The sawtooth is +/-5V (10V p-p) with the mod I made. I found this old
post in the archives:
The sawtooth buffer amp shows a 330K feedback resistor and a 240K bias
on the schematic. I inserted pots and adjusted to get a +/-5V sawtooth.
The values turned out to be exactly 200K / 600K, just like the ASM-1.
This is also just what you would expect to convert the 0-5V signal out
of the CA3140. Double the voltage (200K/100K), then offset the 0 to -10V
result back to +/-5.
-Richard
charlesosthelder wrote:
post in the archives:
The sawtooth buffer amp shows a 330K feedback resistor and a 240K bias
on the schematic. I inserted pots and adjusted to get a +/-5V sawtooth.
The values turned out to be exactly 200K / 600K, just like the ASM-1.
This is also just what you would expect to convert the 0-5V signal out
of the CA3140. Double the voltage (200K/100K), then offset the 0 to -10V
result back to +/-5.
-Richard
charlesosthelder wrote:
>--- In cgs_synth@yahoogroups.com, dustin sedlacek
><dustin.sedlacek@g...> wrote:
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>>speaking of the VCO - anyone made any mods to it ?
>>Dustin
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>Check the archives, Dustin. Both Ken and Richard
>Brewster have made some suggestions.
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>I'll be using Richard's resistor mod for a sawtooth output centered
>on zero volts. Mostly, I'll be removing things - the second CV
>processor input, the extra V/oct ins, the 0-10v sine - but keeping
>everything else.
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>I have another question, though. Is the sawtooth only 5Vp-p with
>Richard's resistor mods?
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>Thanks!
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>Chub
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>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
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