PP5/400 shape Mazda V503 PA40 3B/355B CV563 CV1178 CV3768 DA30 pair directly heated mains output triodes

Description

The V503 is a directly heated power output triode for use in public address equipment and is intended for use in class AB operation.

The valve is fitted with a standard 4-pin  base, the connexion to which are given

It is direct equivalent of DA30 but almost impossible to find a pair even on the web!

Rating>

Filament voltage 4

Filament current 2 amps

Maximum Anode Volts 450

Mutual Conductance mA/V 10

Amplification factor 4.25

Both V503 have been tested with AVO 163

Grid -96

V503 tested  95mA 100% emission

V503 tested  96mA 100% emission