Hum in Anthem MRX 700

[MVW]

I have an anthem MRX 700 purchased and installed in an Home Theater environment around March 2012. I love the unit great sound and great features. However, approximately 6 months ago it developed a significant audio Hum. I made no changes to the system, it just started while we were watching a movie. I have checked power, cables , grounding etc and the hum is still there. It will go away for no reason at all but it always returns. Example: on 3/31/19 the hum went away for no specific reason that I could determine. It returned on 4/11/2019. I turned the unit off and back on and the hum went away. The hum returned 6/9/19 and went away on 6/19/19 only to return about 2 months later on 8/14 19 and it is now constant. I recently again disconnected everything, connected the unit to my neighbors power source to try and eliminate power as an issue and the hum is still there. I stripped the unit down to one speaker and disconnected all external inputs. The input I used was the internal tuner and the main center channel speaker. Hum is still there. The hum level does not change with the volume control and it is there at the same level when I mute the unit. Any ideas on what I can try next. I am thinking the problem is internal to the Anthem MRX 700 but I would like to prove that before I go down that road. Has anyone seen something like this before?

 

[lovinthehd]

It also sounds like the Anthem itself to me. When you addressed cables did you switch cables and/or isolate other components? Try one speaker at a time? Etc.

 

[MVW]

Yes, I tried different speakers and the hum is in every speaker. Switched the cables to different speakers, no change, I removed all the anthem inputs, OPPO player, TV box, FM and AM antenna. I did this one at a time and all at one time. No change.

 

[lovinthehd]

Yes, I tried different speakers and the hum is in every speaker. Switched the cables to different speakers, no change, I removed all the anthem inputs, OPPO player, TV box, FM and AM antenna. I did this one at a time and all at one time. No change.

Time to have the Anthem looked at IMO. Hopefully something simple and easily found....

 

[MVW]

Do you know anyone local to the Houston area who is capable of working on the Anthem MRX 700. The only one I know is in Canada.

 

[Verdinut]

Do you know anyone local to the Houston area who is capable of working on the Anthem MRX 700. The only one I know is in Canada.

I suggest that you call or email Anthem. They most likely know a few service outlets somewhere in the US.

 

[lovinthehd]

Do you know anyone local to the Houston area who is capable of working on the Anthem MRX 700. The only one I know is in Canada.

I'd go with Verdinut's suggestion of asking if there are any particular recommendations by Anthem. Otherwise there are I'm sure capable facilities, but have no idea for your area.

 

[MVW]

I have an e-mail into Anthem and expect a reply on Monday during working hours. Thanks for the assistance.

 

[Verdinut]

I have an e-mail into Anthem and expect a reply on Monday during working hours. Thanks for the assistance.

You're welcome!

Cheers,

 

[AcuDefTechGuy]

It’s 7 years old. Some of these things don’t last very long. My Denon AVP-A1HDCI lasted 8 years. Time for a new unit.

 

[MVW]

I would hope fot the money I paid it would last longer than 7 years.

 

[Verdinut]

For an audiophile AVP or an AVR, in my opinion 7 years is a good average life.

 

[lovinthehd]

I'd call, emails sometimes get no answers.

 

[MVW]

Maybe I am too cheap I expect a t least 10 years. But then again maybe I am too optimistic.

 

[MVW]

Good idea. I will call them on Monday.

 

[lovinthehd]

Maybe I am too cheap I expect a t least 10 years. But then again maybe I am too optimistic.

That would be a long time for email I assume you think that Anthem should last longer before having issues? Maybe....just because they're a boutique brand doesn't necessarily give them any leg up.

 

[PENG]

So the hum is coming through the speakers, not from the unit itself? How loud is the hum, and how's sound quality otherwise?

 

[MVW]

The hum volume varies from very low to louder and annoying. The sound quality is excellent. No change with or without the hum across all inputs.

 

[lovinthehd]

The hum volume varies from very low to louder and annoying. The sound quality is excellent. No change with or without the hum across all inputs.

What is without hum among the inputs?

 

[PENG]

The hum volume varies from very low to louder and annoying. The sound quality is excellent. No change with or without the hum across all inputs.

So if I understood right, sound quality is not affected, just that a power frequency related (e.g.120 Hz in the US) noise is somehow superimposed to the audio signal. In that case, it is most likely a connection (usually connections to "ground" related issue. If there are nothing visibly loose or opened, such as wires coming off, then it could be some bad solder joints that have gone from weak to poor, and could be hard to find by the naked eyes.