Old Haufe Trafo

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rafafredd

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Joined
Jun 3, 2004
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Location
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Just thought some of you would like to see an opened, old Haufe trafo!

opened_Haufe_trafo.jpg


It seems to be a MuMetal toroid.
 
You are probably right CJ. Maybe it´s not a good trafo at all. Have you ever seen a ferrite toroid signal transformer? I don´t think so. It should be just a plain power transformer. I didn´t considered that.

Well, at least I end with a nice mumetal case.
 
Hi,

Haufe call their toroids RKxxxx for 'Ringkern' which meas torroid in german... A you sure it's a tranny? Not a choke f.e.? The leads look quite odd to me.
Tell me the type-number, I have an old catalogue and can take a look!

best regards

Chris
 
Also, it would be nice if you can find specs for:

Haufe:

RK 662
RK 538
ST 644-90478

Neumann:

Bv 09442
90358
09423
90501
90492

A you sure it's a tranny? Not a choke f.e.? The leads look quite odd to me.


Yes. It has three separate windings with the same DC resistance. Close to 50ohms. So I think it may be a 1:1/1 line output transformer or something like this.

Do you think it´s a Mumetal Toroid or plain Ferrite?

I ask this because I have other RK transformers here that works really nice, so I didn´t expected those to be just a ferrite toroid transformer. I may be wrong thought...
 
Thanks for the tip, Kubi!

It seems that a lot of those trafos have a pretty low source impedance, like 50ohms or less...

I should use it as line output but I´ll have to go with a beefy output stage. This is, if they will not work as a mic input! Anyway, I don´t think it will...

Do you think an API 2520 wolud drive a 50 ohms transformer?
This 90358 is a 0,5/0,5:2,2 ratio (12.5+12.5:250 ohms) as I could understand from the german datasheet. The recommended load is 1kohm, but I bet it will work just fine with modern 10k ohms inputs.
22dBu max should be plenty also.
 
Hi, the only one I could find in my list was the ST644 and this is the data for it:

EL19-core
1:6-transformer
resistance: 13 Ohms : 410 Ohms
"Angewandte Anpassung": 200 Ohms : 7,2 kOhms
Frequency-response: 20 - 20000 kHz

I guess that "Angewandte Anpassung" means the conditions under which it shall be used.

regards

Chris
 
[quote author="chriss"]Hi, the only one I could find in my list was the ST644 and this is the data for it:

EL19-core
1:6-transformer
resistance: 13 Ohms : 410 Ohms
"Angewandte Anpassung": 200 Ohms : 7,2 kOhms
Frequency-response: 20 - 20000 kHz

Chris[/quote]

Should make a nice mic input transformer to grid!
 
Yeah it would be nice if someone could Post the specs for the "old" Haufe trafo's as used in the Neumann, Telefunken, Siemens.... stufff.
I mailed Haufe a few times with no response. :sad:
 
So, I´ve also got info from haufe.

It seems that this trabsformer pictured on above is really a signal trannie and specs pretty well:

1:1+1

600:2400 ohms

22dBu

20-30 kHz, +-0,5dB

THD 0,3% at 40Hz

Pretty nice, no?

So, do you think the core is mumetal to get this figures?
May be a nice SRPP output trannie!

Do you think it would work with low level mic signals?
 

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