ALPS Potentiometer for Musical Fidelity V-CAN
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bigevilalien

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Can anybody tell me which ALPS part I need to use to upgrade the volume pot on my Musical Fidelity V-CAN?
 
It's mentioned on this page:
http://wwww.rockgrotto.proboards.com/thread/5227
 
But I'm relatively inexperienced at this and I can't figure out which values or part number is the right one for this application.
 
Could anyone help me out?
 
Thanks!
 
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tomb

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  Can anybody tell me which ALPS part I need to use to upgrade the volume pot on my Musical Fidelity V-CAN?
 
It's mentioned on this page:
http://wwww.rockgrotto.proboards.com/thread/5227
 
But I'm relatively inexperienced at this and I can't figure out which values or part number is the right one for this application.
 
Could anyone help me out?
 
Thanks!

What you're really looking at in the basic V-Can, if I'm interpreting correctly, is a FAKE Alps.  The one shown before by PinkFloyd (some of us miss him around here), is a knurled, press-fit shaft.  Alps does not make those.
 
I've seen this before with the Alps RK27 (Blue Velvet), a much better pot - but a lot bigger than what would work here.  (It was a supposed Alps RK27 with a knurled knob that had surprising issues for an Alps pot until the builder was assured it was fake.  There are no knurled shaft RK27's.)
 
It appears that PinkFloyd replaced the stock pot with what he refers to as a "hand-picked" Alps, but in reality, it's just a REAL Alps, IMHO (with a long un-knurled shaft).  Note that RK097's are still going to have some channel imbalance in the lower registers, but it won't be as much as a fake one.  The implication is that PinkFloyd was able to "hand-pick" one that had better low-travel channel balance, but I believe it's just the difference between a real one and a fake one.**  I have RK097's in a couple of Mini3's and to tell the truth, I don't notice any channel imbalance, period - but I may have just been lucky.
 
 
* The RK27 mentioned earlier has one of the best balances throughout the entire travel of almost any volume control short of an attenuator.
 
** Contact Tangent at tangentsoft.com or AMB at amb.org for ordering a genuine Alps RK097.
 
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bigevilalien

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Wow, that is a lot of great information! Thank you!
 
It appears, however, that Tangent is no longer in business and the only RK097 from AMB has an SPST switch on it, which I'm not so sure I want...
 
It also appears that there are several different part numbers in the RK097 series. Could you provide any more information about which one might be the best direct replacement for my stock pot?
 
It looks like there are several available here:
http://www.mouser.com/ALPS/Passive-Components/Potentiometers-Trimmers-Rheostats/Potentiometers/RK097-Series/_/N-9q0ypZscv7?P=1yzmno7Z1yzv5wkZ1z0zlgm
 
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tomb

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tomb

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bigevilalien

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I've got it installed on the board now. Flawless!
 
Now, any idea where I can find a nice milled aluminum or stainless steel knob? How do I search for one that fits this type of shaft?
 
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Measure the shaft diameter (or just read it out of the datasheet then find a knob that says it will fit. 
 
Depending on your (lack of) luck you may need to cut the shaft of the pot shorter. You can find tutorials on the web, good luck. 
 
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  Measure the shaft diameter (or just read it out of the datasheet then find a knob that says it will fit. 
 
Depending on your (lack of) luck you may need to cut the shaft of the pot shorter. You can find tutorials on the web, good luck. 
Yeah, it's a 6mm flatted shaft, but I'm looking for sources for knobs that will fit...
 
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  Measure the shaft diameter (or just read it out of the datasheet then find a knob that says it will fit. 
 
Depending on your (lack of) luck you may need to cut the shaft of the pot shorter. You can find tutorials on the web, good luck. 
Yeah, it's a 6mm flatted shaft, but I'm looking for sources for knobs that will fit...

Partspipe on ebay pretty much has amplifier knobs that are made for 6mm shafts.
 
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Hi
 
I'm trying to also replace the pot on the VCAN with an ALPS.
 
The one shown on RockGrottos accessories page is a 50k pot, and the one linked on this thread is a 10k.
 
I have less experience with this, what is the difference (beside the resistance rating :/) and which should I get?
 
Thanks !
 
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tomb

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  Hi
 
I'm trying to also replace the pot on the VCAN with an ALPS.
 
The one shown on RockGrottos accessories page is a 50k pot, and the one linked on this thread is a 10k.
 
I have less experience with this, what is the difference (beside the resistance rating :/) and which should I get?
 
Thanks !
 
10K is the usual pot impedance for portables, I guess because it takes less voltage to provide a high input signal.  This increases the Signal-to-Noise ratio and yields better performance overall.  One might conclude that lower impedance pots always result in a higher S/N ratio, but ...
 
10K can result in a loss of bass frequency if your source is AC-coupled (has output capacitors).  If those capacitors are not sized large enough, the resulting RC circuit with the volume pot as the "R" and the output capacitor (per channel) of the source as the "C," will produce a bass cutoff filter.  For most portables, however, this is an acceptable compromise in using a 10K pot.
 
On the other hand, a common impedance historically for volume pots is 100K (tube amps, receivers, etc.).  However, the S/N ratio is worse, because it attenuates the source signal more than a lower impedance pot.  Plus, the cable capacitance in longer connecting cables can result in some high-frequency loss.
 
This is why we typically have settled on 50K for headphone amplifier use.  It preserves bass frequencies for all but the worst-implemented sources, has very little cable interaction that might reduce high-frequencies, and is a good compromise on S/N ratio.  Unfortunately, 50K is not an impedance that Alps likes to manufacture as standard.  Those of us that do have them (AMB, Beezar, or other DIY suppliers) and sell them have to purchase them through high-volume, custom-manufacturing runs from Alps - at considerable expense.
 
Yes, there are other manufacturers of stereo volume pots that can be had at 50K, but none with the excellent channel-matching that exists with the Alps RK27 (Blue Velvet).  The Alps RK097 is not quite as good, but still better than most any other volume pot out there - and of course, it's small enough to be used in portables.
 
I hope that explains it a bit.
 
 
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itsikhefez

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Hi @tomb
Thanks alot for the detailed response.
 
I need to brush up on my physics classes from high school but I understand the general idea.
 
Based on what you wrote, If I understand correctly, 50K would be a better compromise for the VCAN.
 
Regarding availbility, this looks like an RK097 50k, isn't it ?
http://www.mouser.com/ProductDetail/ALPS/RK097122200G/?qs=sGAEpiMZZMtC25l1F4XBUyyd%2fDz0s8BHv3OrztGgnUY%3d
 
I actually bought an RK27 50k (from partsexpress, I assume they stock the real stuff).
I havent received it yet but based on the schematic I'm not sure the pins will fit the VCAN board.
 
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itsikhefez

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  Regarding availbility, this looks like an RK097 50k, isn't it ?
http://www.mouser.com/ProductDetail/ALPS/RK097122200G/?qs=sGAEpiMZZMtC25l1F4XBUyyd%2fDz0s8BHv3OrztGgnUY%3d
 
 
Ok my mistake. That has a switch, not sure if its usable.
The other 50K's there are either 1 gang or linear.
 
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