• 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.

Simple diy tube tester

It's an interesting breadboard device but not a tube tester IMO. Being able to listen to the tube and optimize the output on the wave form like he did are very powerful features!
Too bad you need a complete instrumentation complement to put it to work.