5Y3 & similar tube substitution

[Mars Amp Repair]

Hello folks,
A question has come up lately that I thought I knew the answer to, but now having second thoughts.

Can the rectifier tubes that have cathodes be a substitute for the ones that don't?

ie; 5Y3 (non-cathode) be substituted with a 5AR4 (cathode variety) Or similarly sub a 5AR4 for a 5U4...etc. of course being cautious of the higher output

thanx, glen

[MWJB]

As long as the replacement doesn't exceed the 5VAC current draw of the PT (5U4 draws 3A)...& recto can supply DC current requirements...standby might be nice with anything other than 5AR4 & 5V4 (lack of slow warm up with 5Y3/5U4/5R4/SS).

[Mars Amp Repair]

MWJB,
thanx, that's what I thought...I have to remain mindful of the filiament draw...I tend to overlook that one....thanx, glen