2 Rotel amplifiers with a buzz; DC voltage block?

tn2036
tn2036 Posts: 16
in Electronics
I have two Rotel amplifiers (RB-1070 and RB-1080). Both have developed a buzz or hum recently. The hum is present with no source connected.

I have tried:
- Direct wall connection, no power strip
- Rocketfish power strip with 78dB filter
- A different power circuit
- Turning off all circuits in the house at the breaker

Any troubleshooting ideas or thoughts?

Is it safe to leave speakers connected to this? I’m assuming not (currently disconnected)

Has anyone had luck with DC voltage filters (DC on the AC line)?

Any strong feelings on voltage regulators?

Thank you
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Comments

  • audioluvr
    audioluvr Posts: 5,581
    I would check all the ground connections inside/going to the case by loosening them up then retightening. Especially the transformer mounts. If that doesn't work you should probably take it into an electronics repair shop.
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  • SeleniumFalcon
    SeleniumFalcon Posts: 3,764
    Is the buzz/hum coming from the amplifiers themselves? Or, via the speakers connected to them?
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  • tn2036
    tn2036 Posts: 16
    SeleniumFalcon wrote: »
    Is the buzz/hum coming from the amplifiers themselves? Or, via the speakers connected to them?

    No hum from the amp or electronic components (no transformer plate hum, for example). When powered on and not connected, it is perfectly silent

    Hum comes from both speakers when connected to the amp; both amps exhibit the same behavior
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  • F1nut
    F1nut Posts: 50,500
    A hum is one thing. A slight hiss from the tweeters is another, so which is it?
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  • invalid
    invalid Posts: 1,363
    I know you said no source but is it just the amp and speakers hooked up or is there a preamp in the chain?
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