Transformer in Trouble?

[dmt]

While I was cleaning up my setup tweaking it and getting ti to sound quieter I discovered that one of the power transformers is making alot of noise and vibrating. There is still a humming noise and vibration present even if the fan is unplugged. Not good. It sounds loudest behind the graphic EQ of the amp; if it put some upward pressure on the chassis it stop humming, but the vibration is still present. Feels like it could be the output transformer or the smaller one directly behind it. The sound it makes is identical to the large transformers in the building. I live in an old old building with very large, ineffeciant transformers from at least 40 years ago. This play used to be a Raytheon Missile Factory. I discovered the noise at my friends place, cause the practice space at his house has really sh!t wiring.

I have run the amp with a THD Hotplate attenuator for the 4 years that I have owned the amp. I remember reading someplace that having a resistance load (as opposed to a reactive load) on the amp can be damaging to the output transformer. What are the signs of transformer failure and is there some way I can check if my transformer is dying? Whats the cost of a new one. granted I know it will change the sound of the amp if I do have to get a new one installed.

I do run the amps on as clean of a line as I can get it. I have a APC battery backup unit that I use for a line regulator. It should in theory give the amps a nice clean signal. I need some help with this one.

 

[Blueracer]

I had a similar problem with a power transformer in a Traynor amplifier. The sound was kind of a buzzing sound. The cause in my case was that the varnish covering the laminations had deteriorated. This allowed the laminations to vibrate and make the annoying buzzing sound.

A search of the internet yielded the following advice which was to take a hammer and give the transformer a good wack. Apparently this was a trick used by TV service men in the 50's and 60's. I tried this using a rubber mallet and magically the sound went away. Unfortunately it did return. My final solution was to find the offending laminations, scratch out the last portion of the weathered varnish and then wedge in a thin piece of wood. I cut the wood off flush with the surface of the transformer and then covered it over with some black nail polish. The amplifier has worked noise free ever since. Hope this helpful in some way.

 

[dmt]

Power Tranny: 561110
Smaller silver transformer: 550381 : EIA606-036
Simulclass : 562004 :EIA606-108

 

[Elpelotero]

how's the electricity in the building? have you tried the amp elsewhere?

 

[Blueracer]

BTW the bell end housing can make the same annoying buzzing sound. Make sure that the screws securing these housings have not loosened and if they have tighten them. I wouls also check that the screws securing the transformers to the chassis are tight. Again hope this is helpful in some way.

 

[dmt]

I have not tried it on a different circuit in this building. All of the buildings here have these old transformers that hum very loudly. I imagine that the power here is shitty based on the buildings age.

I noticed the hum at my friends practice space. He says it has pretty **** wiring. It was worse there.

Why would the trasnsformer vibrate? Also, what does the smaller silver transformer do?

 

[Gabriele Barbaraci]

Transformers are subjected to magnetostrictive phenomena, they vibrate because the magnetic field generates small deformation proportional to the frequency, 50-60Hz, from where the vibration.

 

[domct203]

Also, what does the smaller silver transformer do?

Maybe I missed it, but which model amp is this?

Depending on the amp’s configuration that small transformer is either your reverb transformer or it’s being used as a choke. If you don’t have reverb, then it’s a power supply choke.

http://www.aikenamps.com/index.php/chokes-explained
Dom