Experience with this type of potentiometer?

The potentiometer in the image is smaller than the more common round type and seems to be better sealed against dust. I was wondering if anyone here has used this type and can share their experience. It's a carbon type and should in principle be suitable for frequent adjustments such as in audio controls. There are the usual variants - dual (stereo), with and without a switch.

Of course there can be good and bad products in any style of construction, but your experience (or that of a third-party source you consider to be reliable) will be helpful.

How about a manufacturer name and type specification?

No such information, I'm afraid. I've been looking at no-name Chinese products at www.aliexpress.com which is the only practical online source of parts for me. I live in a remote corner of a developing country where online sources for electronic parts never really took off. I stock parts bought from physical shops when I visit the major cities, but such opportunities don't come often enough. I've come to rely more and more on AliExpress in recent years.

I anticipated questions like yours but since I don't have such info, my question is more like whether there's some known issue with this type of construction. Example: When I did a lot of repair work in the past, I found that integrated bridge rectifiers broke down more often than discrete ones.

I see, but the obvious counter-question is: can you predict device reliability when only looking at the component outside?

In some cases, yes. Some engineering products can have shortcomings that are obvious to an experienced eye. But that's not what I'm asking here. My question was whether someone could share his/her experience with this class of product, not specifically those Chinese ones. Something along the lines of my own experience with rectifiers. The experience could be positive or negative; either will give me a starting point.

A prediction is impossible but I can give a wild guess:

It looks like a pre-set potentiometer with a shaft fitted to it. Pre-set types are really intended for setting then leaving alone rather than continuous operation. However, the reason pre-set types fail after many operations is the rotating center mount wears or isn't a precise fit so it has some lateral movement. That doesn't matter in normal use because it wouldn't be expected to move after being adjusted. That lateral movement could cause a resistance change though which would make it less useful as an audio control for example. How much the slack is removed by the metal front and shaft bearing is debatable but it would undoubtedly make it more reliable.

So in short - they are probably as reliable as full size 'normal' potentiometers but I would expect far more variability in manufacturing. Some may work well and be reliable, some may not or have short lives.

Higher quality potentiometers for pro audio and low noise use carbon brush wipers, that one will almost certainly have a spring steel one which tends to crackle as it moves along the track.

Brian.

I've used this type of potentiometers.
They have a good thing going for them: Dirt and humidity can't get inside them, so yes; all other things being equal, they are more reliable.

Thanks. I live in a region where the soil is mostly clay and fine dust gets in everywhere in the dry season. That's what makes this type of construction attractive.

It would be great if someone had something to share from personal experience with those Chinese products but I didn't really expect that. Besides listing those pots as parts at AliExpress, the Chinese use them in many of their products, kits and modules.

I have made several projects in the past using these types of pots.
I've used dual gang pots of the same type for gain adjustments in a
dual channel peak/hold LED VU meters.
Bass, mid and treble pots in some guitar audio projects.
What attracted me the most to these types was, as already stated,
they are a sealed unit, have an extremely smooth travel with no noise.
I always purchase mine from Jaycar and I've been extremely happy with them.
They are extremely reliable, as schmitt trigger has already stated.
I cannot tell of the really long term reliability of these pots, but the first one I fitted over 6 years ago, is still going strong.
Regards,
Relayer

Hi,

They look like ALPS potentiometer. ALPS are fairly good quality.
* but even ALPS recommends/sells higher quality pots for frequent adjustments and low wiper noise.
* and you can not be sure that your pots are the same quality than ALPS pots.

It's just guessing...

Klaus

Thanks, Relayer.

KlausST said:

They look like ALPS potentiometer.

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Yes, I noticed that. AliExpress also offers ALPS pots but at 10 or more times the price of their local products.

* and you can not be sure that your pots are the same quality than ALPS pots.

Click to expand...

True. I don't expect top performance from these products. I've seen some crappy Chinese products but I've seen some pretty good ones too and they offer extremely good VFM.

Examples: For the past six months, I've been using a Chinese replacement for my laptop's internal WiFi module. It uses the same chip and the same drivers, and cost me a tenth of the original with no noticeable difference in performance. Same thing for the thermostat in my bedroom fridge - cost less than one-fifth of what the local Samsung service center asked for.

I think I'll order a few of those pots and try them out. At ~US$2 for a pack of ten, it won't be a great loss if they turn out to be among their crappier products.

Pjdd said:

I think I'll order a few of those pots and try them out. At ~US$2 for a pack of ten, it won't be a great loss if they turn out to be among their crappier products.

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That is exactly my attitude with Chinese products. You win some, you lose some.
At that price, even if a single one out of ten is good, you still come up ahead.

As long as your expectations match the reality, you won't get disappointed.
OTOH, if your project is a hi-rel one where a single field failure would be immensely costly, I don't mind paying US$15 for a single potentiometer.

Hi,

Why using a mechanical pot at all?

There maybe are other solutions. But we don´t see a schematic or an application description.


Klaus

The pots are for general stock, not for a particular project. So no schematic or other details.

BTW, the ~US$2 price I mentioned is for 10 pcs, not for a single pot, with free shipping. I've placed hundreds of orders from AliExpress and except for urgently needed items, I usually go for items with a free shipping option. Transit time is anywhere from 3 to 9 weeks. I suspect that a large portion of that time is spent at customs.