Cary Audio SA 200.2 SE power amp (latest version)

@yowser 

Just want to recap and follow up with you regarding my Cary SA 200.2 ES power amp. I sent it in for repair to Cary Audio in early Dec and just got it back over a week ago. They replaced the transformer and the input board and it kinda solved the humming/buzzing issue in the right channel but not completely and Cary also claimed that the buzz is still present but very faint and we literally have to put our ear right up to the speaker to hear it and didn’t get louder when the amp was left turned on for a day or so with no music playing. that’s what they said.
 

And when I received the amp back over a week ago the buzz/hum is faint and I literally have to put my ear really close to the speaker in order to notice it. I left the amp on with music playing for some 9 to 10 hours continuously and after 9 hours or so I think the buzz/hum in the right channel (right speaker) became somewhat louder and was slightly audible from my listening position which is about 8 feet away from the speaker but my listening room was very very small and very quiet at the time (it was around 1 am at night), but it isn’t as loud as what it used to be before I sent it in for repair, nothing like what it used to be at all. It’s much better now but doesn’t completely go away.
 

And at least now seems like the occasional dropouts in the left channel has been resolved and I haven’t experienced a single dropout in the left channel anymore since after the repair. 
 

Yowser, try leaving your Cary SA 200.2 ES amp on with music playing for 9 hours straight and see if the humming or buzzing would get noticeably louder. 
Thank you.

@dilatante have you swapped in completely different / better shielded interconnects and different speaker cables just for the heck of it to see if anything changes?

While my SA-200.2 was dead quiet, some other adjacent components can generate this  type of low level noise you are referring to. Worth a shot if you’ve not already checked. One of my former SS amps was ultra sensitive to picking up noise like this, fwiw. Best of luck.

I'm using very well shielded interconnects and speaker cables and power cables. My speaker cables and interconnects are Cardas Clear Reflection and as all my power cables are Shunyata Research Delta NR. 

@dilatante Those should work nicely and a great match with your amp too. Nice. I had the Cardas GC and CR ic cables myself and can truly appreciate what you have there. I did have to get one pair Golden Cross reterminated once.  

So, this slight remaining hum still occurs on the right channel when the rest of the system is off, correct? Does the slight hum out of the right speaker still occur if the interconnects are disconnected and you power on the amp by itself?  And does the hum start out a little louder and quiet down after the first minute or two of power-on?  hmm.. just trying to think through it with you as you already sent it back/forth.  

@decooney 

The slight fain hum is there when all my equipments are turned on. Haven’t tried with everything else turned off but the power amp. But the faint buzz is only audible when I put my ear right up to the speaker and isn’t audible from say 2 feet away. But the other night after the amp was turned on for some 9 to 10 hours straight with playing music most of the time, and after 9 or 10 hours I noticed the buzz became a bit louder.