8FQ7 — Small Signal Triode, Noval | TubeofileKnown Equivalents & Substitutes
Similar Tubes (Not Drop-In Compatible)
12.6V heater version — not a drop-in in 8.4V circuits Same tube as 6FQ7 (different JEDEC number) — 6.3V heater 6FQ7
Same electrical characteristics but 6.3V heater — not a drop-in in 8.4V series-string circuits6SN7GT
Electrically near-identical but Octal base — not pin-compatibleElectrical Specifications
Absolute Maximum
Anode Voltage (max)Anode Voltage (max)300V
Anode Dissipation (max)Anode Dissipation (max, each plate)3.5W
Cathode Current (max)Cathode Current (max)20mA
Heater-to-Cathode Voltage (max)Heater-to-Cathode Voltage (max)200V
Notes
- 8.4V / 0.45A heater for series-string TV receiver heater chains. Electrically identical to 6CG7/6FQ7 in all other respects.
- 8CG7 is the same tube registered under a different JEDEC number (same relationship as 6CG7/6FQ7).
- Not interchangeable with 6FQ7/6CG7 without heater circuit modification.
Pin Layout — Noval
1Plate (Section 2)
2Grid (Section 2)
3Cathode (Section 2)
Socket-Compatible Tubes ⚠ Not electrically compatible
Max Grid Resistor
Max Grid Resistor (fixed bias)
1MΩ
Typical Operating
Anode Voltage (typical)Anode Voltage (typical)250V
Grid 1 Bias VoltageGrid 1 Bias Voltage-8V
Anode CurrentAnode Current9mA
Anode ResistanceAnode Resistance7,700Ω
TransconductanceTransconductance2.6mA/V
Amplification Factor (μ)Amplification Factor (μ)20—
Capacitances
Grid-to-Plate CapacitanceGrid-to-Plate Capacitance4pF
Input CapacitanceInput Capacitance2.3pF
Output CapacitanceOutput Capacitance2.2pF
Heater
Heater VoltageHeater Voltage8.4V
Heater CurrentHeater Current0.45A