Here we have a VOX V874 Wah pedal that I modded years ago. But the pot finally failed completely. So needed to be replaced. What does this mod do? A lot of pots get dirty, faulty and fail. But due to the design of these style of wah pedals, the pot is right in the audio signal chain. Causing issues like cracking and at worst, complete signal drop outs. We replace the pot with a non-moving item called an LDR, a Light Dependent Resistor. And the pot controls the amount of brightness from the LED, a Light Emitting Diode. The result is no more scratchy noises. No more crackling. No more sound dropping out. How does it work? The LDR does what the pot use to, change resistance value depending on the position of your foot. However, instead of your foot moving the pot and directly changing the resistance value, now the pot changes the LED brightness. The LED is facing the LDR. The LDR resistance changes depending on how much light hits it. Because the LDR has zero moving parts, nothing wears out. The pot will still eventually fatigue and fail. But without crackling and making horrible, unwanted noises. ... https://www.youtube.com/watch?v=cUgmkNsBA78