Transformer question

[HollowState]

I have purchased a pair of SE 10K ohm outputs supposedly made by Handwound transformers. I've searched the web to no avail. Who and where are they? Does anyone have any experiance with, or info on, this make? Thanks, Victor

[sorenj07]

it looks like the website is defunct. unfortunately it looks like it was a pretty sketchy enterprise while it was around - check out the following info:

http://www.audioasylum.com/scripts/t...ubediy&m=38539

http://www.prodigy-pro.com/forum/viewtopic.php?t=5243

http://www.diyguitaramp.com/parts.html

http://www.diytube.com/phpBB2/viewto...e5e8793e5c608e

[tubelab.com]

Handwound Transformers was one of a few companies ran by a ripoff artist in Pensylvania. He started out selling transformers on Ebay and later from his web site. His early transformers worked very good. I have a pair of 10K SE transformers that were made for 845's in my 845SE amp. They sound good and have excellent frequency response. It took me 3 months of complaining to get the transformers. Friends who bought his early transformers also said that they worked good.

I bought a set of push pull transformers about a year later. They suck. But that is better than most people got, which was nothing. Many people sent him money and received nothing in return. Your transformers could be good, or they could suck, only testing will tell.

There have been at least two threads here involving Handwound Transformers. They were not complementary.

[HollowState]

Gentlemen,
Thanks for your speedy replies. I've read all the posted links and this guy sure sounds like a dirt bag. But that's not my reason for asking. I got these from eBay off a seller that bought them years ago, and never used them. They're the 845 type like yours Tubelab. I wanted to ask them a couple of questions.

They are unused but when I pick them up, I can hear the bobbin and winding assembly move slightly on the core. Now I've taken apart a lot of transformers in my time and know that there is usually a wooden wedge or two that keeps the bobbin tight.

There is a paper that came with the trannys warning against removing the end bells saying that the laminations were critically aligned. I know there's an air gap between the E & I pieces, but upon close examination I cant see any visible spacer. I also know that sometimes the gap is in the middle E lamination only.

It will be a while before I use these in anything. And I wonder if I'll be plagued with a noisy winding on certain notes. But for now I'll leave them alone. When I do get to using them and have a problem, I'll open them up then. It can't be all that esoteric and I know enough to not disorient the steel.

Any other comments will be welcome.

Thanks, Victor

[Miles Prower]

Originally posted by HollowState
They are unused but when I pick them up, I can hear the bobbin and winding assembly move slightly on the core. Now I've taken apart a lot of transformers in my time and know that there is usually a wooden wedge or two that keeps the bobbin tight.

Yes, SOP.

There is a paper that came with the trannys warning against removing the end bells saying that the laminations were critically aligned. I know there's an air gap between the E & I pieces, but upon close examination I cant see any visible spacer. I also know that sometimes the gap is in the middle E lamination only.

This is BS, taking off the end bells will do no such thing. It's usually a real b**** to get the lams apart if the xfmr is made at least half way decently. That admonition sounds like they have something to hide. If you take the bells off, and the lams just fall out, then they did a very lousey job of putting it together. I'd check that out very carefully before putting it in service.

It will be a while before I use these in anything. And I wonder if I'll be plagued with a noisy winding on certain notes.

Thanks, Victor

At this point, I'd bet you can count on it. From what you describe, it sounds like that xfmr was made without the benefit of potting or impregnation. Count on loose windings and a buzzy xfmr.

[tubelab.com]

I have not taken mine apart due to the same warning. If you look at the construction of these transformers, you can see that the "gap" is the spacing between the "E" lams and the "I" lams. It would seem that there is no spacer in these transformers. The only thing controlling the gap width is the bolts on the end bells. It looks like someone set the gap and tightened the bolts. I don't know if the gap was set correctly, or just swagged. It does appear that loosening the bolts would allow the gap to change.

Most transformers that I have dissected use a spacer to set the gap. I do not see one here. I have dissected one of the push pull transformers, and what I saw was not pretty. Lots of Kraft paper and yellow tape, no varnish.

Neither of my transformers made any noise when rattled. However both make noise when driven hard with a load resistor attached. One is much louder than the other. The sound peaks at different frequencies. Both are above 1 KHz, although I don't remember the exact frequencies.

None of this matters in normal use because the sound coming from the speakers is FAR louder. My amp makes 40WPC (845 in A2). I would be more concerned with 1100 volts insulated by paper, tape and wire that is clearly marked "600 Volts". I have been using my amp for over 3 years with no issues yet. I have played my guitar through it well into clipping without failure.