Design for a special MC Prepre needed

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Salas pre-pre
 

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  • Salas Simplisitic pre-pre Low MC 20dBs.jpg
    Salas Simplisitic pre-pre Low MC 20dBs.jpg
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Sure that internal cartridge resistance isn't 5 - 50 ohms? 500 ohms seems very high for any LOMC, and would be quite noisy.. My SPU is 6 ohms and my DL-103D 33 ohms as an example.

Might want to check out the Partridge 977 SUT still cheaply available on eBay - this should be a good match to your cartridge assuming 50 ohms internal impedance. Gain would be 6X or about 15.6dB..
 
No the Internal resistance is 500 Ohm. I spoke with Vandenhul himselve.

This is excatly the problem with this Cartridge. A Transformer will not work. The most of the PrePre will not work too because they are optimized for low resistance.
 
Now I understand the issue.. 😀

I would modify the Salas for 47K input impedance.

Change R2 to 47K, the cartridge source resistance will swamp it from a noise perspective and since it is a fet input there is no significant input current to be concerned about.
 
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