Cool article from EDN on pedal effects – be sure to check out the references on page 3 for additional reading as well.
A common source drain amplifier, based on the LSK489 JFET, is one basis for a distortion pedal circuit.
If you want to replicate the music of your favorite musicians, you will need to know the pedal effect devices they use and the circuitry within them. Furthermore, if you want to design new pedal effects that please your audience, you will need the right tools, the right design flows, the right components, some circuit know-how, and a little creativity.
The design of pedal effect circuits, i.e. circuits that modify the waveforms of musical instruments, is an art and science that has been practiced since the 1920s. Fundamental to the reproduction of era-specific and musician-specific music is the technology contained in these pedal effect gadgets. Different artists prefer different component technology: tubes, germanium transistors, silicon bipolar transistors, MOSFETs, diodes, JFETS, op amps or any mix thereof.
The passive components used in pedal effect circuits, like inductors, capacitors and resistors, complicate the process of analog sound reproduction. Of specific mystical interest to many professional musicians is the “magical inductor.” Thought to be enchanted music’s key, the magical inductor, once placed inside a circuit generates harmonics that separate it apart from all other inductors. The idea of a magical inductor keeps musicians wondering. Is music’s holy grail locked inside the pedal device of a long-ago musician? Is the magical inductor made of a special material? Is the magical inductor lost in time and do the music giants of our times have access to it? One thing most of them agree on is that the magical inductor is one of the analog Muses and not one of the digital Sirens.