# Pots rant



## J-75 (Jul 29, 2010)

As I recall, pots 'back in the day' required far less attention than they do now.
How many times did Mom switch on, and turn up the volume on that kitchen radio? Lasted forever.
My most recent disappointment is a late-model Custom Vibrolux Reverb, which I acquired, used. It shows no visible wear, not even dusty inside, so it has all the signs of being a closet queen.
It 'scratches' fiercely on the FIVE most commonly used control functions on the panel.
That has forced me to take the whole unit apart, only to discover (to no surprise), that the pots are all miniature, bracket-mounted, and each has 7 solder connections to a PCB - (three, plus four on the bracket). There is no physical way of introducing a spray cleaner (not that it always works, anyway).
I simply ordered replacements from one of the parts houses in Arizona, and am awaiting their arrival.
I can guess that whatever brand they are marketed as, they will be all cheaply made in the far east, and as such, probably will have a short lifespan as well.
'We can put a man on the moon, but we can't make a decent volume control' (you may quote me on that, LOL)

Has anyone got any recommendations? I'm sure that CTS is now made in Asia, unless advised otherwise.
Thanks for reading.


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## Adcandour (Apr 21, 2013)

After a long search, I ended up with Emerson cts. Better than the non-emerson ones. I ab'd them with a local guitar tech and it was unanimous. They are also better than the allesandros that we tried as well ($50USD per pot)

Edit: I purchased the Emerson pots after finding out that is what larrivee was using in their RS series.


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## High/Deaf (Aug 19, 2009)

I've never seen the inside of one of those. Any way you could attach good pots to the faceplate and fly the three leads to the PCB?


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## greco (Jul 15, 2007)

adcandour said:


> After a long search, I ended up with Emerson cts. Better than the non-emerson ones. I ab'd them with a local guitar tech and it was unanimous. They are also better than the allesandros that we tried as well ($50USD per pot)


Info about the Emersons:
Emerson Pro CTS Pots | stewmac.com

@adcandour Are there any Canadian suppliers of these pots?

I remember the Allesandro pots. All of the products that I have seen by that name are VERY expensive.....even hookup wire!!


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## Adcandour (Apr 21, 2013)

greco said:


> Info about the Emersons:
> Emerson Pro CTS Pots | stewmac.com
> 
> @adcandour Are there any Canadian suppliers of these pots?
> ...


I can't remember where I bought them, but I can check.


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## KapnKrunch (Jul 13, 2016)

I bought super expensive pots from some aero-space outfit. Meh...

I think CTS is the way to go.


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## Adcandour (Apr 21, 2013)

greco said:


> Info about the Emersons:
> Emerson Pro CTS Pots | stewmac.com
> 
> @adcandour Are there any Canadian suppliers of these pots?
> ...



Turns out I bought them at Axe and You Shall Receive. I think they're in Brantford.


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## knight_yyz (Mar 14, 2015)

Bourns, also I'm not sure if they do anything but you can get dust caps for pots


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## J-75 (Jul 29, 2010)

knight_yyz said:


> Bourns, also I'm not sure if they do anything but you can get dust caps for pots


The amp housing is very clean inside. It's my belief the carbon film inside the pot is being worn/scraped off by the wiper prematurely. The composition of the carbon is not durable enough maybe(?).
P.S. Ya, Bourns is another old, quality manufacturer I should look for.
Adcandour mentioned Allesandros sell at $50 a pop... Yikes! The only pot worth that kind of money comes in bags.
By the same token, I've got some old Bourns 10-turn precision pots in my parts drawer that I could make enough to retire on.
Wait a minute, I AM retired. Terrible how age dulls the memory - now where was I ...


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## Granny Gremlin (Jun 3, 2016)

LOL, to me CTS ARE expensive pots (yes I know there are more expensive post still; especially if you go into HiFi stuff). All Emersons are, are CTS pots with a custom taper (still log but a slightly different shape/slope) and higher QC. That's it.

