Electrical AmplificationThe creation and advancement of the electric amplifier began in 1906 with the invention of the triode, a form of electrical amplification containing three active electrodes of which vacuum tubes are a variety, by De Forest (Leach, 1995). This invention became the major focus of the amplification industry, leading to the discovery of stable-operating vacuum tubes by Langmuir of General Electric in 1913. As a result, the Japanese established a vacuum tube laboratory in 1914 and created a high-quality prototype vacuum tube in 1916. With the start of radio broadcasting in Japan in 1925, vacuum tube technology quickly spread to England and North America (Okamura, 1994). The electric pickup, a device that translates the disturbance of a magnetic field into an electrical signal, became practical enough for production in 1931, thus creating the need for electrical amplification. These early amplifiers, made by the Electro String company, had a power output of around ten watts and used the same technologies as early radios, specifically vacuum tubes. The growing popularity of electric amplification quickly caused demand for stronger amplification. Leo Fender met this need in 1949 with the first 50-watt amplifiers, which is still the standard power output today. The late 1960s saw the next leap in amplifier technology with Jim Marshall's invention of the 100-watt amplifier, which was powerful enough for large shows (Hamm, 1972). In the 1970s, solid-state amplifier technology replaced tube amplifier technology. These amplifiers were inexpensive and physically durable (Horowitz & Hill, 1989). An Introduction to Electrical Amplification At the most basic level, an electrical amplifier is a device... center of paper... engineering and computer science, University of Michigan website: http://bear.ces.cwru .edu/eecs_cad/tut_spice3_tube.htmlMitchell, T. (1993). The audio designer's tube register. New York, NY: Media Concepts. Okamura, S. (1994). Receiving tubes. In History of electron tubes (pp. 126-135). Retrieved from http://books.google.com/books?id=VHFyngmO95YC&pg=PA133#v=onepage&q&f=falseVitz, P. C. (1972). Preferences for tones as a function of frequency (hertz) and intensity (decibels). Attention, perception and psychophysics, 11, 84-88. doi:10.3758/Wedland, P. H., & Horowitz, D. N. (1979, September 5). A decibel measuring instrument for fiber optics. Fiber optics and communications, 121-127. Retrieved from http://books.google.com/books?hl=en&lr=&id=2HS3DysbmZ4C&oi=fnd&pg=PA121&dq=Decibels+wattage+abstract&ots=r62HjrWFFi&sig=fa2ciV_cnVrFmRop7WDamH5iMUs#v=onepage&q&f=false