ASM-1 Filter Tuning...

[Niklas Lindberg]

On 17 Dec, gstopp at fibermux.com wrote:
>      The deflection test is used 
>      at the low-pass output to determine if these pots need to be tweaked 
>      at all - if there is a small DC offset at the filter output, these 
>      pots can be used to get rid of it. You must use small adjustments, on 
>      each pot in alternation, to get this right.

I have a little question about this...

I haven't been able to get rid of the DC offset at the lowpass output,
regardless of the position of the trimmers. I always has an offset of
appr. +- 1V at the lowpass output. The trimmers are only altering the
point on the CV-scale where the offset sets in. There must be something
wrong with my circuit, or ?

I have matched the transistors to +- 1mV using the test-circuit from
the miniMoog manual, I've double checked all values and placings and
the filter sounds the way it should as far as I can tell, so what could
be wrong ?

Any help or suggestions appreciated!

/ Niklas