How deadly is transformer hummm...

I have an amp in my collection, a Smart Theater Systems TA 242, which is based on a Hafler design, nicely built power supply, toroid transformer, highly biased in class A, roughly 120 X 2. I acquired this years ago from a movie theater updating it’s gear. A wonderful sounding amp. When I use my otr microwave while this amp is powering a system, the transformer of this beast, starts getting pretty loud, even though the microwave is on it’s own circuit. So, there is some truth to what many are saying here about the effects of ac. @listening.....you might want to try moving the amp to other electrical outlets throughout the home, just to see ( hear ) if the transformer still hums loudly. Again, I feel it might be normal. @wolf_garcia , without burning that beautiful face of yours, lol, do you hear the transformer of your Had chassis ? @atmasphere, are the transformers you use, completely silent, when close up ?Again, hum, from a transformer, is typical, and to some extent, normal, when close up to it. As long as it does not interfere with the music listening.

Humming is the obvious choice, when you do not know the words....lol.....Seriously......The truth of all transformers...... they all hum, radiate noise ( Toroids produce less than E-I core ) and exhibit, some amount of vibration, as well. I believe all transformers should be separated / isolated from the chassis, as the older HK Citation power amps ( the model 12, 16 and 19 ) had / have. I have modded hundreds of transformers from various audio products by isolating the transformers, with excellent results in sq ( from the speakers / system ), and lower noise from the chassis. Rubber grommets, Dynamat, roofing repair tape, cork, as well as many other materials, can be used. Be safe, and well. Enjoy !

@listening99....I am recommending between the transformer ( where the 4 corners mount ) and the chassis ( the screws will go through the damping material / products ). Transformers do get warm ( in your case, the power transformer, not so much the output transformers ), so covering them " completely " is something I do no recommend, but mounting some material on the outside of the transformer can work. I am not sure how some manufacturers ( generally the higher end products), totally encapsulate the transformers ( for reasons I am talking about ), but....they do it. I recommend you do all 3 of the transformers. Keep in mind, rubber bushings or grommets are easily removable, where Dynamat, is a bitch the remove, once applied.

I believe I found a picture, that allows me to understand what atmasphere was speaking about. The power transformer, seems to be " sunken ", into the chassis, but imo, can still be isolated from the chassis, but likely, not with these that I recommended ( I am sorry ). You can use them on the output transformers, with access through the underside, which is necessary with all transformers, as atmasphere pointed out. I would wait to hear from Mr. Had. I am not surprised you hear the transformer in that thing, close up to the chassis, as it is MASSIVE, for that design. As I said, I hear most power transformers in amplifiers, when close up ( with being careful not to burn myself, as pointed out by wolfie )...lol....I will stay tuned to your progress.

What you purchased, that I recommended, should be fine with temperature, as the mounting area, does not get as warm as other areas of the transformer. Additionally, heat rises. I would like to see a close up of the transformer mounting area, as I am curious to see what atmasphere is speaking of. I have not run into a transformer that could not be isolated, but obviously, I have not seen them all. I am sure Dennis Had will respond, will treat you with professionalism and respect, and, will look to help you. Maybe he will suggest sending him, or his servicer, the amp.

@listening99....check out Lowes...item # 198831, model # 88577......rubber flat washer...10 pack....I should have stated " washer ". Sorry. These work great. No need to tighten too much, as you want to keep the integrity of the rubber.....

Wanted to add, I hear most transformers, when I place my ear, against the chassis of amplifiers ( including this Edge unit ), but, I accept this, as they all make noise, as I indicated. As long as it is not amplified, through the system, out to the speakers ( headphones, if that is your thing ). 

@atmasphere I have not been able to find a close up photo of the transformer mountings of this amp, however, I respect your opinion, and feel, it is quite unfortunate. As I have stated, I have done hundreds of these " mods ", and all for the better, in every way. This is an easy thing to do, with the possibility of using longer mounting bolts. Not all rubber is effected by heat in the same way ( engine hoses, auto tires, as an example, as they last a long time, and the transformers do not get as hot as some engine components....this, ime. @atmasphere ...have you, in your amplifier designs, ever tried decoupling of the power transformers from the chassis ? Remembering now, I also had a Krell amp, a long time ago, that had huge rubber shims between the transformer and the chassis. As far as I am concerned, it should be a part of any design....but, I am not an electrical engineer, nor product designer.....just a tweeker, listening, and looking, to improve things my ear / brain can detect, as improvements is sq. My latest acquisition, and project ( an original Edge M8 power amp, prior to Maker Audio ), was so resonant and vibration prone. I took the amp apart, isolated the huge toroid transformer ( a few layers of Peel and Seal ), isolated and damped the heat sinks ( these heat sinks were the most " ringing " I have ever encountered, not what I would expect from an amplifier that retailed for 5K ), damped the entire chassis, and changed out wiring and binding posts. Now, an incredible, music reproducing amplifier, to these ears. BTW.......looking at many other Dennis Had amplifier designs, it looks as though, these rubber washers, can be used.....based on photos. Anyhoo.......Be well.