Dissimilar double triode Compactron for TV vertical deflection — same base type but different electrical characteristics
Electrical Specifications
Section 1 — Triode 1 (High-Mu Oscillator)
Absolute Maximum
Anode Voltage (max)Max Plate Voltage350V
Anode Dissipation (max)Max Plate Dissipation1W
Cathode Current (max)Max Cathode Current50mA
Heater-to-Cathode Voltage (max)Max Heater-Cathode Voltage200V
Notes
13FM7 and 15FM7 are identical to 6FM7 except for heater ratings (series-string variants) and are not pin-for-pin replacements in parallel-heater circuits.
Section 2 has two grid pins (pins 3 and 8) which must both be connected to the grid circuit.
Pin 6 is an internal connection and must not be used.
Originally designed for TV vertical deflection; the low-mu Section 2 is popular in DIY audio as a low-power single-ended output triode (approx. 1–1.5 W).
Section 2 grid voltage of 0 V at Va=60 V, Ia=95 mA is rated for short interval only (2 seconds max) to avoid tube damage.
In stages operating with grid-leak bias, an adequate cathode-bias resistor or other suitable means is required to protect the tube in the absence of excitation.
Pin Layout — Compactron
1Heater
2
Socket-Compatible Tubes ⚠ Not electrically compatible