Nothing changes the tone of an electric guitar more than its pickups. If you understand what makes a pickup tick, you can make better choices about how to change your tone to your liking. Pickups consist primarily of one or more magnets and one or more coils of very thin copper wire. Thats it.
Understanding how this picks up a strings vibrations is not much more difficult. The magnet creates a field of organized electrons. The coil of wire gives the magnet an infinite supply of electrons to organize. When your guitar string vibrates within this field, the electrons wiggle back and forth. Take this tiny pulse of current and plug it into your basic amplifier and before you know it, you're playing Come As You Are.
You've probably noticed that the jack on your guitar cable has a tip which, when you touch it, gives off a loud bzzzzzz. This is the hot, or positive half of your signal. That bzzzzzz is the sound of your body (or whatever touches the tip) giving the amp an infinite supply of electrons to amplify. The other half of your signal is the negative, or ground. Over in the British Isles they call it the earth. Electrons are negatively charged, so ground = earth = negative. Get it?
It should be pretty easy to imagine that when you feed your amp that quivering back-and-forth pulse of electrons, which your pickup supplies, thats where the sound comes from. To keep things consistent, the two ends of the coil are therefore identified as positive and negative, or hot and ground.
What is totally amazing is that, even with such a simple arrangement, there is an immense range of tonal possibilities. Less wire equals less output and brighter sound. More wire and the signal gets hotter and darker. Wrap the coil in a tight vertical stack and the output brightens. Flatten it out and it gets deeper. Move the magnet closer to the string and the initial attack is accentuated. Move it away and the overall signal is more compressed. Stronger magnets give higher output. Even changing the metals which make up the magnet changes the tone. Lets look at three practical examples of these variations:
Perhaps the simplest pickup ever devised is the Danelectro lipstick tube. This is, quite literally, a coil of wire wrapped around a magnet and stuffed into a chrome lipstick tube. As simple as they are, these pickups have an incredibly even and clear output. Stevie Ray Vaughan and his current wannabe, Kenny Wayne Shepherd, are perhaps the most famous employers of these silver wonders, while Jimmy Page often used them mounted in Supro guitars in the studio.
Using this simple pickup as our standard, lets take the magnet out and replace it with six individual magnets, one for each string. This is the idea behind the Stratocaster and Telecaster pickup, and predictably, the string attack now becomes more prominent. Because these pickups are just a wee bit taller and narrower than the lipstick tubes, the output is a little more focused, allowing the upper harmonics of the string to sing out more fully. The bottom end becomes a little less thumpy, too.
Now lets pull the magnet away from the coil altogether, and place it below the coil. To focus the magnetic field upwards, well put six adjustable screws in contact with the magnet. If we flatten the coil out a bit, we get the design of the Gibson P-90 pickup. And of course, P-90s are known for their clear yet somewhat throaty and thick tone. Theyre considered a great pickup for jazz, big band blues, and hard-driving rock n roll.
So there you have it: One simple pickup design, three very unique sounds. In Pickupology 102 well take a look at two-coil pickups.