Same Octal pinout and same pin functions, but significantly different electrical characteristics: 6080 has mu=2.0 and gm=6.5-7.0 mA/V vs 7802 mu=9 and gm=20 mA/V — not a drop-in as bias points and regulation behaviour differ substantially
6AS7G
Same Octal pinout but mu=2.0 and gm=7.0 mA/V — electrically similar to 6080, same incompatibility with 7802 due to dramatically different mu and gm
6N13S
Russian equivalent listed alongside 6080 and 7802 by Kainel'son & Larionov (1981). Same Octal pinout but Soviet manufacturing tolerances — mu=2 like 6080, not a drop-in for 7802 circuits
Electrical Specifications
Absolute Maximum
Anode Voltage (max)Anode Voltage (max)250V
Anode Dissipation (max)Anode Dissipation (max per section)13W
Cathode Current (max)Plate Current (max per section)160mA
Heater-to-Cathode Voltage (max)Heater-Cathode Voltage (max)300V
Notes
When paralleling sections for higher current, separate cathode resistors must be used in each leg to equalize current division. If output current is not fixed, use the resistance indicated for the lowest current approaching maximum plate dissipation.
Cathode resistance is superior to anode resistance for bias: it provides increasing bias on sections taking greater plate current, and a cathode resistor need only be R/(n+1) of a plate resistor's value, dissipating only one third the power.
A grid resistor of 1,000 ohms is recommended per section to prevent parasitic oscillation while maintaining control. Grid circuit resistance limits: 500-500,000 ohms for cathode bias; 500-50,000 ohms for fixed bias or combined cathode/fixed bias.
A minimum bias of 5V should be maintained to provide a safety margin from the zero-bias line. If cathode resistors are used, this corresponds to at least 5V of cathode-to-grid voltage under all operating conditions.
Heater-cathode voltage is rated at ±300V max. When connecting many high-drain tube heaters to a single transformer, use bus bars feeding alternate ends (Figure 3 in datasheet) with stranded pair to individual sockets.
The 7802 is frequently encountered in OTL headphone amplifier discussions as an alternative to the 6080/6AS7G family, where its higher mu and gm provide different sonic characteristics. It is NOT a drop-in replacement for the 6080 despite sharing the same pinout — the significantly higher gain changes the operating point in any circuit designed for low-mu types.
Pin Layout — Octal
1Grid (triode 2)
2Plate (triode 2)
3Cathode (triode 2)
4
Socket-Compatible Tubes ⚠ Not electrically compatible