Connectors: D25 male

Resistors: 640k,320k,160k,80k,40k,20k,10k,5k,390  (+-1%) (You can use different values of resistors, but the ratio of the values of the resistors must be the same. 0.5, 1, 2, 4, 8, 16, 32, 64 etc.) 1, 2, 4, 8, 16, 32, 64, 128

Capacitor: Electrolytic or solid Tantalum 10 uF 10V

SCHEMATIC
        +---+
        | 2 | ---<640k>---+
        | 3 | ---<320k>---+
        | 4 | ---<160k>---+
        | 5 | ---<80k>----+
        | 6 | ---<40k>----+
        | 7 | ---<20k>----+-----+---- 10 uF -------> Out
        | 8 | ---<10k>----+     |
        | 9 | ---<5k>-----+   <390>
        |   |                   |
        | 25| ------------------+------------------+ 
        +---+                                      |
                                                  ===
                                                 Ground


How to build
Solder all D25 male connector pins to corresponding D25 female connector pins (pin 1 to pin 1 etc)
Connect the resistors according the chematic. It is maybe not possible to obtain exact resistor values. If you can't obtain them, try nearest values. <1% deviation is acceptable.

How to use
Connect this circuit to the centronics printer port of your IBM PC or compatible. Connect the printer cable to the D25 female connector of the circuit. Your printer should work correctly with this circuit and you can keed this circuit connected all the time. Connect the sound output to your stereo system. Line in and mic lines are suitable because the output level of this circuit is adjustable (about 0-2V PP). The sound quality is very good.
