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Re: DCR of S&B LCR RIAA coils ?

194.208.88.198

Brian,

thanks for the quick reply! So the modules seem to be the correct 600 Ohm ones. I wonder how they manage the low freq loss which will occur with such a high DCR, is there a circuit diagram of the internals available ? Are there any means of compensating for the DCR loss ?

Back to my specific problem. A friend of mine uses these in a phonostage. In order to get additional gain he introduced a 1:4 step up transformer (Lundahl 7903) between LCR RIAA and next stage's grid.
The LCR module is properly loaded with 600 Ohm at the output. The secondary of the 1:4 is unloaded. So this transformer adds no additional load to the LCR (at least at mid frequencies).

With the addition of this step up, the output voltage of the RIAA module drops by about 9-10dB, whilst the input voltage of the RIAA is not affected. In fact there should be virtually no loss at the RIAA output.

I've used this configuration with Tango and other LCR RIAAs with no problem.

Anybody an idea what could cause this ? The guy lives far from me, so I can only diagnose through emal and phone. The 1:4 is properly wired and works fine when disconnected from the RIAA. It just seems that the RIAA cannot handle the additional load if the step up is wired in.
But again it should be fairly high impedance....

Any help is welcome

Thomas

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