Stopping buzzing transformers

[seven]

I'm finding a few transformers for my older gear are starting to buzz. Two things I noticed last night. One is a wall wart (easy to replace if needed) and the other is a funky old rack mount delay with an internal transformer.

I can pull the transformer from the delay and replace it, but is there anything I can do to fix the current transformer?

I understand what makes the noise, I've just never gone about messing with transformers to fix a problem like this.

Would putting a ring of epoxy putty around the coils help?

[tINY]

It might.

Though the buzz could be from the iron laminations separating....



-tINY

[space2012]

Originally Posted by seven

I'm finding a few transformers for my older gear are starting to buzz. Two things I noticed last night. One is a wall wart (easy to replace if needed) and the other is a funky old rack mount delay with an internal transformer.

I can pull the transformer from the delay and replace it, but is there anything I can do to fix the current transformer?

There are 2 kinds of 60Hz hum.

the ground loop hum that affects audio signals, hard to remove. usually with balanced power like furman it-20 series ][.
&
the transformer 60Hz hum inside equipment,
easy to remove with psaudio.com humbuster3.
theres also other brand but cant remember the name, also has less watts/amperes capability.

[BlueSprocket]

Originally Posted by space2012

There are 2 kinds of 60Hz hum.

the ground loop hum that affects audio signals, hard to remove. usually with balanced power like furman it-20 series ][.
&
the transformer 60Hz hum inside equipment,
easy to remove with psaudio.com humbuster3.
theres also other brand but cant remember the name, also has less watts/amperes capability.

I do believe the OP is referring to the actual mechanical vibration of the transformer inside the chassis. Not 60 Cycle hum in the audio path

Very first thing I'd check would be is the mounting hardware for the transformer has come loose. This can happen over time, especially if its a big transformer.

If nothing is loose then something else is out of wack. As transformers age they actually loose metal, its possible the windings have seen enough metal fatigue that they are vibrating. If the unit didn't always do this I'd go for replacing the transformer. Maybe something with a higher current capacity is possible.

[Matt Syson]

Hi
If your mains is a bit higher than it used to be or if there is significant distortion of the mains (other high power gear taking 'chunks' out of the wavefoprm) then these can make transformers physically buzz. Try also slackening all transformer related screws and then retighten.
If the laminations are exposed then high temperature varnish 'painted' on may help.
Matt S

[triez]

Transformers are clamped together and often lacquered to stop the laminations rattling together from eddy currents. Some transformers have bolts through the lamination stacks, if so you can check to see if they need tightening. Some transformers have a folded metal bracket wrapped around them, this can be crimped a bit tighter around the edges with a pair of multigrips. If all else fails the tranny might need to be re-coated with the correct lacquer to fill the tiny gaps and stop the rattling.

Also, it may simply be that the mounting bolts that hold the tranny to the chassis are loose, so (with the mains un plugged from the wall of course) check all of the bolts and screws for correct tension.

[seven]

Thanks for the replies.

And yes, I'm talking about the hardware itself making the noise. I can not hear any noise coming through on the audio lines of these devices.

Let's consider for a moment the transformer coils are secured. Is the vibration coming from the stack or the coils - or both or either?

I thought it was normally coming from the coils - which is why I thought a wrap of epoxy putty around the coils would help.

[Matt Syson]

Hi
If it is safe to get to the transformer you can 'squeeze' it with waterpump pliers or something to see if that helps.
Matt S