This is an improved version of the old RIAA amplifier. This one is more true to the RIAA curve. It falls to around -0.5dB at 20 Hz,
else itís pretty flat to 20 kHz. Output impedance is high and should be followed with my line amplifier which has cathode follower
input. If you have low input impedance, add a cathode follower like the output of my line amplifier. The output stage could also
be replaced with a SRPP or mu-follower.