A 3 band tone control you can love. The input terminal goes through a 0.047 uf cap to the grid, pin 2, of a 12 eh U 7. The cathode, pin 3, goes through a 2.4 k ohm res then a 10 k 1/2 watt res to ground. The junction of the 2.4 k and 10 k goes through a 470 k ohm res to the grid. The plate, pin 1, goes to 250 volts. To help with the verbal description we will call two points TCL, left paren, tone control left, right paren, and TCR, left paren, tone control right, right paren. These marks do not exist on the visual schematic. The cathode of the 12 eh U 7 also goes through a 1 uf cap to TCL. TCL goes through a 56 k ohm resistor to the CW end of the bass pot, 500 k ohm linear taper. The CCW end goes through another 56 k ohm res to TCR. There is a 0.01 uf cap connected from the CW end to the CCW end of the bass pot. The wiper of the bass pot goes through a 510 k ohm res to the grid, pin 2 of a 12 eh X 7. A completely different 56 k ohm resistor goes from TCL to the CW end of the midrange pot, after this called the mid pot. The mid pot is a 500 k ohm linear. Another 56 k ohm res goes from the CCW end of the mid pot to TCR. There is a 220 pf cap connected from the CW end to the CCW end of the mid pot. The wiper of the mid pot goes through a 470 pf cap then a 510 k ohm res to the grid, pin 2, of the same 12 eh X 7. A 220 pf cap connects from TCL to the CW end of the treble pot, 500 k ohm linear. There is another 220 pf cap connected from the CCW end of the treble pot to TCR. The wiper of the treble pot goes through a 240 k ohm res to the grid, pin 2, of the same 12 eh X 7. The grid also goes through a 1 meg ohm res to ground. The cathode, pin 3, goes to ground through the parallel combination of a 5.6 k ohm res and a 50 uf cap. The plate, pin 1 goes through a 470 k ohm res to plus 250 volts. The plate, pin 1, goes to the grid, pin 7, of the same tube. The plate, pin 6, goes to plus 250 volts. The cathode, pin 8, goes through a 100 k ohm 1 watt res to ground. The cathode goes through a 1 uf cap to TCR. TCR connects to the output. End verbal description.
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