Home / Shop
7B8 Vacuum Tube New and Used

- Description
- Specifications
The 7B8 is a pentagrid converter vacuum tube designed for frequency conversion and mixer-oscillator service in superheterodyne radio receivers. Electrically equivalent to the 6A8 octal tube, it features a 6.3V filament rating and an 8-pin lock-in (loctal) base in a glass envelope construction. Manufactured by companies including Sylvania, Philco, RCA, and GE, this tube was widely used in mid-century Philco and Zenith radio chassis as well as automotive receivers.
Tube Type: Pentagrid Converter
Base Type: Loctal / Lock-In (8-pin)
Envelope Style: Glass T-9
Filament Voltage: 6.3 V AC/DC
Filament Current: 0.3 A (300 mA)
Maximum Plate Voltage: 250 V
Plate Dissipation: 1.0 W
Conversion Transconductance: 0.55 mA/V (550 µmhos)
Primary Function: Pentagrid mixer and local oscillator (frequency converter)
Condition Options: New Old Stock (NOS) or Tested Used