imput transformer mod for tube preamp

[janusz konar]

I have my Sony sra-2 tube preamp (from a reel to rell recorder) and love it dearly. Unfortunatly, I have to use short cable lenghts because of unbalanced inputs.
I plant to balance input with a transformer. People say Cinemag CMMI-10C also Jensen JT-115-KE are good for tube preamps. Anything else on the cheap?
Im not a tech but I have one who will do it for me. What should I be aware when matching trafo to the circout?
Are there any other ways to balance inputs so I can use longer (10-15m) cable lenghts? Like this type of thing - Hosa XLR Female - 1/4" TS Adapter MIT-435 LoZ Mic - HiZ Line Transformer | eBay

regards

 

[ecc83]

http://www.oep.co.uk/pdf/X187B.pdf
^ That is probably the best bang you will get for your buck. The Hosa traff looks very much like the cheap ones that our Maplin sells. They are err, ok but will probably give losses at frequency extremes.

Sowter uk are also a very old and well regarded transformer firm, bit pricier than OEP.

Since valves are not known for very low distortion I doubt if it is worth spending out on any esoterica!

Dave.

 

[janusz konar]

http://www.oep.co.uk/pdf/X187B.pdf
^ That is probably the best bang you will get for your buck. The Hosa traff looks very much like the cheap ones that our Maplin sells. They are err, ok but will probably give losses at frequency extremes.

Sowter uk are also a very old and well regarded transformer firm, bit pricier than OEP.

Since valves are not known for very low distortion I doubt if it is worth spending out on any esoterica!

Dave.

Thank you for info,
Where can I buy it? Is it gonna change sound much? I really like the preamp sound and will get more expensive trafo if nesessery.

 

[ecc83]

Thank you for info,
Where can I buy it? Is it gonna change sound much? I really like the preamp sound and will get more expensive trafo if nesessery.

The OEP traff hits 0.5%thd at +3dBm at 30Hz it will be far better than that mid band and +3dBm is 1.55volts, not likely to get anywhere near that with any mic or musical source I know of! (in fact 1.55V would almost certainly overload the input valve.)

In any event put the transformers in a metal box and XLR it, best of both worlds? In fact if you put a jack on the secondary you would have a handy passive DI box!

Dave.