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The Multi Amp aka Dynalo Mk2


spritzer
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I am pretty certain that the Alpha pots are relabeled Song Huei potentiometers.

http://www.song-huei.com.tw/product.php?mode=show&cid=19&pid=93

might be a way to source a smaller amount from them

edit:

i just sent Song Huei a message inquiring what a minimum order is. I'll let you know what I find

Edited by cspirou
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34 minutes ago, mwl168 said:

Care to elaborate?

I don't having a smoking gun but I have some circumstantial evidence that leads me to think this. I spent quite a bit of time trying to find a source to buy these pots and the 21mm size isn't very typical of Alpha. I managed to find this site which list them as Alpha/Song Huei

http://theaudiocrafts.com/electronic-parts/potentiometers/alpha-songhuei-2122g-series-a10kx2-potentiometer

I guess Song Huei could be cloning these pots but considering how hard the Song Huei pots are to find as well, it doesn't seem likely. Better off cloning ALPS. Looking at the Song Huei site I found this pot

http://www.song-huei.com.tw/product.php?mode=show&cid=19&pid=93

This has the exact dimensions and pinout as the 21mm 4 gang pot on the following Alpha site.

http://alphapotentiometers.net/html/21mm_pot_4.html

Even further the parts numbers are extremely similar. With the Alpha site using 3RP/2142G and the Song Huei site showing RK2142G. Both have 2142G in common. Again this could mean that Song Huei is just cloning Alpha but I think it's more likely that they have a common manufacturer and that one supplies the other.

But even if they aren't the same pot, the fact that they have the exact same pinout makes it a viable alternative.

Edited by cspirou
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I'd agree on the assessment regarding the Song Huei pots, as they even share the numbering (2142G) as cspirou noted. They also give a complete schematic matching Kerry's board layout. Since I believe he built one, I would assume it works :)

Other than the TKD CP601, this pot is the smallest of the lot (TKD CP2500, Alps RK27), so keep that in mind Kerry before you offer to use a different pot.

I hadn't heard much in terms of reputation regarding sound quality of the Alpha pots vs. the RK27 and the TKD CP2500 (or 601). I know that I have liked the one CP2500 that I used, quite a bit better IMO to the RK27. I also hadn't realized that Justin was using these for a time in the GSX, but he also is crazy enough to buy 1000 at a time :)

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Since I often listen at fairly low levels, I look for low-volume imbalance in volume pots. I noticed that my quad TKD 601s behave as follows:

- 10k: no noticeable imbalance (sample size: 1 build)

- 50k: imbalance up to 8 o'clock (sample size: 2 builds)

FWIW, I hear no imbalance on an RK50 (sample size: 1 build).

Given that 8 o'clock is quieter than I typically listen to, the amount of imbalance on some TKDs is not a big deal. That said, I much prefer not to have it at all.

How does the quad Alpha fare?

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Thanks to cspirou for your rational. 

Interestingly Song Huei's web site mentions collaboration with TKD but not Alpha. I can visit the factory next time I visit home and maybe even strike a deal of some sort for a batch. But the nearest plan I have won't be till November time frame.  

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On ‎9‎/‎25‎/‎2016 at 0:02 PM, Pars said:

I'd agree on the assessment regarding the Song Huei pots, as they even share the numbering (2142G) as cspirou noted. They also give a complete schematic matching Kerry's board layout. Since I believe he built one, I would assume it works :)

Other than the TKD CP601, this pot is the smallest of the lot (TKD CP2500, Alps RK27), so keep that in mind Kerry before you offer to use a different pot.

I hadn't heard much in terms of reputation regarding sound quality of the Alpha pots vs. the RK27 and the TKD CP2500 (or 601). I know that I have liked the one CP2500 that I used, quite a bit better IMO to the RK27. I also hadn't realized that Justin was using these for a time in the GSX, but he also is crazy enough to buy 1000 at a time :)

Justin wrote on here somewhere that he stopped using the Alphas because he had to bin half of them. Don't know if that was a blip, but doesn't make for warm and fuzzy feelings. Plus the 601 is smaller than the alpha so might be the perfect candidate here.

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4 hours ago, MLA said:

Someone might but I don't think I am; I stocked up when running the current one so I now have pots for any foreseeable build in the next year or two....

I'm ok with doing a group buy for the TKD pots.  I know the US distributor is more than ordering from TKD directly but that may be our only option unless someone can buy from them directly and wants to handle that group buy.

What is the correct part number to inquire about?  I know it would start with 4CP601 and end with 10K but I don't know what taper is for volume.  I assume we want a blank value for the mechanical click.

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I have good news. Song Huei responded saying that they can make up to 99 pots for $4 each depending on the shaft we want. It seems cheap but when I converted the price from The Audio Guild site they cost about $6 for the stereo pots. From the email it seems like this is leftover material from bigger orders which is why they can do a small order. Here is what they said:

Okay.. we have element stock for making 99pcs. 
But I am not sure your shaft length.  
If you need 20mm round shaft (20KQ) : 57 pcs. 
25mm round shaft (25KQ)  : 99pcs available. 
 
So... please let me know what is quantity you need ?? 
RK2142G-A10K L-20KQ  or  RK2142G-A10K L-25KQ 
@USD 4.0 each. 
Terms : Exwork.  
 
- - - Have a nice day ^^

Since I have been communicating with them I don't mind doing the order.

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3 hours ago, RudeWolf said:

I'm game. I just wonder how many to get to be on the safe side...

Well if half the pots really are garbage then buying 2 gives you a 75% chance that at least one is good. 3 would be 87% and 4 is 94%. Note that these are probabilities to give a minimum of one good one, they can just as well be all good.

Half being bad seems horrendous so I expect it to be a bit better then that. We can probably get people to commit to buying at least 2 to make sure everyone can get a working one, it doesn't seem unreasonable considering the price. I'll try to figure out a setup to test the pots quickly.

Edited by cspirou
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