• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Manual for the Counterpoint SA1000?

Manual seems missing, but the phono stage is pretty straightforward.
Two 12AX7A gain blocks, with passive RIAA in between.
The input V1 uses grid leak bias (R2) for higher gain, hence the input coupling capacitor (C1).