Power Amplifier Triode
The Balloon 71A / 171A / UX171-A Vacuum Tube is a glass type used in the
output stage of Radios and audio frequency
amplifiers during the 1920's and 1930"s. These are the
Original 71-A vacuum tubes before they changed the glass design to the ST-Type.
It requires a four-contact socket.
Electrical Data:
Filament Voltage .................. 5 DC V
Filament Current ................... 0.5 A
Preferred Substitutes ..................................
71A, UX171A, CX371A, CX71A, UX-71A, ER71A, ER171A, AC4, X-171A, 471A, T71A, MX171A, 171A, 171AC, SX171A, JX-171A