If you want no scratching move to something conductive plastic based (vs carbon track). Some higher end guitars already use them (mostly Bourns, though Bourns also makes carbon pots; very good quality; personally prefer them to CTS, but CTS is the standard everyone knows). FYI you can't clean CP pots with any standard contact cleaner; melts away the CP and strips away the lube (don't use Craigs Deoxit, but something from their F-series line instead).



knight_yyz said:


> I'm not sure if they do anything but you can get dust caps for pots


AKA pot condoms, but what they are really for is to shield the pot casing electrically (e.g. in tight pedal builds with r-angle PCB-mounted pots vs solder lug or even straight PCB pins, so it doesn't short out the traces on the board).

E.g. in this situation:









They look like this:









IMHO they are superfluous in that second pic.

They won't keep dust out because the area by the terminals is open. If someone needs/wants some anyway I have both 16mm (rigid plastic trans white as pictured above) for mini pots (as used in pedals and at least older asian import guitars) and 24mm ( more flexible black plastic) which is the mosre stabndard (American) guitar pot size.


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## mhammer (Nov 30, 2007)

In my experience, dust is a lesser concern than internally generated grime. Maybe it's because we tend to live in air-conditioned homes these days and the windows are often closed. Maybe it's because we don't have any pets and nobody here smokes. Whatever the case, dust isn't a problem.

That said, people forget that pots work by friction. There is a resistive strip inside that is a horseshoe of compressed particles, and the wiper makes contact by being forced against the resistive strip. If it's a pot you rotate a lot, then all that rotation is rubbing and scraping against the resistive strip. My own experience is that wider diameter pots tend to have wipers with a gentler, less abrasive contact with the strip, while the 9, 12, and 16mm pots more commonly found these days tend to have lousier wipers that look like the "cowcatcher" on old locomotives (actually, more like a close up of a kalimba) and scrape the strip more.

The end result is that often much of the dirt inside pots is actually a buildup of residue scraped off the surface of the strip by the wiper. This is why I like to use Stabilant 22, a proud product of Thornhill ON. The analogy I like to use is this. Imagine a freshly-paved stretch of blacktop. Drive on it and it will be extremely quiet, because your tires make perfect continuous contact with the asphalt. Over time, there will be debris on that road, some of it deposited there, and some will be little bits of the asphalt lifted up. If you were totake a big push-broom and sweep everything loose off the surface of that road, it would quiet things down a bit, but your tires would still make noise, because there are many pits in the surface from the asphalt that has been lifted out. Similarly, spraying pots with cleaner will only do so much. Stabilant forms a permanently viscous electroconductive film that fills in all those pits, so that the strip behaves as if it is brand new smooth surface and was never scraped.

There are limits to what it can do, largely because it never dries, so you can'tbuild up layers. If you're in a Cream cover band, and you've been playing Tales of Brave Ulysses and White Room, twice nightly since 1975, it will not make your wah pot perform like it was brand new. But I've descratched plenty of pots and switches, and gotten TV remotes, gamepads, and Nintendo cartridges working again. Even got the SIM card in my sister's cheap phone to work again with the stuff. If I expect a brand new pot to endure heavy duty, I will remove the back of the pot when I get it, put a few dabs of the stuff on, close the pot up again and THEN install it.

In the grand scheme, it is probably a good idea to use better and bigger pots with well-designed, less-abrasive, wipers. But they don't always fit in the available space,so the next best thing is to extend the life of the pot by treating it with something that lubricates the contact between strip and wiper, and addresses any imperfections already caused in the strip. It ain't cheap stuff, but a small bottlewill take you years to use up, since all it takes is a few sesame-seed-sized droplets to treat a pot.


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## knight_yyz (Mar 14, 2015)

I prefer these ones. A bit more expensive but they are sealed. 


















