D/A converter

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    3. HOW TO MAKE AN EVEN CHEAPER D/A
    ─────────────────────────────────────────────────────────

    For the price of 20 1% resistors and a plug, with no power supply
    needed you can make a D/A converter that sounds close to the IC
    one above (it seems only the UK can get a Plessey ZN426E)

    You need one plug for your amp, one for your parallel port and
    9 20k and 9 10K resistors
    Use 1% resistors if possible ─ and 20k sound much better than 22k

          Printer Port:

          signal   pin        20k   20k
          D0       2      >───░░░─┬─░░░──0v
                              20k â–‘ 10k
          D1       3      >───░░░─┤
                              20k â–‘ 10k
          D2       4      >───░░░─┤
                              20k â–‘ 10k
          D3       5      >───░░░─┤
                              20k â–‘ 10k
          D4       6      >───░░░─┤
                              20k â–‘ 10k
          D5       7      >───░░░─┤
                              20k â–‘ 10k
          D6       8      >───░░░─┤
                              20k â–‘ 10k
          D7       9      >───░░░─┤
                              20k â–‘ 10k  100nF
                                  ├──────┤█────> TO AMPLIFIER
                                  â–‘ 10k
          GND      20     >───────┼────────────>
                                  0v
         
     Thanks to Harry Stox for the above circuit.  Again, make sure all
     the 0v lines are connected together.  The 100nF capacitor may not
     be needed, try removing it if this circuit sounds poor.



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