page_title: Vox AC30
section_title: History
hierarchical_section_title: Vox AC30 / History
caption_attribution_description: English: The Edge of U2's original VOX AC30 guitar amp, picture taken in Foxboro, Massachusetts.
context_page_description: The Vox AC30 is a guitar amplifier manufactured by Vox. It was introduced in 1958 to meet the growing demand for louder amplifiers. Characterised by its "jangly" high-end sound it has become widely recognized by British musicians and others.
context_section_description: The Vox AC30 was originally introduced in 1959 at Hank Marvin's request as the "big brother" of the fifteen watt (15 W) AC15 model, Vox's original flagship amplifier, because the AC15 was not loud enough with the screaming fans at Cliff Richard's concerts. The AC15 was powered by a pair of EL84 tubes, an EF86-driven "Normal" channel, an ECC83-driven "Vib-Trem" channel, and rectified by an EZ81. The original first-generation AC30 used a GZ34 tube rectifier, three ECC83s (12AX7) for the Normal channel and the tremolo/vibrato oscillator/modulator circuits, one ECC81 (12AT7) phase inverter, and EL34 tubes in the power amplifier circuit.
  This first generation of AC30s were housed in "TV-front" cabinets, much like the early to mid-50s tweed Fender amps, and had a single 12-inch Goodmans 60-watt speaker, as opposed to the later, conventional twin 12-inch speaker configuration. These early amps sported a thin white covering ("Rexine") with a small printed diamond pattern and larger diamond pattern grill cloth. However, the EL34-powered AC30 was short lived, and a new AC30 version appeared in late 1959. This second generation AC30/4 had two channels with two inputs, hence the "4" in the model name, and a single tone control, and was powered by a quartet of EL84 (6BQ5) power tubes, making it truly a doubling of the AC15 power amp circuit. The AC30/4 also carried over the AC15's preamplifier circuit, which included the EF86 pentode in its "Normal" channel. Vox initially offered a 1×12" version but subsequently introduced the 2×12" AC30 Twin, which solved the volume problem at larger venues. The first AC30 Twins used two Goodmans Audiom 60 15-Watt Speakers, followed by Celestion G12 alnico speakers.
  By 1960, Vox had forsaken the more conservative TV-front look for the now legendary cabinet design that has remained largely unchanged since 1960. The new cabinets featured a different covering known as fawn Rexine, which was a sort of beige leathercloth with a subtle printed grain. The front baffle was now divided by a thin gold-toned strip with the upper valence covered in fawn Rexine, and the lower grille covered in brown diamond cloth. Ventilation was provided by three small brass vents on the top of the cabinet, and the TV-front's single suitcase type handle was replaced with three leather straps.
  Since the higher output AC30/4 shared its preamplifier design with the lower powered AC15, Vox discovered the high-gain EF86 tube was susceptible to microphonics, or even failure, when exposed to the increased vibration present in this uprated amp. Vox soon tired of the problem so to cure AC30/4 reliability issues caused by the troublesome EF86 preamp tube, in late 1960 Vox redesigned the preamp circuit, replaced the EF86 with an ECC83 (12AX7), and released this new design as the AC30/6. The AC30/6 was now an amp with three channels, each channel having two inputs.
  About this time, the "Top Boost" (or "Brilliance") feature became available as Vox's optional addition of a rear panel-mounted circuit that introduced an extra gain stage and tone controls for bass and treble (as opposed to the single "tone" control of earlier AC30s). The unit became so popular that its features were soon incorporated in newer AC30/6 models, and the controls moved from the rear panel to the control panel. Vox AC30/6 amplifiers from around 1963 had already implemented the top boost, and therefore had three tone controls. People began to refer to these amplifiers as AC30TBs. Later on, Vox also offered additional versions of the AC30 unit. In addition to the "Normal" version without the Top Boost, and the Top Boost version (which was a Normal version with the "Brilliance" unit added), Vox, with slight circuit modifications, created two more versions that were "voiced" in Brilliant (Treble), and Bass styles. Over the years many different AC30 models appeared but many consider the AC30 "Super Twin" to be the ultimate AC30, with a "trapezoid" shaped head and a separate speaker mounted on a trolley (see The Vox Story, Petersen & Denney 1993, p.39; see also the Vox show
caption: The Edge's almost-original Vox AC30/6 from 1964, housed in a '70s cabinet on stage. It is known that it is the 'brilliant' model (or top boost) and it was Edge's earliest amp used to record every U2 album
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