This is a simple varitone circuit that you can use on your bass. It uses a 2 pole, 6 position rotary switch that is available at your local Radio Shack for about $3, and a few capacitors. Basically, for about $5-$6 and a little time, you can add a bunch of flexibility to your bass. I used this circuit on a SX P Bass - you can listen to the sound sample below. SIMPLE VARITONE - PRECISION BASS The way this is wired, you will have one "open" position (no tone control), and five different additional tone variations. In the MP3, I started in the "open" position, scrolled through the other five positions, and then went back to the open position again. I played the same simple riff in all positions so that you can evaluate the sounds properly. You will need a soldering iron, solder, some wire, wire cutters//stripper, a multi-meter, a sharpie, some capacitors, the aforementioned switch, and a few minutes of your time. You should also know how to solder and be "practiced" at it, as well as familiar with the use of a multi-meter. I won't go into that stuff - there are a zillion places on the internet to get that info. When you get the switch, turn the switch either right or left till it doesn't turn any more. Sometimes it is easier to attach a knob to the shaft to make it easier to turn. You'll want to set your multi-meter to the "beep" position. You can tell when you're in the right setting because your multi-meter will "beep" when you touch the red lead and black lead together. Now, with the meter in the "beep" position, look at the bottom of the rotary switch. Hold the end of the BLACK lead on one of the two "center" poles on the switch, and then touch the red lead to the outside poles until you hear a a beep. Make a mark next to this pole with your sharpie. That is the first position. Now, turn the switch one click, and repeat the previous process. That is the second position. Repeat this until you have all 6 "active" outside poles marked. Also be sure to mark the center pole that you used. Now, it is as simple as following the diagram that I drew up and attached below. All "grounds" can connect to the back of the volume pot. Make sure that the "switch" end of the capacitor leads do not touch each other. On the "ground" end, touching is fine as they all end up connecting to the same place anyway. Your jack will hook up as it normally does - same for your pickup(s). All this does is replace your tone pot. Enjoy ! PS - you can also use this circuit and put it in a separate enclosure, so you have a "pedal" or "table top" varitone control !