ALPS Potentiometer

Kriskom · 14th July 2004, 10:55 AM

I purchased a new ALPS Potentiometer Blue plastic casing, Dual/Stereo single metal shaft Type RH2702 , value 254 (250K) , clicked type .
It is brand new (maybe NOS).
Anyone who can advise me on the following :

Q1. Completed installation , it produced always a sharp cracks at the right channel at around 3O'clock position when I turn the shaft
Left channel remains silent.
What happened ? Is this defect ?
Q2
Pin3 connected to input , Pin2 as output to Line Valve 12AT7 , Pin3 as ground. There is a pin4 unmarked ,
What is this for , I assume this is probably for a Loudness circuit.
Q3
Have tried to search more info on this, but not available

Anyone who can help me ?
Thanks a lot
Paul
pyahya@cbn.net.id

dhaen · 14th July 2004, 12:42 PM

Q1 Probably a defect

Q2 Probably a loudness tap
Q3 It seems to be available from some Japanese web sites, but as you say, it's not a standard Alps part number. Perhaps it's an OEM part.

tiroth · 14th July 2004, 01:08 PM

I think they are just Chinese fakes, but some of them are supposed to be quite nice (the ones that are stepped, not just detented).

Kriskom · 5th August 2004, 11:34 AM

Dear colleques
The ALPs is now OK.
It appears a genuine old NOS . I have dismantled it, cleaned it rather harshly with a drop of HCl acid, extra fine sandpaper , cleaning fluid . All the resistors are OK and Its performing perfectly.
Thanks for the response
Paul
pyahya@cbn.net.id

Andypairo · 5th August 2004, 11:38 AM

Did you buy them on Ebay?

Cheers

Andrea

jhead · 7th August 2004, 09:32 PM

I believe I seen you say resistors if your pot has very small discreet resitors it is probably the chinese knockoffs I believe the legit Alps blue were only manufactured useing conductive plastic film which means it would have a smooth wiper

Kriskom · 8th August 2004, 04:43 AM

Dear Colleque
Yu culd be right at all.
I have checked ALPS product web page, I culd not find a stepped (with resistors)pot meter as one of their products, the more I am also not a NOS expert (sort of a antique hunter) when it comes to select NOS things.
But its the satisfaction I got from able to fix the problem, the sound is not bad at all, much better than the previous Noble.
See ya.
Paul

tiefbassuebertr · 13th December 2009, 05:51 PM

about this thread you will find a little overview about potentiometer and rotary switch
Potentiometer Overview - Alps, Penny+Giles, TKD and Vishay and more, what's your fav?

14th July 2004, 10:55 AM	#1
Kriskom diyAudio Member Join Date: Nov 2003 Location: Jakarta, Indonesia	ALPS Potentiometer I purchased a new ALPS Potentiometer Blue plastic casing, Dual/Stereo single metal shaft Type RH2702 , value 254 (250K) , clicked type . It is brand new (maybe NOS). Anyone who can advise me on the following : Q1. Completed installation , it produced always a sharp cracks at the right channel at around 3O'clock position when I turn the shaft Left channel remains silent. What happened ? Is this defect ? Q2 Pin3 connected to input , Pin2 as output to Line Valve 12AT7 , Pin3 as ground. There is a pin4 unmarked , What is this for , I assume this is probably for a Loudness circuit. Q3 Have tried to search more info on this, but not available Anyone who can help me ? Thanks a lot Paul pyahya@cbn.net.id

7th August 2004, 09:32 PM	#6
jhead diyAudio Member Join Date: Feb 2004 Location: orange county calif.	I believe I seen you say resistors if your pot has very small discreet resitors it is probably the chinese knockoffs I believe the legit Alps blue were only manufactured useing conductive plastic film which means it would have a smooth wiper __________________ Jack Head

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14th July 2004, 12:42 PM	#2
dhaen diyAudio Moderator Emeritus Join Date: Jun 2002 Location: U.K.	Q1 Probably a defect Q2 Probably a loudness tap Q3 It seems to be available from some Japanese web sites, but as you say, it's not a standard Alps part number. Perhaps it's an OEM part.

14th July 2004, 01:08 PM	#3
tiroth diyAudio Member Join Date: Dec 2001 Location: Pittsburgh, PA, USA	I think they are just Chinese fakes, but some of them are supposed to be quite nice (the ones that are stepped, not just detented).

5th August 2004, 11:34 AM	#4
Kriskom diyAudio Member Join Date: Nov 2003 Location: Jakarta, Indonesia	Dear colleques The ALPs is now OK. It appears a genuine old NOS . I have dismantled it, cleaned it rather harshly with a drop of HCl acid, extra fine sandpaper , cleaning fluid . All the resistors are OK and Its performing perfectly. Thanks for the response Paul pyahya@cbn.net.id

5th August 2004, 11:38 AM	#5
Andypairo diyAudio Member Join Date: Sep 2002 Location: near Milano , Italy	Did you buy them on Ebay? Cheers Andrea

8th August 2004, 04:43 AM	#7
Kriskom diyAudio Member Join Date: Nov 2003 Location: Jakarta, Indonesia	Dear Colleque Yu culd be right at all. I have checked ALPS product web page, I culd not find a stepped (with resistors)pot meter as one of their products, the more I am also not a NOS expert (sort of a antique hunter) when it comes to select NOS things. But its the satisfaction I got from able to fix the problem, the sound is not bad at all, much better than the previous Noble. See ya. Paul

13th December 2009, 05:51 PM	#8
tiefbassuebertr diyAudio Member Join Date: Jul 2005 Location: D-55629 Schwarzerden	about this thread you will find a little overview about potentiometer and rotary switch Potentiometer Overview - Alps, Penny+Giles, TKD and Vishay and more, what's your fav?

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