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Projects => Tech Help - Projects Page => Topic started by: Guybrush on September 09, 2014, 11:50:42 AM

Title: Change a Pot Value
Post by: Guybrush on September 09, 2014, 11:50:42 AM
Hey all
A quick and possibly stupid question.

I have a 10k Log slide pot that I want to magic into a 5K. Is this possible?

Thanks in advance
Title: Re: Change a Pot Value
Post by: RobA on September 09, 2014, 11:57:05 AM
Quote from: Guybrush on September 09, 2014, 11:50:42 AM
Hey all
A quick and possibly stupid question.

I have a 10k Log slide pot that I want to magic into a 5K. Is this possible?

Thanks in advance

You can't do it and keep the same taper. Doing it all depends on what you need it for, voltage divider versus variable resistor.

Also, it may not be that important to have it exact, depending on what you need it for. What are you using it in?
Title: Re: Change a Pot Value
Post by: sumac on September 09, 2014, 12:59:37 PM
this might help
http://www.diystompboxes.com/smfforum/index.php?topic=70732.0
Title: Re: Change a Pot Value
Post by: Guybrush on September 09, 2014, 02:27:03 PM
Cheers guys.

It's for a SHO. The build calls for a 5K Rev Log pot which I can't find in a slider. I went for the 10K standard Log but all volume change happens right at the end of the slide. Just wanted to see what a 5K standard Log would be like. They don't seem to be available to buy.
Title: Re: Change a Pot Value
Post by: mgwhit on September 09, 2014, 02:28:58 PM
The article that really explores this is The Secret Life of Pots (http://www.geofex.com/article_folders/potsecrets/potscret.htm).  In short:

Edit: I think converting a linear to reverse log in a SHO would be the perfect application for this, but you might need a higher than 10K linear to start with.
Title: Re: Change a Pot Value
Post by: RobA on September 10, 2014, 12:27:49 AM
Quote from: Guybrush on September 09, 2014, 02:27:03 PM
Cheers guys.

It's for a SHO. The build calls for a 5K Rev Log pot which I can't find in a slider. I went for the 10K standard Log but all volume change happens right at the end of the slide. Just wanted to see what a 5K standard Log would be like. They don't seem to be available to buy.

You can wire the log pot backwards and it'll work like a reverse log, but you have to move it the opposite direction, so for a slide pot, you'd just need to wire it backwards and then flip it upside down.

Going with a linear pot would be a better choice than using a log pot in this case. A log pot will cause the bunching to be even worse than a linear would.

Since this is used as a variable resistor, you could do the reverse log trick that is described in the Geofex page. But, you won't be able to go with a very good reverse log taper and keep the 5k value with a 10k pot.

Another possibility is to go with a smaller value linear pot. It depends on where you tend to have the gain set, but if you go with more gain out of it, then something like a 2k linear pot might actually feel better and have a nicer control over the gain setting.
Title: Re: Change a Pot Value
Post by: Guybrush on September 10, 2014, 07:42:23 AM
Thanks for the suggestions and advice. Really appreciate it.

I'll get tinkering!