[sdiy] Audio mixers

[David G. Dixon]

> If nothing is plugged into a mixer, and it is turned up, it 
> is an antenna more or less, picking up crap from the outside 
> world. Some line input mixers use switching jacks to ground 
> any unused inputs. This covers the case where input levels 
> are up, but no relatively low impedance source is plugged in.
> 
> If there's a good ground connection to the mixer and the 
> level pots, plugging something in with the pot turned down 
> should not change anything.

Yes, you are right.  You could wire up a pot as a variable resistor and make
it the input resistor, in which case it would be floating, but if it is
wired up as an attenuator into a fixed input resistor, then the input is
grounded regardless.

This would all seem to be a moot point, then.