Strange buzz issue!


Hello audio friends! I’ve got a weird problem. I have an old ARC D-100B power amp (love the sound of it) and bought an ARC LS9 pre amp to match it with. Nice enough. Connected the LS9. Buzz/hum from both speakers. Consistent (clearly audible from listening position) at all volume levels/sources on the LS9. Crap, the LS9 must be faulty, I thought. For fun I connected the LS9 to two other power amps (Yamaha and Vincent). Dead silent. I then connected an old Yamaha pre amp to my D-100B. Silence. Same place, same cables. So, neither the LS9 nor the D-100B are faulty, but together they, or one of them, cause a pretty loud buzz. I’m going mad here! Any ideas? Thanks! 
teppas

Showing 4 responses by teppas

Tanks guys for all the great advice! I’ll go ahead and try all of you suggestions! Tomorrow, I’ll be off to buy some alligator clips:) I’ll keep you posted. The buzz aside, I feel this is a combo with great potential, especially  for a fan of a bright, fast and detailed presentation, like myself. If I get it right, I plan to settle with the ARCs for my Yamaha NS1000Ms:) Thanks again! 
Ah ok, I’ll try some filter options, I think.
 These two sound so good together I really want to get this sorted Out! Thanks! 
Ok, Thanks:) Yeah, it very much sounds  like a ground loop kind of buzz. I think the plug on the power amp cord has been exchanged (due to change to grounded outlets here in Sweden). I tried connecting the power amp to a DC trap, but still the same problem. But a ”cheater plug” is something else? 
Thanks, I tried both of the above suggestions, but no luck. I today went and bought a hifi grade ground loop isolator (for implementation on the interconnect between pre and power amp). It did the trick! No buzz. But regrettably left me with impaired bass response. Clear sound otherwise, though. Damn ground loops😁🥵