Doepfer

Hi Jed,

> i am the owner of an A-100 basic system who just joined your 
group.  it seems as though the oscillators(A-110) in my system are 
not exactly in tune with eachother, when both the range and the fine 
tune (set to 0) are set the same, one oscillator is slightly higher 
>in pitch.  its slight, but still audible.  is this normal?

Yes. The 'tune' knob will have been set to roughly the *centre* 
position, = 5, when set-up at the factory

>  if not, does anyone know of an internal potentiometer of some 
sort, that i would be able to calibrate?

The set-up procedure is detailed in the service manual for the A-110, 
available on Doepfer's website, but if I were you, I'd leave this 
well alone until you have a very good idea what all the controls on 
both A-110 and A-190 do.

>  also, with the factory reference offset at 0, should the A-100 be 
in tune with the rest of my synths, i.e. when i press C on my midi 
controller, should the doepfer be playing a C (when the tune is on 0)?

It's unlikely, that is what the fine tune is for.

<snip>

In common with many analogue synths, the A-100 works on '1 volt per 
octave' - the A-110 VCO should be set correctly at the factory to 
respond to this; the A-190 set-up is just to make sure that it 
outputs the correct voltages when it receives appropriate MIDI notes: 
0 volts for the 'ref note', 5V for the note 5 octaves above this. The 
190 set-up procedure is to ensure these voltages are correct (and my 
190 default settings are not very accurate, yours may not be too).

The whole procedure should be something like this: reset the A-190 to 
factory settings (in particular put the ref. offset to zero).  Set 
the 'ref note' (stick with 36 until you truly understand what is 
going on!); play this note on your keyboard; adjust 'tune' knob on 
110 so that this is what you get; now play 4 octaves above this - if 
not in tune, adjust 'scale' on 190 until it is - *don't touch the 
110*!. Make sure you come out of the 'edit' mode on the 190 - as Joe 
points out, this is most likely reason for screw-ups and sudden odd 
jumps in scale!

Now the 190 should give exactly 0 to 5 volts, corresponding to a note 
and all the way up to 5 octaves above it. Small adjustments to 'tune' 
on your other 110s should now bring them in tune too, and you should 
also be simply able to use 'tune' on the 110s so that they *are* in 
tune with your other kit, all the way up the keyboard. Only if it is 
not, and you are sure that your other kit is in tune, should you 
start thinking about the possibility that the 110s are not set-up 
properly.

Stick with it, it'll take a few times around the loop, but hopefully 
eventually it will all make sense and you'll get it! (and yes, some 
wording of the 190 manual doesn't help....).

Good luck!

Tim