I just bought an Behringer 8 channels splitter-/mixer, 19"model,1 unit.
I like to put it in my 3 unit rack, together with my eq and my DPC 750. When I keep the Behringer on distance for 1 foot, it's totally silent. The more I move it to the rack, the more hum I get. So, it's no ground-problem, must have to do something with electric fields, I guess. Please, help me out.
A desperate Dutchman .....
as the badest steelplayer in the world...
and as a soundman that has sometimes some success, the first thing I would check are the chords... I'm shure that is the problem, change every chord you're using and see what happend... hey Johann... time to see ya again
have a great weekend
Andy
One of the more effective low-cost gadgets for sniffing out electrical noise sources is a cheap transistor radio (like we used to buy at Woolworths in the 60's for $1.69. Turn one all the way up, in between stations, and it will reveal lots (if not all) sources of elec. noise being radiated. It might help in your situation. The professional equivalent is called an "inductive amplifier", used by phone companies with "toners" that put a test tone on a wire or pair of wires for tracing.
I use both the pro & cheapo units...this here ~Progressive Electronics 200EP~ Ind, Amp. is more directional and selective, but it's basically just a high grade AM radio optimized for tracing. It also picks up just about any noise source with a lot of sonic detail about what's going on with the source, i.e. the nature of the beast, once you get a bit of experience listening to power quality issues from the cheapside. I've seen similar units at ham radio swap-fests for under $10 (cost new about $90, I think).
Short of lining the rack with properly grounded "MU-Metal", those fields, If I correctly guess are of the magnetic portion of a field, can be a real bear to mitigate. The electrical portion of a radiated noise source is fairly easy to deal with...for example, the sheilding paints & foils in guitar cavities are pretty good. But you might be lucky and have the "easy noise". Wouldn't hurt to check it out some. Also what about the rack,s manufacturer? I'm sure they have "seen (heard) it all".
But hey, good luck!
I'd make sure you're using real high-quality patch cords, and keep them away from the transformers, wall-warts, and power cords, when possible. Not much hum will leak through a metal enclosure, but cheap patch cords are virtually an "open door" to the input and preamps of the devices. If you <u>must</u> run line cords close to signal-carrying cords, make sure they're at right-angles to each other, and <u>not</u> parallel. ("Neat and pretty" isn't always best.)
Kevin, I did that trick, and that worked great, Thanks, had no hum!
Problem in the rack solved too, had to do with wrong soldered connections, between the tip and the rings on the jacks that connect the preamp to this poweramp rack.Problem wasn't there before, because I didn't have to work with balanced signals.Thanks for your input, guys.
JJ
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Click on the pic!
