6922 can be substituted with a 6N23P. The 6N1P has a plate resistance that is almost three times that of a 6922. You would most likely need to decrease the resistance of your cathode resistor to get optimum performance.
Also be aware that both the 6n1P and the 6CG7 require twice the heater current as the 6922. The 6CG7 will work but you would need to check your voltages and look at the tube data sheets to see if your running at a good operating point. Also the 6cg7 has a lower mu. So gain will be less.
Also be aware that both the 6n1P and the 6CG7 require twice the heater current as the 6922. The 6CG7 will work but you would need to check your voltages and look at the tube data sheets to see if your running at a good operating point. Also the 6cg7 has a lower mu. So gain will be less.