Author Topic: Why logarithmic pots?  (Read 1473 times)


  • Electron Doctor
  • *****
  • Posts: 1041
  • Angelo
    • View Profile
    • Heavy Record
Why logarithmic pots?
« on: September 10, 2012, 09:44:49 PM »
After reading through the website below, I have a question.

Why use logarithmic pots on effects?

If it gets you to the same place, why not just use linear and have a equal turn ration throughout the rotation of the pot?


  • Global Moderator
  • Electron Doctor
  • *****
  • Posts: 7576
  • Jacob - SK, Canada
    • View Profile
    • JMK PCBs
Re: Why logarithmic pots?
« Reply #1 on: September 10, 2012, 09:56:09 PM »
Because sound isn't the same as electricity.

Basically, our ears hear logarithmically, they don't hear things linearly. For instance, it takes 10 times the power to get twice the volume. So a 100 watt amp is twice as loud as a 10 watt amp, not 10 times louder. If it were linear, it would be 10 times louder.

So, when we build pedals, we use A value pots for things like Gain and Master volume because that's how our ears work.

JMK Pedals - Custom Pedal Creations
JMK PCBs *New Website*
pedal company - youtube - facebook - Used Pedals


  • Electron Doctor
  • *****
  • Posts: 1108
  • Paul
    • View Profile
Re: Why logarithmic pots?
« Reply #2 on: September 11, 2012, 12:13:00 AM »
Yep, we perceive "loudness" on a logarithmic scale.

The other reason we use log pots is because sometimes the parameter we are trying to control in the effect doesn't respond linearly with resistance (or change in voltage if the pot is being used as a divider). In that case we use a log pot (or the various other non-linear tapers available) to approximate the feel of linear control over that parameter.