HFT

[Tony Allgood]

Hi all,

Take one sawtooth VCO and standard expo. Whats the best way to get high
frequency trim? The Moog method and others uses a 10K trimmer in series
with the timing cap, seems OK but changes the output waveform. Rene's
and Ian Fritz's method has a 1M trimmer & diode attached from the input
of the expo to the output of the servo op-amp. Seems to alter the pitch
at any frequency. And then there's Oberheim SEM method which takes a
sniff of the expo current and passes that back to the CV input. But
which is best for results and ease of setting up.

Regards,

Tony Allgood  Penrith, Cumbria, UK

MidiDAC Superior midi-cv, SuperLadder, TB303 clone and Filter Rack

http://www.techrepairs.freeserve.co.uk/projects.htm