On Thu, 10 Jun 2004 12:35:51 +0100, "Wally"
wrote:

Trevor Wilson wrote:

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.

All I need to do is find one...


Side by side is fine, AFAIK. Then lay the next winding on top.

Yup, that seems doable.


**Sure. As long as you can drop your lathe down low enough in speed,
I don't see a major difficulty.

Just timed it - 10 turns took 18 seconds - 30-odd rpm.


Big wire demands very low winding
speeds.

Should be okay - it's quite torquey.


Thin wire requires enormous care.

That'll be the fiddly bit, then. My thinking is to rig up a reel in front of
the lathe and feed the wire on by hand while wearing cotton gloves.


**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.

I'll see if I can track it down.

I used (back in the '60s) in a place where we had an old chap who
wound transformers for us. He was some sort of wizard - we would give
him a spec with plenty of different windings and voltages (or
impedances for audio) and the next day we would be handed a work of
art.

I remember his technique, and I had many a chat with him about it. The
first windings would go on very slowly, and he would guide them
tightly alongside each other with a piece of polished wood. Each
winding would then be hammered down. He explained that it was
transformer death to allow an air gap in there - it would make the
windings buzz. Each layer was topped with kraft paper, then the next
was started.

I tried fitting the laminations once, and when I had fitted as many as
would possibly go into the gap, he took over and fitted another three.
"More buzzing, I'm afraid" he said.

Finally the whole thing went into a vat of molten lacquer, a lid put
on and the vat was evacuated. It stayed there for about two hours.

So don't be put off, but don't forget the bits of wood and the hammer.
Oh, and take some time to plane a piece of wood that fits snugly
through the centre of the former while you are doing all this,
otherwise you will smash it.

d
Pearce Consulting
http://www.pearce.uk.com

The Maplin Millennium 4-20. EF86 input, ECC83, two EL34s in a PP ultralinear

OK - if you can solder I'll give you an easy circuit which will sound much
better, more headroom and a lot less sensitive. You just need to change the
front end. Drop me an email. Andy

=== Andy Evans ===
Visit our Website:- http://www.artsandmedia.com
Audio, music and health pages and interesting links.

Attempting to produce a valve amp down to mid-fi prices, is doomed to fail

Not exactly true - attempting to produce a valve amp with mediocre componants
will result in a less than great sound, but not all audiophile componants are
expensive. Mains trannies - isolation toroids/low voltage toroids (cheap, RS
etc)
PSU chokes - Maplins 10H 100mA £7
PSU Caps/cathode bypasses - motor run polypropylenes, e.g. LCR £5-10
Coupling caps - Russian teflons £2 ea bulk
Input valves 6J5G £10, 12B4 £5 (USA) or any of 6N30, 5687, ECC99, 6SN7 etc
Resistors - Holco 1W
Output valves for PP: 2a3 £15+ each Edicron, 6L6 bulk buy on ebay £3 ea etc etc
OPT Maplins 6.6K £30
Put that lot together and you have serious audiophile gear on a very low
budget.
I agree that if you want to sink money into Lundahl iron you will be writing
out big cheques, but you can get into the ballpark with well designed RC amps.


=== Andy Evans ===
Visit our Website:- http://www.artsandmedia.com
Audio, music and health pages and interesting links.

Don Pearce wrote:


Finally the whole thing went into a vat of molten lacquer, a lid put
on and the vat was evacuated. It stayed there for about two hours.

The winder I know paints lacquer on every layer before adding the paper,
he says that even immersing under a vaccum can still leave gaps in the
center of the coil.

Part of why it takes him so long to do one coil.

--
Nick

Andy Evans wrote:
Attempting to produce a valve amp down to mid-fi prices, is doomed to fail

Not exactly true - attempting to produce a valve amp with mediocre componants
will result in a less than great sound, but not all audiophile componants are
expensive. Mains trannies - isolation toroids/low voltage toroids (cheap, RS
etc)
PSU chokes - Maplins 10H 100mA £7
PSU Caps/cathode bypasses - motor run polypropylenes, e.g. LCR £5-10
Coupling caps - Russian teflons £2 ea bulk
Input valves 6J5G £10, 12B4 £5 (USA) or any of 6N30, 5687, ECC99, 6SN7 etc
Resistors - Holco 1W
Output valves for PP: 2a3 £15+ each Edicron, 6L6 bulk buy on ebay £3 ea etc etc
OPT Maplins 6.6K £30
Put that lot together and you have serious audiophile gear on a very low
budget.
I agree that if you want to sink money into Lundahl iron you will be writing
out big cheques, but you can get into the ballpark with well designed RC amps.



Sorry, I meant to mean commercial production. DIY I agree you can do
quite a lot on not so much.

--
Nick

Andy Evans wrote:

The Maplin Millennium 4-20. EF86 input, ECC83, two EL34s in a PP
ultralinear

OK - if you can solder I'll give you an easy circuit which will sound
much better, more headroom and a lot less sensitive. You just need to
change the front end. Drop me an email. Andy

Tried three addresses, but no joy - tonal at blueyonder.co.uk should get to
me.

Cheers,

--
Wally
www.artbywally.com
www.wally.myby.co.uk

"Wally" wrote

snipped for the moment

I'll have a browse at these as well (although I doubt I'd be after
quantities greater than two). If I pursue this beyond looking at specs and
schematics, it would be for the purpose of building a single-ended triode
jobbie - something with a cleaner sound at higher volumes than I get
presently.


:-)


'Homebrew Triode Fever Grips UK Audophiles' on Reuters then....??

I haven't had a chance to read this most interesting thread properly yet,
but if you are considering this route I wouldn't hesitate to recommend Phil
Ramsey of http://www.bluebellaudio.com/ for bits and bobs at a *very*
reasonable rate including Hammond iron at decent prices, if you decide not
to roll yer own. (Audio Note as well, I gather, for those with deep
pockets....??)

Nick put me on to him and he's been superb so far. He promises he can do
everything - down to trannie fixings and hole punches - that anyone might
need for a build. My bits haven't arrived yet (not due for a day or two) but
the guy's 'interested' and very helpful.

If anyone does contact him, mention this ng - he didn't seem aware of it and
was pleased to hear there are still some genuine enthusiasts (idiots) about!

(Might get a 'group disount or summat!! ;-)

"Mike Gilmour" wrote


Good deal Keith - we'll look forward to seeing interesting unusual scope
traces via the website :-)


The way I see it, it's a two-stage thing:

1) Get a dot on the screen

2) Get it to move about a bit.....

;-)

Keith G wrote:

The way I see it, it's a two-stage thing:

1) Get a dot on the screen

2) Get it to move about a bit.....

3) Try and show something useful.


--
Wally
www.artbywally.com
www.wally.myby.co.uk

In message , Wally
writes
Keith G wrote:

The way I see it, it's a two-stage thing:

1) Get a dot on the screen

2) Get it to move about a bit.....

3) Try and show something useful.

4) Realise you haven't a clue what you're looking at and play with
Lissajous (sp?) figures for a while 'cos it looks cool.

--
Regards,
Glenn Booth