Vox AC30
The Vox AC30 is a guitar amplifier manufactured by Vox. It was introduced in 1958 to meet the growing demand for louder amplifiers. Its "jangly" high-end sound made it widely used by British musicians and others, including George Harrison and John Lennon of the Beatles, Bill Wyman of the Rolling Stones, Brian May of Queen, Dave Davies of the Kinks, Hank Marvin, and Tom Petty.
History
Vox's original flagship amplifier was the 15-watt AC15, powered by a pair of EL84 tubes, an EZ81 rectifier, an EF86-driven "Normal" channel, an ECC83-driven "Vib-Trem" channel. After the AC15 proved too weak to be heard over the screaming fans at Cliff Richard's concerts, Hank Marvin asked Vox to build a "big brother".Introduced in 1959, the first-generation AC30 used EL84 tubes, a GZ34 tube rectifier, three ECC83s for the Normal channel and the tremolo/vibrato oscillator/modulator circuits and one ECC81 phase inverter. The amplifier was housed in a "TV-front" cabinet, 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 with a small printed diamond pattern and larger diamond pattern grill cloth.
A new version appeared in late 1959: the AC30/4. It 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 power tubes, making it truly a doubling of the AC15 power amp circuit. The AC30/4 used the AC15's preamplifier circuit, including 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 a now-legendary cabinet design that has since remained largely unchanged. The new cabinets had a covering known as fawn Rexine, a sort of beige leathercloth with a subtle printed grain. The front baffle was 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.
File:EdgeAC30.jpg|thumb|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 and it was Edge's earliest amp used to record every U2 album
Vox discovered the high-gain EF86 tube was susceptible to microphonics, or even failure, when exposed to the increased vibration in this uprated amp. In late 1960, Vox redesigned the preamp circuit, replacing the EF86 with an ECC83. This new version was released as the AC30/6: three channels, each channel having two inputs.
About this time, the "Top Boost" 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. 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, Vox, with slight circuit modifications, created two more versions that were "voiced" in Brilliant, 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. The AC30 Super Twin retailed for $520 at Sherman Clay stores in 1965.
To meet the demand of providing louder sound levels in live settings, the Vox AC50 was introduced as louder yet similar sounding "Super Twin" model, providing over 50 watts of power. And the infamous AC100 was produced shortly after which was the loudest of the Vox AC models ranging in 80-100 watts.
In the late '60s Jennings drifted into financial problems and the company experienced various owner changes. Quality control was also inconsistent.
During the Vox brand's early '70s "Dallas Arbiter" period, the tube rectifiers of AC30s were replaced by silicon rectifiers, which became standard on later AC30TB models. In the late 1970s Vox also introduced a solid-state AC30, which is the AC30 model that was used by Status Quo. A tube AC30TB with spring reverb feature was reintroduced in 1978.
In spite of at least one AC30 production run titled "Limited Edition" of 100 units with starting serial number 0100 , production of the AC30 has practically never ceased: Newer AC30s are reissues of the various top boost AC30/6 models. AC30s made between 1989 and 1993 also had spring reverb as a standard feature.
The Rose Morris company, who owned the Vox name through the 1980s, sold Vox to Korg in the early 1990s, who then manufactured a reissue of the early '60s AC30 Top Boost, correcting previous inconsistencies ranging from the correct style grille cloth to the GZ34 rectifier tube. These AC30 amps were mostly offered in the traditional black Tolex/brown diamond grille configuration, but were also available in limited numbers with purple, red, or tan tolex. These amplifiers, like all AC30s to this point, were manufactured in Great Britain. These were available with a choice of Celestion "Blue" or "Greenback" speakers. In the mid 1980s, a company in Marlborough, MA, called Primo, imported and began re-distributing the AC30s in the U.S.
AC30HW Limited (2003)
In 2003, Vox created the "AC30 Heritage Handwired Limited Edition" amplifier. This amplifier differed from the standard offering in notable ways. First, the circuitry was constructed using old-fashioned tag strips. According to Vox this was far more labor-intensive, but it allowed for easier repair versus circuit boards because there were no copper tracks to burn. According to the Vox showroom site:"1960s era Vox amps were hand wired on tag strips. The connecting lead from each electronic part was manually wrapped around a terminal, or "tag," and then soldered. This mode of amp construction is very labour-intensive and the workmanship and accuracy of the employee building the amp will affect the performance of the product. It was for this reason that most electronics manufacturers transitioned to phenolic printed circuit boards by 1970."
The second notable difference was the features and control layout. Guitar Player magazine reviewed the amp in its "Exotica" feature, December 2002. The article specifies details of the amp, including price, and its control layout:
"The AC30 HW, which was developed with input from boutique amp designer Tony Bruno, features the famous Top Boost preamp, but has a control that is quite different from the standard model. For starters, there are only two inputs, which are marked Hi and Lo. To the right are the volume, treble, bass and tone-cut controls, a tremolo section with speed and depth knobs, a reverb section with reverb and tone controls, and a master volume." Top of the Marque. The AC30HW is by far the best AC variant to date. Few amps come close to matching its radiant complexity and those that do typically don't offer reverb and tremolo. The only downer about the HW is that only 350 of them will be made."