bieling@terra.es wrote:
Looking at the Apple II Red Book schematic, I would do the following: 1.- Remove the 741 OpAmp. 2.- Substitute R41 for a 330 ohm resistor. 3.- Connect the cassette input to pin 6 of the now empty 741 OpAmp IC socket. 4.- Clamp H14-4 to GND and to +5v with a pair of diodes.
That will certainly do it--but the clamping diodes protect the new input better than any of the original ones! ;-) -michael Music synthesis for 8-bit Apple II's! Home page: http://members.aol.com/MJMahon/ "The wastebasket is our most important design tool--and it is seriously underused."