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

So, it's basically the same method as the two-layer version,
repeated. Does the lay-up of the winding have to be done in some
kind of even pattern, or can it just be wound on to produce layers
of even thickness? You said that the process is difficult to get
right - what bits would be difficult to get right?

**The process is not so much difficult, as time consuming and hence,
expensive.

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.



With valve amplifier output transformers, there is no such
thing as a 'free lunch'. You want a quality amp, you MUST spend the
Quid on decent output transformers.

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)



**Low losses, high permeability, which provide better performance than
regular steel. I don't know about the cost. I would speculate that
around 300% higher than the regular stuff.

Righto.

**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)
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.


--
Trevor Wilson
www.rageaudio.com.au