> I am new to this forum and fairly new to analog synthesis, so please
> forgive me if this question sounds stupid, but why would you want your
> synthesizer to drift? I thought the oscillators were carefully designed so
> that they wouldn't drift.
Well, they ∗are∗. My attitude is: it's a lot easier to ADD drift than to try to remove it/live
with it.
Some folks like the "random beating" that was a by-product of older VCO temperature drift. If so,
here are ways to emulate that, without sacrificing the glory of the MOTM-300/310 VCOs:
a) ∗ever so slightly∗ de-track the VCOs by adjusting the 1V/Oct trimmer. Say you have 3 VCOs.
First, set all 3 for 'perfect' tracking, having zero beat frequencies as best you can. Then, on
VCO #1, turn the tracking pot about a 1/8th turn CW, and on VCO #2 turn 1/8th turn CCW. Leave VCO
#3 alone.
b) use "bad" control voltages. Modern MIDI-to-CV converters have 16-bit DACs that are very
accurate. Instead, use the....errrrr....."lowly" PAiA MIDI-to-CV for that great 7-bit accuracy.
So, even though the VCOs are 'perfect', the CV feeding them is not. Use the CV/Gate of an SH-101
(gack!). The older, the better.
c) Use the MOTM-320 LFO with RATE = 0, AND with -5V fed into the 1V/Oct input. Feed TRI into a
MOTM-850 input on '1' setting, then to a FM input on '1' setting (i.e. heavily attenuated). This
simulates the air temperature slowly rising and falling.
At NAMM, we left the modulars on 9hr/day (6 days in a row). The drift was about 0.2Hz per day. To
me, that's GOOD.
Paul S.