Gain stage. The input terminal goes to the top of a volume control pot, 500 k ohm. The bottom is grounded. The wiper goes through a 0.022 micro farad capacitor to the grid, pin 2, of the first triode in a 12AX7. The cathode, pin 3, connects through a 1.1 k ohm resistor then a 22 k ohm resistor labeled Rk to ground, see table below. The grid connects through a 470 k ohm resistor to the junction of the 1.1 k and Rk. The plate, pin 1, connects through a 270 k ohm res to the B plus line which is not actually labeled in the visual diagram. The B plus line goes to the positive side of a 100 mike 450 V cap. The negative side connects to ground. The plate of the first triode also connects through a 0.0047 mike cap to the grid, pin 7, of the second triode. This grid goes through a 470 k ohm res to ground. The cathode of the second triode, pin 8, connects through a 680 ohm res to ground. In parallel with the 680 is a 470 mike 25 volt electrolytic cap with the positive side to the cathode. The plate of the second triode, pin 6, goes through a 56 k ohm res to the B plus line. The plate also goes through a 220 k ohm resistor labeled Rf to the cathode, pin 3, of the first triode. The plate also goes through a 0.1 mike cap to the grid of the first tube inside the global feedback loop. The B plus line goes through a 33 k ohm res to plus 300 volts. End verbal description.
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