jeff