Re: SuperSonic

[Rubywand <rubywand@swbell.net>]

Ronald Clark writes ...
> 
> Is there a way to make sounds not from the sound chip to go in the card?

     If you are connecting your Stereo Board outputs to a stereo
amplifier or to speakers with built-in amplifiers, a simple way to mix
in 'Old Apple' sounds is to connect a capacitor from the signal ("+" or
non-ground) Spkr lead to one of the Stereo Card outputs.

     This connection mixes in combined (mono) IIgs sound, too. This is
why a pot is included in the circuit. It lets you adjust how much of the
Old Apple and mono GS sound to mix in so that, when sound is coming
through the Stereo Board, the Stereo Board sound will predominate.

     The pic below shows a 5uF 15V non-polarized electrolytic cap
running from a pot across the Spkr leads to the center of the Right
Output socket. (You can use a couple regular 10uF caps connected back to
back.)   


 ---------------------------------------------o) Left Output

 ---------------------------------------------o) Right Output
                                           |
                                           x in-line connector
 Spkr sig (+)----|                         |   or clip
                 Z                         |
      approx.    Z <------------|(-)|------|
    5000 Ohm pot Z      approx. 5uF 15V np
                 Z
 Spkr Gnd -------|


     None of the values shown is especially critical and it does not
matter which channel output you connect to. The in-line connector or
clip is to allow disconnecting the Old Apple Sound wire when you wish to
remove the Stereo Board for cleaning, etc.. It can be just a place where
the wires are twisted together and covered with tubing which fits
snugly.

     A handy place to connect the pot leads is on the Speaker connector
at the right front corner of the motherboard. You can tac on wires near
the bottom of the pins to leave room for reconnecting the Speaker plug.

Note: As you face the front, the Left pin is +. It does not matter which
outside leads of the pot go to which pins unless you care about having a
clockwise turn = more volume. Otherwise, just connect the end leads and
set the pot for the output level you like.


     If your Stereo Board has outputs which can drive speakers and you
want to connect plain (unamplified) speakers to the board, the above
connection will not do the job. If you do not mind poking around on your
Stereo Board, you can probably find a couple of mini pots which set
output volume for each channel. (I do not know if the SuperSonic board
has these. It's a fairly common feature on sound boards with power amp
outputs.)  The middle lead of one of the pots (either one) is a pretty
good bet as the place to connect the lead coming from the in-line
connector.

                                                        |---------
                                                        Z
                                 ...  ----------------> Z 
                                        |               Z
                                        x in-line       |---------
 Spkr sig (+)----|                      |  connector     mini-pot
                 Z                      |  or clip        vol. adjust
      approx.    Z <---------|(-)|------|                 on Stereo
    5000 Ohm pot Z      approx. 5uF 15V np                Board
                 Z
 Spkr Gnd -------|




Rubywand