Can anyone name a good company that does transformer work? Mine has a hum issue. Its a 1kva toroidal unit. No longer available anywhere, not even from the OEM. I need a new custom built tranny!

Contact Alden at Heyboer. They are here in Grand Haven Michigan where I live. I have had 4 power supplies built by them and no issues at all. Top notch work.

Heyboer Audio Transformers
17382 Hayes Street
Grand Haven, MI 49417-9305
616) 842-5830

Thanks for the info! I'm going to contact them right now.

What is too much transformer hum? Any hum at all? The power transformer on my ST-70 (new kit, not original) has a hum to it.

This is a 1kva toroidal tranny in a solid state amp (Hafler). When new, it was DEAD quiet. Now, after 17 years, it hums and I can hear it from 12 feet away, if the room is quiet. When playing music, it is not so noticeable unless you are sitting next to the amp.
To my ears, any noticeable mechanical noise is too much!
Heyboer Audio was no help. I have since contacted Toroid Corp. of Maryland. Looks like they are willing to build a "one off" custom design for less than a King's fortune.

Have you tried decoupling your amplifier from the surface (shelf) upon which it is resting? The probable reason you hear the hum from 12 feet away is that the surface is being excited by the vibration and thus acts like a soundboard. You can try "Vibrapod" feet or for an even cheaper experiment, try using 3 or 4 artgum erasers under the chassis.

Charlie

I have had it sitting on a kitchen table in another house, as well as various shelves all with the same result. The transformer is vibrating somewhere between 60hz and 100hz.
Very irritating, to say the least!

One other thought. There should be a foam or rubber disc between the toroid and the amplifier chassis. If this has become brittle or overly compressed after 12 years, then it could be the source of the problem. It might not be the transformer itself.

Charlie