Turns out if I plug any module directly into the amp (bypassing the
mixer) the hum is completely eliminated. (The mixer does not have a
3-prong plug - time for an upgrade.) JLH suggested the 900 makes the
mixer hum; I agree. I'll just bypass it for now.
Thanks for the info.
GK
--- In motm@y..., "Paul Schreiber" <synth1@a...> wrote:
>
>
> > Paul, I live in a condo, so that's a safe bet! Turns out a 2-wire
> > adapter eliminates the hum, but now whenever I connect a jack from
> > the out-board mixer to a module there is a good sized POP. If I
> > first zero the mixer's input level, this becomes just a slight
> > "scratch" which is not too objectionable. Once the mixer's
plugged
> > in, everything's pretty quiet.
>
> The ∗only∗ way to fix this is to use isolation transformers. 1 on
the mixer,
> 1 on the MOTM.
> Allied carries these for about $50ea. I have a big-assed honkin'
one on my
> bench (it 'floats'
> the whole test equipment setup).
>
> Paul S.