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-   -   Alps, RH2702 50K pot. (http://www.world-designs.co.uk/forum/showthread.php?t=8039)

bob orbell 7th July 2021 04:55 PM

Re: Alps, RH2702 50K pot.
 
Looking from the front, the two pins "front and rear" on the left, cut off and did you know that Matthew now has PCB's to fit these available in shunt or conventional for about £3.00 each. Bob

colin.hepburn 7th July 2021 06:00 PM

Re: Alps, RH2702 50K pot.
 
Quote:

Originally Posted by bob orbell (Post 92913)
Looking from the front, the two pins "front and rear" on the left, cut off and did you know that Matthew now has PCB's to fit these available in shunt or conventional for about £3.00 each. Bob

Yep Just as bob has described. I have done this with the other standard Alps pots I have and will do just the same with these hereís the link to the WAD forum Shop and Matthew s Pot Connection PCBs
And all the other WAD related kits and parts that Matthew has
http://www.world-designs.co.uk/potentiometers.htm
Colin
,

Pingushome 7th July 2021 06:33 PM

Re: Alps, RH2702 50K pot.
 
Thank Bob & Collin I got it. Order on outs way I think
:thumbsup:
Martin

Mark 8th July 2021 03:16 PM

Re: Alps, RH2702 50K pot.
 
Quote:

Originally Posted by bob orbell (Post 92901)
That's the 100k Greg, here is the link for one I purchased, but they do come cheaper,( 1Pcs potentiometer 50K log alps audio amp volume control pot stereo ) ebay no. 294047120678. Bob

Hi Bob,

Thanks for the heads up. Can you feel the "click steps" as you rotate the shaft, or does it feel continuous with jumps in level as the wiper goes from one segment to the next ?

All,

My understanding is that genuine Alps Blue pots have conventional carbon tracks not SMD resistors. All the ones I have (from reputable sources) feel like they have carbon tracks. Is Alps now making Alps Blue pots with SMD resistors that are being copied, or has someone copied an Alps Blue casing and label and put SMD resistors in it ? (which could sound better than the genuine article :-))

Thanks

Mark

bob orbell 8th July 2021 04:58 PM

Re: Alps, RH2702 50K pot.
 
First question Mark is, yes, you can feel the clicks, I am not sure about who makes this pot, although it does say Japan made and Alps, and made very good, the casing is identical to the more expensive Blue Velvet, but the price is too good to be sure. Bob

Mark 8th July 2021 09:36 PM

Re: Alps, RH2702 50K pot.
 
Quote:

Originally Posted by bob orbell (Post 92925)
First question Mark is, yes, you can feel the clicks, I am not sure about who makes this pot, although it does say Japan made and Alps, and made very good, the casing is identical to the more expensive Blue Velvet, but the price is too good to be sure. Bob

Bob,

I have seen reports on the internet about fake Alps Blue Velvet pots. I even saw one post where the fake label was compared with a genuine Alps label. The price alone means that the one you have found is a "knock-off" but one with an unusual twist - it seeks to solve the poor channel matching at low volumes that afflicts all pots with carbon tracks by replacing them with SMD resistors. Many also say stepped attenuators give a better sound. At that price I will be buying a few for some of my projects !

Thanks

Mark

colin.hepburn 8th July 2021 10:09 PM

Re: Alps, RH2702 50K pot.
 
Quote:

Originally Posted by Mark (Post 92927)
Bob,

I have seen reports on the internet about fake Alps Blue Velvet pots. I even saw one post where the fake label was compared with a genuine Alps label. The price alone means that the one you have found is a "knock-off" but one with an unusual twist - it seeks to solve the poor channel matching at low volumes that afflicts all pots with carbon tracks by replacing them with SMD resistors. Many also say stepped attenuators give a better sound. At that price I will be buying a few for some of my projects !

Thanks

Mark

Hi Mark/all
Well, I have a hand full of the cheap Alps Carbon track and found all my 50k/100k track evenly on the meter and channel match at low volumes just fine. which canít be said for some of the standard lower cost pots I have but at this price fake or not its a no brainer :)donít care maybe bob can test his for channel tracking
Colin

bob orbell 9th July 2021 06:57 AM

Re: Alps, RH2702 50K pot.
 
maybe bob can test his for channel tracking
Colin. yes, I have already done it Colin, the one I have is almost identical left and right. Martin, the beauty of individual resistors, SMD or through hole, is that the Logarithmic law can be perfect, the carbon track of good pots only has four changing sections, another way is to use a linear pot with law faking resistor from wiper to ground. Bob

Mark 9th July 2021 01:48 PM

Re: Alps, RH2702 50K pot.
 
Quote:

Originally Posted by bob orbell (Post 92929)
maybe bob can test his for channel tracking
Colin. yes, I have already done it Colin, the one I have is almost identical left and right. Martin, the beauty of individual resistors, SMD or through hole, is that the Logarithmic law can be perfect, the carbon track of good pots only has four changing sections, another way is to use a linear pot with law faking resistor from wiper to ground. Bob

Bob,

The photo on ebay shows a splined shaft instead of a round one with a flat for a grub screw. Do you use splined knobs, or have you successfully fitted a knob with a grub screw ?

Thanks

Mark

Mark 9th July 2021 02:00 PM

Re: Alps, RH2702 50K pot.
 
Quote:

Originally Posted by colin.hepburn (Post 92928)
Hi Mark/all
Well, I have a hand full of the cheap Alps Carbon track and found all my 50k/100k track evenly on the meter and channel match at low volumes just fine. which canít be said for some of the standard lower cost pots I have but at this price fake or not its a no brainer :)donít care maybe bob can test his for channel tracking
Colin

Colin,

You were lucky.... :-). I am probably over-sensitised to the problem by my Naim Nait 2 Chrome Bumper amp fitted with the original Alps (not Blue Velvet) pot : it's painfully unbalanced from 7 - 8 o'clock. I agree : the stepped SMD resistor versions are a no brainer.

Mark


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