6688

The 6688  (European: E180F) is a miniature high-slope VHF/UHF pentode vacuum tube with a B9A (Noval) miniature 9-pin base, primarily intended "for use in wideband amplifiers in telephone carrier systems, radar equipment and measuring equipment".

It is used in:

• the staircase generator circuit of the 3T77
• the P80 cathode-follower probe
• TR-4602, Hungarian 551 clone
• the 526

Tek part number: 154-0215-00

Links

• Raytheon CK 6688 Datasheet (PDF)
• 6688 @ radiomuseum.org

Pictures

• 

  P80 probe internal view