I noticed that those pot condoms are actually blocking a few holes though


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## Granny Gremlin (Jun 3, 2016)

Those are Bourns conductive plastic, no? They look the same in any case. CP pots have the advantage of often being sealed like that, as well as more consistency in taper and value ( higher tolerances, usually 5% vs typical carbons which are 20 %; Emersons are selected from the CTS production line via an extra QC process and therefore unnaturally 8%; the rest are thrown back as it were).

The pot condoms aren't blocking any holes that actually do anything useful ( the one on the bottom) and you can take them off if you want to.


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## knight_yyz (Mar 14, 2015)

Conductive polymer element


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## jbealsmusic (Feb 12, 2014)

Alpha = Made in Taiwan
Bourns = Made in China
CTS = Made in Taiwan

Can't speak for the other brands or specialty ones (like the Emerson ones). Does it really matter these days anyways? Product quality is about design and quality control, not where it is made.

I will say this much... In the past 2 years NG has shipped and received thousands of pots. Alpha probably outsells Bourns and CTS combined by about a 2:1 ratio (probably due to the price difference). Despite that, we have had more CTS pots arrive DOA (visibly defective) or get returned by customers due to non-visible defects than either Alpha or Bourns. In fact, I can only recall one Alpha pot arriving DOA because one of a solder lug snapped off in transit (very tightly packed and poorly treated box). Never had a single problem with a Bourns pot, but we don't sell a ton of them. Very few people like the feel of them, fast and loose.

That said, that all has to do with fresh pots coming in from the factory. It says little to nothing about product longevity. For all I know the contacts on Alpha pots will crap out sooner than a good CTS one. So take the above with a grain of salt.

There are premium pots out there for upwards of $50+ per pot. Precision (Canadian company) and Alessandro are a couple of examples. I'm sure there are more, but I don't know them all and don't know where to get them in Canada. It would be super cool to know how every component in each brand/type of pot is different, what materials and build methods are arguably better, and what the biggest factors in lifespan are.

Sounds like someone needs to make a pot documentary.


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## bolero (Oct 11, 2006)




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## Granny Gremlin (Jun 3, 2016)

knight_yyz said:


> Conductive polymer element


yeah; same difference. Just a fancier name.


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## Granny Gremlin (Jun 3, 2016)

knight_yyz said:


> Conductive polymer element


yeah; same difference. Just a fancier name.



jbealsmusic said:


> That said, that all has to do with fresh pots coming in from the factory. It says little to nothing about product longevity. For all I know the contacts on Alpha pots will crap out sooner than a good CTS one. So take the above with a grain of salt.


Alphas are good quality; just about every pedal DIYer uses them, and most pro (boutique) opedal builders as well. Some of the majors too IIRC. I use them in my builds; they hold up just fine. To be fair I don't have a modern CTS in use (a few in the parts drawer) to compare to though.... even my vintage instruments have Centralab pots not CTS.


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## J-75 (Jul 29, 2010)

bolero said:


>


GOL-LEE ! that was SWELL !


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## mhammer (Nov 30, 2007)

Granny Gremlin said:


> Alphas are good quality; just about every pedal DIYer uses them, and most pro (boutique) opedal builders as well. Some of the majors too IIRC. I use them in my builds; they hold up just fine. To be fair I don't have a modern CTS in use (a few in the parts drawer) to compare to though.... even my vintage instruments have Centralab pots not CTS.


It's a good time for the development of a "stickie" about pot characteristics and quality. For instance pots can have great longevity but poor compliance with the tolerance spec, or the taper spec. They can have great longevity and precision, but lousy feel. And so on.

There's a lot more to a pot than simply "good quality" or "crap". And in many instances, what you REALLY need a given pot for is simply its ability to fit into a predetermined space, whether that being having a long-enough collet to poke through the top of a guitar from a control cavity, or fit in a 1590A enclosure.


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## Guest (Mar 24, 2017)

mhammer said:


> t's a good time for the development of a "stickie" about pot characteristics and quality.


