Well, weird for me, at least. I got a PE plate amp some time back, and it's hummed from the first day I've hard it. Recently I spent some time trying to narrow it down. Here's what I know so far:
* There's no video/cable in the system, and I added power strips and cables so everything was off the same power strip/outlet, and it did not make any difference.
* I have separate stereo and HT systems with a shared subwoofer, so I have cables from my stereo's XO and my receiver's pre-out going to the L/R inputs on the BFD, then outputs from the BFD to the L/R inputs on the plate amp. At any time, only the L or R side is playing, obviously.
* The sub is quiet if I remove both interconnects from it.
* The sub is quiet if I have the ICs between the BFD and the plate amp, but no inputs to the BFD, and no power cable in the BFD
There are 2 things that make the sub hum:
* The sub hums if I now connect the power cable to the BFD, even if the BFD is turned off, and has no inputs connected. Both power cables (BFD and plate amp) are on the same power strip, and I've tried sending that to the main power strip of the rest of the system, as well as sending that to the wall and unplugging everything else. No difference. Tried different power cords, no difference.
* The other scenario is if I disconnect the power from the BFD (which makes the sub quiet), then hook up the input cables to the BFD. The one from the receiver is fine, but the one from the Behringer XO makes it hum. I haven't diagnosed this too far at the XO end, but I think it's similar - if the power cable is plugged into the XO, then it makes the sub hum. Or it's picking up hum because it's a pretty long cable and maybe isn't well shielded... don't know this one yet.
I had the same setup with the Behringer A500 as the sub amp, and it did not hum.
So... any ideas? I might have a toddler crawling around in that room so I'd prefer not to use a cheater plug as a long-term solution. It almost seems like Behringer products do something with their grounding design that the PE plate amp does not like.
I remember adding an RC circuit to my tube amp to address ground loops, but I don't remember what I did. I think it went between audio ground and earth, and the values were chosen to break the DC connection, but to effectively be a short at higher frequencies... or something like that, but I don't remember. I'll go research this, but if anyone has any ideas for changes i could make to the plate amp's grounding that would be safe and would eliminate this, then I'm interested in hearing them. Of course, if there's a solution that does not require making circuit changes, that would be best.
* There's no video/cable in the system, and I added power strips and cables so everything was off the same power strip/outlet, and it did not make any difference.
* I have separate stereo and HT systems with a shared subwoofer, so I have cables from my stereo's XO and my receiver's pre-out going to the L/R inputs on the BFD, then outputs from the BFD to the L/R inputs on the plate amp. At any time, only the L or R side is playing, obviously.
* The sub is quiet if I remove both interconnects from it.
* The sub is quiet if I have the ICs between the BFD and the plate amp, but no inputs to the BFD, and no power cable in the BFD
There are 2 things that make the sub hum:
* The sub hums if I now connect the power cable to the BFD, even if the BFD is turned off, and has no inputs connected. Both power cables (BFD and plate amp) are on the same power strip, and I've tried sending that to the main power strip of the rest of the system, as well as sending that to the wall and unplugging everything else. No difference. Tried different power cords, no difference.
* The other scenario is if I disconnect the power from the BFD (which makes the sub quiet), then hook up the input cables to the BFD. The one from the receiver is fine, but the one from the Behringer XO makes it hum. I haven't diagnosed this too far at the XO end, but I think it's similar - if the power cable is plugged into the XO, then it makes the sub hum. Or it's picking up hum because it's a pretty long cable and maybe isn't well shielded... don't know this one yet.
I had the same setup with the Behringer A500 as the sub amp, and it did not hum.
So... any ideas? I might have a toddler crawling around in that room so I'd prefer not to use a cheater plug as a long-term solution. It almost seems like Behringer products do something with their grounding design that the PE plate amp does not like.
I remember adding an RC circuit to my tube amp to address ground loops, but I don't remember what I did. I think it went between audio ground and earth, and the values were chosen to break the DC connection, but to effectively be a short at higher frequencies... or something like that, but I don't remember. I'll go research this, but if anyone has any ideas for changes i could make to the plate amp's grounding that would be safe and would eliminate this, then I'm interested in hearing them. Of course, if there's a solution that does not require making circuit changes, that would be best.
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