AW: VCO-1C #2

[Tony Allgood]

Ingo wrote:
I'm asking because in my selfmade poly synth (without autotune) nine of
the ten 3340s are pretty stable, after a warm up time of 20 minutes or
so. But one is drifting very much. I thought that one had gone bad, but
maybe I just had luck with the other nine?

Tony writes:
Me too. I have two bad ones out of 16 VCOs. I replaced the really bad
one with another and I think its liveable with. I have just been mailed
by someone, Colin F I think, who said that Roland selected their CEMs
for the Jp8. I don't know whether thats true, but some 3340s are better
than others. They will always be fine for a mono, it is as you say, a
real bummer in a poly. I actually reduced my 8-voice to four because I
was fed up with retuning each VCO before a gig. Funny thing was I used
to have internal trimmers only until I had to gig with the thing. Then I
put them all on the front.

However, I must say that after 30 minutes any drift seems to have
stopped. But my Poly will soon be undergoing a major rehouse, with a new
front panel from Germany and internal MIDI.

Regards,

Tony Allgood, Cumbria, UK

e-mail: oakley at techrepairs.freeserve.co.uk

Rack mounted Moog VCF module. Details to be found at...

http://aupe.phys.andrews.edu/diy_archive/schematics/effects/filter.html