The Sound of Rock
The first Marshall guitar amplifier

Thoughts of music stir emotion from the depths of our being. The impact of music is both universal and omnipotent. There is not an era in the history of man where music is not present. Poets, painters, and even political theorists use musical terms such as "harmony" and "rhythm" to describe their world. This impact signifies music's importance to man. Each era of history, each stage of man, has its own musical ideas and methods. In modern times, the concept of music is extremely varied, more so than ever before. The genres in which one can partake of music are numerous. Classical, jazz, blues, folk, tribal... the list is seemingly endless.
A few decades ago there was an rise in the genre of rock music. This was in part due to the reconstruction of a classic instrument, the classical guitar, into the electric guitar. Following the basic design of a classical guitar, which in turn followed the lute of Elizabethan England, the guitar had evolved into the primary rock instrument. (Ardley 36,42,58) In order to be heard, the guitar had to be amplified. The first guitar amplifiers were based on radio technology of the time. (Fliegler) As time progressed, people wanted more. Amplifiers became louder, and as they became louder they began to distort. The guitarists of early rock and roll avoided this distortion like the plague. As the attitude of the people changed, so did the music. As the 60's came into being, distortion was no longer deadly. By the late 50's and early 60's, guitarists liked to distort their guitar sound. It was not until Jim Marshall created his first guitar amp, the JTM 45, that distortion was fully used. Marshall defined the sound of rock in 1962 when he and electronics expert Ken Bran created the first Marshall amp. The JTM 45 changed the sound of rock music and increased the genre's popularity. Blues and jazz, the roots of rock, began to resurface. Jim Marshall's first guitar amplifier changed popular music, helping the musicians to better express the mood of their time.
Since the early 20th century, radio broadcasting had caused electricity to play a part in music. The microphone was used to record and transmit music by converting sound waves into electrical signals. The pick-up on an electric guitar work by a similar principle. Each pickup contains six magnets (one for each string on a six string guitar). When the string of the guitar vibrates, it changes the magnetic field produced by the magnets. With this method, the pick-up directly converts the vibrations of the strings into electric signals. This very weak signal must then be amplified to be heard. (Ardley 58) Thus the guitar amplifier was born. Using basic amplification run through public address systems, the electric guitar was heard. These early amplifiers used "thermionic vales" or vacuum tubes (as they are commonly known - Fliegler 52). In the early 1940's, vacuum tubes were used in almost every electronic device. When the cool running and virtually defect-free transfer resistor (transistor) was created in 1948 by Bell Telephone Laboratories, the vacuum tube was in trouble. The only people who held on to their tubes were guitarists. One may ask why guitarists held on to this ineffective technology? "The very ‘limitations' that made tubes undesirable are what we [guitarists] love: tubes distort, they are unpredictable under stress, their operating characteristics change under certain conditions..." (Fliegler 52). These defects are what gave the guitar amplifier its warmth and depth.
In July 1960, Jim Marshall opened a retail shop in West London that mainly sold drum equipment. The store soon stocked guitars and amplifiers because many drummers brought their bandmates with them. Owning this store opened Jim's ears to what guitarists wanted in their amplifier sound. Jim Marshall set out, in 1961, to create the sound that so many guitarists yearned for.
It was Ken [Bran] who said to me that it was rather silly to keep on buying in amplifiers when we could probably produce our own. So I told Ken to produce something and let me listen to it. (Doyle 11)
Marshall and Bran first set out to create a lead amp similar to the popular Fender amps of the time. The Fender amps produced