Haufe line out transformer

[victordascalescu54]

Hi,
I just owned a pair of Haufe RK 430 transformers from a WSW / Siemens PM-2TV dual line driver / mic pre

I intend to use them as Line out from my SRPP preamplifier (my line stage is ECC82 equped) going balanced to the power amps.
Unfortunately I did not found anny specs about them.
Can someboady give me a clue?

 

[Osvaldo de Banfield]

Perhaps they are custom manufactured, Siemens do/did it several times. With a VOM, you can try identify the windings, and with an audio oscillator you can measure inductance, turns ratio, leakage inductance, etc., by your own.

 

[victordascalescu54]

Perhaps they are custom manufactured, Siemens do/did it several times. With a VOM, you can try identify the windings, and with an audio oscillator you can measure inductance, turns ratio, leakage inductance, etc., by your own.

I suppose modules are custom made as you say but the transformers are standard.
You are right suggesting to check by an audio generator but using VOM to identify the windings can induce remanent saturation into the core.
First I'll wse my wim bridge to get some inductance and winding ratio but for the DC I have to think twice.
Nevertheless I sow many other Haufe transformers specs but this one not...

 

[Osvaldo de Banfield]

You are right suggesting to check by an audio generator but using VOM to identify the windings can induce remanent saturation into the core.

The current in a VOM is very little, and also the voltage, so remanence seems to be not a problem, imho.

 

[victordascalescu54]

I just faund those two inside, unfortunately no specs again.
They are RK 492

 

[bbp]

I just faund those two inside, unfortunately no specs again.
They are RK 492

Normally, you can measure ~20ohm and 1H-2H inductance on a 600 ohm winding; 100-500ohm and 50H on a 10K winding.

 

[victordascalescu54]

Normally, you can measure ~20ohm and 1H-2H inductance on a 600 ohm winding; 100-500ohm and 50H on a 10K winding.

Thanks, my warry was about injecting DC and cause saturation of the core.
I shall get a try with my wim bridge for inductance and resistance but precautions shall be taken for winding raport as I shall use a low impedance signal generator.

 

[bbp]

Thanks, my warry was about injecting DC and cause saturation of the core.
I shall get a try with my wim bridge for inductance and resistance but precautions shall be taken for winding raport as I shall use a low impedance signal generator.

Another normally
No DC offset (> a couple millivolts) is allow for a permalloy core transformer like this. Coupling capacitor or DC-servo driver is recommended to driver this transformer.

 

[Mark Tillotson]

That's when its operating to avoid saturation. For measuring the dc resistance of the coil you don't care about saturation.

 

[victordascalescu54]

That's when its operating to avoid saturation. For measuring the dc resistance of the coil you don't care about saturation.

Thanks, I was waried about saturation being remanent after measuring dc rez.
In fact I must be interested abtesmation ratio and in/out impedance in order to find the best setup.
I asume, the big one is line transformer and the small one is the stepup which the seller pretend to have 30 dB amplification.