[sdiy] Tube amp problem

[John L Marshall]

Hello,

I believe that the plate resistance is always high; triode, tetrode or
pentode compared to the recommended load impedance.

The only time you reach the theoretical efficiency of 50% is with full
output swing and when source impedance and load impedance match.

Efficiency might go up with a cathode follower circuit. Certainly lower
impedance. Voltage gain is less than one but that doesn't matter in the
power stage. Linearity will be high.

Besides a class project, did we hear what this amplifier will be used for?
Maybe distortion is not an issue.

I still have a fantacy of building a tube power amplifier without an output
transformer. I would use five 6AS7-G tubes in a push-pull totem-poll
arrangement. Look at the plate resistance of this glass jar, 280 ohms.

Take care,
John