Help With Buzzing Sound

A look inside of the Hegel H30 SS

Any internet routers or such on the left channel side of the Amp? 

Do you have any RCA shorting plugs? For a test totally isolate the amp from everything. Install RCA shorting plugs on the RCA input jacks on the amp. 

Unplug all other audio equipment from 120Vac power outlets. Everything. 

Power on the amp and check for the buzzing.

Buzzing still there?

Does it sound like this?

60Hz buzz

Like this?

120Hz

If it sounds like 120Hz, good chance a left channel power supply rectification/filtering problem. 

How are you feeding 120Vac power to the amp? A separate dedicated 120V branch circuit? (Dedicated circuit with its own, Hot, neutral, and ground, conductors?) 

  If yes plug the amp into a different branch circuit feed. Check for buzzing.

Still a buzzing sound?

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@thecarpathian  I have checked with AI, but find it very unreliable.  So often the AI answer is blatantly wrong.  Thanks to all who have responded.  It would appear the most likely issue is a failing capacitor.  Everything else has been eliminated.   The sound is there when no signal source is connected, it is not affected be volume when source is connected,  and disappears completely when another amp is switched in.  I guess I start calling around to see if any local repair facilities will look at it.  Cheers. 

@jea48  Thanks for that.  Definitely the 60 Hz buzz.  

Hi , sorry to hear you have an issue.  Off topic but possibly helpful. I recently had an issue with one of my tube mono blocs. At 55 lbs I feel your pain for shipping cost. When I sent my amp for repair I decided to send both. The culprit was a resistor on the phase tube circuit, but they diagnosed tired diodes in the power supply sections of BOTH amps. The other amp sounded fine and I guess until I had a failure I would not have known. I used Pirate Ship at the recommendation of the manufacturer and that eased the sting a bit. Also I’d like to compliment you on your listing room and appreciate the details you posted as I’m looking at acoustic treatments and building my own rack. Thank you for taking the effort to share your hard work. Respectfully, Mike B. 

@buellrider97   Thanks Mike.  I did a very long post a few years ago on building my system. (link on my virtual system) Creeping up on 10,000 views, and garnered some very nice comments.  I'm going to do another words & pictures post on the construction of my new listening room, that was part of a basement development.  

On the buzz issue, I'm a bit embarrassed to say I think it has been resolved.  This morning I took another run at it, just to be sure I had covered every base.  The last thing was to reverse the XLR cables at the preamp to see if the problem was cable specific.  Buzz gone.  Put the cables back in their right place and the buzz is still gone.  So, the culprit seems to be a slightly loose connection with one XLR cable?  When all else has been eliminated, the remaining solution is correct regardless of how unlikely?  Or something like that.  Anyways, thanks again to everyone who pitched in.  Your repeated suggestion to check the connections made me go back to that.  Cheers.