mic output transformer bv8 gotham version

edit

Try Oliver Archut over at PSW (Klaus Heyne's Mic Lab). He seems to know a shit-load regarding Neumann, and I remember him discussing the BV8 (does its design not originate from a transformer used in the V2 rocket??? I can't remember.)

Have a look.


Roddy

The picture looks to be one of Olivers transformers. I have a few.

hey roddy - how are you doing - any new projects on your side?

i read the thread http://recforums.prosoundweb.com/index.php/m/158137/0/?srch=bv8#msg_158137
which is in fact very interesting.
my question was meant in a more "practical" way - did someone already build his own mic output transformer, and where did he/she gets the materials from?

-max

gus, it´s michael wagener´s attempt of the copy of a bv8.

It looks like Olivers work I wonder if he makes them?

http://recforums.prosoundweb.com/

[quote author="ioaudio"]hey roddy - how are you doing - any new projects on your side?
[/quote]

Hey Max, I'm doing good - I've just moved down from Scotland to London for a new job which is good fun.

I've got a few projects on at the moment, but they are nothing new! I'm hoping the equipment I can use at work will help me speed up. I'm thinking of getting back into ribbons again as I haven't been experimenting much with that recently.

It's good to see you are enjoying your microphone related stuff - I enjoy reading about it. I've got too many mics and need to focus on preamps for a while.

edit

absolutely shameless bumb²

Do you have the dimensions of the transformer shown?

mu-metal, Germany: http://www.marchandise.de/global/index.php

thanks jacob!


-max

I have a original BV8 but it was one of those made for the American market U47 having a lower output

http://www.box.net/shared/it78oktw8g
http://www.box.net/shared/cb4i0txk4g
Where can I find more information about the BV8 windings,what are the primaries and secondaries,etc
The closest I found in my search here was one of Ioaudio's posts but any information from the above pics would be welcome.
I put this thing in the backburner but I got interested after the recent BV8 discussions and grp buys.Planning to use Dale's M7 and ef12 maybe.Any suggestions welcome

it´s the same transformer, just hooked up differently.
see this schematic:

edit: the transformer from codered is a special bv8 version with half of the secondary turns

i myself have wondered about winding my own trannies...
i guess for first timers its easier to use other transformers for the iron.
You can recylce the scraps and such and wind yourself. You should be able to find info about this on the web.
as far as winders go, there are ways to make your own.
When it comes to the ratios and such..i dont know any info on that really.

http://archive.ampage.org/articles/5/gadc/288380/DIY_Transformer.html

that link is a post with a ton of links for reading up on making transformers.
its mostly about tube output transformers, but most of the theory is the same

haha - thanks - but meanwhile i know :green: look at the date of my questions

[quote author="ioaudio"]it´s the same transformer, just hooked up differently.
see this schematic:[/quote]

Thanks for the pinout -that was a big help.
The transformer is the same outside ,but the windings were different.
Some info here:
http://recforums.prosoundweb.com/index.php/mv/msg/15724/222341/0/#msg_222341


I believe all the Gotham issued U47s & 48s had this after a certain date.Trying to find out what exactly the differences were.
Also just below the G.Neumann sign it says

1300 - 0.07
100 -0.35

do you know what it means?

ahh i see - could you provide a pic from the bobbin marking?

neumann often printed the turns count and wire diameter on their bobbins:
1300 turns 0,07mm diameter wire
100 turns 0,35mm diameter wire

so yes you are right its the special version, it has half of the turns count on the secondary - a 1:13 instead of 1:6,5 ratio...


if interested contact me for rewinding it to original specs.

[quote author="ioaudio"]ahh i see - could you provide a pic from the bobbin marking?
[/quote]

Sure..

http://www.box.net/shared/0eqyfko00c
http://www.box.net/shared/mvhqzm5ss4

if interested contact me for rewinding it to original specs.

Click to expand...

I really want to do it but would like to ask some questions before doing it.Mind if we do it on the same thread or start a new one?
edit: just found that the thread title itself has been changed..brilliant!
I heard that Gunter and Mike Castro use a different ratio to match the non Vf14 tube's impedance.Would that give any benefit.
I am positive I wont be getting a Vf14M in my lifetime.Gotta do the best with what we have.
I assume you'll be using the same bobbins and lams- what about the copper winding ..how much contribution do they have towards the sound

[quote author="ioaudio"]1300 turns 0,07mm diameter wire
[/quote]

Holy shit : you look at it and it'll snap
stole that line from drpat :green: