2. home-theater
  3. 1038508090

Help amp hum is driving me crazy

To start with I have a B&K ref20 pre with Polk SRT speakers. I have Kimber Monacle XL and 8tc for speaker wires and Phoenix Gold RCA cables. I use a Panamax 1000 and a DBS for protection. I had a Sunfire CG with no problems but felt I needed more explosive power for home theater so I bought a used Cinepro 3K6 II. It hummed like crazy at first (50db). So I began the sytematic aproach, I started unhooking items looking for the culprit. I eventually ended up with just an amp hooked to speakers, still humming. I tried an extion cord plugged into several other outlet in the house, some worse none better. The Panamax DBS works the best at filtering out the most. I tried cheater plugs in every combination I could think of to no evail. The ground lift switch on the Cinepro helps very minutely. I tried different interconnects. What else can I do besides get rid of it or spend thousands on filters I never needed before? I am an electrician and would like to think I am fairly well schooled but I feel like an idiot.
wcj56
blueswan
211 posts
 
This sounds like a problem that you cannot simply cover up with filtering or lifting the ground. You should probably consider a reputable repair shop. I am sure someone here knows of a good shop in your area. The only other alternative is to replace the unit, perhaps with another used unit from here.

Do not get rid of your filters (or buy any others) just yet. You may find they are quite helpful once your hum problem is resolved.
buckingham
333 posts
 
Lift the ground with a cheater plug.
jameswei
883 posts
 
Perhaps the ground lead on your amp's power socket is not properly connected internally. It certainly doesn't sound like its doing its job as a ground. Try grounding the chassis separately, i.e., maybe run a wire from a chassis screw to the grounded screw on your electrical outlet. Good luck.
tpsonic
1,092 posts
 
Had you checked the connection on your interconnects?Occasionally.the outer diameter of the female RCA connector and inside diameter of the cable connector needs adjustment.Same can be said for the center pin on your cables.Try spreading the center pin ,if it is of the expandable type and check contact of outer grounding connection.Good luck!
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