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The Fender Prosonic guitar amplifier was produced by Fender Musical Instruments from 1996 to 2002. Available in head and combo versions, the Prosonic featured several departures in design from traditional Fender amplifiers such as the Bassman, Twin Reverb, and Deluxe Reverb. Designed by Bruce Zinky as a project for the Fender Custom Shop, the amplifier later had a non-Custom Shop production run at the Fender facilities in Corona, California. (Most contemporary Fender amplifiers are produced in Mexico.) It was initially priced to compete with buyers in the so-called boutique amplifier market who were seeking more distortion than any previous Fender had ever offered. It is believed that high list prices, and deviations from established Fender amplifier designs, swayed many buyers away from the Prosonic. It developed a cult following among serious guitarists, aided by the rise of musician-centric internet communities. ==Innovations and sound== The Prosonic introduced several features that had previously been seldom, or never before, seen in Fender amplifiers. Its most unusual feature is the switchable rectifier and power amplifier bias scheme, allowing on-the-fly changes of operating mode and output power (as well as subjective tonal differences). This feature, originally found on Randall Smith's Mesa Boogie amplifiers, allows the Prosonic to achieve a versatility very rarely seen from mass-market instrument manufacturers. The Prosonic's rear-mounted RECTIFIER/BIAS switch lets the user select from the following three options: #Solid-state rectification with fixed bias (marked "S.S. AB2"). Listed at 60 Watts R.M.S. #Tube rectification with fixed bias (marked "AB2"). Listed at 50 Watts R.M.S. #Tube rectification with cathode bias (marked "A"). Listed at 30 Watts R.M.S. Unlike many amplifiers marketed as "Class A", the Prosonic truly functions as a Class A power amplifier in the "A" position. Class A refers to the amount of current flowing through the power tubes with zero audio signal, with Class A meaning maximum current flow even with zero signal. This makes the tubes run hotter, and gives the power section even more gain at the cost of tube life and noise. The Class-A designation for guitar amplifiers is often a misnomer; Few amps outside of the heralded Vox AC-30, also with cathode bias, operate in a true Class-A mode (it only did so up to ~21 watts RMS ). While the Prosonic featured cathode bias in the Class A mode and fixed bias in the Class AB mode, not all class A tube amplifiers are cathode-biased, and not all fixed biased amplifiers are Class AB. Fixed bias amps, however, require lower B+ Voltages to stay within the Plate Dissipation of the power tubes used; Cathode biasing "throws away" this voltage using conventional Higher Voltage power supplies. A channel-switching amp, the Prosonic offers a clean channel that features a blend of traditional Fender sounds with the influence of Vox amplifiers, frequently attributed to the Class A mode. Many players praise the Prosonic's clean channel as being "softer," and more prone to break-up and musically desirable distortion, than more contemporary Fender designs. Detractors view this trait as an apparent "darkness" in tone, and perceive this lack of the typical Fender "sparkle" as merely an undesirable lack of clean headroom. The Prosonic also brought levels of gain (distortion) previously unavailable in a Fender amplifier. Taking a major cue from the first generation of Mesa Boogie amplifiers such as the Mark I (itself a modified Fender design), the Prosonic used additional gain stages in the preamp section that cascaded into one another. Although Fender had been designing amps with some facility for built-in distortion/overdrive since at least the late 1960s, never before had they arrived at a sound so readily usable for modern high-gain styles of music, and far removed from what many players consider to be archetypical Fender tones. The Prosonic's factory manual states, "Gain 1 functions as a standard gain stage whereas Gain 2 functions similar to a compressor, adding sustain while reducing 'edge' when the volume is increased. This channel produces great high gain sound at any volume - from bedroom to stadium." 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Fender Prosonic」の詳細全文を読む スポンサード リンク
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