i am trying to make some kind of an amplifier. I got an amp board but want to read out the value from the potentiometer. The problem is that this pot is connected to the amp and has to be connected to the amps power Is there any way i can still read data (with an arduino) so that i can have a volume percentage on a lcd? Or is this imposible?

Amp 24v Potentiometer = 6pin. B50k

also what zould happen if i connect a 10k resistor instead of a 50k ressistor (audio potentiometer) what would the effect be?

  • Would this work?? btw thanks for helping! aliexpress.com/item/… Commented Dec 20, 2018 at 22:30
  • and does it mater that the last one is 100k (i need (50k) can i use the 100k for the arduino? Commented Dec 20, 2018 at 22:32
  • or this??? aliexpress.com/item/… Commented Dec 20, 2018 at 22:32
  • can you clarify the meaning of "some kind of amplifier". Do you want a preamplifier (signal voltage amplification), or a power amplifier (high current)?
    – MichaelT
    Commented Dec 20, 2018 at 23:13
  • high current 24 50amps per channel Commented Dec 20, 2018 at 23:28

2 Answers 2


It's impossible. The pot is most probably acting as a passive variable attenuator. As such the top end will be the incoming audio signal, the lower end will be ground, and the wiper will be the attenuated incoming signal. There's not a lot you can do with that.

You would need to replace the pot with an equivalent triple pot (if such a thing exists) and have one third of it connected to the Arduino. The pot you have at the moment is a dual pot, and a log taper at that.

Alternatively adding some kind of quadrature (motor) encoder to the shaft of the pot may be a possibility.


A few options come to my mind:

  • I see you're using a double potentiometer, if you're using only one of it's outputs to control, you can use the other output to measure it's setting. (Or indeed use a "triple potentiometer" or added encoder as Majenko suggested.)
  • Use the Arduino as an intermediate (have the potentiometer as an input on the Arduino and control the output accordingly on the output of the Arduino).
  • Measure the output of the potentiometer. I'm not quite sure but the resistance over the potentiometer shouldn't be anything different depending on what is connected as well. Though you could also measure the output voltage on the potentiometer and from there deduce what it's value is (which may be difficult if it's an audio signal on this point in your system).
  • thanks for the comment i am using a double pot to have stereo i will try to get a triple pot do you think this one will work? even with 100k on the last one the reading should be the same right? Commented Dec 21, 2018 at 10:21
  • aliexpress.com/item/… Commented Dec 21, 2018 at 10:22
  • I don't see why not, and for the price it's worth a shot? Quite interesting part actually, what would've been the odds of finding this locally ;p Though note it may be difficult to find a pinout of this pot, which is worth a check before ordering.
    – aaa
    Commented Dec 21, 2018 at 10:34

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