ALPS Potentiometer 100k ... Blue RK27112MC noise ?? - diyAudio
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Old 8th September 2014, 08:51 AM   #1
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Default ALPS Potentiometer 100k ... Blue RK27112MC noise ??

Hello everyone,

about a month ago I bought this pot ;ALPS Potentiometer RK27112MC Blue Velvet motorized Pot 10K 50K 100K log o linear | eBay , a few days ago I noticed that turning, both manually and remotely controlled, it emits a noise on both canali.La strange thing is that from position 0 to 9 o'clock is normal no noise, passed 9 o'clock starts to make noise .I changed the cables but nothing to do ... you think it is damaged?
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Old 15th September 2014, 09:12 PM   #2
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Quote:
Originally Posted by mprivitera1 View Post
Hello everyone,

about a month ago I bought this pot ;ALPS Potentiometer RK27112MC Blue Velvet motorized Pot 10K 50K 100K log o linear | eBay , a few days ago I noticed that turning, both manually and remotely controlled, it emits a noise on both canali.La strange thing is that from position 0 to 9 o'clock is normal no noise, passed 9 o'clock starts to make noise .I changed the cables but nothing to do ... you think it is damaged?
Hello mprivitera
First i need to say that there is nothing wrong with the potentiometer, unles you didnt see anything that indicates the potentiometer used before you. If you have any doubt about the seller please kill them because i am also an ebay seller and buyer, most of the seller out of some places in the world do not sell the used parts as indicating they are new even ebay dont let this kind of intentions.

Here is your problem and the solution
Your problem is gronding network , your potentiometer is in wrong grounding path, you need to change potentiometer's grounding , sometimes it helps to connect potentiometer's body to ground ( front metal face ).

99% i am sure that you grounding network cause that problem after 9oclock position. To be sure you can connect potentiometer in reverse position ( swap the side leads by keeping the middle leads constant) in this case at the right end of your potentiometer position your amplifier will be fully silent and start to open towards to left side. The problem stay same but in opposite side positions ( i mean problem starts at the counter 9oclock position).

You need to connect potentiometer to the ground in different points forexample to the rca input's ground or power supply capacitors ground or to ground somewhere on the pcb board.

I hope those info will help
good luck
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Old 15th September 2014, 09:15 PM   #3
jono1 is offline jono1  United States
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If you bought it from China, there is a good chance it is a fake. I have had lots of problems with the counterfeit ones.
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Old 15th September 2014, 09:47 PM   #4
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I don't think Familygate (Germany) deal in fakes. I buy a few similar motorised pots from them periodically without problems but certainly, Chinese traders are often selling copies of ALPS products. However, neither should have a fault like the one described as making noise only when used outside the normal range of operation (7-9 o'clock)

Question: is this noise the same and does it commence at the same position in both channels? If so, I would try another type to check that behaviour, making certain of the correct and recommended grounding of metal work and motor drive circuit, because if it is related only to the physical position in a new product, there will be a serious (wear) problem and you should seek a refund/replacement - outside Ebay if need be.
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Old 16th September 2014, 11:32 AM   #5
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Join Date: Jul 2012
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Quote:
Originally Posted by huseying View Post
Hello mprivitera
First i need to say that there is nothing wrong with the potentiometer, unles you didnt see anything that indicates the potentiometer used before you. If you have any doubt about the seller please kill them because i am also an ebay seller and buyer, most of the seller out of some places in the world do not sell the used parts as indicating they are new even ebay dont let this kind of intentions.

Here is your problem and the solution
Your problem is gronding network , your potentiometer is in wrong grounding path, you need to change potentiometer's grounding , sometimes it helps to connect potentiometer's body to ground ( front metal face ).

99% i am sure that you grounding network cause that problem after 9oclock position. To be sure you can connect potentiometer in reverse position ( swap the side leads by keeping the middle leads constant) in this case at the right end of your potentiometer position your amplifier will be fully silent and start to open towards to left side. The problem stay same but in opposite side positions ( i mean problem starts at the counter 9oclock position).

You need to connect potentiometer to the ground in different points forexample to the rca input's ground or power supply capacitors ground or to ground somewhere on the pcb board.

I hope those info will help
good luck
thanks for advice, ...... I feel this change of rotation and test other points gnd
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Old 16th September 2014, 11:40 AM   #6
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Join Date: Jul 2012
Location: SICILIA
Quote:
Originally Posted by Ian Finch View Post
I don't think Familygate (Germany) deal in fakes. I buy a few similar motorised pots from them periodically without problems but certainly, Chinese traders are often selling copies of ALPS products. However, neither should have a fault like the one described as making noise only when used outside the normal range of operation (7-9 o'clock)

Question: is this noise the same and does it commence at the same position in both channels? If so, I would try another type to check that behaviour, making certain of the correct and recommended grounding of metal work and motor drive circuit, because if it is related only to the physical position in a new product, there will be a serious (wear) problem and you should seek a refund/replacement - outside Ebay if need be.
the seller is trustworthy ..... think that the problem is in connecting GND or perhaps the preamplifer .....
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Old 16th September 2014, 03:46 PM   #7
Bare is offline Bare  Canada
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Join Date: Dec 2001
Location: vancouver
Alps stopped building Blue velvet pots a while back :-)
Fakes/copies don't feature subtle details like fully recessed into the ali casting, philips head screws .
If in doubt... temporarily insert a cheap(er) pot into the circuit to see if there is difference or noise.
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