Substitute for reverse log pot

[bertmar]

Hello!
I ruined the pot on my original MXR microamp and now I have a hard time finding another. The schematics says it uses a 500K reverse log pot. Is there any substitute for this? What happens if I put a 500K log (not reverse) in it? Shouldnt it produce the same sounds, although it may be a bit touchier on some part of the sweep?

Thanks
Martin

[choklitlove]

here's one:
http://www.smallbearelec.com/Detail.bok?no=116

you don't want to use a regular audio pot backwards or anything because then it will be uneven when you turn it.  a linear pot would work (just wired backwards) but it would be too even when you turn it.  hope this helps!

[jbm222]

When you have a pot used as just a variable resistance between two nodes (wiper connected directly to either side) you can approximate a log taper by using a larger pot than you need and running a resistance in parallel.  For example  100k pot // 10k resistor is roughly a 10k log taper pot.  If there's not enough difference between the intended pot value and the bigger pot value, there won't be as noticible of a difference.

I don't really understand what reverse log means though in terms of how you want the resistance between the two increase/decrease as you turn the knob. 

So this may or may not help.

Or you could just order the reverse log pot from smallbear.

[Paul Marossy]

I don't get the idea behind a reverse log pot, either. All I can think of is that if it is wired like a standard log pot, it will start out full bore and then go down from there. Is that correct? 

[smccusker]

The dark horse taper is reverse audio, or more strictly "right hand logarithmic" taper. This taper traverses resistance very quickly at first, then more slowly as it is turned further. It's the inverse of the audio taper. This is used in some bias circuits and in controlling the speed of certain RC oscillators, which is where the audio tinkerer runs into it most.

[Paul Marossy]

Well, duh. That answers my question, doesn't it? 

[smccusker]

i wonder why wiring a log pot backwards wouldnt work then?

[nelson]

It does.

Atleast to my knowledge.

Wiring a rev log pot backwards gives you a log pot. If you turn the pot the other way.