MOTM

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@...