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Hum issue - driving me more crazy

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Not sure if this should be here, Tech talk or Cables...

Audio Research Ref 2 Preamp, Pass labs electronic Xover, Bryston 4B ST amps (2), MAGGIE 20.1 speakers. All eqpt working OK.

Pre source eqpt left rear of room
spkr amp & XOVER left front of room
spkr amp right front of room

Separate 20 amp circuit for hifi eqpt. Other plugs in rooms for lamps, etc. Many of lamps on dimmers

Singlended IC's (now double shielded)are "under" flooring (pier and beam construction) & has been moved away from other wiring & cross at right angles

Initially some hum from dimmers (on separate circuit), etc. Have learned to leave them off.

But there is constant low level hum - right side only EVEN with preamp and XOVER turned off.
imdoc
rwwear
2,854 posts
 
You can probably remove the RCAs from the cables and replace them with XLRs. Most ICs have three wires inside anyway. If they do it's pretty simple if you can solder to attach XLR's. You don't even have to be able to solder with some of the new clamping XLR connectors.
Neutric solderless XLR
jea48
4,324 posts
 
"Bringing the IC to the right amp TO ABOVE the floor-> RESOLVES NOISE. In my unknowing frog brain, this implies something is inducing noise in the right sided IC (when under the floor - down about 12-16" is all though)."
05-26-11: Imdoc

Imdoc,

*How long is this IC cable?
*What type of cable supports are used under the floor? Plastic? Metal?
*How often is the cable supported, distance between supports?
*What is the area, space, under the floor? Basement? Crawlspace?
magnumpi205
504 posts
 
The dimmers must go, off is not good enough.
Have replaced components, cables, used cheaters,aligned cables, changed conditioners and surge, replaced tubes, replaced power cables.
As soon as I took out the dimmer switches, problem solved.
shay123
72 posts
 
I had the same issue with my Dynaco pas 3 preamp. All I had to do to eliminate the hum was to twist the rca connectors from the phono in the socket until it made good contact. Try this first with all of your rca plugs and see if that solves the problem. It did it for me, no more hum.
forrestc
106 posts
 
You don't have a TV or tuner connected to cable or satellite whic is connected to your system do you?

Cable and dish installations are often grounded in a different location than your mains ground which almost always creates a ground loop though your audio system.
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