Another nice aspect of the 6N7 is the similarity of it's pinout to that of the 6J5, which is pictured on the right. Heater and cathode connections are at the same pins. The pins nr 4 and 6 which are used in the 6N7 for grid and plate connections of the second triode system are unused in the 6J5. A 6J5, which is basically one triode system of the popular 6SN7, will drop right into a socket which is wired for a paralleled 6N7 and will bias up correctly in a circuit which is sized for the 6N7. It will just provide less voltage amplification. The 6J5 has an amplification factor of 20. This will result in 3dB less gain. This might be just the right reduction if a system has too much overall gain.
So, if you are planning a project, check out the 6N7, it might be just the right tube.