SCRATCHY SOUNDING POTS – My guitar sounds terrible! What should I do?
This happens to all players at some point in time. You discover at a practice that the pots in your coveted electric guitar sound a little… well, scratchy. Just a little. Not enough for you to be too concerned but, over time, they get worse. And worse. Until, finally, you’ve had enough and need to DO something about them.
But what do you do? How do you repair scratchy pots? CAN you repair them? Or will you need to replace them?
All very good questions. We are going to help you with the answers.
First, why do pots, after a time, get scratchy sounding. To understand that, you need to understand how a pot is made and how it works. What follows is the inside of a typical guitar volume or tone control. On the right, you’ll see a “doughnut” shaped piece with a black ring on it called the “wafer”. That black ring on it is carbon dust. In the picture, the middle piece has a brass interior called the “wiper”. The way the pot works is simple:
- when you turn the volume/tone UP, the wiper slides across the carbon dust ring and lowers the resistance of the pot, increasing the signal (volume/tone) out of your guitar.
- when you turn the volume/tone DOWN, the wiper slides across the carbon dust coated wafer increasing the resistance of the pot which results in lowering the volume/tone.
Look at it as a variable resistor or rheostat. Like the dimmer that you have on your lights in your house. Turn the knob one way, it turns up the lights. Turn it the other way and it turns the lights down.
Now, here is why your pots sound scratchy: as time goes on, dust settles inside of your volume & tone controls. Or possible sawdust from when your guitar was built. We’ve all found sawdust inside the electronics cavity when we’ve opened it up to look at something. That can get into your pots.
When it does, it settles on top of that carbon coating on the wafer. When you turn the UP/DOWN knob on the pot, the wiper grinds that dust into the carbon coating resulting in less contact between the wiper and the carbon coating. As more and more dust/sawdust gets ground into the wafer, less and less contact happens and your pots get that scratchy sound that you’ve come to hate.
What can you do about it?
Well, a couple of things. There probably is some sawdust/dust that can be cleaned away by a can of pressurized electronics cleaner. You simply spray it into the hole in the pot and it washes some of the sawdust/dust away. That MAY relieve some of the scratching. But, it will not clean away any of the sawdust/dust that has already been ground into the carbon coating by the wiper. That is there to stay and replacing the pot is your only alternative.
If you have any specific questions regarding cleaning your pots or replacing your old, scratchy sounding pots, drop us a note and we’ll try to answer them for you. firstname.lastname@example.org
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