While many guitarists fully embrace solid state clipping when it comes to fuzzes, overdrives, and distortion pedals, solid state amps carry a stigma about them often being described as harsh, cold, and sterile. So how did these seemingly contradictory notions become predominant in the guitar community?
The year was 1945, and the world was about to be revolutionized. Bell Laboratories, the research arm of American Telephone and Telegraph (AT&T), was on a mission to develop a device to improve the reliability and reduce the heat and power consumption of the vacuum tubes which were used for signal amplification across telephone wires used for long distance phone conversations. The team assigned to the job was lead by Bill Shockley who hired Walter Brattain and Joe Bardeen to assist. The team worked unsuccessfully for two years on a “field effect” based design until Bardeen and Brattain abandoned Shockley’s original design, opting for a point-contact transistor design. Shockley was furious that he hadn’t been included in the new design and in a flash of inspiration, feverously designed and built a new device, the junction transistor which proved to be more rugged and easier to manufacture. This device is fundamentally the design on which the entire age of information has been built upon.
While Leo Fender was busy modifying tube radio designs for guitar usage, the radio industry was working on shrinking their product in order to allow consumers to carry it with them on the go and in 1954, Regency released the TR-1, the world’s first consumer transistor radio.
Music and technology has always been intertwined, much more so than other forms of artistic expression, so it seems almost as if destiny was waving her wand while the words of Rock and Roll and the transistor collided when Radio & Television News published an article by recent Amherst College graduate Paul Penfield, Jr. (later to serve as Professor of Electrical Engineering, Emeritus, in the Department of Electrical Engineering and Computer Science, MIT) titled "Transistorized Guitar Amplifier" in 1956.
The details are a bit sketchy, but it is generally believed that Kay, a budget guitar manufacturer whose products were sold in department stores, brought the first solid state amp to market in 1962 to replace their “two-tone” line. Gibson and Vox quickly followed suit in 1963 and 1964, respectively and by the mid 60’s pretty much every amp maker on the market was competing for a slice of the pie including: Fender, Standel, Carvin, Univox, Baldwin, and Kustom. Players were being barraged with advertisements featuring celebrity endorsees. However, they weren’t being told the whole story.
In the rush to bring solid state guitar amps to market, very few companies performed extensive testing on their designs and simply followed the semiconductor field manuals for tolerances. Many of the first solid state designs were simply tube circuits slightly modified to use transistors. Consequently, the number of field failures proved to be extremely high. Fender’s first production run of solid state amps, for example, was considered to be a complete failure due to the volume of servicing requests and Standel amps which failed in the field were nearly unserviceable due to their circuit boards being sealed in epoxy to keep others from reverse engineering their design. According to Jack Sondermeyer in The Peavey Revolution, the early RCA semiconductor manuals were wrong, resulting in designs which were pushing the transistors far beyond their tolerances, and he should know as he helped write the manual!
By the late 60’s, the lessons learned from the early production flaws and been taken to heart and solid state amp design was coming of age. Acoustic Control Corporation introduced their line of amplifiers which The Who reportedly used the Sunn Orion for the Magic Bus recording session and tour, Fender brought the Seth Lover designed Super Showman to market, and Santana even used a prototype Gallien Kruger solid state at Woodstock (in conjunction with a prototype Big Muff).
The 70’s continued the evolution of solid state designs and saw the birth of two of the most revered solid state amps in history: the Roland Jazz Chorus JC-120 and the Moog designed Norlin Lab Series. However, in 1973 the Journal of the Audio Engineering Society published Russell Hamm’s famous paper “Tubes Versus Transistors - Is There An Audible Difference?” which would be misinterpreted (sometimes intentionally by savvy marketers) and virally spread to the masses. In it, there is research to support that in the test circuits, the tube variety had an initial stronger emphasis of the second harmonic and the transistor of the third. This oversimplification could easily lead one to believe the preface that tubes produce even harmonics and transistors odd. But upon further reading, the paper is quoted as stating that “…the major characteristic of the tube amplifier is the presence of strong second and third harmonics, sometimes in concert with the fourth and fifth, but always much greater in amplitude…”. The even vs. odd harmonic debate is further disproved by the one of the earliest and most coveted effects in the guitarist’s arsenal: the FuzzFace whose solid state circuit was designed to asymmetrically clip with a prominent second harmonic.
While the 80’s did see a brief period of mass acceptance of solid state amps by the consumer market with the Peavey Bandit becoming the best selling amp in the world, it also saw the birth of digital effects processing. While digital amp modeling was still a few years away, the end of the 80’s also saw the birth of the modern vintage movement likely a reaction to the flamboyant and modern design emphasis of early to mid 80’s era heavy metal combined with a generation of guitar players looking to collect the instruments of their youth.
Even though numerous artists from the Beatles and Rolling Stones to Iron Maiden and Pantera and everything in between have recorded and performed countless hits using solid state amps, they remain the third class citizens of the amp world. While a handful of companies such as Peavey, Pritchard, and Tech 21 continue to try to push the envelope in developing solid state circuits, which sound and react like their tube brethren, the recent vintage trend in guitar tastes and regurgitation of marketing propaganda on the internet has served to keep many from exploring the tonal options possible from solid state designs. For those willing to look just beneath the surface, you just might find one of your favorite songs was recorded using a solid state amp.
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