The 6BA8A  (P/N 154-0163-00) is a triode-pentode combo vacuum tube with a B9A (Noval) miniature 9-pin base.

See also 6BA8.

Links

Some instruments using part 6BA8A

Instrument Manufacturer Class Model Description Introduced
3A72 Tektronix Plug-in 3A72 Dual channel amplifier plug-in 1961
526 Tektronix Audio/Video 526 NTSC Vectorscope 1959
59 Tektronix Plug-in Type 59 400 kHz low-cost amplifier plug-in 1960