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Amp humming need help

1019 Views 1 Reply 2 Participants Last post by  Wayne A. Pflughaupt
I've got an older Rotel receiver (rsx-1057) that I was trying to get some more power from, so I picked up a used B&K amplifier It's an av125.5. The amp sounds great when on and does a better job of feeding my B&W 703's. My problem with it is, after turning the receiver off, the amp goes in to bypass mode and after about 2 hours it develops a hum through my center channel speaker. I've experimented with turning the amp off completely and that resulted in a slight pop followed by the hum when I turned it back on, this is prior to the receiver coming on. Once the receiver is on no hum. I'm curious if anyone else has this issue or is familiar with the problem. https://speedtest.vet/ https://vidmate.bid/ My concern is if it's a filtering capacitor, will it eventually let go and blow the amp and or speakers. Is it worth repairing, as I can still send it back? Thanks for the help.
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I’ve seen similar problem before, an amplifier generating hum through speakers after whatever is feeding it a signal has been turned off, although the time lapse thing is curious.

I’ve had good luck in this situation using a separate power sequencer that would disconnect the amp from the electrical service (i.e. the equivalent of unplugging it from the wall). However, finding a sequencer that will work from an AVR’s 12v trigger is a challenge, especially at an economical price.

Lacking that, your best option is unfortunately the most inconvenient: Manually turning on the power amp after turning on the AVR, and then on power-down, turn off the amp wait 15-20 seconds before turning off the AVR. This will prevent pops in the speakers.

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