← Reference

EL34

also 6CA7 · 6CA7 (US beam-tetrode equivalent)

Mullard/Philips A.F. output pentode — the output valve of the Marshall model 1959 Super Lead 100, which carries four of them in parallel push-pull, of the model 1987 50 W lead head, and of the wider JMP Super Lead / Super Bass family. Higher transconductance and a sharper overdrive than the KT66 it replaced when Marshall moved off the JTM45's British beam-tetrode pair; the EL34's screen behaviour is much of what gives the Plexi its aggressive top end.

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

Viewed from below (socket / wiring side) · octal · basing K8A

⚡ 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
Mullard / Philips EL34 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=-13.5 V → Ia=100 mA, Ig2=14.9 mA, gm=12500 µmho
Source
Mullard/Philips EL34 data sheet, January 1969 (A.F. Output Pentode)
Note
µ is the grid-No.1-to-grid-No.2 amplification factor (11), the tabulated amplification factor on the same Class-A data row as Ia/gm. Unlike the KT66, the datasheet tabulates Ig2 (14.9 mA) at the very same plate/gm operating point, so KG2 is anchored there directly — no separate screen point is needed. EX=1.5 and KVB=30 (pentode) are project defaults per METHODOLOGY.md.
File
models/el34.inc ↗

See these parameters drawn: the load line explorer plots the EL34's plate-curve family from this model and solves an operating point on it.

Maximum ratings

Limiting values under the design-centre rating system. Two anode-dissipation figures are printed: 25 W with no drive, rising to 27.5 W once the stage is driven. The idle figure is the one an operating point is judged against.

Anode voltage
800 V
Anode voltage, no current
2 kV
Grid No.2 voltage
500 V
Anode dissipation, no drive
25 W
Anode dissipation, driven
27.5 W
Grid No.2 dissipation
8 W
Cathode current
150 mA
Grid No.1 resistor
0.7 MΩ class A/AB · 0.5 MΩ class B
Rating system
Design centre — carries an allowance for manufacturing spread
Source
Mullard/Philips EL34 data sheet, January 1969 — limiting values (design-centre rating system) ↗