Behringer A500 Hum

[Fowl]

Ok guys, I am seeking some help in eliminating this cursed low pitch hum that is coming out of my center channel. I figured that it might be ground loop problems, but how can I eliminate this without spending a ton load of money.

I have checked all the wires and it is only apparent when I connect the RCA lead from the prepro to the input on my A500.

The amplifier plays quite good, but the hum is there. Help me with a few suggestions.

 

[bandphan]

Is the center the only speaker you are using a pro amp with? I've never had issues with the a500 and hum that hasn't been related to ground loop (not to say that it doesn't happen). Have you tried disconnecting one component at a time to see if one is causing the issue? Also there is a sticky in the beginners forum that deals with ground loop as a reference.

 

[Rickster71]

If I may add a bit to what Bandphan said:

Is the prepro connected to a cable box in any way? If so, as a test disconnect the cable hook up.
If there isn't any cable box in your scenario; plug the amp & prepre into the same power strip or outlet.
How is your CD or DVD player connected?
The key is getting everything connect to the same ground.

 

[Fowl]

If I may add a bit to what Bandphan said:

Is the prepro connected to a cable box in any way? If so, as a test disconnect the cable hook up.
If there isn't any cable box in your scenario; plug the amp & prepre into the same power strip or outlet.
How is your CD or DVD player connected?
The key is getting everything connect to the same ground.

Thanks, guys. I am at work now, but soon as I get home will check these things out.

 

[mike c]

can you also try a cheap RCA to TRS adapter? use the 1/4" TRS (microphone jack) instead of the RCA

 

[TLS Guy]

Ok guys, I am seeking some help in eliminating this cursed low pitch hum that is coming out of my center channel. I figured that it might be ground loop problems, but how can I eliminate this without spending a ton load of money.

I have checked all the wires and it is only apparent when I connect the RCA lead from the prepro to the input on my A500.

The amplifier plays quite good, but the hum is there. Help me with a few suggestions.

Check out the cable.sat box as suggested. However it is not a good idea to ground a preamp and an amp. Normal practice is to ground the pre amp and not the amp. I know a lot of people disagree about this here, but it is accepted audio engineering practice. I can tell from experience grounding a pre amp and the power amps frequently leads to trouble. So if sorting the cable/sat issue does not solve it, ground the preamp but not the amp.

 

[Fowl]

Check out the cable.sat box as suggested. However it is not a good idea to ground a preamp and an amp. Normal practice is to ground the pre amp and not the amp. I know a lot of people disagree about this here, but it is accepted audio engineering practice. I can tell from experience grounding a pre amp and the power amps frequently leads to trouble. So if sorting the cable/sat issue does not solve it, ground the preamp but not the amp.

Went home and started pulling everything down, I realized that when I move the amp plug aroung in the socket the humming gets a bit lower.

I will be replacing the RCA cables as some seems to be badly twisted. I will also be changing which socket the amp plug into and doing some rewiring today.