madbeanpedals::forum

Hey guys.

   What will the difference be if I use a audio 10k vs a Linear 10K pot on the volume/ output of a drive pedal?  Will there be a noticeable difference ?

-Shane


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There won't be any audible difference. The only difference will be in where you have to set the knob to get a certain volume and volume levels distribute around the rotation of the pot.

Hi Shane. I'm usually not confident enough to answer questions here, but I think I have a good understanding of the difference between different pots. The first thing to remember is a 10k pot is a 10k pot. It's a variable resistor between zero and 10k. The difference is obviously in the range between zero and 10k.  Our ears live in a logarithmic world and that's why many volume or output pots you see are Audio or logarithmic pots, but the truth is even a linear pot can get you to the same variable resistance point and therefore sound exactly the same. The difference will be how much we have to turn the knob to get to that variable resistance point.  At 50% turn, the linear pot will get you 50% increase in resistance (in this case 5k). Notice how I didn't say 50% increase in volume because our hearing doesn't work that way.  At 50% turn on an audio/logarithmic pot, 50% turn will only increase the resistance by maybe 10-20%. We have to turn the knob clockwise by 80-90% until the resistance exponentially increases (just like our perceived hearing).   I hope this helps and if anything I said is incorrect, please correct me. Steve.

That's basically correct, especially the part about how we perceive volume levels. The only thing I'd change really is that you don't want to think of a pot used as a volume pot as a variable resistance. A typical volume pot is set up as a variable voltage divider. The output volume is directly proportional to the voltage swing of the signal, so a voltage divider sets the volume by setting how much of the voltage on the input to the divider shows up on the output.
 

Hey, thanks Rob. That's very helpful to my understanding of this subject.
Cheers. Steve.

Quote from: sdlogan9 on July 19, 2014, 05:07:44 AM
Hey guys.

   What will the difference be if I use a audio 10k vs a Linear 10K pot bot the volume/ output of a drive pedal?  Will there be a noticeable difference ?

-Shane


Sent from my iPhone using Tapatalk

It have been said that Finnegan when building the klon have sometime used Linear and Log pots but it was probably a matter of availability or what he had laying around like lots of builder also do wich create variants within the product, hence having a whole myth around it.

I personnaly prefer the Linear, the output is really well delivered and there's no «bunching» at the end of the pot.

Quote from: TGP39 on July 19, 2014, 05:34:48 AM
Hi Shane. I'm usually not confident enough to answer questions here, but I think I have a good understanding of the difference between different pots. The first thing to remember is a 10k pot is a 10k pot. It's a variable resistor between zero and 10k. The difference is obviously in the range between zero and 10k.  Our ears live in a logarithmic world and that's why many volume or output pots you see are Audio or logarithmic pots, but the truth is even a linear pot can get you to the same variable resistance point and therefore sound exactly the same. The difference will be how much we have to turn the knob to get to that variable resistance point.  At 50% turn, the linear pot will get you 50% increase in resistance (in this case 5k). Notice how I didn't say 50% increase in volume because our hearing doesn't work that way.  At 50% turn on an audio/logarithmic pot, 50% turn will only increase the resistance by maybe 10-20%. We have to turn the knob clockwise by 80-90% until the resistance exponentially increases (just like our perceived hearing).   I hope this helps and if anything I said is incorrect, please correct me. Steve.

Great info thanks man!  I will be trying to get my head around this.  Mainly how an Audio pot works.  Linear pots seem logical to me. ;D

-Shane

Quote from: GrindCustoms on July 19, 2014, 06:10:50 AM

Quote from: sdlogan9 on July 19, 2014, 05:07:44 AM
Hey guys.

   What will the difference be if I use a audio 10k vs a Linear 10K pot bot the volume/ output of a drive pedal?  Will there be a noticeable difference ?

-Shane


Sent from my iPhone using Tapatalk

It have been said that Finnegan when building the klon have sometime used Linear and Log pots but it was probably a matter of availability or what he had laying around like lots of builder also do wich create variants within the product, hence having a whole myth around it.

I personnaly prefer the Linear, the output is really well delivered and there's no «bunching» at the end of the pot.

Good point Rej!  You are correct about preferring Linear... I feel the same way.   " no «bunching» at the end of the pot.  "

In layman's terms, a log pot typically gets louder at the end of the rotation, a linear pot gets louder throughout the rotation. :-)

Quote from: GrindCustoms on July 19, 2014, 06:10:50 AMI personnaly prefer the Linear, the output is really well delivered and there's no «bunching» at the end of the pot.

That! I pretty much stopped using audio pots for my Muff builds because of that. Best decision ever!

I have one pedal though where I could use some spread in the beginning. I have an LPB that becomes insanely loud once you hit 08:00. Would be nice have some more usable spread in the beginning. With a reverse audio be of any help?

I need visual represntation to figure anything out so to that end...



You can also so create pot tapers that when graphed, sort of resemble an 's'.



dave

A volume pot "feels" right if you have a constant db change per degree rotation.

The usual  voltage divider output volume pot feels right with a log pot but a linear pot still allows all possible volume levels - it just pushes the change of volume to end of the rotation.

Andrew

Hey Dave.....Great graph. I printed one out for my own understanding. I love the idea of the S taper pot. What does the 100nf cap do? Does it filter out noise? Also if I were to build this S taper pot, would I start with a linear pot and solder the 3k3 Resistor to lugs one and two, then solder the 4k7 resistor to lugs 2 and 3?  Thanks for showing me this. Steve.

Hi Steve, The 's' graph is from an excellent article on potentiometers here. http://sound.westhost.com/pots.htm

The 's' is used in lighting to adjust for how are eyes/lamps work together as the audio pot's tailored to how we hear. Not sure of the caps purpose, not mentioned in the article.

dave

Thanks Dave. Much appreciated. Steve.