DIY inductors for B182 and B211

[Batuu]

I would like to wind my own inductors for a 1073 eq. Can anybody give me a hint, where to find a useful bobbin? Seems to be very difficult. Most of the bobbins I found with ferrit core i.e. on farnell have an AL between 2000 nH and 3000 nH. That would mean I need more then 2000 windings on these small bobbins to get nearly 10H like the T1295 has.

Any ideas or is it impossible to do my own inductors for pcb mounting in the dimensions like the carnhill inductors?

batuu

 

[ioaudio]

edit wrong math

here´s a link for lots of ferrites in germany, also higher Al values available:
http://shop.spulen.com/default.php?cPath=41_57_121

you could run into problems with saturation when taking too high Al values.

-max

 

[Batuu]

Thanks for the link.

He max. I can't follow your math. N = sqrt(L/Al) right? I get N = 1825.

For example:

http://www.audiomaintenance.com/acatalog/Transformers_and_Inductors.html

here you can see a picture from a vtb9047. It looks like they use RM-core N48 AL400. Maybe this one : http://shop.spulen.com/product_info.php?cPath=41_91_43&products_id=252

The inductor has 5,11H after this http://www.vintagedesign.halmstad.net/transformer_cross_table.htm

Lets do the math: N = sqrt(5,11H/400nH) = 3574 turns on such a little bobbin?

 

[ioaudio]

yes you´re right - sorry for my math mixup.
i am afraid i also mixed it up my math for someone else on this board too, dont remember the thread.

here on this thread http://www.groupdiy.com/index.php?topic=23964&postdays=0&postorder=asc&start=15
i wound some inductors for the 1073, and i needed about 4500 turns of 0,05mm for the 10H inductor, not so unusual - have a look at the dc-resistances here
http://www.sowter.co.uk/eqinductors.htm

 

[Batuu]

I never found your post ... wrong search ...
but very interesting ... I would need a winding machine otherwise it will become very difficult to count such amount of turns.

In your thread you say something about 50%nickel iron core and its behavoir in satuaration. I can't find cores made from this material.
Your material must have an Al of about 500nH, right? Are they from http://shop.spulen.com/?

I don't want to contest your business, so don't get me wrong. :grin:

 

[CJ]

there is a ton of neve stuff around here,
just find out what everybody has settled on for the inductor source.

 

[ioaudio]

batuu,

dont worry its rather like some kind of a service than a business. i found a couple of the nickel iron material while shopping around in some surplus shops. Al = 500
i can send you a few+bobbins for winding your own.

for the winder just use a counter (search conrad for LCD-ZÄHLERMODUL 7010 4 STELLIG, with max 12Hz it´s good for winding speed up to 700 turns/min) for 9 euro and a motor most important a footswich. you can use a cordless drill, i used a more quiet setup cause i like winding at night (i used a papst motor intended for a record player with a belt drive 1:7)

 

[CJ]

came across this at turner audio:

http://www.turneraudio.com.au/output-trans-winding.html

of wow, this just in from:

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

Caps-Mag Circuits-and....Transformers!
pdf download-use foxit-or adobe 6.00.00.00.00.000.00.00.0

http://www.pmillett.com/Books/intro_Matsch_capacitors.pdf