Hi
Hoefully all is well, but FYI…
I had a similar issue with a very late model, one of the last few made, BAT VK 500 WBAT pack SS amp some years back.
One of the two amps within the chassis had a hum when initially energized. Noticeable. Easily. Within 10 to 15 mins the hum lessend and lessend to near inaudibility within an hour. If you got right on top of it after then you could hear an ever so slight humming.
An ancilliary ground loop made it more e exasberating. Fixing the ground loop did not fix the humming along T former in one of the two amps though. Calling BAT and talking with Victor K his input was something loosened up up inside the channels T former. Somehow. Somewhere.
Victor also said, ensure your gear is on the same phase.
I had several dedicated power lines by then. Still, it hummed.
The hum never intruded into the audio. There was a bit of hash one could hear if immediately next to one of the loudspekars, but a foot or two away and it too was inaudible. Bacon sizziling sort of sound. Grunge on the power line. Adding in some passive PCs helped… but once more did not entirely irriradicate the hum or hash at the squeakers tweeters.
Nothing seemed amiss during listening sessions. The presentation was exceptionally good. Outstanding in fact, and I was running the big VK500 single ended from my preamp… not balanced by then. Formerly, it was being run fully balanced yet still the hum was present then too.
So the proposition was to pay round trip shipping to BAT, or something then close to $180, or live with the humming T former.
As it was not affecting the audio, I kept it for a while longer.
It was then the best sounding rig I had owned. So, I sold it all off and began building another one exclusively with tube monos instead of SS power. Smart, huh?.
What I’m saying here is this…. Unless something is actually affecting the presentation, an outage, audible noise as with a ground loop, its gonna come down to just how pedantic one truly is about their outfit. If I could hear buzzes, or hums from my listening position, I’d have to get it fixed or get rid of it, if I could NOT hear anything from the LP, so what?
As its in an older home with an older home’s wiring there are tons of areas for electrical issues, provided it ain’t in the amp.
If you have hopefully a breaker box and not a fuse box, What I would try is:
1. Switching off every breaker except for the one (S) supplying power to the outfit.
2. have someone then switch each breaker back on and see if there is any change whatever as to hum from the amp, or noise at the speaker (s).
3. naturally, if with all breakers OFF and you still have hum in the amp, and or noise at the speakers with the volume dead low or mutted, then its time to send the amp off to Misassaugua NY and let Anthem check it out.
I’ve had to do that too with an Anthem Processor I owned some years back. They are great folks, but do keep in contact with them so everyone is on point during the assessment and or repairs, so it ain’t sent back with the same issue. My pre/pro came back with the same prob and had to go back again, but then better communication finally resolved the issue which was two fold on my end and one with the pre/pro. My TV provider, my home wiring and an firmware update or reconfig with the pre/pro.
Hopefully, your amp doesn’t weigh 140 pounds shipped.
Best of luck.
