Harry Klippton
Well-known member
@Rpschultz13 what do you think the advantages of 9mm pots are? Especially when Robert doesn't use them as the default on his layouts.
Why doesn’t everyone use 9mm pots?!?
- Thread starter Rpschultz13
- Start date
chris.knudson
Well-known member
Reasons I like 16mm pots:
1. they're easier to work with
2. they feel sturdier when mounting to an enclosure
3. It's a lot easier to read the values on them (I've had a couple of 9mm pots that I couldn't find any marking on them and had to rely on a DMM to know what I had in my hand)
4. they're cheaper
Reasons I like 9mm pots:
1. they're sealed (which means they're generally less noisy and more reliable)
2. you can more easily fit them into 1590A enclosures
3. I can store a lot more of them in the limited amount of space that I have
4. I've never broken the legs off of a 9mm pot
But probably the biggest reason I prefer 9mm pots to 16mm pots -- I'v never empaled myself with a 9mm pot
1. they're easier to work with
2. they feel sturdier when mounting to an enclosure
3. It's a lot easier to read the values on them (I've had a couple of 9mm pots that I couldn't find any marking on them and had to rely on a DMM to know what I had in my hand)
4. they're cheaper
Reasons I like 9mm pots:
1. they're sealed (which means they're generally less noisy and more reliable)
2. you can more easily fit them into 1590A enclosures
3. I can store a lot more of them in the limited amount of space that I have
4. I've never broken the legs off of a 9mm pot
But probably the biggest reason I prefer 9mm pots to 16mm pots -- I'v never empaled myself with a 9mm pot
Rpschultz13
Active member
Yeah ok. I used 9mm pots in my 1590A and 1590LB designs, seems almost required. But anything bigger than that I can see 16mm being better. About ready to build some Conspiracy to Commit Electronics tube pedals... he uses 9mm exclusively.
Rpschultz13
Active member
I’m not exactly sure, certainly not advocating for them. Just trying to understand, which is why I started the thread.
Some of us prefer 24mm pots.. or even better, sealed 28mm pots. But really who wants to pay $15-25/pot that has limited values available, would eat up a lot of valuable real estate, and isn’t PC board mountable?
Now when I finally get around to building a replacement for my “perfect” Plexi that I like an idiot sold, I’ll likely get them.. but for pedals, I’ll stick with 16mm PCB mount
Now when I finally get around to building a replacement for my “perfect” Plexi that I like an idiot sold, I’ll likely get them.. but for pedals, I’ll stick with 16mm PCB mount
finebyfine
Well-known member
I saw some 12mm pots in person for the first time on a cctv monitor my brother is refurbishing and I’ll be danged if they didn’t look like an ideal middle ground on a lot of these fronts
Rpschultz13
Active member
I’m intrigued. Where can you get them from?
Harry Klippton
Well-known member
Small bear used to have them. I've used em a couple times to squeak something in
Rpschultz13
Active member
12mm pots = the metric system
Might be better in EVERY way, but it’ll never stick.
Might be better in EVERY way, but it’ll never stick.
Or BetaMax compared to VHS… or HDDVD over BluRay
Rpschultz13
Active member
Aentons
Well-known member
The whole world uses the metric system. It definitely stuck. It's just the USA that is having a hard time with the last 25% or so of the switchover
Rpschultz13
Active member
Jameco has a wide selection of straight, not right angle.
bean
Well-known member
I generally prefer the right angle 9mm pots because they are a very secure mount, but they make 1590B layouts more challenging than 16mm. There is less useable real estate with 9mm.
With 16mm there are only 3 contact points. With 9mm there are 5 plus the 2 external standoff tabs to work around.
With 16mm there are only 3 contact points. With 9mm there are 5 plus the 2 external standoff tabs to work around.
Robert
Reverse Engineer
They have their place. The Paraphrase layout, for example, wouldn't be possible with 16mm pots.
The rate of change is dependent on the ole fulcrum and lever.
How big is the knob?
