03-09-2022, 10:16 PM
Agree with the 5Z3 vs the 80. 80s are easy to find. RCA replaced the 80 with the 5Y3. Electrically the same but the 5Y3 has an Octal base. Think RCA likely made the tube up to the late 40s or newer, as the latest 80s I have found are "GT" style bulbs and look like rebased 5Y3s.
One "Mod" that I make on any electronics using 80s is to disconnect the HV Secondary wires of the Power Transformer from the plate contacts of the rectifier socket and add a 1A 1000PIV silicon diode in series between each transformer HV Secondary lead (But not the center tap) and each plate terminal of the rectifier socket. This is to protect the transformer and electrolytics if the rectifier develops a plate to filament short (and they do, especially the S and the ST style tubes). It is also a good thing to do with 5Y3s, 5U4s and any directly heated full wave rectifier.
One "Mod" that I make on any electronics using 80s is to disconnect the HV Secondary wires of the Power Transformer from the plate contacts of the rectifier socket and add a 1A 1000PIV silicon diode in series between each transformer HV Secondary lead (But not the center tap) and each plate terminal of the rectifier socket. This is to protect the transformer and electrolytics if the rectifier develops a plate to filament short (and they do, especially the S and the ST style tubes). It is also a good thing to do with 5Y3s, 5U4s and any directly heated full wave rectifier.
"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
Best Regards,
MrFixr55
