Cgs synth

>I do have a question for Ken. 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. I think
>maybe the 330K/240K values are for a +/-12V power supply.

More thoughts on this - the ASM-1 sawtooth is centered around 0V, while the
output of mine SITS on 0V, so it is 0V-10V. The +/- 5V wave form is then
available from the AC coupled output. There may be slight offset
differences when running off 15V instead of 12V, but the above is the
primary reason for the somewhat different values.

Ken

_______________________________________________________________________
Ken Stone sasami@... or ken@...
Modular Synth PCBs for sale <http://www.blaze.net.au/~sasami/synth/>
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