V76 Choke Recipe

[StarTrucker]

I read up on the V76 threads here on the forum and wondering if anyone has the recipe for the V76 chokes. If not a recipe, does anyone have specs for the laminations or bobbin dimensions? Could 3d print some, but would rather buy some bobbins if they're available.

 

[Evertide]

Ask Haufe , they made / make the originals...

 

[gyraf]

Afaik, no one makes the originals, for a long long time..?

..like the input transformer..?

 

[TimG]

Like these?

 

[Evertide]

Afaik, no one makes the originals, for a long long time..?

..like the input transformer..?

Like Tim showed Sowter , Haufe if asked ( a very modern prices... )

 

[StarTrucker]

Yeah but it would be inappropriate to ask a manufacturer to send me their specs so I can wind my own version of their product. Should have been clear in the OP that this is just for me (and others who are interested) to wind our own.

Didn't consider Haufe for the full units, though, so thank you for that.

Anyone have the dimensions of the lams and bobbin, wire specs, etc.?

 

[Bonnie1]

Afaik, no one makes the originals, for a long long time..?

..like the input transformer..?

Oliver Archut made re-issues of all the V and U series transformers and inductors from 1996 to 2014. Currently Atelier Magnetics, repairs/ rewinds the originals. In the future after other priorities... AMI will be producing these again. The CT V72/1 and BV 511 are likely the most labor intensive transformers ever produced, and command a hefty price. Oliver did share information about V/U series transformers over the years on various forums.

AMI/TAB-Funkenwerk
-dmax

 

[gyraf]

Yeah, know these, but arent these modern "adaptations", i.e. not really like the originals other than in coarse functionality? And at least some of these "recreations" are full of it imo.

I was under the impression this is why there is no current production V76 that acts like a real one, no matter how esoteric price is asked..?

/Jakob E.

 

[Murdock]

The original were wound on M42 cores (Bv.514) and EI48 cores (Bv.515) as far as I know.
I think the Bv.514 is something around 28.000 turns with 0.06mm wire divided on three chambers.
And the Bv.515 around 20.000 turns with 0.07mm wire divided on three chambers.
The lamination properties are not that important as the gap dictates the permeability.

 

[Bonnie1]

Yeah, know these, but arent these modern "adaptations", i.e. not really like the originals other than in coarse functionality? And at least some of these "recreations" are full of it imo.

I was under the impression this is why there is no current production V76 that acts like a real one, no matter how esoteric price is asked..?

/Jakob E.

Not sure where this idea came from, it's however wrong.
Oliver wound them just like the Originals. The Mu-metal enclosures have a few less layers, so the transformers can fit in a 1-RU chassis. Attached is a pic, (L - R, OG BV. 511, AMI BV. 511 rewind, AMI BV. 511 Bobbin w/windings, OG CT V72/1, AMI CT V72/1 Bobbin w/windings)

 

[StarTrucker]

The original were wound on M42 cores (Bv.514) and EI48 cores (Bv.515) as far as I know.
I think the Bv.514 is something around 28.000 turns with 0.06mm wire divided on three chambers.
And the Bv.515 around 20.000 turns with 0.07mm wire divided on three chambers.
The lamination properties are not that important as the gap dictates the permeability.

Yes! Thank you!

 

[StarTrucker]

The original were wound on M42 cores (Bv.514) and EI48 cores (Bv.515)

Is M42 an outdated size? The only thing I can find on the internet is E42 size bobbins. Before I go any further, am I right in assuming that these are codes for standard sizes?

https://en.aet.com.pl/BOBBINS-AND-ACCESSORIES/E-BOBBINS/E42-21-20-BOBBINS

Ei48 bobbins seem more available

 

[Murdock]

Is M42 an outdated size? The only thing I can find on the internet is E42 size bobbins. Before I go any further, am I right in assuming that these are codes for standard sizes?

https://en.aet.com.pl/BOBBINS-AND-ACCESSORIES/E-BOBBINS/E42-21-20-BOBBINS

Ei48 bobbins seem more available

It's definately not that common anymore. But I think you can still get some. At least here in Europe.
The numbers I gave are NOT from originals. These are just guesses and information from other people. But I think you can take them as a starting point.
I got two chokes with the following specs:

21.000 turns with 0.06mm wire on 3-chamber M42 core but with smaller gap. I was lucky to find these cores and I don't think you can get them anymore. This choke has 400H @100Hz and has a DCR of 10k Ohm. With normal "standart" gap you need more turns. So I think the original is on standard M42 core with more turns. It also has higher DCR than mine. As there is only 3.6mA flowing through this choke the gap doesn't need to be that big.

The other one has 18.000 turns with 0.071mm wire on 3-chamber M42 core with "standart" gap size. It has 250H @100Hz and DCR of 6k5 Ohm.

Do you have a winding machine which is capable of winding this fine wire?

 

[StarTrucker]

The winding isn't a problem but the materials are.

Anyone have a source for low volumes of EI laminations (ferrite or audio cores)? Found a source for bobbins but with 100 qty minimums. USA source is ideal but happy to go European if they have better options.

 

[StarTrucker]

found a post from CJ in a Neve thread

He said :

"You can get lams from Heyboer and Edcor if in the US.

A few permalloy shapes on evilbay."

 

[My3gger]

Try this company, they used to sell various Fe EI and UI lams in small quantity:
https://www.trancerieemiliane.it/en/trasformatore.php#
Some Chinese sellers on Alibaba sell EI/UI Ni lams treated according to standards.

 

[Disco Volante]

Italtras.us in Italy are very helpful in spite of terrible english, and ships fast.
Don't use a lot of chokes myself, but usually a tad bigger core is not a bad thing..
Good luck