madbeanpedals::forum

Projects => Tech Help - Projects Page => Topic started by: Guybrush on March 03, 2014, 09:03:15 PM

Title: Trimmer to pot
Post by: Guybrush on March 03, 2014, 09:03:15 PM
Hey all

After ballsing up my first attempt, I'm having another go at Music PCB's Tap Tempo Tremolo.

I've decided to wire the internal volume trimmer as an external volume pot. Just wondering how to go about this. The build doc says to use a 25K A pot but doesn't say how to connect it. Do the trimmer's PCB pads correspond to a pots lugs as I've numbered below or have I mixed things up?

(http://i.imgur.com/11E47No.jpg)

Thanks in advance.
Title: Re: Trimmer to pot
Post by: selfdestroyer on March 04, 2014, 12:59:08 AM
This might help
Edit:
Just realized how stupid my help was.. lol

Cody
Title: Re: Trimmer to pot
Post by: brucer on March 04, 2014, 02:32:59 AM
Hi Guybrush.

I'm a newbie, but I understand trim pot pins are numbered like this:

  2
1  3  (see this: https://dlnmh9ip6v2uc.cloudfront.net/assets/6/3/e/5/e/511ac8f5ce395f5846000000.png (https://dlnmh9ip6v2uc.cloudfront.net/assets/6/3/e/5/e/511ac8f5ce395f5846000000.png)

Looking at your PCB picture, that would reverse 1 and 3.  Looking down on the knob of a linear pot, pins 1, 2 and 3 are numbered left to right (see http://www.beavisaudio.com/techpages/Pots/images/Potentiometer-Lug-Numberes.png (http://www.beavisaudio.com/techpages/Pots/images/Potentiometer-Lug-Numberes.png)).

Hope that helps, hope I'm right!  At least the links might send you in the right direction!

Bruce.
Title: Re: Trimmer to pot
Post by: Guybrush on March 04, 2014, 04:21:22 AM
Thanks for the replies and advice.

Looks like the way I've numbered it the pot would work in reverse. I'll switch lugs 1 and 3 round.

Thanks again.