vman
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slight hum
Elk
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Do you still get the hum if you disconnect all of the interconnects from the amp? That is, do you get a hum when only the speakers are connected to the amp?

bifcake
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Is your amplifier connected to a grounded outlet? If it is, try defeating the ground.

vman
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I unplugged all the interconnects and the hum went away. The problem is coming from my AppleTV:

1. cables connected to AppleTV = hum
2. unplug AppleTV power source and there is still a hum
3. keep cables connected to the amp, but remove from AppleTV, no hum

I will try other devices with these cables, but it looks like it may be the AppleTV itself.

Jan Vigne
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Have you tried rubbing your tummy and patting your head?

Try the amp without anything connected other than speakers, as suggested above. Does the level of hum change with the volume setting or remain constant?

vman
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It's there even if the volume is all the way down, it gets a little worse as you go up - but not much worse. Strange thing is that I still get the hum even if the AppleTV has no power source.

vman
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OK - here is the deal with AppleTV.

If you are using a HDMI cable for the television and RCA cables for a second audio out (amp) then you get the hum. Pull out the HDMI cable and the hum goes away.

I tried this with component video cables and still had hum.

So - AppleTV works fine if you remove the TV - which means you can't navigate. I'll keep troubleshooting, but it looks like a SqueezeBox may be in order.

vman
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So I revisited this one last time - looks like the culprit was the cable from my cable TV.

Elk
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Good find.

cyclebrain
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Dynamo Hum, Dynamo Hum, where's this dynamo cumming from?
By Frank Zappa.

audiohound
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I have a Carver THX 5 channel amp with a pair of AR HO towers bi-wired...  When I power-up, I get a low steady hum - not horrible, but enough to drive my discerning ears nuts.  Not sure if the cause is the bi-wiring config., the pre-amp, cd player, or if it's the amp itself.  The hum is present even when the other components aren't powered up - amp only. The volume level adjustment on the pre-amp doesn't raise or lower the hum level.  Here's the little twist...  the front pannel of the amp has 5 light indicators - one for each channel. With the exception of one indicator, they all illuminate green (normal) including the two channels driving the speakers.  The indicator light that is illuminatiing red is not a channel being used.   Anything to recommed before I de-cable the amp and run it down for a check-up? Much appreciated! 

pentode
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CATV seems to be a common cause of hum.  I installed a quick connector on the 75 ohm F-connector used for the cable signal, so it can be easily disconnected.  While I don't usually suffer from system hum, it does intermittantly come from the CATV line.

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