Sharp-Cutoff Pentode
The Western Electric 403A tube is a miniature type. It is used as an RF or
IF amplifier especially in high-frequency wide-band
applications at frequencies up to 400 MHz. It requires a
miniature 7-contact socket.
The 403A is a prefered substitute for the 6AK5.
Electrical Data:
Heater Voltage ...................... 6.3 V
Heater Current .................... 0.175 A
Maximum Heater-Cathode Voltage ...... 120 V
Preferred Substitutes ........... 6J1, 6AK5, 5591, 5654, EF95
Substitutes ................ 6AG5, 6BC5, 6CE5