Mathias Lenz wrote:
Has anyone experience with Furman Power Conditioners. They claim to have RFI
filtering.
I'm working in a theater and dimmer-buzz is introduced trough the power line
to my BSS FDS 360 Crossovers. I'ts not much but enough to disturb the
audience during silent scenes. Would this thing fix the problem?

My experience (mainly in theatre) has been that dimmer buzz is almost
always down to a problem with sound system grounding rather then problems
with the racks, RF or power line noise. Try unplugging everything from the
crossovers (except the amps) and see if the buzz is still there, if so fix
the problem then work on the desk-crossover link, then add the outboard,
then the mic ties...

I often find that a better fix then disconnecting the screen is to add an
additional low impeadence ground path with a bit of 10mm earth cable
running in parallel with the signal cables and tied to case ground at both
ends.
In particular if you have impulsive noise (contactors, motor switching),
this can work much better then approaches based on telescoping sheilds.

This sort of thing can be a real bear to track down and lots of
experimentation is really the only way.

If the humm is low level, it can be worth experementing with gain
structure (if the amp clips at 1V input with gain at max, and the
crossovers clip at say +22dbV, then you can turn the amp gain down 22db
and still have enougth drive available to get full output. Obviously
this depends on the desk being able to drive the crossovers hard enougth
(should be a given, but....). Not a real fix, but sometimes it does
enougth.

Regards, Dan.
--
** The email address *IS* valid, do NOT remove the spamblock
And on the evening of the first day the lord said...........
..... LX 1, GO!; and there was light.