View Single Post
  #42   Report Post  
Posted to
[email protected] is offline
external usenet poster
Posts: 1,630
Default Taper of Potentiometers

"A simple way to get *very repeatable* "log" type curve for audio is to wire the two sections of a dual linear pot in series. The wiper of the first half goes to the top of the second and its wiper becomes the output. Bottom ends are both grounded.

At the centre (50%) position, this reliably gives -15dB attenuation when loading effects are taken into account.

At the 75% setting, attenuation is -6.5dB, at 25% it is -25dB while down at 10%, attenuation is -40dB.

...... Phil"

That is what high end audio equipment does. Have seen it a few times. It does make for a nice smooth taper. Also in preamps it enhances the S/N ratio at lower volume settings. Usually the first pot is somewhere near the tone control circuit, if any. The second pot is right at the preamp outputs.

Actually if a volume control is "too fast" a resistor between the wiper and ground side makes a pretty decent taper.

One time a guy broings in a receiver, an upgrade from the one he had but oth the same brand. He asked why he had to turn it higher to get the same volume level even though it was more power. I had to explain it so I used the accelerator in a car. I told him they could make the linkage so it is just about floored when you give it half a pedal, but does that make the car go faster ? Nope, it has the same horsepower (kilowatts for youse across the pond) no matter how the accelerator linkage is designed. I think he understood. I told him it gives him more accurate control.