Hello VCO builders-
Just finished building my 2nd MOTM-300 and I've noticed a couple of
oddities. I'd like to compare notes with other builders to make sure
nothing is wrong with my VCOs.
1. Tuning - has anybody been able to adjust the 1V/oct dead on? I know
this is basically impossible but I'd think that over 5 octaves (which is
the range I tune over), I should easily be able to tune so I get a slow
phasing type beating between my reference oscillator (a digitial synth
generating a sine) and the MOTM-300. The pot seems so touchy when you zero
in on that "perfect tune" point that actually nailing it with a slight turn
of the pot happens more by luck than by anything else - in other words you
can't turn it small enough which is what you need to do. Has anybody else
had this problem?
2. Dirty coarse freq pot? - I noticed that when I turn the coarse freq pot
I hear a little dirt in the sweep of the frequency of the VCO. I was
hoping for a good clean sweep just as if a freq CV input sweep was driving
it but it sounds to me like the coarse freq pot is dirty a bit. Has
anybody else noticed this? This happens on both of my MOTM-300s one
slightly worse than the other. Maybe because the ear is so sensitive to
pitch this problem is unavoidable?
3. Hard sync - it says in my manual that any waveform will work as a source
for hard sync but after carefully looking over the schematic, it looks to
me like only waveforms having a fast fall time will actually work (the
pulse signal or the syncIO jack when set to soft). My experience confirms
this. Have I completely missed the idea on this or is this truly the way
it should work? Is the manual wrong?
John Speth (just trying to understand it all)
Object Engineering, Inc
mailto:
johns@...