100 mA series-heater variant (19 V) — different heater series, not interchangeable
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
Series-heater (150 mA) version of the ECC85. Electrically identical sections — only the heater voltage/current differs (17.5 V at 150 mA vs 6.3 V at 435 mA).
The H-prefix (150 mA series) is relatively uncommon — most series-string receivers used either 300 mA (P-prefix) or 100 mA (U-prefix) heater chains.
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.
Pin Layout — Noval
1Anode 2
2Control Grid 2
3Cathode 2
Socket-Compatible Tubes ⚠ Not electrically compatible