Battery Powered Line PreAmplifier

The simplified schematic in Fig. 1  uses the  T.H.D. Cancellation Technique. We can see which the upper cathode resistor in the SRPP is lesser than the lower one.

The distortion is very low for a power supply of 24Vcc. The minimum approaches the 0.1% when Vout is 1.4 Vout(rms). The E188CC tube  produce better sonic results than ECC86.