Different heater voltage (19V series string) — not a drop-in replacement in 6.3V circuits
Electrical Specifications
Absolute Maximum
Anode Voltage (max)Anode Voltage (max)300V
Anode Dissipation (max)Anode Dissipation (max per section)2.5W
Cathode Current (max)Cathode Current (max)15mA
Heater-to-Cathode Voltage (max)Heater-to-Cathode Voltage (max)90V
Notes
The ECC85 was the standard FM front-end double triode, almost exclusively used in VHF/FM tuner circuits. One section typically served as an RF amplifier and the other as a self-oscillating mixer.
The two triode sections are nominally identical but the datasheet provides separate RF amplifier and self-oscillating mixer operating conditions at different bias points.
An internal screening plate between the two sections provides inter-section shielding for VHF stability.
Pin 9 is connected to the internal screen/shield — it should be grounded for proper inter-section isolation.
ECC865 is a higher-quality selected grade of the same tube — pin-compatible but may have tighter parameter spread. Listed separately by some manufacturers.
Pin Layout — Noval
1Anode 2
2Control Grid 2
3Cathode 2
Socket-Compatible Tubes ⚠ Not electrically compatible