Figure 3 A 12J8 Power Amplifier Stage. On the left the audio input connects to one end of a capacitor which is not labeled. The other end goes to grid 1, pin 1, of a 12 J 8. The grid also goes to ground through a 2.2 meg ohm resistor. The cathode and suppressor grid, pin 2, are connected to ground. The screen grid, pin 3 is connected to plus twelve volts. The plate, pin 6, goes to the top of the primary of the output transformer which is an iron core audio transformer. The bottom of the primary goes to plus twelve volts. The secondary is labeled Headphones or transistor base. End verbal description.