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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

Showing 2 responses by three_easy_payments

three_easy_payments's avatar
three_easy_payments
2,097 posts
 

SET amps can inherently be a bit hummy but should not be to the point you can't enjoy the music. I've read reviews of $20K Air Tight 300b's where the reviewer noted hum from the power supply.  With the Line Magnetic 805ia (for example) there are hum pots in the corners for each channel for the output tubes. The reality is more efficient speakers and SET amps can bring out more noise and the LM amps have been designed to help counter this effectively. Sometimes new SET amps will be a little hummy, and then mysteriously it goes away so you may give it some time to settle.

 


three_easy_payments's avatar
three_easy_payments
2,097 posts
 
Also if the amp only has 50 hrs on it it's possible the hum may go away to some extent with further run-in.  My Line Magnetic amp hummed slightly at first but after 60 hrs or so it pretty much went away except during the initial 10 minutes of start up.  Once it gets warm and presumably the transformers expand a bit everything becomes dead quiet.
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