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How deadly is transformer hummm...

Hello Folks,

I recently collected a lightly used (less than 50 hours) Dennis Had - Inspire - "Fire-Bottle." Within some few days, I noticed a humm emerging from somewhere within the chassis of the unit. As the unit was sold in "perfect" condition, I found the humm startling. Mind you, I've discovered absolutely no evidence confirming the sound is compromised; I mostly hear the sound within a couple feet of the amp, when the surrounding environment is silent.

This amp truly is a work of art. Nevertheless, I am now dealing with this 'humm' sound. I bought an Emotiva CMX-2 as a way to deal with DC offset, and this has not impacted the situation to any detectable improvement. Perhaps there is a slight improvement, but negligible. What to do?? Should I just relax, shake it off, and assume the amp will live well, or a down-the-road transformer replacement will simply become part of my experience with this amp? Should I put pressure on the seller to "right" the situation? He claimed, as I asked him, that it was the quietest amp he's ever owned. His add boasted that the fire-bottle exceeded amps from Pass Labs, a Cherry Amp, and one other that escapes memory. The seller has presented all of his communication in the manner of friendly professional etiquette. 

Your thoughts are appreciated. 
listening99
listening99 OP
172 posts
 
@atmasphere how tight? I see the four screws from the top, so they are accessible from above the amp. Why remove the bottom panel?
listening99 OP
172 posts
 
@mrdecibel this is done inside the amp, covering the entire transformer, from inside the chassis, with dynamat? 
brownsfan
1,508 posts
 
Listening99, the easiest way to detect a bad tube is to replace them one at a time, provided you have spare tubes.   Microphonics can be detected by gently touching the tube.  If you get more than just a soft thump, it could be a faulty tube problem.   Reading more on this thread, it seems more likely you have a loose transformer.  Follow atmospheres advice on fixing it.
atmasphere's avatar
atmasphere
11,753 posts
 
I see the four screws from the top, so they are accessible from above the amp. Why remove the bottom panel?
If the screws are loose, the nuts on the bottom might spin when you try to tighten them up.
mrdecibel
3,060 posts
 
@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.
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