Can moving wire location at circuit breaker reduce hum?

@ptss - Yes, unless it starts to hum instead. 😁 The output of a transformer is going to lack DC, eliminating the hum from your amp but it may just move the problem to the Equitech.

The reason DC causes physical humming is because of the laminations in the transformer. Of course, some transformers are more susceptible than others, but none are 100% immune.

My point is just that if this is significant the OP should do everything possible to eliminate the root cause first.

@jb1 That's interesting.  Was the cooktop 120V or 240V?

OP:  I encourage you to replace all upstream outlets if they use backstabbed connections. Again, not suggesting you spend a lot, $4/$5 per outlet for new, commercial grade/tamper resistant.

So I just looked online at a couple of DC blockers.  You have to be careful as the two I found were rated for 7 A or less.  If you are using monoblocks I am going to guess you are going to easily exceed this. 

My recommendation that you need to have your power evaluated by a pro stands no matter what.

OP: One other thing to consider is, how old is your house?? If those are older outlets or using back-stabbed connectors they need to go.

You can get good commercial grade / tamper resistant outlets for ~ $4 a piece.

So far in this 17 year old home I've replaced 28 light switches and about 20 outlets, including 7 GFCI outlets.  Given how many issues I found I'm glad I did. 

Another question, do you use LED lights on a dimmer switch? Not sure why, but I’ve issues when I used an outlet on the same circuit for a HT receiver.

I have used modern dimmers without a problem, but the older LED power supplies were awful.  The problem is they would only take power from one direction of the AC signal.  If the AC signal goes to +140 V and turns around and does -140V, and you have relatively high impedance on the wiring then you suck down one side, making it +135 to -140 and voila, DC.

OP:

You still need this evaluated, regardless of a dedicated circuit. 

Also, keep in mind they do make dedicated DC blockers that are quite effective.

You did the test kind of backwards. :) 

Turn off all breakers but your stereo.  If your hum disappears then start turning breakers on until it re-appears. If it remains even when the only thing on it is your amps then it's most likely a wiring issue.

Fortunately, the first test, to identify if this is caused by another electrical component is fairly simple.   Turn everything else off in the house. 😀

Flip off every breaker and make sure nothing is left on your circuit but your amps.  If the problem is gone, you know it's something else, and that's my bet, but yeah, it could be a bad neutral.

Here's a great meter to use for basic testing, including Neutral voltages:

https://amzn.to/3y55cdF

@milpai  That's correct but I think you missed that this is mechanical, not electrical hum. 

Mechanical hum comes from DC on the line, not from ground loops.  DC is when the AC voltage is shifted up or down by a DC voltage.  So the AC may be 120V, but it's shifted so it's 0 crossing is no longer 0. 

So, we are talking about a mechanical hum that you can hear or feel at the amp itself, right? OK, that’s a sign of DC on the line.

If you move to another "leg" of the panel it may fix the problem but only if the source of the DC is on another circuit. See if you can locate the source which is often something like LED power supplies or some wall wart somewhere or old dimmer switches. If the problem is on the same circuit as your audio gear then no amount of moving a breaker around will fix it.

If you are sure the source is not on your circuit, then try moving to another leg. Panels alternate legs horizontally, so pick a new location that is off by odd row numbers. 1, 3, 5, 7, etc. If you move horizontally or an even number you will stay on the same leg.

Of course, they also make DC blockers specifically for this purpose.