The Physics of Jimi Hendrix
What is Distortion?
To begin with, normal sound waves are sin-usoidal. So they oscillate back and forth along the axis of time normally, given that there is no change in either amplitude or frequency like the picture left. When the guitar pickups transmit the vibration changes to the speakers and there is NO distortion in the sound wave, the sound waves look like the picture left, and the sound itself is what guitarists would call 'clean.'
Mild Clipping
This is what the sound wave (sine wave) looks like when it is being 'clipped.' Hence distortion is in effect at this point. Clipping is caused when the output voltage desired is beyond what an amplifier is capable of producing. You might ask yourself, 'Then why are we using an amplifier, if we can't produce the proper output voltage?' The answer to that, is that guitarists INTENTIONALLY use amplifiers with lower rated voltage outputs in order to actually create the intentional clipping effect which in turn causes the desired distortion sound. The actual distortion sound is just a hard fuzziness more or less.
Jimi Hendrix's Wah-Wah Pedal
Wah pedals were the some of the first technical machines used to create clipping or distortion for guitar sounds. Jimi Hendrix was probably one of the biggest advocates of the Wah-wah pedal. Some of his most famous uses of the wah pedal is in his song Vodoo Child. Hendrix was also probably one of the first famous guitarists ever to be seen using a wah-wah pedal.