A Class A2 amplifier with 845

Photo 1 Details with SV811-10

A Lofthin-White Stage drives the 845 tube into A2 Class for 28 watts of power. The SV811-10 Common Cathode Driver is the core of design. Although this circuit is not conceived for T.H.D. Cancellation, we can obtain a better figure of distortion by varying the 845's grid resistor. Sonic response is astounding.

Photo 2 Tubes Grouping

The  power supply for the Lofthin-White part features a vacuum diode rectifier and a capacitor input filter. An inductor input filter power supply sources the output stage. All caps are in polypropilene film.

Power supplies for D.H.T. are in dc.