Transformer hum - is it normal?

P

PENG

Audioholic Slumlord
Anthem MRX 300 AVR, ear on front panel and ear on the top panel over the (EI core) transformer (which was surprisingly hot...): no audible hum
I am not surprise, my MCA225 is hardly audible too, but don't be so sure about some of their other amps..oops...

Oppo BDP-83, ear ~1" from front panel (only part that is accessible): no audible hum
Those little ones are too small to make much noise anyway. Too bad I could hear the fan of my 95 (from a few inches away) though.

Sadly, one generally cannot expect solid engineering from the so-called high end...

(Obvious exceptions: McIntosh, Bryston, Boulder, Meridian, and like quality-focused firms.)
Exceptions? I just don't want to name any of the high end brands, including the ones you listed but I can assure you I heard some of them at within a few inches from the front plate. Yet I can hardly hear any of my Denon AVRs (especially the old 3805), AV7005 and the low cost and old Yamaha RX-V659 and the GFA-555.

If a unit's hum was audible from a foot away, no question that I'd return it.
Me too! I almost returned one, it was heard from about that distance, luckily that was the only bad one, of all the ones I have owned so far.
 
A

algava

Audiophyte
They all hum because of alternating magnetic forces induced in the metal core, some more than others according to how well they were designed.
The human ear is definetly not the way to measure this noise and compare.
And I don't know who listens to their music 1 foot from the amp, it's more a matter of like/dislike, it should be more or less quiet.
I have never even thought about it and I've gone thru pleanty of cheepo and mid end receivers, I use to repair them for a living.
Al
 
P

pcosmic

Audioholic Intern
They all hum because of alternating magnetic forces induced in the metal core, some more than others according to how well they were designed.
The human ear is definetly not the way to measure this noise and compare.
And I don't know who listens to their music 1 foot from the amp, it's more a matter of like/dislike, it should be more or less quiet.
I have never even thought about it and I've gone thru pleanty of cheepo and mid end receivers, I use to repair them for a living.
Al
The guy who took the stethoscope to an amplifier most probably needs some psychiatric treatment. (A stethoscope?!?!....facepalm).
 

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