winding an output transformer

[srinath]

Hello,
I have a dynaco st 70 I am hoping to wind output transformers for.
Could someone point me to a location where such information lives, or post what I need from past knowledge, like x turns of this wire primary and y turns of that size wire secondary.
And any way to improve and get better/more power ?
Thanks.
Srinath.

[astouffer]

This book is a good reference if you can locate a reasonably priced copy. It used to sell for a few bucks...

http://www.amazon.com/Coil-Design-Co.../dp/0859340503

The OPT design calculator works well too

OPT Calucator

[CharleyW]

You might find this useful - diytube.com :: View topic - The A470 OPT, an interesting work of art.

[srinath]

Thanks guys, and, Woweee, that is scary. I think I can wind a trafo, just not sure my first attempt needs to be somehting this complicated and great.
I guess I am buying the trafo I need then ...
Cool.
Srinath.

[Alain Poitras]

Originally Posted by srinath

Thanks guys, and, Woweee, that is scary. I think I can wind a trafo, just not sure my first attempt needs to be somehting this complicated and great.
I guess I am buying the trafo I need then ...
Cool.
Srinath.

Here's a very interesting page about that :

http://www.geofex.com/Article_Folder...es/xformer.htm

But like you said, you are better to buy one, wiring a good output transformer is a real monk job ... It can take hundreds hours of work to do it ...

There is actually four brand new ones for sale on eBay for 113$ + 50$ shipping each, "Buy Now" price ... Here's the link :

ST-70 transformers for sale on eBay

This sale end in 10 days but they already sold four of them since july ... Don't miss that chance. For comparison, a 1650N Hammond transformer 4300 ohms CT 60W about the same size cost over 130$ each + shipping ...

Cheers,

Alain.

[Alastair E]

Ive used Yvesm's 'OPT Calculator' and found it very good, pretty easy to use once you know whats what....

I made a couple of Tx for a 6C33c, Worked out well too....

[flatheadmurre]

Agree with Alastair, Yves calculator works good.

If you don´t have a coilwinder of some sort don´t start winding !!

Build something out of a small motor with footcontrol and a firm chuck for the coil.

You need both hands to wind a nice coil.

It´s a lot of fun when you get going.

Good luck

[TheGimp]

Be sure to get a counter to count turns with.

[dchisholm]

Originally Posted by CharleyW

You might find this useful - diytube.com :: View topic - The A470 OPT, an interesting work of art.

"Wowee" is right!

There is a LOT of thought about coupling and inter-winding capacitance there. I'd sure like to see the designer's notes, and maybe some test results from the initial experiments and prototypes, on that one!

Dale

[quadtech]

Or rig up a diy coil winder. There are some ingenious efforts out there -

DIY Hand-Driller Coil Winding Machine with Digital Counter

The counter on this one by Anthony is from skipping/jump rope!



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