My recently purchased second hand dirty cheap Yamaha guitar had a noise problem and after some testing I narrowed it down to the volume and tone pots. They wouldn’t turn smoothly and the noise changed as I turned them being the less annoying when both pots where at their maximum.

The offending Yamaha

To illustrate what I mean here you can hear the noise before. This is with the tone and volume pots at their maximum:

Download audio file (20090915 – Before pots replacement.mp3)

Therefore I ordered some replacement pots from eBay. I made sure the size would fit in the guitar. Initially I only wanted to change the tone pot so I ordered 3 A250K since the tone pot was that type and their dimensions are length 3/8” and diameter 1/4”, which while being bigger than the existing ones still fit comfortably in the guitar body hole. The volume pot was 500k as is the standard with humbucker pickups. After replacing the tone pot there was still some noise so I decided to give a shot to replacing the volume pot as well. The essential difference is that a 250k pot will give a slightly warmer tone than the 500k, especially since humbuckers already give a warmer tone but since the main problem was getting rid of the noise I didn’t mind slightly affecting the guitar tone and I was also happy to experiment with the sound, something I had never done before.

250k pot

The elements we’ll need are: a soldering iron, solder wire, screwdriver, cutter and some wire for making connections (instead of using wire I just took some of the wire from some trashy earphones that were sitting around at home).

The tools

These tools are cheap, you can find them in any electronics shop or eBay, the prices I paid are: 40W soldering iron 7.5 USD and soldering wire 1.5 USD, 6.99 USD plus shipping for 3 250k pots from eBay and I already had the screwdriver and cutter but were very cheap originally.

Before going further of course I recommend that if you want to do this yourself that you are very careful using the soldering iron since the tip gets extremely hot. These guidelines can be useful.. Finally, I accept no liability for any consequences of trying to put into practice the information in this post. Do it at your own risk and don’t come telling me that you don’t like the new tone in your 1959 Goldtop Les Paul since you replaced the pots. If you are not sure of what you’re doing the best thing is to leave it to a professional.

I laid everything on a flat and clean surface. Turned around the guitar carefully. I used a pair of old jeans as a cushion to stop the pickups and strings from being damaged by having the guitar body lying on that side. Unscrewed the tone pots and coil switch lid. Mine looked like this:

Volume and tone pots, before

First I removed the tone button on the front of the guitar and unscrewed the thread to be able to remove the pot. Before doing anything it is very important that you make a little schematic of the wiring. It’s easier to see all the connections once we have removed the thread and the pot is loose. Unless you know what you are doing we want to replicate the same connections that were there originally. Make a note where each cable (and its colour) is soldered to. Below you can see a snapshot of my schematic.

Wiring schematic

It is useful if you can get your brother/sister/girlfriend/buddy to hold the pot with the cutters (don not hold with your bare fingers, the pot will get very hot) while you are doing the actual soldering since then you can concentrate on holding the soldering iron with one hand and the wire with another.

Then it’s time to do the actual soldering. To undo the existing connection just touch the connection with the tip of the soldering iron, that’ll melt it and you’ll be able to easily pull it out. To make a new connection just slide the wire through the new hole and put the tip of the solder wire touching the spot where the connection is to be made and touch the tip of the soldering iron until the wire melts and creates the new connection.

First I replaced the tone pot and checked that it was working fine and then I did the same with the volume pot. You can see the result in the picture below.

The volume and tone pots, after

I plugged it to my soundcard and voilà, the noise was gone. The result can be appreciated in the following recording.

Download audio file (20090915 – After pots replacement.mp3)

There’s still some noise that can be heard if you process the sound through an amp simulator. This is caused by a bad grounding connection with in my laptop that disappears when I unplug it.

The sound has lost some brightness as a result of replacing the 500k volume pot with a 250k but I’m gonna try it for a while to see what I like best. I’ve already ordered some 500k pots in case I change my mind in the future.

Please note that I don’t recommend replacing the pots every time you have a noise problem in your guitar system since every case is completely different. It worked for me in this case and if the worse had happened I didn’t mind destroying the guitar since it was so cheap. If you’re not sure of what’s going on the best thing is to ask a professional before doing anything yourself.