Cgs synth

Hi Ken,
Sure did. I used 100K resistors there, and I used this for the two 1n caps:

http://www.mouser.com/ProductDetail/EPCOS/B32529C102K/?qs=sGAEpiMZZMv1cc3ydrPrF1iYn56hZ3YmhsEj8dPJEuE%3d

Thank you,
Andrew

On Mon, Feb 11, 2013 at 9:06 PM, <sasami@...> wrote:

> **
>
>
> Re locking up, have you seen the modification to replace the 10n caps with
> 1n in the cycle switching circuit? 150k also go down to 100k.
>
> Ken
>
>
> >Hi Dean,
> > Thanks very much for the reply. Regarding EG operation, I'm okay with the
> >fact that the pots will work "in reverse" if wired with cycle mode's audio
> >freq. in mind.
> >
> > Speaking of cycle mode, it does work as an oscillator in this mode,
> though
> >I'm not sure if it works in the correct range. If I move the pots
> clockwise
> >to a high freq. extreme, it will lock up. I have to toggle the cycle sw.
> >off and on to make it work again.
> >
> > I'm ohming the pots out as I type this. CW and CCW is referenced viewing
> >the pot from the front (shaft towards you). They are wired like this:
> >
> > Rise pot:
> >CW - Gnd
> >CCW - +15V
> >Wiper - RRW
> >
> >Fall Pot:
> >CW - Gnd
> >CCW - +15V
> >Wiper - FRW
> >
> > Rise CV:
> >CW - RCCW
> >CCW- RCW (GND)
> >Wiper - RW
> >
> >Fall CV:
> >CW - FCCW
> >CCW- FCW (GND)
> >Wiper - FW
> >
> >
> >The odd thing is that FCW and RCW are at ground reference, so that should
> >be the CCW pot terminal, not CW. Unless I'm confusing myself... is the
> >silkscreen wrong for these two?
> >
> > Thanks again,
> > Andrew
> >
> >
> >
> >
> >
> >
> >On Mon, Feb 11, 2013 at 3:38 PM, goldencardigan dean.lowe@...
> >wrote:
> >
> >> **
>
> >>
> >>
> >> Hi A S
> >>
> >> To me it sounds like you need to check your pot wiring. Have another
> read
> >> of the wiring list and confirm your connections, as a lot of people have
> >> had problems with this. Can you tell us which connections you have used
> for
> >> the Rise, Fall and respective rate pots.
> >>
> >> Just for the record, I also want to address the claim on the 'mods' page
> >> you listed below that the Rise and Fall connections are reversed. The
> VCS
> >> is in a way an Attack/Release Envelope with a looping function. If you
> give
> >> it a trigger it will respond accordingly and the Rise will control the
> >> attack time exactly like any other envelope (the Fall acting like the
> >> release control). Now if you engage the looping feature, yes the Rise
> and
> >> Fall pots do seem to be reversed if you compared it to a LFO. But it
> does
> >> work exactly like every other envelope with a looping feature. As the
> >> attack and release times of the envelope decrease, the quicker the
> >> oscillations get.
> >>
> >> IMHO I always try to build my boards as per the designers notes and make
> >> any mods after verifying the board is working as intended. If I do have
> any
> >> probelms with the board I can gaurantee that it is a mistake I have made
> >> and not due to a mod that I have installed.
> >>
> >> Sorry, I'll get off my soap box now. Double check your wiring and let us
> >> know how you go.
> >>
> >> Cheers
> >> Dean
> >>
> >>
> >> --- In cgs_synth@yahoogroups.com, A S wrote:
> >> >
> >> > Hello,
> >> > I have a CGS75 Rev 0.0 where the Rise and Fall pots don't give
> typical EG
> >> > slew rates.
> >> >
> >> > For the following symptoms, I'm using a square wave output from an LFO
> >> set
> >> > about 1 Hz to the input of the VCS. The output of the VCS is driving a
> >> VCO
> >> > FM input, so that I can hear what the output of the VCS is doing.
> >> >
> >> > 1. The VCS outputs the input LFO signal pretty much unaffected if the
> >> rise
> >> > and fall pots are at the 9 o'clock position. If I lower either the
> fall
> >> or
> >> > rise pot to minimum, there is a small amount of slew for each
> function.
> >> >
> >> > 2. If I raise either (or both) pots from the 9 o'clock position, it
> >> doesn't
> >> > do anything different up to the 12 o'clock position.
> >> >
> >> > 3. If I increase the rise pot further (with the fall pot at 12 noon),
> >> > there is a positive dc offset added to the LFO input as the pot level
> is
> >> > increased. There is no slew.
> >> >
> >> > 4. Conversely, if I increase the fall pot further (with the rise pot
> at
> >> 12
> >> > noon), there is a negative dc offset added to the LFO input as the pot
> >> > level is increased. There is no slew.
> >> >
> >> > I added the mods mentioned on this page:
> >> > http://electro-music.com/forum/viewtopic.php?highlight=cgs75&t=54330
> >> >
> >> > and on the CGS page:
> >> > http://www.cgs.synth.net/modules/cgs75_vcs.html
> >> >
> >> >
> >> > Here are some of the check I've done....
> >> >
> >> > I tried replacing the TL074, and have checked the resistor values,
> >> > orientation of diodes, and transistors. All parts seem to be correct
> >> after
> >> > double checking them. I've also checked the board for solder shorts,
> and
> >> > have ohm'd out many of the traces from component to component.
> >> >
> >> > I checked the voltage at the base of the 2n3904 and 2n3906 (from the
> rise
> >> > and fall circuits). The range as I turn the pots is from 0V min. to
> 384mV
> >> > max.
> >> >
> >> > I input a manually adjusted CV at the gate input. The TL072 Pins 5
> and 6
> >> > follow the gate input. Pin 7 outputs 477 mV no matter what the gate
> input
> >> > voltage is. There is still 477mV if I disconnect the input cable.
> >> >
> >> > Any help would be appreciated, and I can send pics of the PCB if that
> >> > would help.
> >> >
> >> > Thanks,
> >> > Andrew
> >> >
> >> >
> >> > [Non-text portions of this message have been removed]
> >> >
> >>
> >>
> >>
> >
> >
> >[Non-text portions of this message have been removed]
> >
> >
> >
> >------------------------------------
>
> >
> >The CGS Modular Synth home page: http://www.cgs.synth.net/
> >Yahoo! Groups Links
> >
> >
> >
> >
> __________________________________________________________
> Ken Stone sasami@... otherunicorn@...
> Modular Synth PCBs for sale http://www.cgs.synth.net/>
> Australian Miniature Horses & Ponies http://www.blaze.net.au/~sasami/>
>
>
>


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