The Technology That Led To Rock and Roll, Part 2: The Guitar Amplifier

“Hey mister, what a cool electric guitar! Can I hear it?”
“Sure kid” said the aging rocker, lifting his guitar from its case and beginning to play.
“Awh… it don’t sound like nothing!”

Well actually it does sound like “nothing.” Almost exactly like nothing. That is… until you plug it in.

The fact is, a pure electric guitar – one without designed-in acoustic properties – depends almost solely on an amplifier to create its sound. And the sound of the instrument is so much affected by the nature of the amplifier that according to some guitarists it would be more accurate to say they “play an amplifier” than that they “play the guitar.”

In the beginning of the Rock Era, guitarists used whatever amplifiers they could find. Most of the early amps available to them were not originally designed for a guitar. They were basically small, general-purpose, amplifiers originally designed to amplify record players and microphones. Their electronic circuits — made up of myriad resisters, capacitors and tubes connected with a web of wire — were by today’s standards very primitive. And since they were not designed to produce the level of loudness that Rock and Roll demanded, both the electronic circuits and the speaker/driver would create a lot of distortion as well as dynamic compression.

From an electrical engineer’s point of view, those distortions and the dynamic compression were “flaws” that needed to be overcome by better designs. But to musicians those “flaws” came to be seen as integral to the sound of Rock and Roll.

Before long, guitar companies such as Fender and Gibson started making and selling amplifiers specifically designed for their guitars which came to have a sound that was characteristic to its maker. Fender amplifiers sounded bright, bold and in your face. Gibson amplifiers had a sound that was smooth, dark and smoky — very jazz-oriented. For this reason Gibson’s amplifiers, unlike their guitars, never became a major part of the sound of Rock and Roll.

An early Fender “Champ” guitar amplifier — 5 watts of power driving a single 6 inch speaker

A much later Fender “Twin Reverb” guitar amplifier — 85 watts of power driving two 12 inch speakers

In the early 1960s, when transistor amplifiers became available, they were touted by their designers as superior because they did not distort the same way the old tube amplifiers did. However, when guitarists tried them they were dissatisfied. Why? In part, because the early solid state amplifiers, when pushed to their limits, had their own limitations and distortions — ones far less “musical” than the older tube amplifiers — and because these new amplifiers simply didn’t distort enough.

This preference for distortion may seem odd to a non-musician reader, as it certainly was to the non-musician amp designers! Perhaps it can be understood by comparing it to what happened when advancements in refrigeration technology made fresh and frozen vegetables and meats available to people who were used to eating food preserved the old-fashioned way with lots of salt and spices, such as sauerkraut and corned beef. A person in the food trade could make all sorts of claims about how those newly available foods were “better” and “healthier.” But to the eater these “new and improved” products — in comparison to what they had come to love — seemed tasteless and bland. And so it was with amplifiers and guitarists. The whole world moved on to the clean, clear, almost distortion-free, sound of modern “solid state” electronics, but guitarists continued to insist (and in some cases still continue to insist) that their amplifiers be built the old-fashioned way – with tubes.

Guitar amplifiers did change, however, in other ways. The demand by rock musicians to be able to play louder led designers to create more and more powerful models, amplifiers with thirty watts, forty watts, up to 85 watts of power output. Louder and louder these amplifiers became. Yet into the mid-sixties those amplifiers remained, for the most part, small and easily portable. That, too, was about to change.

The author, airborne, above his 40 watt combo-style amplifier circa 1964

http://www.youtube.com/watch?v=nYHPht_mYiQ

In its early days, Rock and Roll was almost exclusively an American style of music. But via phonograph records it quickly spread world-wide. And no one took it to heart more enthusiastically that the youths of Britain.

The story of the so-called “British Invasion”– lead first by the Beatles and followed by many other groups — is outside the purview of this series of articles, but their effect on the technology of rock is not. And one of the areas they first affected was guitar amplification.

The Beatles were the first rock band to play in a venue as large as a stadium. But when they did so they were using the relatively small combo-style amplifiers we have discussed so far. This didn’t matter much to their fans however as they couldn’t be heard over the screaming anyway! Other British groups, however, started to look for guitar amplifiers that would allow them to actually be heard by such huge audiences – and that at ear splitting levels. Enter Jim Marshall.

Jim Marshall was a drummer. In 1962 he opened a small music shop in London initially with its focus on drums. But the shop quickly became a popular hangout for all sorts of musicians, including many guitarists. Among these was a young man named Peter Townshend who would go on to be the guitarist and principle songwriter for the band The Who. Pete and his friends started pressing Jim Marshall to provide them with guitar amplifiers, as amps imported from America were difficult to find and very expensive. So Marshall turned to the shop’s repair technician, Ken Bran, and an EMI technician named Dudley Craven, to design and build them.

At first Marshall’s amps were little different from the Fender amps available from America. But when the guitarists started requesting more power so they could play louder, something new came to be: Amps with a darker, thicker sound – a sound that pounded the listener — a sound that came to be known world-wide as “The Marshall Sound.”

At first these new Marshall amplifiers were built in the “combo” style – a single cabinet containing both the electronic components and the speakers. But later, as Marshall heeded the call for “bigger,” “louder” and “more powerful” amplifiers the number of speakers grew. So Marshall followed another scheme that had also been pioneered by Fender – that of having a separate, relatively small, amp section called a “head” connected to a speaker cabinet.

In time even that concept expanded. Instead of the single, very powerful, amplifier “head” being connected to a single speaker cabinet it would be connected to a pair of large cabinets, each of which held four specially designed, heavy-weight, 12 inch drivers. This became known as the “Marshall Stack.” And with it Rock and Roll entered a new period of growth and stylistic experimentation, one that included soaring guitar leads over driving guitar/bass/drum rhythms. One of so-called “power chords.” And, in short order, the extraordinary music of Jimi Hendrix.