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Discussion Starter · #1 ·
I did a search, but did not find this specific problem addresses.


I have been trying to isolate a ground loop.


During the process I have stuck my ear in a few places I don’t usually stick it. One place I listened is the amp itself.


I have two amps, a Cinepro 3k6 and an Adcom 5800. When I stick my ear on the top of either amp, I can hear a buzz. I believe it is a 60 Hz buzz. Not a loud noise, and I can only hear it when I am right on top of the amp. Both of these amps have fans, but I do not believe it is the fan I am hearing.


Is this normal? Transformer noise or something like that?
 

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You got it - transformer noise.


If you're the tinkering type (and know how to work safely inside AC powered components), you can effectively decouple the transformer from the amplifier chassis, and this will greatly diminish the hum you're hearing.


If you subscribe to the notion that vibration can negatively affect audio gear (I don't want to open that can of worms, but I do encourage you to read about the topic and perform your own experiments to draw conclusions), decoupling the transformer from the chassis can subject the other components inside the amp to much less vibration.


Once again, you do need to understand what you're doing. A good example of a gotcha is that if you have a toroidal transformer, and you decide to tweak it (many folks will replace the steel bolt with a non-ferrous one), if the bolt were to somehow contact both the top and bottom of the amp chassis, you will find that the bolt may wled itself to the chassis. This is because there will be a voltage difference between the top and bottom of the bolt, and since there's very little resistance in the amp chassis, the result is a large amout of current passing should the bolt contact both top and bottom.


Watch out for those charged caps, too! Know what you're doing or stay out of the chassis.


-Tweak
 

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Discussion Starter · #3 ·
I am the tinkering type, but may be reluctant to try and decouple some rather large toroidal tranformer from the chassis.


If the sound I am hearing is transformer hum, I assume this would not be the cause of the speaker buzz/ground loop I am trying to kill.

Quote:
Watch out for those charged caps, too! Know what you're doing or stay out of the chassis.
I hear you about caps. There was an electrical engineer where I used to work who would charge up this big cap, then discharge it on all sorts of materials. Some interesting results. :eek:


Thanks Tweak for the info.
 
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