ECH81

Name: ECH81
Brand: Philips

Triode-Hexode — Noval — Philips

Data: HighHigh quality — base, heater, all universal parameters present, and ≥50% of desirable parameters filled in. Safe to use for design decisions.

↗ TDSL ↗ Radiomuseum

Known Equivalents & Substitutes

6AJ86C12CV2128X719

Similar Tubes (Not Drop-In Compatible)

ECH83

Higher maximum ratings variant — reportedly identical internally, only stamped differently

HCH81

Different heater voltage variant

UCH81

Series-heater version (100 mA) — same Noval base and pinout but different heater voltage

Electrical Specifications

Section 1 — Triode (Oscillator)

Absolute Maximum

Anode Voltage (max)Anode Voltage (max)250V

Anode Dissipation (max)Anode Dissipation (max)0.8W

Typical Operating

Anode Voltage (typical)Anode Voltage (typical)100V

Grid 1 Bias VoltageGrid Voltage-1

Notes

The triode and heptode sections share a common cathode.
ECH81 and ECH83 are reportedly equal — not even tested differently, only stamped differently. They show different performance values depending on anode voltage application.
Triode section: Va_max 250 V, Pa_max 0.8 W. Used as local oscillator.
Heptode section: Va_max 300 V, Vg2_max 125 V, Pa_max 1.7 W. Used as mixer.
Conversion conductance (gc) = 0.75 mA/V typical.

Pin Layout — Noval

1Heptode Anode

2Heptode Screen Grid (g2+g4)

3Common Cathode

Socket-Compatible Tubes ⚠ Not electrically compatible

6DS8 AL860 ECH83 HCH81 UCH81

References