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What is causing my speaker hum?

My speakers, Joseph Audio RM22si's, hum (unwanted noise) when the receiver is on. It was the same with my old Infinity speakers. It's there when the receiver (Denon 70Watt x 5 channel receiver) is on, but it's much louder when I'm playing a CD and then pause the CD (using a Toshiba DV333 DVD/CD player). I am using the digital out from the player into the receiver (and therefore using the D/A built into the receiver).

Is this just bad amplification? Could it possibly be bad grounding, and if so is that something I can fix? I don't think it's the CD player, because I'm using the digital out, and when that is paused there should be zero signal sent, yes?

One other very weird side note. Usually it is just white/pink style noise, but one time I heard a song playing. I'm not schizophrenic, there was actually a song playing silently in the noise, different from the one on my CD. Could that be the receiver's tuner leaking out or something coming through the power lines?

One thing I'm trying to figure out is if I buy an amplifier and plug the receiver into that, if my problems will go away, or if you guys think the problem is upstream from the amp.

Thanks,
Matt.
matt8268
marakanetz's avatar
marakanetz
5,473 posts
 
If the hum is monophonic it's probably from power line. You need to use power conditioner. Try to unplug CD player and bring the volume up. If no hum or just a-little than CD-player is the guilty one. A lot of CD players have digital out but they cannot be dedicated transports for using them with DAC meaning that digital "trash" is corrected inside the CD-player. So first, try to use analogue outs, then again: digital sources are the most volatile devices to malfunctioned or "dirty" power lines and need a power conditioner even more than any amplification ones.
rcprince
3,059 posts
 
The hum could be a ground loop between your source and receiver; if either has a three-pronged plug try cheater plugs on all of the cords to start. There are other possibilities, but I'll leave those to other posters. As far as the song, it could be cross-talk from the tuner portion of the receiver (can you turn off the tuner function?) or else you're getting rfi through your cables, power line or equipment. I once auditioned an expensive amp which gave me a broadcast of a Rutgers University basketball game through the right channel while I was listening to other sources, and the fault was that the amp was picking up and amplifying rfi signals in my listening room. Too bad, it was otherwise a great-sounding amp (but a bad game!). You might try ferrite clamps on your interconnects or speaker cables; I'm sure others will have possible solutions as well.
ljgj
955 posts
 
If it is by a cable tv cable it could be that. Also the digital cable from the CD player to the receiver could be the problem. Does it hum when you have the rca cables from the CD to the receiver plugged in instead of the digital?
kublakhan
717 posts
 
It doesn't know the words?
AAAAhhhhhhhhh. i'm not back - i just couldn't help that one and i'm wired on 2 triple espressos.
while i'm here though...WHAT'S AAAAAAAAP, fREaKS!?
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