It's me again (of the mu-metal core aspirations), moving slowly but
surely. It's taken a while but I have the winding machine together--the
tubes I bought new are now somewhat-vintage! (last year?) Due to a
computer crash a while ago I lost all my tube web links; what do you use
for insulating winding layers and where do you get it? Same material for
power and output xfmr's? ~~~~~~~ reply: (take
out the eighty-fourzzz)
~~~~~~~~

If I have sheets of polycarbonate lying around, I use them.

Otherwise I use 24# paper.

--
Gregg t3h g33k
"Ratings are for transistors....tubes have guidelines"
http://geek.scorpiorising.ca

DougC wrote:

It's me again (of the mu-metal core aspirations), moving slowly but
surely. It's taken a while but I have the winding machine together--the
tubes I bought new are now somewhat-vintage! (last year?) Due to a
computer crash a while ago I lost all my tube web links; what do you use
for insulating winding layers and where do you get it? Same material for
power and output xfmr's? ~~~~~~~ reply: (take
out the eighty-fourzzz)
~~~~~~~~

For mains transformers, 0.2mm mylar sheeting cut to fit neatly between the
cheeks of a bobbin
is OK, or perhaps the 0.8mm electrical grade cardboard.
The thicknesses should be in accordance with your country's official
standards, and you should have a copy
which you have studied well to understand the need for correct isolation
between
mains and the amp you are making.

For OPTs, mylar is also OK, and 0.5 mm should be used between P&S windings,
to give adequate insulation for the B+ from speaker secs which always should
be grounded.
between layers of primary, use 0.05mm mylar.

Mylar is a polyester material, and very plentiful and cheap.

Better, but way more expensive and difficult to work with is teflon.

The teflon has a slightly lower dielectric constant, and thus capacitance
between P&S windings in OPTs is less.
Polyethylene, or polythene has even lower dielectric constant,
so C is effectively 1/2 that of mylar, but it has a melting point at around
120C
whereas mylar is at 200C+ . Polythene should only be used in OPTs, which
rarely
will run hot unless a sustained fault is present with a tube which is
saturated.
Active protection against excessive tube current should be present in *all*
tube amps.
Curing a varnished transformer for 5 hrs at 150C using polythene is
impossible,
so for OPT, wax impregnation can be used for OPTs.

For more tranny info try my website at
http://www.turneraudio.com.au/htmlwe...ersupplies.htm
http://www.turneraudio.com.au/htmlwe...utputtrans.htm

Companies which supply winding wire for motor rewinds will often stock all
you need to
wind your own trannies.

Patrick Turner.

DougC wrote:

It's me again (of the mu-metal core aspirations), moving slowly but
surely. It's taken a while but I have the winding machine together--the
tubes I bought new are now somewhat-vintage! (last year?) Due to a
computer crash a while ago I lost all my tube web links; what do you use
for insulating winding layers and where do you get it? Same material for
power and output xfmr's? ~~~~~~~ reply: (take
out the eighty-fourzzz)
~~~~~~~~



I use high temperature stuff with a
trade name of "Pyrolam" in different thicknesses.

"NOMEX", 10 mil and 15 mil works great.

"DougC" wrote in message
...
It's me again (of the mu-metal core aspirations), moving slowly but
surely. It's taken a while but I have the winding machine together--the
tubes I bought new are now somewhat-vintage! (last year?) Due to a
computer crash a while ago I lost all my tube web links; what do you use
for insulating winding layers and where do you get it? Same material for
power and output xfmr's? ~~~~~~~ reply: (take
out the eighty-fourzzz)
~~~~~~~~

"NOMEX", 10 mil and 15 mil works great.

Nomex and sometimes a little mylar tape to hold it in place while your
winding.

