The input terminal connects to the top end of a 1 meg ohm audio taper pot, the bottom end is grounded. The wiper connects to one end of a 0.1 micro farad capacitor. The other end connects to another 0.1 mike cap. The junction of the two caps goes to ground through a 1.5 meg ohm resistor. The other end of the second cap goes to ground through another 1.5 meg ohm res. The junction of the second 0.1 and 1.5 meg goes through a 10 k ohm res to the grid of V1a, half of a 6SN7. The cathode of V1a goes through a 1 k ohm res to ground. The plate goes through a 47 k ohm 1/2 watt res to B plus 3. The plate of V1a also connects directly to the grid of V1b, the other half of the 6SN7. The cathode of V1b goes through a 22 k ohm 1 watt res to ground. The plate of V1b goes through another 22 k ohm 1 watt res to B plus 2. The plate of V1b goes through a 0.22 mike cap to the grid of V2a, another 6SN7. The cathode of V1b goes through another 0.22 mike cap to the grid of V2b. The grids of V2a and V2b each go through their own 470 k ohm resistors to ground. The cathode of V2a goes to the top end of a 500 ohm linear pot labeled AC balance. The cathode of V2b goes to the bottom of the balance pot. The wiper goes through a 1.1 k ohm res to ground. The plates of V2a and V2b each go through their own 47 k ohm 1 watt resistors to B plus 1, 400 volts. Each plate of V2a and V2b goes through its own 0.22 mike cap then a 100 k ohm res to ground. The junction of each cap and res goes to one grid of a power output tube. B plus 1 goes through a 3.9 k ohm res to B plus 2. B plus 2 goes through a 47 k ohm res to B plus 3. B plus 1 and B plus 2 each go to ground through their own 100 mike 450 volt cap. B plus 3 goes to ground through a 47 mike 450 volt cap. There is a legend on the drawing which goes as follows. Vo = 17 v, T H D 1 = 1.3 percent, T H D 2 = 1.35 percent. Vo = 25 volts, T H D 1 = 1.85 percent, T H D 2 = 1.92 percent. Gain = 140. F sub 2 = 300 k c. End verbal description.
Go back.