Question - What is a cermet pot apart from more expensive ?

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Actually cermet pots tend to have much shorter lifetimes (fewer turns) than other types. Their main advantage is excellent temperature stability. This makes them well suited for use as trim pots where they are adjusted once and rarely touched again.

Here's a nice little primer on pots. http://sound.westhost.com/pots.htm

Thomas
 
Thanks Thomas

An interesting article.

The section with the table detailing the letter sufix for the different tapers is strange. They quote C as being the old code for Log. When you oreder pots from OMEG C is reverse Log.

It also says that CERMET trimmers are typically only good for 200 operations !!!
 
The letter suffix for the different tapers were (and are) different in Europe, US, and japan.

We love standardized descriptions - that's why we have so many different ones of them..

Jakob E.
 
[quote author="gyraf"]The letter suffix for the different tapers were (and are) different in Europe, US, and japan.[/quote]

I didn't know that! Here in the U.S. we use A for logs, B for linears and C for reverse logs... I just remember "A is for Audio" and the rest falls into place.

How does it work over in the Old Continent?

Peace,
Al.
 
In Europe:

10KA means 10K lin
10KB means 10K log (audio)

In Japan - and now often in US:

A10K means 10K log (audio)
B10K means 10K lin

Note difference between pre- and postfix - that shows the difference between European and FarEastern numbering..!

Jakob E.
 
[quote author="gyraf"]In Japan - and now often in US:

A10K means 10K log (audio)[/quote]
And then there's the log Alps pots (from Japan) that are labelled 10KA, just to make things easier...

Best regards,

Mikkel C. Simonsen
 
He-he.

So much for standards.

I always check anyway. set the pot to approx. half way, and measure. If reading is 40-60% pot value, then linear. If further out, it's log of some kind.
 
[quote author="barefoot"]Actually cermet pots tend to have much shorter lifetimes (fewer turns) than other types. [/quote]
I mean, that life time of CERMETs are veryvery long.
But their resistive surface is not planar and
they are not useful as fader.
More useful here are carbon pots, but they are obsolette and have short life.
Actual for faders now are pots with conductive plastic. But still costly.

xvlk
 
> cermet pots tend to have much shorter lifetimes (fewer turns)

It Depends.

Cermet is VERY stable (as you say) so it is good for HOLDING a setting. And in that case, you probably will never change it 200 times in the life of the gear. Most trimmers are rated only 100 or 200 cycles. Even though they may be good for much more, they just don't bother to specify that. Even if you calibrate every month, you may not trim every month, and 200 cycles is 16 years which is long enough to go obsolete, or at least go out of warranty.

A hand-operated pot does not need to be super-stable (if things drift, you adjust it) but does need some cycle-life. 10,000 operations is typical for good audio pots and sliders, though you can find 50,000.

And then there are the extreme situations. Servo-stabilizing a jiggly platform. Series V Cermet Potentiometers: Cermet Element for long life and high stability claims 100,000 operations. (But conductive plastic can be had in a 5 million operation rating.)

Also: cermet isn't cheap so they don't make cheap cermet pots. A $0.39 carbon-comp and a $5 Cermet trimmer may both claim 200 cycles, but the $0.39 pot has very very loose specs (high contact resistance, high wiper noise) while the $5 pot has much tighter specs it must meet after cycle abuse.
 
Back
Top