I get questions occasionally about tone capacitors and their effect on your tone. Hopefully this will help some people. The very basic: tone capacitors are what make your tone knobs work. The one(s) that came in your guitar look like little pancakes. They are very bad. You have probably noticed that your tone knob is only usable on 9 or 10. The stock capacitor is to blame. There are two characteristics you should be concerned about when changing your tone cap. The first is value (the amount of capacitance) and the second is construction. Value: Standard tone cap for strats and les pauls nowadays is .022 or .047 microfarads. A larger value will cut off more of the treble frequencies. Start with the standard value and move up or down depending on what you like. You should be able to use nearly the entire range of the tone knob if you have selected the right cap. Construction: Capacitors are made in a few different ways, and some are better suited to your tone control than others. Here, in rough order of quality, are the common types: Old paper in oil caps: These include thins like Bumblebees, Vitamin Q, Black Beauty, etc etc. They have a very woody and warm tone and are excellent, but are no longer made and relatively expensive: $10-20 each is the usual range. New paper in oil caps: Caps like the mojotone "Vitamin T" and the RS guitarworks "GuitarCap" are close to the vintage types. They don't sound quite the same but they are more readily available and usually cheaper. Mallory 150: These are polyester film caps, cheap and easy to find. They are bright yellow and commonly used inside amps. They have a smooth top end and don't mess with your original tone much. Sprague Orange drop: These are the most common upgrade of your tone cap, with good reason. They have a stiff and sparkly high-end and are very clear. They're also cheap and easy to find. The 715 and 716 series are the ones most people use in guitars. Silver mica caps: These are hard to find in reasonable values. They have a big emphasis on the mids which usually makes the guitar sound kind of odd. You can use them, but I wouldn't suggest it. Radio shack green poly film capacitors: Decent, but they don't sound as good as better poly film caps when turning the tone down. Ceramic disc capacitors: Your stock guitar tone cap. Throw it away.
You forgot to mention that in a guitar, the cap is only shunting signal out, so the type and construction mean nothing. The differences in linearity are negligable and only show in the whole sweep of the pot. Tones are usually set-and-forget-awhile adjustments.
'Negligible' is in this case a statement of opinion. There is, without a doubt, a difference to my ears.
Tone controls are only set-and-forget if your cap only lets you get one sound out of that pickup.
The shunt of signal varies by frequency; different caps types are more or less efficient or thorough in the range of treble they cut.
Well, no. You probably already have a .022 in your guitar, so changing to the same value in a ceramic will make no difference, and going to a .047 will make it even worse. You may still be able to find polyester caps, they're quite common. They're usually green with a chiclet sort of shape. Alternatively, a better brand of pot will help as well. Many larger electronics suppliers will ship anywhere in the world, so places like mouser are worth a look.
my guitar is basically a practice guitar really, i started guitar late and i don't have a respectably gearlist right now, but hopefully i will finish my first tube amp build and then move on to my first guitar build and such.