Cary Audio SA 200.2 SE power amp (latest version)

@yowser

Did the buzzing eventually become louder with yours? Try running your amp for several hours like some 6 or 7 hours of playing music non-stop and see if the buzzing gets louder and becomes really loud to the point where it’s audible from a listening position (8 to 10 feet away from speaker) and was distracting from listening to music. That’s what happened to mine couple days ago but only on the right speaker (right channel). The left speaker remains dead quiet. It’s bizarre. It started out as faint buzzing on the right speaker (very faint) almost inaudible unless if I put my ears right up against the speaker. I literally had to get super close to the speaker (right speaker) in order to hear the buzzing.
I’m going to send it in to Cary Audio so that they can take a look at the issue and will hopefully address it.

I never had buzzing issue with my Classe Sigma class D amp. I’ve had this amp for almost 5 years now and not a single issue. I’m keeping this amp just in case if the Cary SA 200,2 ES amp keeps getting me buzzing issue.
But I like the SA 200.2 ES better, more musical than my Classe Sigma class D amp. I would love to upgrade to the new Classe Delta Stereo power amp (class A/AB amp) but it is $14k to $15k. it’s way out of my price range and will be overkill for my speakers. I’ve heard the Classe Delta Mono monoblock amps (class A/AB amp) before and they are stunning but cost $25k/pair.

I had the prior non-SE version SA-200.2 and it was pretty quiet, did not hum. Nice amp. I reluctantly sold mine to go back to mono tube amps.  

Before you ship it out, make sure to plug it in to a comletely different wall plug, on a different circuit (if you can), use a different (back to stock) power cord, and different interconnects (or swap R to L), different speaker cables/connectors if you have them. Some basic troubleshooting might be worth giving a try before you send it out. Best of Luck.   

@dilatante 

I turned on my amp yesterday morning and let it run about 10 hours with no music playing, then played music during a normal session of about 2 hours.  During the day (no music playing) there was a faint buzz that would sometimes change to a faint hum -- audible from up to 2 feet to less than 6 inches with the grills off (it fluctuated).  It was never audible beyond 2 feet during the entire 12 hours, and usually audible only within 1 foot .  So no, it never increased during under these conditions. IIRC about 20 years ago I had a Parasound amp that was humming and one side of the amp was noticeably warmer than the other.  Parasound repaired it under warranty but I don't recall what was repaired.

try using balanced connections if you can

@avanti1960 

I always use XLR balanced analog interconnects throughout.