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What potentiometer to use as audio control in car stereo? Answered

Hello all

I am working on installing a tablet into my car instead of the original head unit. But since the tablet will be permanently mounted inside the dash, I have no way of turning the volume up or down on the tablet, therefore I need to install a potentiometer into the audio cable that goes into my amplifier. 

I have tried with a dual LIN 100kOhm potentiometer, which worked to an extend, but not as well as I had hoped. 
It did turn the volume up and down, but it couldn't turn the volume all the way down as I had hoped it would be able to.

I just want it to be able to turn up quite loud, but also turn all the way down, so I don't have to pause the music everytime I want it to be quiet. 




How did you wire in the pot 1. 2. or 3.

Click on the Image to see all three.

Answer 21.bmp

I'm not 100% sure, as I have used this for reference as to how to wire it.


If shield is signal ground input then it will work..

If shield is chassis connect and signal ground is different then it won't work !

OK so you have 3 wires from your tablet.

One wire should go to ground.

The other two should go to channel a signal and channel b signal.

Channel a shield and channel b shield should go to ground.

Then the two inside pins should go to to the amp with a ground wire.

Like this schematic with three wires from the tablet and three wires going to the Amp.

Answer 21b.bmp

Sounds like a variation of # 1, because Mat said

he "couldn't turn the volume all the way down"..


1 year ago

+1 to each D. J. S.

The way to get noisy turn static out of a used pot is to drop a bit of CarbonTetraChloride fluid into the wiper track of the pot, is all that I can add.

You need a LOG or audio taper pot as a volume control.

The phrase is, "worked to an extent". "extent" is a noun. "extend" is a verb.

Anyway, the signal coming out of your tablet is probably intended for driving headphones, and there exist potentiometers for attenuating headphone audio.

Some headphones come with a little thumb wheel potentiometer built into a little plastic bulge in one part of the headphone cable itself.

This instructable,


considers a few different ways to wire a potentiometer, volume control knob, into a headphone cable.

By the way, if all you want is to know is the size (in ohms), and character (linear taper, or log taper) of this kind of potentiometer, I think I have a few of these heaphone-cable-lump style pots, in my box of dumpster-scavenged, broken headphones.

Upon request, I can put the multimeter probes on, one or more, of these, for to give you some numbers about their electrical characteristics.

Use a potentiometer with build in switch ;)
Getting hard to find these days but were and still are used in small analog and portable radios...