• 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.

New build: Loftin-White 6BM8 SE


2019-01-13 9:33 am
Just finished soldering the last wire. Too tired, will attempt power-up tomorrow.



Good luck. Fingers crossed the first power up goes well. You may need to play with the triode’s plate or cathode resistor to get the pentode bias right.

Have you seen TubeCad’s article reliability upgrades?

Loftin-White Amplifier

A nice upgrade when yours is up and running might be to implement the simple current limiting transistor version. I actually built his inductor version recently.

What’s up with the 100k resistor at the pentode’s cathode?