The circuit begins with S1A. This is the source selector switch. Each position is wired to an input jack. S1B selects for the other channel. The swinger of S1A goes to position 2 of S2A, tape monitor selector. The swinger of S2A goes to the top of the volume control. S2B is in the other channel. Position 1 of S2A is connected to the input jack where the signal from tape deck B is fed to the preamp. It is labeled tape input deck B. Position 3 of S2A goes to tape input deck A. The swinger of the source selector switch, S1A goes to position 2 of S3A and position 2 of S3B. S3C and S3D are in the other channel. The swinger of S3A goes to cathode follower A which feeds signal to tape output deck A. The swinger of S3C goes to cathode follower B which feeds signal to tape output deck B. Cathode followers A and B are powered from B plus 3. There are 0.1 u f capacitors connecting between the cathodes of follower A and B to their respective tape output jacks. There are 3.3 meg ohm resistors connected across each tape output jack. S3 is the tape copy switch. Position 1 of S3 is the copy A to B position. Position 1 of S3A is grounded. Position 1 of S3B goes to the tape input deck A jack. Position 3 of S3 is copy B to A. Position 3 of S3A goes to tape input deck B. Position 3 of S3B is grounded.
The signal from the swinger of the tape monitor switch, S2 goes to the top of the volume control pot, 500 k ohm dual audio taper. The lower end is grounded. The wiper goes to the input of cathode follower C. the B plus point of this cathode follower is connected to b plus 2. The output goes to the input of the response control circuit (RCC). That's right, no DC blocking capacitor. The input point goes through a 10 k ohm resistor to the CW end of the bass control, 100 k ohm linear. The other end goes through another 10 k ohm resistor to the output point. There is a 0.056 u f capacitor connected across the bass control. The input point also goes through another 10 k ohm resistor to the CW end of the midrange pot, 100 k ohm linear. The other end goes through another 10 k ohm resistor to the output of the RCC. There is a 1600 p f capacitor connected across the midrange pot. The input point also goes through a 1000 p f capacitor to the CW end of the treble control 100 k ohm linear. The other end of the treble control goes through another 1000 p f capacitor to the output of the RCC. The wiper of the bass pot goes through a 100 k ohm resistor to the center of the RCC. The wiper of the midrange pot goes through 3300 p f capacitor then a 100 k ohm resistor to the center of the RCC. The wiper of the treble pot goes through 47 k ohm resistor to the center of the RCC. The center of the RCC goes through a 0.1 u f capacitor to the grid, pin 7, of a 12 A X 7. The grid goes to ground through a 1 meg ohm resistor. The cathode goes to ground through the parallel combination of a 3.9 k ohm resistor and a 100 u f capacitor. The plate, pin 7, goes through a 750 k ohm resistor to B plus 2. The plate goes directly to the grid, pin 7 of a 12 A U 7. The plate goes to B plus 2. The cathode goes through a 33 k ohm resistor to ground. The cathode connects directly to the output side of the RCC. The cathode goes through a 0.22 u f capacitor to one end of a 120 k ohm resistor. The other end goes to the top, CCW, end of the balance control, dual 250 k ohm linear. The other end goes through another 120 k ohm resistor to ground. The wiper goes to the input of the output gain block. In the other channel the two ends of the balance control pot are interchanged so it will work the opposite way.
End verbal description.
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