Potentiometer materials

[flester]

Trying to pick pots for amp projects. Any view on track material i.e. carbon, cermet, conductive plastic etc? Longevity, price, noise etc.? Trying to choose what local vendors can supply me at reasonable cost. Farnell and Radionics both have good delivery costs to Ireland for example.

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[phatt]

conductive plastic = Longevity = expensive
Carbon tracks are cheap and work ok.
both do the same job,, there is no magic mojo if that is what you are wondering?
Phil

[flester]

Not a question of Mojo. Just when I ordered some generic 1k carbon pots from Amazon they were particularly bad and fell apart when soldered. And there is a huge choice so hoping to get something usable. How about wirewound ones? They look a bit  bulky for my current project though.

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[Enzo]

Well, I for one would not be ordering parts I care about from Amazon or ebay.  I would use reputable parts vendors.

Those nice sealed military grade pots are terrific, but overkill.  They have been using plain old carbon pots for decades on amps.   If I were building something for someone else, I would chose a line of pots I could get ALL the values I need from.  Nothing screams amateur like mismatched collection of pots.

[phatt]

Awe shucks Enzo,,you talkin bout me again?  :lmao:
My problem is that a store that used to stock all the small Alpha pots went broke and now I have to use what ever I can get.
One day I'll have to bite the bullet and buy online I guess.

@ Flester; When you say they fell apart,, I hope you are aware those pot lugs are rather delicate so don't stress them too much and don't apply heat for too long when soldering.
I've used cheap alpha pots for years and some last longer than others.
Phil.

[Enzo]

I buy online all the time, from real qualified vendors.  But for my own stuff, my parts collection has world war 2 replacement pots still in the sealed containers, up to the modern new stuff.  I still have pulls from old TV sets in the 1950s.

[phatt]

I buy online all the time, from real qualified vendors.  But for my own stuff, my parts collection has world war 2 replacement pots still in the sealed containers, up to the modern new stuff.  I still have pulls from old TV sets in the 1950s.

Would it be ok to ask the names of your suppliers?
I've actually never purchased anything from the net as I'm still stuck in the 80's,,
I hate mobile phones and ipads/ipods/ipads.
I hardly have time to watch free to air TV these days.
But I can see that I'll have to embrace some of this fancy technology soon otherwise I'll be left in the world of .. iDUNNO? :duh
Phil.

[phatt]

Not a question of Mojo. Just when I ordered some generic 1k carbon pots from Amazon they were particularly bad and fell apart when soldered. And there is a huge choice so hoping to get something usable. How about wirewound ones? They look a bit  bulky for my current project though.

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Oh yeah while trying to be funny bugga,,I forgot to mention;

Don't bother with wire wound pots as they are not really meant for small signal circuits and may even cause noise when moved. They are for higher current circuits.
Audio preamp circuits only carry a few milliWatts so carbon track is ideal but do wear out, some faster than others. If you are lucky enough to have old stock like "Enzo" then they were made to a much higher standard and will last much longer than the pots you buy today.
I have some old pots with Brass bushings and solid terminals. But now even the Conductive plastic Alpha pots have aluminum housing and shaft and although it works,,, anyone with understanding of metals would pick the quality difference just by looking.
Alloy shaft against alloy bush is prone to jamming, they can cease up over time.
maybe a bit off topic but here is a 1/4 inch chassis mount socket from years ago, maybe 1940's, the arrow mark is likely British Military stock.
Now compare that to what is on the shelves today.
Sadly quality has fallen victim to a profit hungry industry,, so they cut cost at every chance.
Even so called quality guitar cable is mostly just twisted stands for outer shield (Crap) while the old stuff was *Woven* outer shield,, but more expensive to manufacture.
Rant over, Phil.

[Enzo]

I am actually a bit of a Luddite myself.  I was at the store yesterday asking if they had a certain meat product.  The butcher said, "You have a smart phone?" and was absolutely astonished when I told him I did not.  I don;t even have a dumb phone.  I told him I had both phone and internet at home though.

If you can get to this forum, I have to think you can get to any internet parts seller.

For general parts, I look to Mouser, Digikey mainly.  I used to use Allied a lot, but the selection was better for me at the others.  Newark is another big house.  I never use them, but not for any reason that matters.

For amp specific parts, I use AES a lot (I use CEDist, their wholesale wing).  They are at www.tubesandmore.com.  There are other similar companies, but AES has served me well.  Companies that sell tubes often sell other amp parts.  Other guys may have other favorites than mine, nothing wrong with others, I just find a place I am happy and I stop looking.

Jameco is a smaller house, aimed more at the hobby or enthusiast crowd.  But sometimes they have just what I need.  I look there for LEDs and photocells it seems to me.

[flester]

Thanks all. Farnell seems a good  supplier with free delivery to Ireland as long as you dont pick something from their US warehouse then its €20 delivery. (nearly got caught with that). Just ordering from them so will keep u posted. Theres also Radionics and both of the above supply the industrial market. Theres also a Maplin store locally with high prices.

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[flester]

Awe shucks Enzo,,you talkin bout me again?  :lmao:
My problem is that a store that used to stock all the small Alpha pots went broke and now I have to use what ever I can get.
One day I'll have to bite the bullet and buy online I guess.

@ Flester; When you say they fell apart,, I hope you are aware those pot lugs are rather delicate so don't stress them too much and don't apply heat for too long when soldering.
I've used cheap alpha pots for years and some last longer than others.
Phil.

Didnt physically break but would not conduct.
I may have overheated one but the others were never soldered and still did not work. It is harder to get good materials for making anything these days. My Dad used to make or fix anything and still does but its becoming harder.

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