WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
Building, troubleshooting and testing of these amplifiers should only be
performed by someone who is thoroughly familiar with
the safety precautions around high voltages.
It can be used in the same circuits, may not be optimal. Draws 2x as much heater current (600mA), so may draw too much for the power supply (i've had to replace 6N1P with 6922 because of just such an issue).