Tamura input transf. from TEAC mixer

[Emmathom]

Hi !
I bought 4 of these transformers with the aim of using them in a microphone preamp. Then I acquired CAPI 2622s and so these transformers remained in their box...

The seller claimed that they were Tamura transformers recovered from a TEAC mixer "model 3" or "M-30" and their primary DC resistance is 150Ω and secondary DC resistance is 6.4KΩ and the AC ratio is 1:10
A link I found searching Google : https://buyee.jp/item/yahoo/auction/l1130908567?conversionType=YahooAuction_DirectSearch

Do any of you have more information on this transformer ref? on its quality? are they suitable for a decent mic pre ?

I read somewhere that to properly measure the ratio, you must inject 1kHz under 100mV (for example) at the primary and measure the voltage at the secondary... but without a scope, I can do that measurement. But I've got REW so I think I could measure the bandwith by injecting a white noise (from smartphone) and plug the secondary straight to my sound card in line input mode (?)

 

[ruffrecords]

If it is a 1:10 mic input transformer then it will need a lighter load than the 10K or 20K line in of your sound card. If it has a high Z instrument input use that instead to get a more realistic reading. You do know that REW has a white noise option in its sig gen?

Cheers

Ian

 

[Emmathom]

If it is a 1:10 mic input transformer then it will need a lighter load than the 10K or 20K line in of your sound card. If it has a high Z instrument input use that instead to get a more realistic reading. You do know that REW has a white noise option in its sig gen?

Cheers

Ian

Ok for the Hi Z input.
I don't know how to "loop" the output of the card to the transformer then back to the card : will check that...

I think : white noise line output 1 > transformer In > Transformer out > input 2 Hi Z

Thank you