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.
As far as I know it has been used as driver at low voltage (?) and low current. But you need a substantial choke or CCS to load it due to its high Rp and care must be taken with the following stage.