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Hum and Buzz on XLR Interconnect

Recently purchased a Balanced interconnect to install between pre-amp and amp. I have the same interconnect in balanced form from my CD player to pre-amp. The new interconnect connecting to amp has now a buzz/hum. When I re-install my RCA interconnect the buzz/hum is gone. Never had this problem before. My house is older and I don't think it is grounded although I use a 3 prong hospital outlet for the power cords. Any way to eliminate or is this particular unshielded interconnect just not compatible with my amp although it works on my CD player. Thanks, Steve
7671
lgregory
29 posts
 
TOO MANY GROUNDS IN YOUR SYSTEM CAN CREATE THE SAME EFFECT. ARE YOU USING A LINE CONDITIONER? THIS IS A MUST! IS THER CABLE IN YOUR SYSTEM TRANSFERRING ELECTRICAL ENERGY FROM AN OUTSIDE SOURCE. CABLE GROUNDS AND TOO MANY GROUND PLUGS ARE A DEADLY COMBINATION.
madisonears
117 posts
 
Why in the world would you install a balanced cable if it only causes hum? The only reason to use a balanced cable with XLR's is to eliminate noise. If it makes more noise, why not just use the single-ended? Why attempt exotic, expensive and potentially dangerous (lifting grounds can be deadly) solutions to a problem you can eliminate by simply going back one step? Your amplifier is probably not a balanced design, and no amount of fiddling with balanced cable will get it to run quietly.
cspra
6 posts
 
You didn't list your components, and I gather they are of diffent mfg. Use a meter/ tester, and check for phase, continuity, etc., of the 3-pins at each end of cable.. If checks out Ok, Take apart the Male XLR and notice how it is wired. If shield is connected to Pin #1, snip it. Same goes for if shield is connected to shell. Also, if a strand from shield is touching shell that may be the problem also. Signal Ground is touching chassis Ground and causes hum from Ground loop. A .10uF ceramic cap from Pin 1 to chassis cures the hum also 9 0f 10 times. If all gear isn't Balanced, its really worthless with most home audio gear. Also mixing different Bal gear causes as many noise problems. Compatability is the answer. If it sounds good with SE cables leave it alone. Good Luck! Charlie CS Audio
brianmgrarcom
1,317 posts
 
Did your amp come with plugs for the RCA inputs for when using the balanced inputs? I had the same problem till I realized I needed to put these "dummy" plugs in the RCA inputs, as soon as I did the hum disappeared; I am sure it will be the same for you.
7671 OP
163 posts
 
Thank-you Brianmgrarcom!! Once I put the plugs on to short the RCA inputs on back of amp, The Hum went away!! If I would have read the manual, I could have saved myself alot of time and hassel. To the above parties, My equipment is totally balanced and of the same manufacturer!! Thanks again to all input. Steve
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