[sdiy] Group buys: Alpha-style, dual pots, and Joysticks (WAS: RE: Dual-gang reverse-log pot group buy ?)

Bruce Duncan modcan at sympatico.ca
Mon Nov 17 19:57:02 CET 2008

One thing to watch out for on Asian pots is the shaft sizes are often metric.
Alpha makes a true 1/4" shaft while others are 
often 6mm. It is not a big difference but
North American style knobs will rotate in a 
non-concentric way on shafts that are undersize.
It looks wonky.

I made this mistake buying from non-alpa supplier 
and now have 1000 10K pots I can't use.


At 09:23 AM 11/17/2008, you wrote:
>Hey, if there's enough, I'm up for it!
>And, I've actually found much better pricing:
>Song-Huei quoted $0.16 each for 1000. They sent me some samples too, very
>nice! Identical to Alpha, except their washers are a much tighter tolerance
>so they pretty much stay centered without having to hold them while
>tightening the nuts.
>Even better, G&H quoted me $0.099 each at 1000 MOQ! Harvestman told me about
>them and let me check out a sample - I didn't think to check the washers,
>but they are also just like the Alphas in feel and build. They also carry
>those Illuminated caseless slide-pots I was hunting.
>Dual pots: I've been hunting for affordable concentric-shaft duals, and
>finally found some. Top-up has these 9mm duals:
>55, and quoted $1.21 each at MOQ 1000. I was planning on getting B100k/B100k
>pots for Coarse/Fine control on the upcoming Imp module.
>Joysticks: I finally found these people and got a quote! This has been a
>long quest, but they are worth it. These are the joysticks I use in the
>Infernal Noise Machine (big one on the right):
>http://www.flightofharmony.com/images/Stuff/Joysticks.jpg. They have a 90°
>arc of travel and are the SMOOTHEST feeling joysticks I have ever used. For
>the large, I was quoted $13.10 each for 500 for B100k, no center-return
>spring, with knob. The small, same options, is $12.48. The USD is rather
>unstable compared to the Yen right now, so the price will fluctuate a bit.
>The standard resistance value for the joysticks is B10k. The pots are built
>for each model - the large ones have pots that go from 0-->Rmax in 90°, the
>smalls in 60°.
>I've been drumming up interest in these on Muffwiggler and we're off to a
>good start. The plan is to make the purchase in January.
>flight at flightofharmony.com
>-> -----Original Message-----
>-> From: Andre Majorel [mailto:aym-htnys at teaser.fr]
>-> Sent: Monday, November 17, 2008 5:45 AM
>-> To: synth-diy at dropmix.xs4all.nl
>-> Cc: flightofharmony
>-> Subject: Dual-gang reverse-log pot group buy ?
>-> Regarding the recent talk of a group buy of Alpha pots...
>-> Parametric equalisers often use anti-log pots for the frequency
>-> control. Would anybody be interested ?
>-> If Kevin orders direct from Alpha, minimum order is one thousand
>-> of each reference, meaning we'll be lucky to reach MOQ for *one*
>-> value. Here's what the circuits I've seen use :
>->   Moog 3-band http://files.muziq.be/schematics/moog_pareq.jpg :
>->     100 k dual for each band
>->   Rane PE 15 http://rane.com/pdf/old/pe15sch.pdf :
>->     100 k dual ("100KE" antilog assumed)
>->   Rane PE 17 http://rane.com/pdf/old/pe17sch1.pdf :
>->     100 k dual ("100KE" antilog assumed)
>->   Speck ASC http://www.speck.com/asc/asc_2.shtml :
>->     500 k single for the low band (simulated inductor, peak/shelf)
>->      50 k dual   for each mid band
>->     500 k single for the high band (simulated inductor, peak)
>->   Ethan Winer's SVF http://www.ethanwiner.com/spect-1.gif :
>->      50 k dual   for each band (SVF)
>-> What would be the best value ? 50 k ? 100 k ?
>-> Don't know how much duals cost but the prices Alpha have quoted
>-> for singles are pretty good (0.22 USD). At that kind of price, you
>-> wouldn't need to stock both singles and duals...
>-> No promises, though. This is Kevin's group buy, it's his decision !
>-> --
>-> André Majorel <URL:http://www.teaser.fr/~amajorel/>
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>Synth-diy at dropmix.xs4all.nl

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