Two simple modifications to the CGS 75 Serge VCS
2010-04-19 by Richard Brewster
I made two mods to my VCS. I changed the 470K resistor to -15V on the
TL071 to 590K. This results in better centering of the Bipolar output
signal if you trim for a +5V maximum
at the main output.
I use switching jacks with a center switch lug. For the Processor input
I ran a 200K resistor from +15V (available from the Rise or Fall Pot on
the panel) to the switched lug. This makes the
Processor be a +/-5V source when nothing's patched to its input. (There
has been discussion about whether to connect the Processor output to the
normal lug of the 1V/octave
exponential input. Would not be a good idea if you did this bias mod.)
Richard Brewster
http://pugix.com
TL071 to 590K. This results in better centering of the Bipolar output
signal if you trim for a +5V maximum
at the main output.
I use switching jacks with a center switch lug. For the Processor input
I ran a 200K resistor from +15V (available from the Rise or Fall Pot on
the panel) to the switched lug. This makes the
Processor be a +/-5V source when nothing's patched to its input. (There
has been discussion about whether to connect the Processor output to the
normal lug of the 1V/octave
exponential input. Would not be a good idea if you did this bias mod.)
Richard Brewster
http://pugix.com