Will 9mm pots shorten the horizon of "vintage" effects?

[pinkjimiphoton]

ummmm... mark mentioned waza.

yeah.... nothing more "boutique" than mass produced boss pedals. <smh>

[Phend]

rated 15000 cycles, I'd think those P09x pots are going to last longer. (6.66x longer? maybe, unless something unrelated to rotation wears out first...)

Number of cycles is interesting,  15000 is a big number, how long would it take to turn the knob back and forth 15000 times. It might be suprising.
I remember our Jr high math teacher telling us we would get an A if we wrote up to 100000. Some tried. I am still writing.

[dschwartz]

In 2030, when everyone use 6mm smd pots, 9mm pots will be considered "vintage"..
Just sayin

[PRR]

> TT Electronics 9mm P09x series are sealed, conductive plastic, rated at 100000 cycles, and feel silky smooth.

Dood!! Those are two-buck pots!! SIX BUX for a 3-knob pedal!! You know what we could buy with $6? A pack of smokes! (No.) A quarter ounce!! (No.) Two gallons of gas! (No.)

[AtomicRob]

Number of cycles is interesting,  15000 is a big number, how long would it take to turn the knob back and forth 15000 times. It might be suprising.
I remember our Jr high math teacher telling us we would get an A if we wrote up to 100000. Some tried. I am still writing.

I don't adjust mine that often. Let's say once a week average. So those cheap pots will only last for ~288 years. Except my daughter (5) likes to adjust the knobs while I'm playing (and not playing) and I'd guesstimate it would take her roughly 10 minutes to spin it 15000 times.

[GGBB]

As I alluded earlier about the TT conductive plastic pots, the conductive element type probably matters, and based on TT vs Alpha / plastic vs carbon - plastic outperforms carbon. A cycle rating tells as much about how quickly it wears as it does about how long it will typically last. So (if my math is correct) a 100000 cycle pot should have 15% of the wear of a 15000 cycle pot at any point in time with equal use - whether that's 10, 100, or 1000 cycles. So 100000 is always better than 15000 and - on paper at least - should exhibit less signs of wear over the entire lifespan of the pedal.

More math fun - a 10 year old pedal with 100000 cycle pots will have wear equivalent to 1.5 years using 15000 cycle pots. 20 years old = 3 years. You get the picture.

[Mark Hammer]

The "cycle" figure pertains to how long the wiper can maintain functional contact with the strip.  And, while certainly useful, does not convey anything specific about the extent to which scraped residue from the resistive strip may build up inside to produce a noisy pot.  I have little doubt that the TT pots do less of that. I'm just saying that there is more to the continuing usability of a pot than figures like the #cycles indicates.  Plenty of pots continue to "work" well past significant arcs of their rotation becoming intolerably noisy.  If such pots provide points of access to eliminate dirt and residue buildup, then they can be persuaded to honour the number of cycles promises in noise-free manner.

[GGBB]

I think there's another part to the equation as well. At least in my experience, that crackle or "wear" spot that seems to always eventually develop is typically where the wiper is left "parked". I'll guess this is oxidation or whatever is the correct term for the interaction of two dissimilar conductive materials in contact with each other. So perhaps when pots are not used much, this is the primary problem, not actual wear. And maybe conductive plastic is better in that regard too. Surely size of pot wouldn't matter here - or would it? Then again, maybe it is mechanical wear - caused by sonic vibration. All I really know is that my conductive plastic 16mm TT pots seem to never exhibit these problems yet - been using them for close to 10 years now. In fact, it's the full size guitar pots that seem the worst in this area - good brands CTS and Bourns.

[Phend]

Fact, The pots you you can get are the pots that are available.
Want to advertise your effects for "30 day guarantee on moving parts" then get the inexpensive ones.
Want to advertise your effects for "lifetime warranty on moving parts" then buy the expensive ones.
Building for yourself, then, ?

[garcho]

...in my experience, that crackle or "wear" spot that seems to always eventually develop is typically where the wiper is left "parked".

I wonder how linear pots compare in longevity to pots with detents.

[Mark Hammer]

I think there's another part to the equation as well. At least in my experience, that crackle or "wear" spot that seems to always eventually develop is typically where the wiper is left "parked". I'll guess this is oxidation or whatever is the correct term for the interaction of two dissimilar conductive materials in contact with each other. So perhaps when pots are not used much, this is the primary problem, not actual wear. And maybe conductive plastic is better in that regard too. Surely size of pot wouldn't matter here - or would it? Then again, maybe it is mechanical wear - caused by sonic vibration. All I really know is that my conductive plastic 16mm TT pots seem to never exhibit these problems yet - been using them for close to 10 years now. In fact, it's the full size guitar pots that seem the worst in this area - good brands CTS and Bourns.

