Does your tone get dull when you turn down? Does this prevent you from controlling your amp from your guitar in the way you'd like because your sound gets muddy? If so, there's a very simple modification that will retain the high frequency content as you turn down.
Guitar circuits might look simple, but there's actually a lot going on. The pickups, pots and cable all interact to produce a low pass filter effect. When you turn down your volume, the cutoff frequency of the 'filter' drops into the audible frequency range, and the effect becomes increasingly noticeable.
Try soldering a capacitor between the input and output terminals of the volume pot (see Fig 1). When the volume control is fully up you won't know it’s there, but when you turn down, some of the high frequency content is able to bypass the volume pot and go straight through to the output. How much high frequency gets through depends on the value of the capacitor – and the best value for your guitar should be determined through experimentation.
You can use cheap ceramic disc or Mylar film type capacitors, and as a starting point we'd suggest that you try a 0.001mf. If the capacitor value is too high, your tone can actually become brighter as you back off the knob. A 130K resistor can be wired in series with the cap to reduce the amount of treble bleeding through the bypass capacitor (see Fig 2).
Alternatively, Seymour Duncan recommends a 100K resistor in series with the cap because it alters the taper of the pot to match the treble bleed (see Fig 3). This mod seems to widen the range of the pot, so it's slower to react. Violin-type volume swells and tremolo effects aren't so easy but the timbre remains constant wherever you set the guitar volume, so it never becomes thin and you get much finer control.
Tone Control for a Stratocaster
A lot of players find the bridge pickups on their Strats too bright, but when they turn down the treble on their amps to compensate, the neck and middle pickups sound too dark. So what about swapping the second tone control from the middle to the bridge? This is a really simple modification because you only have to move one connection: as you can see in the diagram, the wire connected to tag B moves to tag C.
Maybe the stock Stratocaster wiring had always struck you as a bit fiddly (see Fig 4). How about a master tone control? Simply remove the wire connected between point B and the second tone control and join tags A, B and C together. Even some of the most iconic Strat players, amongst them Rory Gallagher, have preferred this 'master tone' layout.