To add to that list;
- linear and audio taper; how they work and for what situations (vol/tone)
- cap values to match kind of pup's or flavours of tone


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## mhammer (Nov 30, 2007)

Popped into the local Active Tech store yesterday, and was surprised and pleased to see that they have now started carrying Stabilant 22. A 15ml bottle is $44.80, but it will do you for lots and lots of pot rehabilitation.


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## Granny Gremlin (Jun 3, 2016)

LOL @mhammer - I see you pushing the Stabiant on DIY Stompboxes too. I will try some eventually.

Anyway, the reason I cam back to this thread is because I just noticed that Trinity Amps uses Alpha pots (as well as Bourns; mix of both). Says so right on their kit description pages. So there [rasberry] .


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## mhammer (Nov 30, 2007)

Yeah. A little embarrassed about that. B#(* I'm starting to feel like one of those fast-talkers with the British accent selling AMAZING non-stick cookware at 6:00AM on AMC. Just LOOK how fast I was able to cook that 25lb turkey...and everything wipes off so easily!

I have no connection to them, by contract, by marriage, by Facebook, or any other manner. Not to take anything away from DeOxit, Cramolin, and other fine products that techs have relied on for years, but Stabilant is just one of those things that I never see mentioned anywhere, and it has just impressed the heck out of me. It's just a damn shame it isn't cheap. And quite honestly, if I hadn't been able to buy some of those little 50-cent "testers" from a local place before they closed, you wouldn't have been hearing about it from me either.


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## J-75 (Jul 29, 2010)

How many times has this happened to you...

(Knock, knock)...
Who's there?
Murphy.
Murphy who?

After receiving and installing an order of replacement pots, I have run into two gotcha's:

#1 I failed to notice on the schematic that the 250K pot on the Treble control, channel 1, has a CENTER TAP! ie., I ordered an incorrect part.

#2 The 'genuine Fender replacement' parts (made in China) have different shaft lengths than the originals. No problem? Well yes, unless you don't mind some of your knobs protruding a quarter inch further from the panel than the rest. I could just re-seat the remaining knobs to protrude further and comply, but how dorky will that look? (I tested that idea).
So, some careful hacksawing in-situ, took care of the over-length shafts. In all probability, the original pots were also probably made in China, but in which plant? Reminds me of an old (Toronto) saying: "Does Eaton's talk to Simpson's?" (suggesting an obvious, deliberate, lack of communication between competitors).

So I sprayed the original center-tapped pot with contact cleaner (not DeOxit - can't find that stuff in Canada), re-installed it, along with the new replacements, and bench tested the rig. All was silent except for the re-used noisy center-tapped pot.
Now, I have to locate a 250K audio, with a center tap, and in a 16mm, snap-in bracket mount format.

Stabilant? Sure, where do I get it in Niagara?


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## Granny Gremlin (Jun 3, 2016)

Hey @J-75 

1) Center tapped pots are very uncommon - you sure you didn't mean center detent (a click when in middle position vs an electrical connection; a 4th terminal on the pot)? Just checking, cause if center detent it will still work fine without (you just don't have a clear mechanical indication of where center is, but rock n roll is not such an exact science). If center tapped then, yeah, you're boned.

2) Too long is not a problem (too short and yer screwed... well, maybe not screwed but more of a challenge), you have 2 options depending on the situation.

If the threaded part of the shaft (bushing) is too long get a second nut (or a few washers) + a lock washer and put them on the shaft to stop the pot from going all the way through the panel hole - like choking up on a baseball bat (i.e. the extra length hangs out the back vs the front):










If the rest of the shaft (the part where the knob attaches; not threaded) is the too long part, saw it off to the appropriate length (measure twice; cut once). I love my Dremel.


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## J-75 (Jul 29, 2010)

Thanks GG,

After a second look at the schematic's fine print, the tap is not a center tap. It's tapped at 50K above its ground end on an audio taper.
The tap leads to the wiper of the Bass pot. This pot has to be a Fender model-specific custom part.

(P.S. Is that Riverside as in Humber?)


