Rev Log Pot to Log Pot?

Started by ringworm, December 17, 2009, 07:25:29 AM

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ringworm

I have a 150k rev log pot I want to put into my Neutron Filter. Is there a way to wire it to make it a log pot?
i can find plenty of info on how to get linear pots to log etc but none this way round. Any help?

GibsonGM

Don't think so.
Go here: http://www.geofex.com/
and search on the left for "secret life of pots".   R.G.  has pretty exhaustively researched what you can/can't do with pots...
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ringworm

#2
I've read that a number of times. I was wondering if I switched the wiring to the other end of the pot (leg 1 rather than leg 3) would that create a 150k log pot, albeit with the knob rotation going the other way (not a problem for me, I'd sooner get a smooth control with the correct value)?
I've also tried using the Analog Alchemy EMH to make a 150k log pot from a 470k lin pot but having tested the results, I've got a 198k log pot with very strange readings around the first quarter ratio of the turn (readings start to jump around). the general curve is good though.
0 turn = 198k
0.25 turn = readings jump around
0.5 turn = 170k
0.75 turn = 93k
1 turn - 0

T1bbles

This electronic maths help page from Analog Alchemy allows you to calculate how to turn a linear pot to a fake log pot by attaching two resistors to it;

http://www.diystompboxes.com/analogalchemy/emh/emh.html

You can probably work out how to do it from there, maybe switch the resistors around? I dunno, it'll probably be of some help :)
Behringer don't do signatures, but if they did, they'd probably stop working mid sen

trjones1

Quote from: ringworm on December 17, 2009, 11:42:12 AM
I was wondering if I switched the wiring to the other end of the pot (leg 1 rather than leg 3) would that create a 150k log pot, albeit with the knob rotation going the other way

Yup, that'll work.