in the circuit shown, a reduction of 20:1. The op-amp is easily powered from the same source that is used to power the vacuum tube heaters. Since the op-amp output is at or near common potential, the ...

It’s a conventional tube amplifier circuit in which the triode is a preamplifier for the pentode power output stage. The pentode is running in class A mode, and the high impedance of its output ...

The pentode is controlled with the pre-amplified signal and acts as a power amplifier ... schematic should be all you need to get started. If you want some more background information about tube ...

One of the first tube amps I ever heard was an MC275 ... and there's now a High Speed Sentry Monitor circuit that automatically turns off the power when a worn tube is detected.

The preamp circuit features a single mother board ... substituting it for a Musical Fidelity kW tube/transistor power amp. The Cayin is less powerful than the MF (40 watts against 750 watts ...