CMX2, go figure

[gus4emo]

So I got the cmx2, plugged it in straight to the wall, plugged the CMX6 into the cmx2, still a bit of hum, which I wanted to get rid of, it wasn't a loud hum but was still there, then it was LOUDER, got really upset, then plugged a 14 gauge 6 feet extension cord to the outlet and the CMX2 to the extension cord, hum is GONE, please explain.

[509Paul]

What does plugging a CMX-6 into a CMX-2 do for you other than more outlets? Don't they both have the same filtering except the CMX-2 also includes DC offset filtering? I just plug a surge strip into the CMX-2.

[gus4emo]

Exactly, the cmx2 is supposed to get rid of the hum, but my surprise was after adding the extension cord between the wall and the cmx2, hum is gone! Where are the experts? Lol...

[gus4emo]

Anybody?

[creimes]

First off you do not need to plug a CMX-6 into a CMX-2, I use the CMX-6 for my Oppo, pre/pro and display(before i went to a projector) and use the CMX-2 for my XPA-5 and Behringer amp

And for 509Paul the Emotiva amps have built in surge protection and if you have your amps plugged into a surge bar it could limit the amplifiers peak output when needed, just plug your amps directly into the CMX-2 as recommended by Emotiva themselves.

[gus4emo]

Thank you creimes, I will plug both the XPA7 and the XPA200 to the CMX2 and everything else to the CMX6, but still wondering why did the hum stopped after plugging the CMX2 to a 14 gauge, 6 feet extension cord?

[creimes]

Feb 18, 2016 23:42:03 GMT -5 gus4emo said:

Thank you creimes, I will plug both the XPA7 and the XPA200 to the CMX2 and everything else to the CMX6, but still wondering why did the hum stopped after plugging the CMX2 to a 14 gauge, 6 feet extension cord?

The extension cord thing I have no idea lol, I have no issues with hum in my system so I cannot give advice on the matter but could be a ground issue, does the extension cord have a ground lead ?

[509Paul]

Maybe the longer extension cord changed the interference frequency being picked up like an antenna. 

[Boomzilla]

I've had the exact same hum experience with two different amps:

The Rogue Audio Magnum 88 (tube integrated)
Some Chinese tube hybrid integrated (Don't remember the name).

Hum when plugged into ANY surge suppressor - no hum when plugged directly to the wall.

No idea why. Boom

[gus4emo]

Thanks guys, we'll the hum is gone now, should I still go ahead and plug the 2 amps in the CMX2 and everything else to the CMX6, what about sub number 1, it's plugged there too, I have sub number 2 plugged into the back wall.

[gus4emo]

thatcher, last year I started hearing the hum in almost all channels, started separating power cables from audio cables, it diminished the hum but still there, got a piece of wire to one screw from the receiver (Denon 4500) to a screw of the XPA7, diminished some more, still there, someone from this forum advised to get an CMX2 and plug the CMX6 to it, didn't do that until now, hum was only coming from 2 channels but it was a bit higher, pulled out the 14 gauge 6 feet extension cord plugged it to the wall and the CMX2 into it out of curiosity, checked and GONE, lol, that's why the subject says "go figure ", lol...

[kazoo]

Not sure where I read it and I could be making it up but somewhere I read something about the length of your power cord should not be less than 6 feet. Something to do with the way the cord filters the power coming in. That is why some buy those expensive cords and say they make a difference. There might be something to it. You might have noisy power coming in from outside or inside the house and the longer cord filtered out the noise. Just a guess. Some amps you can't hear it on and some are just prone to picking up noise. It would be interesting to see if you could pick up an isolation transformer to see if the noise would go away with not using the extension cord.

[gus4emo]

Kazoo, I will leave it the way it is, since the hum is gone, if it comes back I plug both the CMX2 and CMX6 straight to the wall, but right now I don't even want to look at it, lol.