Iron learning.

[Tweeker]

Does anyone have any suggestions for learning about transformer and choke design, either online or off?

Im also interested in commentary on iron and things such as magnet wire insulation choice, potting, and so on.

[Brian Donaldson]

Great, Another brave soul to dive into the black art of iron spinning with me. I have a few links on my computer at home that I'll post this evening. I'm ordering the Radiotron Designer whatever book that has a chapter on iron design.

The cost and availibility of 200w SE transformers for 833 transmitting tubes has forced me into this

I may have found a supplier of EI laminations, but they were closed for the holiday Monday. Any other sources will be helpfull

[Brian Donaldson]

Here's 2 sites about output transformers.

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

http://www.diyaudio.8m.com/Ot/out_tran.html

I also found a 100+ page manual on audio transformers that is basicly a cookbook with little theory, but explanations of what makes one not work as it should, But it's on my computer at work Also it's $45.00 and home made and bound and I have no idea if the info is at all acurate. It may be $0.50/sheet toilet paper that's not very aborbant! We'll see what kind of infor the radiotron designer's handbook has when it comes.

[Tweeker]

I have the Radiotron Designers Handbook 4rth ed. in PDF form, Transformers and Iron Cored Inductors is chapter 5. I can email it to persons interested. Email me. 3MB.

A page on a diy double c core transformer for 845SE.

A 2 watt SE diy C core.

Lessons In Electric Circuits -- Volume II Chapter 9 TRANSFORMERS

[tubelab.com]

Forum member "GEEK" has the entire Radiotron Designers Handbook 4rth ed. posted on his web site.

http://geek.scorpiorising.ca/RDH4.html

Pete Millett has several electronics books posted on his web site including the RD3 and a book called Electronic Transformers and circuits.

http://www.pmillett.com/tecnical_books_online.htm

When you figure out how to make a big SE transformer that works, let us know. I have decided that my success rate is much higher making amplifiers, so I have given up on transformers for now.

Did your 100 page cookbook come from David Lucas?

[Brian Donaldson]

It was this

http://www.rgwdesign.com/page0003.htm

Sure sound easy.


I just spent $15.00 for a cd PDF of Radiotron Designer' Handbook 4th ed. Wish Google would have pulled up Geek's site.

[wirstinson]

Ok.you may try this link:
http://www.livinginthepast.demon.co..../vxformers.htm
very interesting.
check also under:
Transformers:
a lot of info,I hope you find useful data.
Saludos.

[Brian Donaldson]

Looks like I'm building a 50 lb transformer. 40 lbs of iron and 10 lbs of copper.

Tell me what's worng with this idea. For testing, I want to put a resistor parallel to a choke + current source across the primary to model the staning bias, and drive the secondary with a SS amp measure some results. I'm trying to avoid playing with full tube amp and 1500 v B+ supply to check the transformers extreme bandwidths. I'f the tranformer doesn't measure up, I may abort the whole mess and go to my 6C33C OTL plans.

[anatech]

Hi Brian,
You know, when something goes wrong with an OTL, it goes really, really badly wrong. I wish you nothing but good luck with this.

-Chris

[Tweeker]

First problem I see is iron loss, that much iron:copper is going to mean more distortion.


From what I can tell, there are two ready approaches to the problem of a 200 watt plus SE transfomer:

1.) Have it wound by a wizard using spendlon wire on an amorphous unobtanite core.

2.) Accept lower bandwidth. It shouldnt take a wizard or exotic materiel to wind 200 watt SE transformers with 8 octaves bandwidth. On the bass xformer accept some HF rolloff due to capacitance. Have the other transformer have it wound more like a 400hz power transformer, sacrifice inductance and accept some LF rolloff. Use less turns of heavier copper taking care to minimize capacitance and core losses. Of course, biamping with 2 833As would be way over the top.