Simplistic NJFET RIAA

Member
Joined 2009
Paid Member
Thank you Felipe, but I alredy have some 47nF US made teflons, and I would eventually try some USSR ones.
If you want to "get rid" of a couple of the 23 pcs 15nF teflons, still count on me.

How many caps do you need?

As you no longer have the RC filter on the first and second stage of the riaa amp, any mod you do on the output of the shunts is clearly audible.

Teflon are the best for all situations not only for highs & is a huge improvement in my RIAA. The quality of zobel resistor it's audible?
 
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Joined 2009
Paid Member
Due to the high perfomance I want to do a new single ended Simplistic NJFET RIAA for my MM Linn K9, cart specs:

Output 4.5mV
Compliance 12Cu
Coil Inductance 400mH
Suggested load capacitance 100-200pF?

I have the following NJFET stash:

2SKJ170BL

Units Idss

2 6.60
1 6.63
1 6.64
1 6.65
1 6.66
1 6.67
1 6.69
1 6.72
3 6.73
1 6.74
1 6.75
1 6.77
1 6.78
1 6.81
1 6.83

2 7.67

2 8.16
1 8.71
1 8.80
1 8.88
1 8.98
1 8.88

LSK398BL

1 6.89 + 6.92
1 6.68 + 6.57
1 6.76 + 6.93
1 6.85 + 6.92

1 7.25 + 7.02
1 7.42 + 7.50

1 8.05 + 8.24
1 8.37 + 8.77
1 8.88 + 8.58
1 8.96 + 8.89

1 9.29 + 9.28
1 9.22 + 8.91
1 9.65 + 9.54
1 8.84 + 9.11
1 8.94 + 9.01
1 9.03 + 8.76

1 10.68 + 10.84
1 10.05 + 10.27
1 11.15 + 10.72
1 10.20 + 9.97
1 11.15 + 10.90

1 11.07 + 11.08
 
diyAudio Chief Moderator
Joined 2002
Paid Member
There is the second values table in the PDF with 100R Rs change in first stage for 37dB, also described there. Use your 8.16mA pair in first stage, your 8.88mA pair for second, and your 8.80,8.71mA ones for buffers. I don't suggest load capacitance, I suggest you use only what the TT cable provides and a 100K quality trimmer instead of the 47K load resistor. That will give you many different alignments, very audible for MM cart to tune. Don't be afraid to try steps from 10K to full 100K.
 
Member
Joined 2009
Paid Member
Is this schematic changing R2 100R instead 56R also taking off 50pF Cload, right?

134308d1243470113-simplistic-njfet-riaa-mm-hmc.gif