Different Potentiometers

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DickyKnee
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Different Potentiometers

Post by DickyKnee » Thu Jul 14, 2016 7:06 am

Now that my modular is finally becoming a sum of the parts, I thought I'd post up how i built my Oakley modules using something other than the 16mm alpha carbon potentiometers. I prefer to use Bourns 91A1A conductive plastic potentiometers in all my builds, but these don't fit the .fpd files on the site, the brackets nor the PCBs

firstly, I modded the .FPD files for a 3/8 hole, also adding a cavity on the reverse to accomodate the tab of the top potentiometer - that was the easy bit.

secondly, I purchased one of these to make the holes bigger in the brackets:
Image

I initially tried using a reamer to make the bracket holes larger, but this was very time consuming and the result wasn't very good.

the lead depth of the 91A1A potentiometers don't align with the PCB and the spacing is different so they need to be adjusted to fit but the 91A1A legs are long enough to accommodate the hole misalignment. The final result almost looks like they were meant to fit, here is one of my 3 SVCOs:
Image
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mmeixner
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Location: Austria

Post by mmeixner » Tue Sep 13, 2016 7:01 am

A short follow-up question:

at Mouser I find these with two shaft lengths: 3/4 or 7/8 inch

Mouser Parts:
652-91A1A-B24-B18L
652-91A1A-B28-B18L

pdf:
http://www.mouser.com/ds/2/54/1_95-777139.pdf

Which one did you choose? Would like to order a bunch for 10-12 Oakley modules, so would like to get them right

Thanks for short answer!

DickyKnee
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Posts: 77
Joined: Sun Mar 30, 2014 10:39 am
Location: Thailand
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Post by DickyKnee » Tue Sep 13, 2016 9:30 am

mmeixner wrote:A short follow-up question:

at Mouser I find these with two shaft lengths: 3/4 or 7/8 inch

Mouser Parts:
652-91A1A-B24-B18L
652-91A1A-B28-B18L

pdf:
http://www.mouser.com/ds/2/54/1_95-777139.pdf

Which one did you choose? Would like to order a bunch for 10-12 Oakley modules, so would like to get them right

Thanks for short answer!
B24, but i guess you should choose shaft length based on the knobs you're using. in some instances the pot size is only available in B28, nothing a file won't fix.

If you've never used a 91a1a pot before, i'd recommend that you try one first before committing to such a large order. not everyone likes the "feel" of them, they have much lower friction than most other pots.

mmeixner
Common Wiggler
Posts: 126
Joined: Tue Aug 09, 2016 9:27 am
Location: Austria

Post by mmeixner » Tue Sep 13, 2016 9:37 am

DickyKnee wrote:
mmeixner wrote:A short follow-up question:

at Mouser I find these with two shaft lengths: 3/4 or 7/8 inch

Mouser Parts:
652-91A1A-B24-B18L
652-91A1A-B28-B18L

pdf:
http://www.mouser.com/ds/2/54/1_95-777139.pdf

Which one did you choose? Would like to order a bunch for 10-12 Oakley modules, so would like to get them right

Thanks for short answer!
B24, but i guess you should choose shaft length based on the knobs you're using. in some instances the pot size is only available in B28, nothing a file won't fix.

If you've never used a 91a1a pot before, i'd recommend that you try one first before committing to such a large order. not everyone likes the "feel" of them, they have much lower friction than most other pots.
Yes, I'll do that...
My main synth is a Hordijk system, the knobs have VERY low friction, and I'm already accustomed to them, they are very playable, so to speak.

Thanks for your answer!

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