Okay let's talk Beyer Dynamics Transformers

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jeroddumas

Well-known member
Joined
Jun 19, 2004
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264
Location
georgia, USA
Since everyone will be recieving their transformers soon, lets talk about how we are going to be using them. And the results you got. What circuitry, zobel networks, etc. How do you like the sound. I will start. I am using mine 1:10s in an api 312 clone circuit. The board is a copy of the original. I am liking the way it sounds so far, although I haven't done any serious recording with it. I will reply more after I do a couple of sessions with it.
 
Good idea, this is promising to become a nice thread.

Just one remark: let's try to keep signal to noise ratio here high.
In other words, we could probably avoid quite a few questions by diving into the catalog first:
http://home.hetnet.nl/mr_7/66/chickennerdpig/FILES/BeyerDynamic_AudioInputTransformers_catalog.pdf

That Beyer-numbering system may look a bit cryptic, but hey, we managed to order those TXs, so finding the relevant tech-info in that catalog should be doable as well. We could of course freely talk about the interpretation; that is allowed here :wink:

OK ? Then let them come those experiences :thumb:

Peter
 
sorry for the assumption that I would be understood... and the noise I added doing so :oops: (need some hours of extra sleep really urgent),
I missed the beyergrouporder thing completely and was wondering how much a 312 compatible trannie costs. I'll shut up for now. My apologies
 
[quote author="tony dB"]sorry for the assumption that I would be understood... and the noise I added doing so :oops: (need some hours of extra sleep really urgent),
I missed the beyergrouporder thing completely and was wondering how much a 312 compatible trannie costs. I'll shut up for now. My apologies[/quote]
Please don't apologize :thumb: . And I didn't want to &%$-up this thread by flaming at all non-relevant stuff, just a little suggestion to have a look at that catalog for the various details. And this thread is for & of everyone
here, not mine.
Those TXs seem nice, weren't expensive (especially not when from the Kubi-order, but still, new @ full price they're not insanely priced either:

http://www.electricsound.com/PRIJSLIJSTEN/Prijslijsten_2005_PDF/Beyer_trafos_2-5-05.pdf )

I guess their only drawback is their relatively smaller signal handling-capability, but pads are easy & they're said to distort nicely.

Bye,

Peter
 
It's ok Peter, no harm done :wink:
Thanks for the prijslijst!

I remember talking to Jakob about a guy in Denmark (who visits Feedback Recording Studios every now and then) who mixes tru a nice board (EMT Vintage) with Beyers on the line inputs inside. Would like to find out wich ones exactly those are.
 
[quote author="tony dB"].. mixes tru a nice board (EMT Vintage) with Beyers on the line inputs inside. Would like to find out wich ones exactly those are.[/quote]

The trick with the beyer input transformers in pro-level equipment is applying an attenuator in front of it - this both raises the input impedance, presents lower impedance to the transformer, and avoids overloading. The only minus is that you need some gain after it - but in all but the tube circuits, clean line-level gain is cheap.

I haven't anything on the EMT's, but here's the NTP179-160 - working the same way:

http://www.gyraf.dk/schematics/NTP_179-160_Compressor.PDF - see page 12

Jakob E.
 
thanks Jakob, will ask mr TM what type of desk it is,
maybe I can find out a little more that way.
 
[quote author="dukasound"]Hi
Anyone have some details about zobel network for Beyers :?:
Duka[/quote]
Sorry, I don't get this. I've seen your alike question somewhere else here and answered there's info in the catalog. Nevertheless now here's that question again. Have for instance a look at page 11 of the pdf linked above, it's all there. It isn't in the form of the usual Zobel (R+C in series), but when you're asking for a Zobel it sounds like you want to even out frequency response. Which is exactly what those described R & C (in parallel, '//') do. If I sound harsh then apologies, it's not meant that way. If I sound confused, then yes, that's what I am about that repeated question. Maybe I don't understand what you're looking for ?
 
I'd like to try Beyers in positive feedback zero field circuit which also uses resistors in front of transformer. Here's a link to a Lundahl LL6404 (a very small line input transformer) datasheet where you can find the details:

http://www.lundahl.se/pdfs/datash/6404.pdf

The R3 is selected usually so that it equals the static (DC) resistance of secondary.
 
[quote author="mhelin"]I'd like to try Beyers in positive feedback zero field circuit which also uses resistors in front of transformer. Here's a link to a Lundahl LL6404 (a very small line input transformer) datasheet where you can find the details:

http://www.lundahl.se/pdfs/datash/6404.pdf

E: It's not actually told there but the R3 is selected usually so that it equals the static (DC) resistance of secondary.[/quote]
Sounds like a good idea. :thumb: As I understood it this will
make those Beyers contribute less of any bad or pleasant sonic nastyness.
PRR scanned something from a book a while ago, see this thread:

http://www.groupdiy.com/index.php?topic=4864
Over there, note though that those zero-field TXs are still quite big (line).

Bye,

Peter
 
I found this Zero-Z (or Zero Field) circuit in a Finnish diy hifi equipment book (Tee itse HIFI-laitteita):

ZeroField.gif


It uses the TR/BV 351 005 003 transformer, and the gain of the transformer + the first stage is 40 dB. So if the signal overdrives these stages you will need attenuating input resistors. The circuit is a little bit different than the one (8.35a) from the zero-Z.PDF (in the linked thread).
However, the formula seems to give reasonable values also in this configuration.

To get the saturated sound you could maybe use a DPDT switch (or relay) there which converts the circuit to the regular non-inverting amp circuit.

E: Not a DPDT but might work, don't want to know what happens when the switch is in in-between position (so a shorting rotary switch might be preferred here).

Link: link


-Mikko
 
It's interesting to see what transfromers Beyer were using for balancing their FET condenser microphones:

beyer%20dynamic%20cv710%20pre-amplifier%20-%20inside%20and%20socket%20wiring.jpg
 
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