Cermet Potentiometers -Where do you get'm in Oz

Mark_Walsh · « **on:** 17 Mar 2004, 05:31 am »

Dear All,

Read the FAQ from the aksaonline site regarding pots. Hugh's advice is to get a Bourns Cermet 100k Ohm pot and "law fake it" into something like log pot. "Preferably in the 81 or 82 series" ... but I cannot see anything in an 81 or 82 on any Bourns related website. The Bourn's site only mentions Cermet in connection with their trim pot and ONE potentiometer - a push-button 3680/3682 precision pot. Nothing that looks like a "Volume Knob" pot.

Where can I get one, or perhaps have they dropped the products?

Local suppliers look at me with a sad, puzzled expression when I ask for same.

Any ideas please?
Regards,
MW

Pleb Plebian · « **Reply #1 on:** 17 Mar 2004, 05:47 am »

Try RS Components (used to be Radio Spares).
Lots of stuff - and worthwhile talking to yr local rep (I found some stereo prs not listed in their catalog by getting our rep to go looking for me).

FWIW - ended up using one sourced from Hugh tho :-)

I built a "mechanical" geared mechanism to drive 2 mono pots for a while - this was effective and gave simple balance control - but a stereo pot is simpler to fit and I don't really need balance....

HTH anyhow
-Pleb (Good to be back!)

AKSA · « **Reply #2 on:** 17 Mar 2004, 08:18 am »

Mark,

Forget about getting 'em in this country; the one I use comes from France and I buy through Belgium.

I have to say that since sourcing is such a PITA, and so expensive given customs, middle men, French manufacturers who won't deal with you unless you speak French, and a whole host of other reasons too trivial to mention here, I'm considering just trying to find a decent stepped attenuator made in Asia at lower cost.

Anyone got any ideas? I've seen the 12 step ones out of China - thanks but no thanks, not good enough for my constructors - any others at moderate cost around???

Cheers,

Hugh

Mark_Walsh · « **Reply #3 on:** 17 Mar 2004, 08:22 am »

Thanks Phlebian,

So far RS Electronics don't have them BUT at least now I have found the Bourns Data sheets which DESCRIBE them. (They really have strange site). I will chase up more tomorrow. I wasn't going to hit Hugh for one because I have yet to purchase any of his products, and that would seem unfair in case of running him out of stock for his bona-fide customers. I will be using this as my volume knob (read that as "pre-amp") for my Easter Holiday Subwoofer Project. It will be re-used for my (yet-to-be-ordered, taking-this-slowly-with-wife) AKSA 100N.

Continuing search.

Regards,
MW

EchiDna · « **Reply #4 on:** 17 Mar 2004, 09:41 am »

Quote from: AKSA

Mark,

Forget about getting 'em in this country; the one I use comes from France and I buy through Belgium.

I have to say that since sourcing is such a PITA, and so expensive given customs, middle men, French manufacturers who won't deal with you unless you speak French, and a whole host of other reasons too trivial to mention here, I'm considering just trying to find a decent stepped attenuator made in Asia at lower cost.

Anyone got any ideas? I've seen the 12 step ones out of China - thanks but ...

hmmm I got a few up my sleeve Hugh, PM me...

Occam · « **Reply #5 on:** 17 Mar 2004, 02:26 pm »

Stepped attenuators at low cost -
http://search.ebay.com/search/search.dll?query=new+alps+volume&sosortproperty=1&ht=1&from=R10&BasicSearch=
and here is the caveat - they're not 22 step Alps attenuators, but rather Chineses manufactured stepped attenuators fraudulently labeled as Alps. Nevertheless, the response has been quite positive (no personal experience)
http://www4.head-fi.org/forums/showthread.php?s=fb302971806519ddaeb9d8ca3e3fd879&threadid=11704&perpage=15&highlight=alps&pagenumber=1

One of you Australian compatriots is selling these as actual Alps attenuators at substantial prices....

I personally feel that stepped attenuators are the work of the devil. Whenever I've used them (unless they've 40+ steps), I always experience volume remorse....

And a potential source for ladder attenuators -
http://www.diyaudio.com/forums/showthread.php?s=e97ab1475db64a9d73496405c7cc659a&threadid=22650&perpage=15&highlight=&pagenumber=1

The most serious concern for anyone obtaining such components is quality controll, which can be quite a crapshoot.....
A savings of $X can be a poor choice unless someone (such as Hugh) goes through the process of vetting, which by definition would substantially raise the cost.

Mark_Walsh · « **Reply #6 on:** 18 Mar 2004, 12:49 am »

Hugh ... we must have hit the "send" button at the same time yesterday. (See time codes.)

Thanks for your (unfortunate) advice.

Regards,
Mark Walsh.

TG · « **Reply #7 on:** 19 Mar 2004, 02:56 am »

Quote from: Occam

Stepped attenuators at low cost -
http://search.ebay.com/search/search.dll?query=new+alps+volume&sosortproperty=1&ht=1&from=R10&BasicSearch=
and here is the caveat - they're not 22 step Alps attenuators, but rather Chineses manufactured stepped attenuators fraudulently labeled as Alps. Nevertheless, the response has been quite positive (no personal experience)

I've used them in a couple of DIY projects and they are remarkably good attenuators. $50 is a lot for a Chinese fake, but then again it is the same as the cost in Australia of a genuine Alps Blue potentiometer from Farnell, so if you prefer stepped attenuators it's a bargain.

Beware that these seem to be based on a non-shorting switch (most of the time

) and so will "pop" as settings are changed. The fix is simple - place a high value resistor between the wiper and ground on each channel to preserve a path to ground between settings. Try a 1M resistor, and if the popping persists move to a 680k or 470k. The lower the value the more the pop will silence, but don't go too far or you'll end up with an effective voltage divider permanently in circuit.

TG

PS - I've never had a problem with only 23 steps. In fact I've never had a problem with only 11 steps on my old DIY attenuators. It all depends on the values of the steps and the attenuation level you choose.

EchiDna · « **Reply #8 on:** 19 Mar 2004, 03:38 am »

how much are the alps fakes in Oz? 50$!!!

I can buy them over the counter here in Singapore for S$15 (approx AU$11 as we speak), probably a lot cheaper in bulk...

TG · « **Reply #9 on:** 19 Mar 2004, 09:12 am »

Quote from: EchiDna

how much are the alps fakes in Oz? 50$!!!

The only local source I've seen is a guy in Melbourne who was auctioning them on Ebay. Starting price $35, Buy It Now $50. I don't know if he still has them or not. I bought one at auction from him last year before I found out about the Chinese source. Oh well, at least it works and sounds OK.