When I have volume pots that need rehabilitation with Stabilant 22, the area that needs it most is usually the zone between the 7:00 and 9:00 settings, because that's where the wiper tends to be moved around most for a lot of things, especially for volume pots that have a power switch on the back and need to be set to 7:00 to turn the device off.

[Electron Tornado]

Mark, I think the longevity question goes farther than just the pots. Some of these have already been mentioned - thin PCBs, any mechanical part that is PCB mounted, quality of the enclosure, etc. Lower priced pedals are disposable.

Will any of these eventually become sought after as "vintage" pedals? It depends - will someone want that old, cheap pedal they had as a kid (maybe feeling nostalgic), or will people seek out the pedals that may have been higher end and used by their favorite musician because now they might be able to afford one?

Eventually, it all might become moot, as effects (and amps) evolve more in the digital modelling realm. One day, DIY and modding effects might all be done by coding.

[Big Monk]

One thing of note about the 9mm pots that I don't believe has been mentioned: They have less threads on the shaft so are a very close fit in Tayda enclosures, which are a little thicker than their Hammond counterparts.

[Jarno]

I use both 16mm and 9mm but haven't noticed that, even with the 3mm acrylic panels I use for eurorack DIY synth modules, there are ample threads for a secure mounting. The PC mount 3.5mm jacks is a different story, those have just to little threads (so usually I just stick them through a panel without fixing them).

[amptramp]

There was a design many years ago where a potentiometer was patented that was completely non-contact.  It was activated by a light shining up the hollow shaft from the back of the pot and just forward of the resistance element, it had two mirrors to deflect the light onto the resistance element.  The resistive element had concentric rings.  The inner one was the standard potentiometer resistive element.  It was connected to the stationary 1 and 3 pins of the pot. Around this was a ring of CdSe in contact with the resistive ring all around.  The outer ring was metal and in contact with the CdSe all around and was connected to the slider.  The light is directed to a narrow sector of the element and the CdSe shorts out the slider electrode with the particular section of the resistive element.  There is never any physical contact.  The only issue is the resistance of the CdSe which is in series with the slider.  For most applications, a few hundred ohms is not important.  For tone controls, it might be more important in a tone stack than in, say, a Baxandall tone control.  CdSe is easy to deposit since you can mix powdered cadmium and selenium together and heat it in a vacuum.  Since they have almost equal vapour pressure, they deposit as CdSe without excessive amounts of one or another.  (I used to do this at one job I had.)

Maybe some enterprising soul on diystompboxes should set up a potentiometer foundry to make use of this.  This could be the second manufacturing operation to be set up in Germanium Valley.

[Kevin Mitchell]

Was dragging my feet on having an opinion on this subject. However it did prompt me to pry open one of these pots (forgot to take pictures!)

Other than being sealed, the construction is very similar to a typical potentiometer. In fact, it's more-or-less the same. Carbon tracks on a waver and a conductive rake on the actuator shaft. Seeing the inners of these kind of gave me peace of mind on the matter as it's not impossible to clean them. However, considering the price you'd be better off replacing them rather than clean & rebuild.

Also, they're not really sealed. Not with glue at least. The two parts of the plastic body is simply riveted together with two pins. All you have to do is clip two of the heads and it'll come apart.

Now the question I have is will these continue to be produced and will they become the norm over our beloved 16mm pots?
Like most questions raised here, only time will tell. I only use them when I need to as I prefer the 16mm right angle pots. But when space is a problem there's no reason to discount the 9mm variety.

Edit:
I'll also add the implication of hardware compatibility. When using them with something like a push button assembly or even a toggle switch they will protrude further outside of the enclosure's face due to the pot's lower profile. I can imagine that the easiest way for companies to get around this is to special order their pots with longer shafts - I've seen this with a couple of DSI synths and wondered how they did it - which they likely had special ordered the pots rather than redo the circuit board.

[Jarno]

If you look at these 16mm pots:


You'll notice a big opening where the pcb comes out from the housing, and an indent on the side of the housing which is open. Dust gets in there and sticks to the grease on the PCB.
You're right that the plastic parts of the 9mm pots are just riveted together (at least in the lower cost ones), but, no big holes is already an improvement.

I really don't think there's a meaningful difference in lifetime between the 9/16/24mm variants of the Alpha pots, there's a big improvement when going to conductive plastic, and also a big improvement if you use the Bourns pots like the 53RAA series, or other industrial quality potmeters. If you want quality, you need to spend upwards from 5usd on a pot, else it's all the same (well, you can go cheaper than Alpha pots, and those very likely will fail earlier).
Still, it might be fine for a guitar pedal.