2 Amp ?'s - Thanks for help!

[Pensacola Hi-Fi]

Question #1
I have a Monster Cable MPA 5125 and there is a slight humm or more like buzz in the speaker. I guess a little is to be expected but I notice when I unpluge the hdmi, it gets worse. Does the amp need to be grounded. If so, what is the easiest way? The amp is located in the middle of the house... more or less.

Here is the route of the HDMI, if it matters:

Cable box or Blu Ray to receiver, out to wall plate, hdmi in wall to LED. When I disconnect the hdmi to the wall plate, it gets significantly louder.

Question #2
Same amp. Tonight one of the front channels did not work. It occasionally had some static/music mix. Changed the speaker connections and the rca inputs to see if it was the speaker or the pre outs on the receiver. it seems to be that channel. After appx 20-30 min, it started working. Is it going out? or does it need to warm up in its old age.... probably not just wishful thinking on my part.

Thanks for all the help.

 

[Pensacola Hi-Fi]

The noise problem has been solved. The hum was coming through the cable coax. Ran the cable line through the surge protector and now it is totally quiet.

Amp channel is still not working. About once and hour the amp shuts down and turns back on. Checked and there is not wires touching in the back. Not sure what is causing it, but it is an old amp.

 

[lsiberian]

The noise problem has been solved. The hum was coming through the cable coax. Ran the cable line through the surge protector and now it is totally quiet.

Amp channel is still not working. About once and hour the amp shuts down and turns back on. Checked and there is not wires touching in the back. Not sure what is causing it, but it is an old amp.

I have a bad channel on my amp too. Given the branding I'd not expect high QA. Monster is very good at the external, but even their speaker cable puts cheaper plastic in the middle to make it look bigger.