Make a LOG pot out of a LIN pot?

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Make a LOG pot out of a LIN pot?

Postby kierc » 26 Mar 2009, 12:55

Hi,

Is it possible to say get a 100k Lin pot, do some electric voodoo, and end up with a 100k Log pot??

I did a googley search but most stuff is amp related, but I found something that said a resistor of about 20% value of the pot across lugs 1 and the wiper would create a Log pot... would this work for pedals? :scratch:

Thanks!

Kier.
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Re: Make a LOG pot out of a LIN pot?

Postby lolbou » 26 Mar 2009, 13:19

By adding a 10k resistor between pin one and wiper. (see image)

edit: if you have a 4k7 lin pot, then add a 470 ohms resistor, and so on...

Try this http://www.sonelec-musique.com/logiciels_freewares_potmodcurve.html, still from http://www.sonelec-musique.com which a french site I simply adore...
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Re: Make a LOG pot out of a LIN pot?

Postby kierc » 26 Mar 2009, 14:53

Cheers for that :thumbsup

So it's 10% of the value?

Also, that's looking at the back of the pot right?

Am I right in thinking (from that French site) that if the resistor is placed on the other side it will create a reverse-log pot?

Cheers for the speedy helpful reply 8)
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Re: Make a LOG pot out of a LIN pot?

Postby lolbou » 26 Mar 2009, 15:05

kierc wrote:So it's 10% of the value?


yes. when you lower the resistance value (starting from the pot value), then you lean towards a log curve. This very log curve is almost reached for 10% of the value.

kierc wrote:Also, that's looking at the back of the pot right?


yes again. the resistor goes between the "zero lug" and the center lug.

kierc wrote:Am I right in thinking (from that French site) that if the resistor is placed on the other side it will create a reverse-log pot?


that's it. french ain't that difficult, uh? :wink:

Here's the english by famous R.G. Keen... http://www.geofex.com/article_folders/potsecrets/potscret.htm

kierc wrote:Cheers for the speedy helpful reply


My pleasure! :D
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