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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
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.
Post removed 
ablang OP
165 posts
 
Well, I said I'd post again if the thing worked--and it does. Even the usual quiet transformer hum is reduced to practically nothing, my TT strobes at the steadiest speed I've seen, and sound has improved subtly but noticeably--better resolution of low-level detail, a slightly tighter bottom end, and improved soundstaging, especially front to back. The EMI/RFI filtration has a good bit to do with all that, I'm guessing. It's the only AC cond I've tried, but I'm pleased--it works, it's cheap, and it's a tank. Thanks for the leads, one and all.
mrjstark
1,112 posts
 
Hi,
I have also a problem with my 2nd system.
Noise/hum in both spks. but a specialy in left.
Disconnected everythig but amps and spks, still there.
Used power stabilizer, quantum 800, PS ult. outlet and
Granit Audio Ground Zero. Nothing helps.
It is a real pain in the neck. By adj. gain on Supratek preamp I get it down somewhat but not 100%.
I am giving up now.
Was thinking about running new line from the basement but not sure if it is going to help.
I am not sure if any of you guy have any ideas how to fix it.
Thanks

P.S
Sorry for coming in without knucking.

Mariusz
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.
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