← Reference

KT66

British beam-power tetrode from GEC / M-O Valve Co. — the output tube of the JTM45, the amplifier that carried the 6L6-class Bassman topology across the Atlantic. Its higher plate dissipation and different drive give the JTM45 its louder, firmer character.

Basing (pinout)

Bottom view — the socket as you see it from the wiring side. Hover, tap, or focus a pin to name it. Read from the datasheet basing diagram (how to read these →).

1 2 3 4 5 6 7 8

Hover, tap, or focus a pin to name it.

  • High voltage (B+)
  • Control grid
  • Cathode
  • Heater / filament
  • No connection
  • Internal connection

Viewed from below (socket / wiring side) · octal · basing 7AC

⚡ Oxblood pins sit at B+ — hundreds of volts in service, lethal, and still charged after power-off.

Datasheets

Primary manufacturer data, via public tube-data archives. The model below is fitted to the tabulated "average characteristics" in these sheets; the datasheet files themselves are linked, never rehosted.

PublisherTypeSource
GEC / M-O Valve Co. KT66 frank.pocnet.net ↗

Circuit Codex model

A CC0 ngspice model in the Koren form, fitted here to the published anchor — no parameters copied from other model collections. Methodology →

Anchor
Va=250 V, Vg2=250 V, Vg1=-15 V → Ia=85 mA, gm=7000 µmho (gm test point)
Source
GEC / M-O Valve Co. KT66 data sheet, Issue 4, April 1963
Note
µ is the grid-No.1-to-grid-No.2 amplification factor (9.5), from the triode-connection gm·ra on the same sheet. KG2 is anchored on the Class AB1 push-pull quiescent point (Vg2=300 V, Vg1=-27 V → Ig2=2.5 mA).
File
models/kt66.inc ↗