• 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.

21kW audio power amp?

Sometimes I come into contact with interesting tubes and I enjoy looking at the data sheet. I knew that this one(ML-7120) was a transmitting tube of some sort, but what shocked me was the inclusion of data for use as a class AB1 AF power amp.

Here is the data sheet:

7120.pdf

Highlights from the data sheet:

Filaments: 7V, 85A. 400A cold.
Max plate voltage: 10kV
Plate dissipation: 12.5kW
Peak grid-to-grid voltage: 4.6kV
Power output: 21kW

Seriously, has such an audio amplifier ever been made?
 
You can modulate lower level stages and then mix them up to the desired frequency, and amplify that. That doesn't produce the best quality of audio.

I've even used severely unbalanced balanced modulators to make crude AM transmitters.

The preferred way to produce AM is to directly modulate the final amplifier stage, and that's what these high power AB1 amplifiers were used for. If you listen to a good high level AM transmitter on a quality receiver with a flat passband, they sound really good.

Lots, maybe most, of the RF tubes were used for high power modulators.

Win W5JAG