Same Loctal base and identical pinout but higher mu (20 vs 16), higher gm (2.6 vs 2.1 mA/V), and different heater current (0.6A vs 0.3A)
Electrical Specifications
Absolute Maximum
Anode Voltage (max)Anode Voltage (max)300V
Anode Dissipation (max)Anode Dissipation (max, per section)2.5W
Heater-to-Cathode Voltage (max)Heater-to-Cathode Voltage (max)90V
Typical Operating
Anode Voltage (typical)Anode Voltage (typical)250V
Notes
Sylvania rated the nominal heater voltage at 7.0V in the ratings section, though the typical operating voltage is 6.3V as with all loctal types. Heater current is 0.320A per Sylvania, though other sources list 0.300A.
The 14AF7 (also designated XXD) is the 12.6V/0.15A series-string heater version. Pin functions are identical.
The Sams Tube Substitution Handbook No. 16 lists 7N7 and 7AF7 as substitutes for each other, but only for parallel-filament circuits (marked with asterisk). The different heater current (0.3A vs 0.6A) makes them incompatible in series-string heater circuits.
Compared to the 7N7, the 7AF7 has somewhat lower interelectrode capacitances, which may be desirable in applications that do not require the higher mutual conductance of the 7N7.
Pin Layout — Loctal
1Heater
2Cathode (section 2)
3Anode (section 2)
4
Socket-Compatible Tubes ⚠ Not electrically compatible