"Wally" wrote in message
...
Trevor Wilson wrote:

Does that mean that the specifics of the lay-up aren't too critical?

**Nope. Any good transformer (and output transformers are more
critical than power) requires a nice lay of the windings. A messy lay
will ensure that the transformer may not demonstrate predicted
performance. It will also reduce efficiency and proper coupling. This
will affect the frequency extremes.

Duly noted. Are there any particular patterns that are preferable, or is a
neat side-by-side lay-up okay?

**Here's where you really should talk to someone who REALLY knows what
they're talking about. Side by side is fine, AFAIK. Then lay the next
winding on top.



Are there substantial savings to be made by winding them oneself?
Any major pitfalls?

**I've never wound one, but, it ain't rocket science. It is more of a
'black art'. Experienced winders are sought after for their talents.
So, I say: Go for it. If you have the time, patience and inclination,
then it could be a rewarding hobby. I have wound a few power
transformers, with a speed controlled electric drill, and normal
workshop equipment. It was not much fun, but satisfying, since I
needed a low profile transformer, which was not available at the time
(early 1970s). Now, they're easy and cheap to obtain. (GRRR)

I've got a little lathe with electronic speed control (and a back-geared
reversible leadscrew) and I've been interested in trying some coil winding
for a while. While I can appreciate the black art aspect, it strikes me
that
working to an established spec should produce a reasonable result. IOW, a
careful build using the right gauge of wire and the right number of turns
should get a decent result that's nearer to the high end kit than the
'cooking' transformers.

**Sure. As long as you can drop your lathe down low enough in speed, I don't
see a major difficulty. Big wire demands very low winding speeds. Thin wire
requires enormous care.



**Just a guess, mind you. You could ask a transformer winder. He/she
might tell you. Look in the Yellow pages (or whatever your Pommy
equivalent is) ...

I believe it's called 'the internet'. :-)

**We're gonna get that internet thingy down here, real soon now.


... and choose a smaller manufacturer and call them up.
You may be surprised to learn that they may even supply all the
materials you need. Or not.

I'll see what I can come up with.

**Good luck. At worst, it will be entertaining. Whilst there are probably
lots of books around, you might try to secure a copy of the Radiotron
Designer's Handbook. I don't have one, but I'll betcha transformer winding
is covered therein.


--
Trevor Wilson
www.rageaudio.com.au