Slight hum in my amp. Is this normal?

oldschool1, I can't remember.  Did you ever try a cheater plug just to see if it eliminates the hum from the speakers?  Not to use permanently, but to narrow your investigation?  In any case good luck in finding the issue.

From a photo of the A5 back panel, it looks as if the IEC inlet is only two prong - not the 3 prong w/ground. (It’s difficult to tell from the angle.) If this is correct, then a cheater plug won’t do anything. A hum coming out of the speakers (ever how many are hooked up to the amp) is usually caused by a bad ground somewhere in the system - or a culprit in the house wiring. Sending the unit back to Canada won’t fix the problem. Here are some possibilities:
- A dimmer switch, old kitchen/bathroom appliance or a bad fluorescent lighting ballast is sharing the same circuit. Have you tried turning everything off - except the system?
- Try running a 24 gauge wire (a la Home Depot) from a screw on the amp chassis to the outer sleeve of any RCA connector on each your source components - one component at a time. See if the hum goes away.
- The power cable to the amp is wired backwards between the hot & neutral on one termination - the reverse of the other termination. Have you tried other power cords?

I tried a different power cord. If it were a ground issue, wouldn’t running it through a power conditioner such as the Torus correct it? Also, the Torus is plugged into the outlet by the left channel and I tried plugging directly to the outlet by the right channel. And the electrical connection is a two wire AC connection to the power source.

No, the Torus is not a miracle cure. The electrical outlets by the left/right channels may simply be on the same circuit. The two prong IEC means that there is no connection to ground. This may or may not be the problem. Try grounding the amp via an external wire as mentioned above. See if the hum goes away.  Before incurring the expensive cost of shipping an amp to/from Canada, be sure to speak with their technical customer service.  Also, the AudiogoN discussion archives has a wealth of information.  Type in 'ground loop'.  This is no different than a car mechanic trying to figure out why your car is stalling. It could be any number of things. Good luck!

After all this, my problem isn't a ground loop, bad ground, or anything external. Reading my email to the repair shop will explain;
Hi Morris,
Ok, I’ve exhausted my resources and have isolated the problem. I have a dedicated AC line I tapped from that powers my tankless water heater. This is a new line installed about 4 weeks ago and the water heater is the only thing powered by it so I ran an extension cord to the Anthem. The only connection after the Anthem is speakers. No input connections what so ever. The “hum” is in the amp AND audible through the speakers, all 5 channels.
I still have my Integra DTR 50.3 and for giggles, unboxed it and connected it. Again, AC line into the Integra and speaker wires to the corresponding speaker. Result, DEAD QUIET! I went a step further and connected the Integra to the wall (not the dedicated line), same result. Another step further and connected the AC line to the Torus, Torus to the Integra, Oppo BDP-103 Blue Ray to the Integra, speakers connected. Again, DEAD QUIET!!
My comparison is a $700.00 Integra AVR to a $4,000.00 Anthem amplifier.
Conclusion; there is something going on internal to the Anthem. No question about it. It’s something common to all 5 channels.
Lets review the chain of events….
When I lived in my condo, you serviced the Anthem and it worked beautifully! Had there been a “buzz”, I would have noticed. I’m POSITIVE of this!
I moved to this house and upon installation, I found the Surround Right channel dead, so I brought it to you. Then technicians finding was everything was good. Considering the contradiction, you recommended the technician disassemble and reassemble the amp.
Up to this time, I never heard a “hum” from the amp. Again, I would have noticed it.
As soon as I got it home, connected everything, I heard the “hum” immediately and brought it back. You called me and said there were no problems and I took a leap of faith doubting my own observations. I’ve never heard a “hum” from an amp before. You stated all amps have a little bit of noise if you put your ear close enough. I wondered why I could hear it from my seating position. Were my ears that good? Possibly but, thats when I put my ear close to each and every speaker and discovered the same “hum” from the amp, I heard coming from each and every speaker.
This is when I brought it back to your shop. In addition to the “hum”, the right side front panel ear was loose which got fixed.
Immediately when I put it back in the system, the “hum” was apparent and I tried to describe it best I could. Again, doubting my own judgement, I gave it a day or so. I came to the realization that what I was hearing was not normal.
It all became real to me today when I put the Integra in the system! To add icing on the cake, the technician neglected to install one of the housing screws and your office lady, had to mail it to me. It arrived today and I installed it.
Morris, I’m at a loss on what to do at this point. It’s clear the amp is not functioning properly. A piece of gear of this caliber should be light years better than the Integra it replaced in my system, and it was, until the technician disassembled and re assembled its innards.
I need to know how we are going to address this. I’m very upset and exhausted at this point and ready to send it to Anthem in Canada. Before I do, I need to know what you can offer for a solution. I know this will get resolved, the question being by who and at what cost. I’ve thrown a lot of $$ at this already.
Thank you and I look forward to resolving this expeditiously.