• 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.

5C4M / 5Ц4М vs 5AR4 / GZ34

Has anyone successfully swapped in a Russian / Soviet 5C4M / 5Ц4М rectifier in place of a 5AR4?

They claim that it is equivalent, and they're cheap as dirt right now compared to 5AR4/GZ34 which are starting to get ridiculous.