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Filson 216 phono rework, advice please

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I should get French amplifier Filson 216 later today. Only schematic I can find is for Filson 215, I assume its more or less the same.

What I see from schematic is that input ECC83 has cathode grounded (?) and input resistor has been set to 27K. Probably at 1963. it was proper for phono carts those days.

I am thinking to replace 27K with 47K+100 to 200 pF parallel with resistor.

Also I cannot figure it out how RIAA here works, its not as passive eq, its not as feedback line.

Basically I am interested is it enough to put 47K+200pF on phono input (as suggested for my phono cart) and leave everything else as is?

Second, how RIAA here works?

el84_1.gif
 
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