Figure 20. The upper input terminal goes through a 0.047 u f cap to the grid, pin 1, of a 7 5 4 3 / 6 A U 6. The lower input terminal is grounded. The cathode, pin 7, goes through a 510 ohm res then a 20 k ohm 1/2 watt res to ground. The junction of the 510 and 20 k goes through a 510 k ohm to the grid, pin 1. The plate, pin 5, the screen, pin 6, and the suppressor, pin 2 all go to B plus 3. A 1.0 u f cap connects from pin 7, cathode, to the left side of the tone control circuit. This point connects through resistors and / or capacitors to the left end of the control pots. The center of the tone control connects through resistors and / or capacitors to the wipers of the control pots. The center goes to the grid, pin 7, of the pentode section of a 7199 tube. The grid goes to ground through a 1 meg ohm resistor. The cathode, pin 6, goes to ground through a 1 k ohm res. The suppressor grid is connected to the cathode inside the tube. The cathode goes through a 3.3 u f cap to the screen grid, pin 3. The plate, pin 2 goes through a 150 k ohm res to B plus 2. The plate also goes to pin 9, grid of the triode section. The triode plate, pin 1, goes to B plus 2. The triode cathode, pin 8, goes through a 16 k ohm 2 watt res to ground. The triode cathode also goes through a 160 k ohm res to pin 3, pentode screen. The triode cathode also goes through a 1.0 u f cap to the output terminal. The lower output terminal is grounded. The output point also goes to the right side of the tone control circuit. This connection is exactly symmetrical with the left side. B plus 1 is positive 300 volts. it connects through a 27 k ohm res to B plus 2. There is a 33 u f cap from B plus 2 to ground. An 18 k ohm res connects from B plus 2 to B plus 3. There is another 33 u f cap from B plus 3 to ground. End verbal description.
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