7025 / ECC803S / 12AX7A Tube Phono Preamp Schematic
7025, ECC803S, 12AX7A Tube RIAA Phono Preamplifier Schematic
This two-stage audio preamplifier is intended for use with high-fidelity magnetic phonograph pickups. The overall gain of the circuit is about 150. The circuit is from the RCA tube receiving manual and meant for use with the famous RCA 7025 twin triode. 12AX7A and ECC803S twin triodes can also be used with this circuit. The phono preamp uses a passive RIAA equalization filter.