With early (cathode biased) B15N that calls for 5U4GB I have 412V on the plates (filament & high voltages are right), so a bit on lower side. Schematic calls for 450V...
Later models had 5AR4.
I know that 5U4GB drops more than 5AR4 and are interchangeable in most cases, so I've tried the 5AR4 and I'm getting now around 421-422VDC on the plates. Would it be 100% safe to use 5AR4 here? With the 220ohm cathode resistor (schem. calls for 250) I'm getting 31V across it, so around 95% dissipation which is okay I would say.
Later models had 5AR4.
I know that 5U4GB drops more than 5AR4 and are interchangeable in most cases, so I've tried the 5AR4 and I'm getting now around 421-422VDC on the plates. Would it be 100% safe to use 5AR4 here? With the 220ohm cathode resistor (schem. calls for 250) I'm getting 31V across it, so around 95% dissipation which is okay I would say.
Comment