DougC wrote:
It's me again (of the mu-metal core aspirations), moving slowly but
surely. It's taken a while but I have the winding machine together--the
tubes I bought new are now somewhat-vintage! (last year?) Due to a
computer crash a while ago I lost all my tube web links; what do you use
for insulating winding layers and where do you get it? Same material for
power and output xfmr's? ~~~~~~~ reply: (take
out the eighty-fourzzz)
~~~~~~~~

----I think I will just go the paper route--use brown kraft paper for
the main, a few layers, and tissue paper for the layering. I had heard
of newer materials but can't find anyplace right off that seems
especially eager to sell any of their supplies. The first attempt I
suspect may not go well, I will be pleased if it is useable at all. I
don't plan o trying to impregnate it until I can hear it first.

----One other question: I have planned a SE with one 12AX7 feeding a
pair of EL84's (per channel). I notice that some SE amps run their
(multiple) output tubes all to one OPT winding. I had planned to use
separate windings for the two tubes, hadn't really thought about it
until now... Assuming I won't want to be able to pull one of the tubes
to cut power anyway, which way here is better? Run all the output tubes
to one winding, or have separate windings for each? Does it matter?
~

On Wed, 21 Jul 2004 18:33:41 -0500, DougC wrote:

----I think I will just go the paper route--use brown kraft paper for
the main, a few layers, and tissue paper for the layering. I had heard
of newer materials but can't find anyplace right off that seems
especially eager to sell any of their supplies. The first attempt I
suspect may not go well, I will be pleased if it is useable at all. I
don't plan o trying to impregnate it until I can hear it first.

----One other question: I have planned a SE with one 12AX7 feeding a
pair of EL84's (per channel). I notice that some SE amps run their
(multiple) output tubes all to one OPT winding. I had planned to use
separate windings for the two tubes, hadn't really thought about it
until now... Assuming I won't want to be able to pull one of the tubes
to cut power anyway, which way here is better? Run all the output tubes
to one winding, or have separate windings for each? Does it matter?

A single winding will have lower capacitance.

The classic xfmr insulation is called "fish paper". If Antique don't
have any more, email me and I'll look around.

Chris Hornbeck

DougC wrote:

what do you use for insulating winding layers

Mylar/polyester foil

and where do you get it?

The local supermarket. You can buy it as bags or on rolls - it's used
for oven frying food...

Best regards,

Mikkel C. Simonsen

Mikkel C. Simonsen wrote:
DougC wrote:

what do you use for insulating winding layers


Mylar/polyester foil


and where do you get it?


The local supermarket. You can buy it as bags or on rolls - it's used
for oven frying food...

Best regards,

Mikkel C. Simonsen
Yea but would that be FOIL-covered? Hmmmm... dunno about that. I can
get foil-mylar balloons also, but wasn't going to use them either! --The
plain cooking bags might go though, if that's what you mean. I asked at
the local electronics shop and one fellow there said drafting
polyester/mylar, sold at art or drafting supply stores--and teflon tape,
at most hardware stores. HE said he did not know of anywhere locally (in
St Louis) that carried transformer or motor rewinding supplies at all.
He assumed SOMEWHERE in the area did, but the small area shops he used
to know of had all stopped because the calling for such jobs has pretty
much disappeared.
~~~~~~

DougC wrote:

The local supermarket. You can buy it as bags or on rolls - it's used
for oven frying food...

Yea but would that be FOIL-covered?

No, the rolls I can get here are just polyester film with (easy to
remove) aluminium at the edges.

Best regards,

Mikkel C. Simonsen

"Mikkel C. Simonsen" wrote in message ...
DougC wrote:

The local supermarket. You can buy it as bags or on rolls - it's used
for oven frying food...

Yea but would that be FOIL-covered?

No, the rolls I can get here are just polyester film with (easy to
remove) aluminium at the edges.

FWIW in USA mylar tape is everywhere in different names/forms & teflon
tape is in every hardware & plumbing supply house. There's no need to
revert to kraft paper & when it was used, it was usually first
varnished or otherwise impregnated which is a PITA. But the OP
appears (a few posts ago) to not know the difference btw PP & SE
operation, so maybe he is getting ahead of himself thinking about
building xfmrs - someone help him out?