User`s guide

______________________________
From: Tom Mage
012- How can I get 'regular Apple sound' (like BEEPs,
etc.) to play through my Mockingboard's outputs?
I recently got a Mockingboard C, which, it turns out, has a plug and cable
specifically for connecting in sound from the Speaker! (Most likely, the MB A
has a similar connection.)
______________________________
From: Rubywand
Evidently, older Mockingboards (like our Sound II) do not include the
built-in Speaker connection; so, users with these boards will need to do a
simple mod.
The Apple II speaker is in the Collector circuit of the sound output
transistor-- one end of the spkr goes to a resistor and capacitor connected to
the output transistor Collector and the other goes to +5V (not ground). To get
an audio output signal, the spkr must be in place; or, you can substitute a 1
watt resistor-- something in the 22-39 Ohm range.
The output should come from the side of the spkr (or 1 watt resistor) going
to the resistor & capacitor connected to the transistor-- i.e. the side which is
_not_ the +5V side. The output goes through a coupling capacitor to the center
lead of your RCA plug. The Ground side of the RCA plug goes to ground.
"Ground" is DC ground = any motherboard trace area which is connected to the
ground side of the power supply. For example, the outside "shell" of the
composite video output is soldered to ground.
Here is a rough picture ...
+5V side
|
|
[]< Speaker or 27 Ohm resistor
|
|---------------------|(--)|------------------------ Output
| 10uF 10uF to Amplifier
| 2 caps connected as bi-polar capacitor
|
Transistor _________________ Ground
side |
DC Ground
You can get a bi-polar coupling capacitor at Radio Shack or make one by
connecting two 10uF caps neg end to neg end. The value is not critical, a 2uF-
5uF bipolar cap or two 5uF caps connected back to back is fine. Voltage rating
should be 10V or better.