Here are two pics (Left and Right PCB shots):
http://imageshack.us/a/img826/7277/vcspcbleftside.jpg
http://imageshack.us/a/img811/5241/vcspcbrightside.jpg
Andrew
http://imageshack.us/a/img826/7277/vcspcbleftside.jpg
http://imageshack.us/a/img811/5241/vcspcbrightside.jpg
Andrew
On Mon, Feb 11, 2013 at 9:28 PM, A S <synthasaurus@...> wrote:
> 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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