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Blue Hawaii Special Edition


pabbi1
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I saw that first bit, but read it as 'Mini-V series', as in the Mini-V series of attenuators. That second bit I did not see. :)

I wonder if the Singlepower stepper I use is series, ladder or shunt?

It seems that second quoted paragraph answers your question though, at least from Goldpoints position.

The ladder attenuators always had 4 decks for stereo...i don't know if this has changed

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I saw that first bit, but read it as 'Mini-V series', as in the Mini-V series of attenuators. That second bit I did not see. :)

Yup, that's why I linked to the second bit. Although for those of us that have built ladder type attenuators before it's pretty easy to see that the Goldpoint's aren't ladder types, there simply aren't enough resistors.

The ladder attenuators always had 4 decks for stereo...i don't know if this has changed

That's pretty much the way I remember it. There previous version looked a lot more like a stock elma stepper like this one:

medium.jpg

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Basically, you count the resistors. For each channel, a series attenuator will have a resistor for each step, a shunt will have a resistor for each step plus one resistor as the series element, a ladder has 2 resistors for each step.

Thus a 24-step stereo series pot has 48 resistor for series, 50 for shunt, and 96 for ladder. Shunt may have 48 as well if they simply short out the contact for zero volume.

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I just had the option of hearing a preamp with a Alps HQPro and then it was switched out with a standard stepped attenuator using Riken resistors. Yeah, I'd take the HQPro any day...

random, but I noticed that there's one for sale at diyaudio with pics :)

http://www.diyaudio.com/forums/showthread.php?s=&threadid=112437

Have you gotten the Joshua Tree yet?

Bout time you got here... :o

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Howdy pabbi1! I've been lurking / stalking KGs posts to see if anything cool shows up over here ...

yup, I built a few JTs, I really like them. Only problem with the JT I've seen is playing the input / output impedance game with them. Haven't thrown one on the new KGSS. Nice segue though.

According to Russ, the input impedance of the JT attenuator ranges from approximately 2.2K to 10K and the output impedance is 750R (this is for the 50k "version" of the Joshua Tree, this obviously is not set in stone, and there are resistor calculators on diyaudio). The original KGSS schematic has 500K input resistor for Zin. I was wondering if this combination will "work", or if I should look at reconfiguring the JT? With the relatively high Zin of 500k that the KGSS/BH uses by default, is either output offset (I assume not) or noise a problem? By noise, I mean noise due to stray capacitance between the input terminals and the board inputs? I have heard that this can be a problem when using high values for Zin and that this could have an effect on the high frequency response.

Also, has anyone experimented with a RF filter (R+C) right off the jacks on headphone amplifiers such as these? Of course upstream impedance might have to be calculated and the filter "fiddled" with a bit...

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I just had the option of hearing a preamp with a Alps HQPro and then it was switched out with a standard stepped attenuator using Riken resistors. Yeah, I'd take the HQPro any day...

random, but I noticed that there's one for sale at diyaudio with pics :)

http://www.diyaudio.com/forums/showthread.php?s=&threadid=112437

THe RK50 is in a league of its own. It's the standard pot in the Kondo preamps and the upgrade is a huge Shalco switch with hand made silver resistors. Costs something like 3k$...

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  • 2 weeks later...
  • 2 weeks later...

Justin,

Have you ever compared the Alps RK50 to the TKD CP2500? WOnder how they compare, as the CP2500 is considerably better than the Alps Blue IMHO. What about the Penny and Giles RF16 or RF11 whichever it is?

The P&G RF15 is the best pot they offer and it is supposed to be a step down from the RK50 and there have also been some issues with them. Impressive pots though but I'm glad that my new source has a built in volume control so I remove all steppers and pots from the signal path.

The RK50 gets the best recommendation I can think off... Kondo uses them. That's enough for me. :)

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