MOTM

>
>1. Tuning - has anybody been able to adjust the 1V/oct dead on


Each VCO will be diferent. I have built about 12, and probably 8 came
quickly to
"perfect" The other 4 took some back&forth compromises. (BTW: the pot is a
20-turn unit).
However, even the 'worst' one was within 0.65Hz over 5 octaves.

I use a $3000 Philips freq counter with oven time base. Just a guess, but
the digital synth
is not as accurate as you think!

>
>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


This may be for several reasons:

a) the pot is cermet. This is for temperature stability. As a test, unsolder
the 2 sets of wires,
and use the WIDTH pot. This pot is a Bourns conductive plastic unit. Not as
temperature
stable, but uses a different conductive element. The cermet may be
"rougher".

I will happily send a Bourns pot to anyone that proves this is a "fix".

b) There are 5 seperate servo loops, all adding correction voltages to the
VCO.
Remember, turning the pot is a 10 octave move. The servos may 'jitter'.

However, if 1V/OCT input, using a full -5V to +5V sweep, *does not* do this,
it's the pot.


>3. Hard sync - it says in my manual that any waveform will work as a source
>for hard sync

It's a little misleading. Yes, you need a saw or pulse. The SYNC I/O is a
narrow pulse.

Paul S.



>