--- In SergeModular@y..., yahoo@h... wrote:
connect two or more devices where each device has a different
ground (reference voltage). The ground loop will be audible
as a slight hum at 60 Hz. Let's say you have another synth
you are trying to process with the Serge. Because they have
different power supplies and each is plugged into a different
place, the grounds may not match, and you'll experience hum
in the signal path. The same problem if you're
plugging the Serge into a second device, such as a mixer.
Fortunately there is an easy solution if you route all I/0
through an external mixer (I assume you have plenty of individual
channel outs or aux sends to use for this purpose.)
Then you only have to make sure the grounds of the mixer and the Serge
match: all other devices are conditioned through the mixer.
For this purpose, there is a black-coded "ground" jack on the
back of the Serge power supply. You first need to find a special
"grounding plug" (this is a female banana plug attached to
a thin strip of metal designed to fit underneath a screw. I got
one from Rex, and I've never lost it, so I don't know offhand
where to order something like this. Can anyone find a picture
on the web?) Now find the screw on your mixer's back panel
which is closest to its own power supply (which should be near the
ON/OFF switch) Unscrew it slightly and attach the metal strip on the
grounding plug underneath the screw. Screw the grounding plug back
down. Now patch the Serge power supply's "ground" jack to the mixer's
grounding plug and voila! Serge/mixer share the same ground =
No more problems with hum!
What else -- sometimes there is a slight bleed-through
of the oscillators and especially the clock inside the Wilson
delay. This should not be confused with hum because you can
affect this by changing the unused oscillator frequencies.
Be sure to set the frequencies of oscilators you're
not using to maximum frequency, or somewhere
up above the audible range.
Other power distribution problems are not necessarily ground
loops, because ground loops are associated with hum.
If you accidentally patch outputs into outputs or
do anything to cause a significant drain on the power supply,
you can get all kinds of weird crosstalk, especially with DC
control voltages. THe best solution is to quickly
unpatch everything and start over. Usually doing weird
things with feedback (such as taking the audio mixer's output
and patching to one of the inputs, turning the gain just below
self-oscillation for a cool distortion effect) can't really
cause a drain on the power supply.
Happy patching...
--Harvey
> --- In SergeModular@y..., dbauer847@y... wrote:From
> > The next issue I have with this system is a 'grounding issue'.
> > research on the web it seems that Serge is famous for strangetake
> > grounding. On this 4 pannel system when all for pannels are
> > connected to a PS6 there is NO problem with grounding. When I
> > the pannel off with the 2 channel mixer (that I use for theoutput)
> > And use the pannel with the UAP as the output mixer I get groundpatched
> > loops on *all* the outputs of the system (even with nothing
> > together). This seems strange.Could
>
> I'd like to second a request for info on Serge grounding issues.
> someone knowledgeable give the non-EE types among us some basictips?
> Like, what, exactly, is a "ground loop"?Roughly speaking, you'll experience a ground loop any time you
connect two or more devices where each device has a different
ground (reference voltage). The ground loop will be audible
as a slight hum at 60 Hz. Let's say you have another synth
you are trying to process with the Serge. Because they have
different power supplies and each is plugged into a different
place, the grounds may not match, and you'll experience hum
in the signal path. The same problem if you're
plugging the Serge into a second device, such as a mixer.
Fortunately there is an easy solution if you route all I/0
through an external mixer (I assume you have plenty of individual
channel outs or aux sends to use for this purpose.)
Then you only have to make sure the grounds of the mixer and the Serge
match: all other devices are conditioned through the mixer.
For this purpose, there is a black-coded "ground" jack on the
back of the Serge power supply. You first need to find a special
"grounding plug" (this is a female banana plug attached to
a thin strip of metal designed to fit underneath a screw. I got
one from Rex, and I've never lost it, so I don't know offhand
where to order something like this. Can anyone find a picture
on the web?) Now find the screw on your mixer's back panel
which is closest to its own power supply (which should be near the
ON/OFF switch) Unscrew it slightly and attach the metal strip on the
grounding plug underneath the screw. Screw the grounding plug back
down. Now patch the Serge power supply's "ground" jack to the mixer's
grounding plug and voila! Serge/mixer share the same ground =
No more problems with hum!
What else -- sometimes there is a slight bleed-through
of the oscillators and especially the clock inside the Wilson
delay. This should not be confused with hum because you can
affect this by changing the unused oscillator frequencies.
Be sure to set the frequencies of oscilators you're
not using to maximum frequency, or somewhere
up above the audible range.
Other power distribution problems are not necessarily ground
loops, because ground loops are associated with hum.
If you accidentally patch outputs into outputs or
do anything to cause a significant drain on the power supply,
you can get all kinds of weird crosstalk, especially with DC
control voltages. THe best solution is to quickly
unpatch everything and start over. Usually doing weird
things with feedback (such as taking the audio mixer's output
and patching to one of the inputs, turning the gain just below
self-oscillation for a cool distortion effect) can't really
cause a drain on the power supply.
Happy patching...
--Harvey