• 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.

changing diodes with 5AR4 tubes

Look before you leap. The 1300 VAC CT exceeds the PIV rating of the 5AR4. So, you can't use a 5AR4.
5AR4 Data Sheet

You could use a pair of damper diodes to replace the SS diodes. Be aware that the forward drop in vacuum rectifiers is greater than that of SS. You will also need additional heater power.

Oh yeah, plates are anodes (SS triangles) and cathodes are cathodes (SS bars). The SS diode symbol indicates the direction of conventional current flow.


2002-08-15 10:16 pm
Indeed you should be able to use the PY500,s. They are reputed to be more reliable in the long term.
However you have to face the fact that you will need two of them, and if my memory serves me correctly - they draw considerable heater current - which might mean a seperate heater transformer. I seem to remember that underrunning them might adversely effect their durability.