Though, 16mm have a few more degrees of turn iirc.
chris.knudson
Well-known member
@Robert is correct. They both have their place. I don't think this is a case of which is better, but rather which is right for a particular application.
jessenator
Well-known member
I've only made one (very ugly mag echo in 1590BB(WHY?)) board with both 16 and 9. Ran into issues, and even had similar issues with other not-my builds: mostly the drill points not lining up after population. I stopped using them in my own boards, but it's not just 16+9 pot alignment, it's other things like board mounted LEDs.
And I'm not blaming board makers on the slightest here.
@jwin615 and I were talking about this, because even lining stuff up in CAD, a 3d printing a test enclosure would fail to line up. Enough to require bending the 16mm legs more than one would think reasonable.
He's mentioned this elsewhere, but it comes down to variants (not talking margin of error here) of pots' physical dimensions in the legs before they bend 90° by not simply the manufacturer, but where they're sourced and sold from.
In our personal inventory sample sizes, Alpha brand 16mm pots from Tayda measure differently from US-vendor-sourced specimens. This is from pot stem center to leg pin center, the differential if which is 65 mils. It's very consistent. Variance/tolerance of one group (from one vendor) pots is only 5–10 mils at most. Even comparing against Tayda's house brand, they measure the same with the same tolerance. I.e. Tayda's house brand is identically spaced with the Alpha stock they sell.
I took my measurements off an Alpha and compared it to a board/drill footprint: center point of pot stem drill maker and center of pin pad/hole, and that's where I got the 65 mils differential.
To test, I offset the pot holes for a printed box by 65mils and lo and behold the holes for all pots and the on board LED aligned nigh perfectly; no bending required.
65mils isn't much, (1.65mm) but at that scale it's enough to cause alignment issues.
And yeah, you can bend pins—not hard to do—but I'd rather it just work and be neater. I made a custom footprint for myself, since 90% of my pots are alpha brand and 90% of those were gotten from Tayda.
I bet if I assembled another one of those boards I made with both 16 and 9 there would be 0 fitment issues.
again, I know this is really in the weeds, but it's something that kept me from using 9mm since.
And I'm not blaming board makers on the slightest here.
@jwin615 and I were talking about this, because even lining stuff up in CAD, a 3d printing a test enclosure would fail to line up. Enough to require bending the 16mm legs more than one would think reasonable.
He's mentioned this elsewhere, but it comes down to variants (not talking margin of error here) of pots' physical dimensions in the legs before they bend 90° by not simply the manufacturer, but where they're sourced and sold from.
In our personal inventory sample sizes, Alpha brand 16mm pots from Tayda measure differently from US-vendor-sourced specimens. This is from pot stem center to leg pin center, the differential if which is 65 mils. It's very consistent. Variance/tolerance of one group (from one vendor) pots is only 5–10 mils at most. Even comparing against Tayda's house brand, they measure the same with the same tolerance. I.e. Tayda's house brand is identically spaced with the Alpha stock they sell.
I took my measurements off an Alpha and compared it to a board/drill footprint: center point of pot stem drill maker and center of pin pad/hole, and that's where I got the 65 mils differential.
To test, I offset the pot holes for a printed box by 65mils and lo and behold the holes for all pots and the on board LED aligned nigh perfectly; no bending required.
65mils isn't much, (1.65mm) but at that scale it's enough to cause alignment issues.
And yeah, you can bend pins—not hard to do—but I'd rather it just work and be neater. I made a custom footprint for myself, since 90% of my pots are alpha brand and 90% of those were gotten from Tayda.
I bet if I assembled another one of those boards I made with both 16 and 9 there would be 0 fitment issues.
again, I know this is really in the weeds, but it's something that kept me from using 9mm since.
coltonius
Well-known member
One benefit would be size constraints. For 1590A builds with more than 1 or 2 pots, they’re a must! Another is sturdiness on the PCB. If you have the space for the stabilizer tabs, there’s less of a chance the legs will flex and break than on a 16mm with flying leads.
And let’s not forget that non-Alpha pots used to be garbage not too long ago. The Mammoth stuff was junk; nearly 1 out of 4 would have stripped threads! Now we have SBP’s house branded pots, which seem to be a high quality alternative to Alpha at half the price. The 9mm, however.. Not a lot of competition it seems.
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