Re: volume control adapter?

[eeastman@apple2.com]

Simon:
You are assuming that they get the thing on with the proper polarity.  If they
reverse your curcuit then there will be problems with an absolute ground
reference.

Again without looking at the circuit that drives the speaker, the safest way to
control the speaker is with a pot in series between the wiper and one end.  I
used this on my II+ for a couple of years without incident.  I had minimum 8
ohms for the speaker (max volume) and 10Meg ohms (min volume).  Very safe.
(Linear 10M pot sucked, it muted about a quarter turn but at least I didn't wake
Mom up.)

Thankx,
Ed

Simon Biber wrote:

> When turned all the way up you have a large resistance from the control in
> parallel with the speaker. Since the speaker is only 8 ohms this won't make
> a big difference. When turned down all the way you have no current through
> the speaker, and all going through the backplane of the control. It's hardly
> shorting it out, a 1k resistor will pass 5 milliamps.
>
> <eeastman@apple2.com> wrote in message 39E8A271.F64B9CFD@apple2.com">news:39E8A271.F64B9CFD@apple2.com...
> > Leave off that common ground!  The signal from the computer is either 5V
> or 0V
> > and 'click' the speaker when it changes.  If you move the potentiometer
> all the
> > way to one end, you will short the 5V line to ground in the speaker
> circuit.
> > This may cause damage to the Apple.  I would recommend that you leave that
> > Common ground lead on the pot just hanging (don't hook it up.)
> >
> > I must admit that I never looked at the schematic to see if the sound
> circuitry
> > can handle a direct short to ground, but better safe than soundless.)
> >
> > Thankx,
> > Ed