Can anyone help me with diagnosing an electrical problem somewhere in my system?

How old is the house wiring?First thing I would look at is the receptacle your plugged into and make sure ancient wiring and $.10 cent plug are’nt melting down from the current draw of a power amp...Next I would,immediatlly upon smelling odor unplug everything and confirm smell is indeed coming from inside amp.Next I would look to see if something is causing a dead short in your amps.The only thing I can think of would be an energized neutral backfeeding into the amp...

Years ago, I had a McIntosh MC275 amp fail (under warranty) with a loud pop through the left speaker. The system went dead immediately but there was the acrid smell of burnt electronics. The company repaired it without issue and it has worked fine since then. However, for the first year or so, it always produced a slight odor. It finally went away. Apparently a tube shorted and destroyed a few components in the process.

I suppose the same is occurring with your repaired amp. If it is playing normally, I would give the odor a chance to diminish on its own. Of course if the odor is getting strong, I would shut it down and contact the repair facility at once to report the problem.

Hopefully not a problem!

Best, Fred

If nothing else was connected to that outlet other than the amps, I would look at the wall receptacle and see what sort of shape its in.

It could be a simple as a loose screw on the back of the receptacle, which could be heating it up.