Krell KSA 200s ground hum

I REALLY appreciate the ideas! You guys are kinda talking over my head right now. Not sure what was said in the last few posts that I can physically apply or check for a resolution. I need something like :

take your meter, put it here..

look for this…. 

if this is this then it’s probably this… lol

Cool, I had that Amp, the hum was unreal, it would hum Loud when it was off on standby and kick up in the morning when the Mr. Coffee came on. It blew fuses and Tannoy drivers with abandon. Go to eBay and find those amp fuses now. Kicked ass tho.

@strawj said:

I had that Amp, the hum was unreal, it would hum Loud when it was off on standby and kick up in the morning when the Mr. Coffee came on.

If I understand your post correctly the loud hum you heard from the Krell Amp was a mechanical hum from the large Toroidal power transformer in the amp. Large Toroidal power transformers are very susceptible to DC offset on the AC power mains. It doesn’t take much DC on the Line to cause the Toroid transformer to mechanically vibrate loudly either. Big boys like Pass Labs, Bryston, and others manufacturers install DC Blocker circuitry in their power amps that use toroid power transformers... Krell does not. At least they never used to...

Easy fix, buy an outboard DC blocker and plug the Krell amp into it. That should block the DC from getting on the primary winding of the toroid transformer in the amp. Well maybe it will block the DC IF the DC blocker is sized for the VA rating of the toroid power transformer in the amp.

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If I had only known…