I have no idea what the intention was with the voltage follower.
But potentially (get it?) one could put the pot across the output of the amplifier then take divided down signal from the wiper and use that to drive a voltage follower. Which in turn drives your speaker. We now have a volume control.
Of course it makes the original power amplifier redundant and is probably adding distortion. And won't work with an output that goes negative.
Actually having a rethink using a 1k resistor in parallel with the pots winding or track might work as the wiper would eventually short the resistor giving 0 ohms?
Is that assumption right?
True, but the curve of resistance vs. pot position would be highly non-linear, i.e. virtually level at 1K with a precipitous drop-off at one end.
A volume control should really be logarithmic to get smooth change in volume. What with the logarithmic response of our hearing.
There is trick that can be used to make a linear pot respond like a log pot. Just add a resistor from the pot wiper to ground. As shown in Figure 1 on this page: http://sound.westhost.com/project01.htm With explanation.
Looks like a 1K resistor will do here if whatever is driving this can handle the load.
Comments
I've been wondering about this for a while, actually. Why would you use a voltage follower to act as a pot?
(note: my background is software, not hardware. so I acknowledge that the answer may be obvious to the hardware-oriented set among us.)
He parenthetically indicated that 100 ohm was preferred. But either way, why a voltage follower?
But potentially (get it?) one could put the pot across the output of the amplifier then take divided down signal from the wiper and use that to drive a voltage follower. Which in turn drives your speaker. We now have a volume control.
Of course it makes the original power amplifier redundant and is probably adding distortion. And won't work with an output that goes negative.
-Phil
A volume control should really be logarithmic to get smooth change in volume. What with the logarithmic response of our hearing.
There is trick that can be used to make a linear pot respond like a log pot. Just add a resistor from the pot wiper to ground. As shown in Figure 1 on this page: http://sound.westhost.com/project01.htm With explanation.
Looks like a 1K resistor will do here if whatever is driving this can handle the load.