Re: volume control adapter?

[Rubywand <rubywand@swbell.net>]

sixtyfourK writes ...
> 
> Hey there A2 users/enthusiasts!
> 
> I was wondering if there is a way to add a volume control to an Apple //e
> (or even ][ Plus, and ][) in between the built in speaker and the speaker
> connector on the motherboard? If so, how?
> 
 ....

      A pretty good way to do this is to snip one of the leads going to the
Speaker and insert a medium-resistance pot-- like a 500 Ohm wirewound pot rated
at 3 watts.

      Connect the center lead of the pot to one outside lead. Run wires from
this point and from the other outside lead to the snipped leads. The circuit
looks like this:


____________________________________   /
_____________  <snipped>   _________[ < )  Speaker
             |            |            \
             |            |
             |\/\/\/\/\/\/
             |     ^      
             |_____|      

         approx. 500 Ohms, 3 watts


     The maximum value of the pot is not critica. Any 3 watt or larger
wirewound pot with a max value in the range 400 Ohms - 1000 Ohms should give
you pretty good control of output volume for the built-in speaker on any Apple
II.

Note: At a setting of about 250 Ohms, speaker output will be nearly
undetectable. 500 Ohms max lets you obtain near silence and have a decent range
over which turning the knob makes an audible difference.


     An alternative circuit lets you obtain true zero output; but, it is a lot
more bother to wire:


__________________________
_____________             |
             |            | 
             |            |
             |\/\/\/\/\/\/   approx. 25 Ohms max, 3 watts or larger
             |     ^      
             |     |      
             |     |________   /
             |______________[ < )  Speaker
                               \

                                 
This circuit requires snipping both speaker leads. You run them to the end
terminals on the pot and connect the speaker to an end terminal and the middle
terminal.

     Max value for the pot is not especially critical; but, you probably do not
want to go below 20 Ohms or above 100 Ohms.




Rubywand