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## mhammer (Nov 30, 2007)

J-75 said:


> Stabilant? Sure, where do I get it in Niagara?


Well, they make it in Thorn Hill so if you're in the neighbourhood....

Check out the March flyer for Active123.com. I don't think there's any stores near you, but maybe they deliver.


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## gtrguy (Jul 6, 2006)

J-75 said:


> DeOxit - can't find that stuff in Canada


Burlington, ON:

Caig-DeoxIT D Series Cleaners


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## jb welder (Sep 14, 2010)

mhammer said:


> I have no connection to them, by contract, by marriage, by Facebook, or any other manner. Not to take anything away from DeOxit, Cramolin, and other fine products that techs have relied on for years, but Stabilant is just one of those things that I never see mentioned anywhere, and it has just impressed the heck out of me. It's just a damn shame it isn't cheap. And quite honestly, if I hadn't been able to buy some of those little 50-cent "testers" from a local place before they closed, you wouldn't have been hearing about it from me either.


I remember the rep bringing stabilant 22 around when it came out, late '80s or early 90's ? We were all extremely skeptical of the claims and figured it was some very expensive super-snake-oil. 
It turned out to be everything Mark has described, definitely the most impressive contact rejuvenator I've ever used, and those tiny bottles last a long time. I'll be checking for it at activetech next time I'm in the big city.


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## J-75 (Jul 29, 2010)

mhammer said:


> Popped into the local Active Tech store yesterday, and was surprised and pleased to see that they have now started carrying Stabilant 22. A 15ml bottle is $44.80, but it will do you for lots and lots of pot rehabilitation.


When you apply Stabilant 22, do you have to pry off the back dust cover of the pot and brush the stuff right on the track?


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## mhammer (Nov 30, 2007)

J-75 said:


> When you apply Stabilant 22, do you have to pry off the back dust cover of the pot and brush the stuff right on the track?


That would depend on the space afforded by the pot cover itself. But yes, my experience has generally been that removing the back cover is the fastest route to applying an efficient amount over the entire resistive strip. It also lets you see that you have done so, rather than blindly wasting the stuff, hoping that it lands in the right spot. I find that all I need to do the job on a standard 16mm Alpha pot is 3 or 4 well-placed sesame-seed-sized droplets. You placeone just ahead of the wiper, and use the wiper to spread it as far as it will go, place another droplet, and so on.

The part I have never really understood is why it conducts between the wiper and strip but doesn't conduct "sideways". I'm sure there's a reason but it goes beyond the perimeter of my knowledge. My sister's phone wouldn't read her SIM card, and it was driving her nuts because all her pics were on the card. I brought a little vial of the magic stuff over, smeared a few droplets over the pins with the little plastic applicator, pushed it into the phone and it has worked flawlessly since.

The thing I like to say is that, in the land of electrons, a couple of microns may as well be the Grand Canyon. If the discontinuity/gap is of appropriate size, the stuff will fix you up real good.


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## Wild Bill (May 3, 2006)

Lot of in-depth coverage here but I feel the need to add one little point. Sometimes a coupling cap can go leaky and allow some DC voltage to flow through a pot, depending on how it's wired in a circuit. Usually this voltage has little current so nothing is frying and the resistance of the pot itself can keep this leaky voltage from rising to a point that noticeably affects the following parts of the circuit.

However, what it CAN do is make the pot sound scratchy! As an example, this is the likely reason Marshall changed the presence control circuit in its early models away from a 5k pot bypassed with a cap to a 25k pot with the cap wired to block any dc flowing through the control. In the original control you didn't have to worry about a leaky cap 'cuz the pot was a direct path for DC voltage!

Anyhow, I have seen this leaky cap/scratchy control issue a number of times over the years and thought I'd pass it along. It's not really a common thing but when it does happen if you aren't aware of it you can waste a lot of time and swear words trying to track down the source of the scratchiness.

Wild Bill


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## Guest (Apr 6, 2017)

Welcome back Bill!
We all missed ya!


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