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  3. 1197248387

Transformer hum with AC fluctuations

I was about to buy an isolation transformer (Tripp Lite) in hopes of cleaning up my inexpensive CDP's sound a bit (Tobias's rec on the cables forum), and now I've run into another AC-related problem.

I live in an old, small rural town in PA, and this time of year power demands start overwhelming our grid: our lights dim for brief moments (a second or so) and then come back to normal all evening long. Coinciding with that--and only at high-usage times on the grid--the transformer of my NAD C325BEE has started making a hum that's audible from across the room. The trannie has always hummed faintly (had to put my ear above the amp to hear), but now it's hard being in the room with it. It doesn't come through the speakers or headphones.

I have two questions: is an isolation transformer likely to hum just as much as my NAD's transformer? and is there a better route to cleaning up my AC (the kicker: within a $200 budget)? I appreciate any other suggestions/solutions. Thanks in advance.
ablang

Showing 6 responses by johnmcalpin

johnmcalpin
58 posts
 
Tvad,

Have you used that Channel Islands product? How did you configure it in your system? I've had transformer hum no matter what conditioner I've used.
johnmcalpin
58 posts
 
Thanks, Tvad.

My amp's massive transformers hum from time to time. I've got the amp powered through an Equi-Tech balanced power unit which runs off a dedicated 20 amp line. The hum is definitely audible and varies. It was there in my old place and here in a new house. Plugged into the wall directly or through all sorts of power boxes. But the sound of the amp is still amazing.

A friend who designs and builds large scale manufacturing machines told horror stories of transformer hum, with some folks resorting to hand wiring and other techniques. He said old timers believed some times there was a harmonic built into the transformer through the wiring and nothing would rid it.
johnmcalpin
58 posts
 
It certainly is odd. I figured the Equitech would take care of it, but it's still there. But, and more frustratingly odd, is that it is intermittent. It's a head scratcher.

I also have the amp -- and every other component -- sitting on a Sistrum platform. I wonder if setting it on something else might do the trick.

Don't get me wrong, this amp is amazing and in the grand scheme of my system the hum is a very minor flaw. And while I go through all sorts of system do-over fantasies -- like the one I'm in now -- I know the Zeus is a keeper.
johnmcalpin
58 posts
 
When I first got the amp it sat on a Polycrystal stand for a month or so. I might go back to something like that, or a maple block. Sistrum has been awesome for the speakers and other components. Time to experiment.

Swampwalker, you've got some very sound tips. I kicked around the idea of losening the nuts the other night while I was biasing the tubes.
johnmcalpin
58 posts
 
So I spent part of yesterday thinking I needed a new amp stand and searched out the Symposium and others and decided to make a switch after Christmas.

And then last night not a peep out of those transformers whatsoever.

Talk about audio nervosa!
johnmcalpin
58 posts
 
Same here!
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