if this only happens when logic is running, you might want to take a
closer look at the software routing. have you tried your old
template/autoload

i had a midi-feedback loop once that was provided by (new) logic's own
autoload in combination with the rest of my setup. using my old
autoload solved it.

hth,

stu

--- In Doepfer_a100@yahoogroups.com , <hardware@...> wrote:
>
> > Hi,
> >
> > I would like to appeal to anyone with experience in eradicating a
> > probable ground loop. I've just done a bit of upgrading in my studio,
> > and I've developed a nasty buzzing in my system. I've narrowed it
> > down to the interplay between Logic 7 and my analogue synth. Of note
> > is that I have not changed anything inside the synth since before the
> > upgrade and that the problem exists even when the synth is turned off
> > but not when it is unplugged from the wall. In fact, I've just been
> > jiggling about with the plug and the buzz come back as soon as the
> > earth pin of the plug makes contact.
> >
> > The problem also only exists when Logic is running but not when i
> > run things like iTunes etc. It can also be controlled by the mixer;
> > turning down the channel volume or EQing it out work. I've also gone
> > around turning off and unplugging everything except the computer,
> > synth and mixer, but the buzz remains.
> >
> > Can anyone help
> >
> > Yours Aye
> >
> > Stuadh
>
> We had similar problems when we changed the arrangement of the A-100
demo
> system, mixer and computer. The solution we found was the usage of a
passive
> DI box between mixer and computer.
>
> Best wishes
> Dieter Doepfer
>