• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Buzzing Edcor transformers

So I did have Edcor send me the insulator pad for my very loud power transformer. Before installing this insulator pad I actually measured the noise as 27.5dB from a foot away!

As you can see from the attached pictures it appears the pad was incorrectly designed as it does not fit the transformer. I had to cut up the rubber to get the wires to fit. It’s also possible that Edcor sent me the wrong insulator pad for my specific transformer.

It was a real pain to install!!! The entire time I was installing I was cursing myself, thinking this insulator would not do anything.

Sure enough though, even though the pad looks terrible (see finished installed pic) it does indeed actually works. The buzz is dampened. I can now sit in my listening position 8’ away from the transformer and not hear it at idle.

So the bandaid solution to a poorly designed/manufactured transformer does seem to work…
 

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Antek supplies a shoulder washer to insulate the bolt. Even without that, there's a chance if the paint isn't chipped - there's only a fraction of a volt, so it doen't take much insulation.
About 1 year ago, I bought the higher-grade Antek transformer shield without knowing exactly how it was supposed to mount to the chassis and avoid the shorted turn. When I received it, there was no shoulder washer to insulate the bolt. I decided that I must either: (1) use a nylon shoulder washer and regular washer (difficult to find in that size) to insulate the central mounting bolt from the chassis; OR (2) use an insulating pad - rosin paper, dampening material, rubber pad, whatever - to ensure that the case never touches the chassis. The rubber pad on the inside of the case is for deepening and protection of the transformer and its windings; it does nothing to prevent shorted turn issue.

Perhaps I should contact Antek to ask them to send me the apparently-missing shoulder washer but I am doubtful that they can and will do that. I guess no harm trying, so I will do that and post my experience here
 
About 1 year ago, I bought the higher-grade Antek transformer shield without knowing exactly how it was supposed to mount to the chassis and avoid the shorted turn. When I received it, there was no shoulder washer to insulate the bolt. I decided that I must either: (1) use a nylon shoulder washer and regular washer (difficult to find in that size) to insulate the central mounting bolt from the chassis; OR (2) use an insulating pad - rosin paper, dampening material, rubber pad, whatever - to ensure that the case never touches the chassis. The rubber pad on the inside of the case is for deepening and protection of the transformer and its windings; it does nothing to prevent shorted turn issue.

Perhaps I should contact Antek to ask them to send me the apparently-missing shoulder washer but I am doubtful that they can and will do that. I guess no harm trying, so I will do that and post my experience here

Apparently the way those covers work is that the center post is a fraction of an inch longer than the case, creating an air gap between the cover and the chassis. But a lot of people seem to feel this is risky. It shouldn't be difficult to find a nylon shoulder washer, Amazon carries them and a good hardware store will have them.
 
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Thanks for the review! The anti vibration mounts I've used seem to do the job - not 100% but you can only hear the noise close to the transformers.

On Edcor's site they say "It helps mitigate the vibration a transformer might produce at certain times". How about all the time!
 
transformer vibrations are non existent in my traffo builds. Why?
because I made sure that the lamination stacks and the bobbins are a tight fit...
and add to that, I dip the whole assembly in a vat full of air drying polyurethane varnish..
the process takes about 30 minutes....
 

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