Pots--taper log or Linear?

[gengis]

Pots--Taper log or Linear?


Why is one prefer than the other on audio application?

[richie00boy]

Depends on the application. Volume controls have to be log or the rotation vs attenuation won't be right at all.

[AndrewT]

Hi,
use a linear taper and you will find that the control is only down by -6db at half rotation and -12db at 3/4 rotation. This then means that almost all the attenuation control is squeezed into the bottom 1/4 rotation. Not very nice to use nor adjust.

Use a log taper and the decibel attenuation is more evenly spread around the mechanical rotation making for a more gentle volume adjustment at the bottom end of the mechanical rotation.

The disadvantage of log tpaer is the difficulty of matching the two stereo channels for accurate balance at high attenuation levels.

Some use a linear taper with a log faking resistor attached between wiper and ground to gain the advantage of better stereo gain matching and the log effect over most of the mechanical roatation. The lin taper pot value is chosen at about 10 times the intended final input impedance and the faking resistor is chosen at between 10% and 15% of the log pot value. The final input impedance is very approximately 10% of the pot value but unfortunately does vary with rotation.