This is a fixed version of the Audio Digitizer: The other file works,
but the change involved in this file reduces the high frequency noise
introduced into the sample due to the digitizer. The fix is simple if
you already have one built: cut the "link" between pins 3 and 5, and
move the wire from the DB25 Pin 10 to pin 5 and solder another wire from
pin 3 on the A to D chip to pin 1 on the DB 25.


This is a simple two chip Audio Digitizer for the Amiga (specifically the
500, but the DB25 pinouts can be changed for the other models). The parts
list is:

Qty        Item/Desc         Value
 1          Resistor           1k
 1            Pot             100k
 3           Caps        .1uF,47pF,10uF
 1      Mini Plug or RCA plug
 1          Connector         DB25
 1        A/D converter      ADC0804    (Heathkit usually has these)
 1         Audio Amp         LM386N     (Radio Shack)

This circuit will work with the program from the Perfect Sound digitizer
with one small exception--it won't digitize in stereo.

All the Vcc's (Pin 20 on the ADC0804 and Pin 6 on the LM386N) can be
powered from the printer port (at least it is working for mine with no
power supply problems!).

Use the monitor signal level option in the Perfect Sound program to adjust
the pot to the correct level (NOTE: If the circuit is hooked to a line
level--e.g. to the Audio Out of a VCR or stereo--the pot should be turned
WAY down, just listen to the "monitor" and you'll see what I mean).

I do have this circuit built and running on my Amiga so I know it works.
(I just hope you can read the diagram!)

                                     Jamie C.MUELLER (GEnie)