Vox AC30
Encyclopedia
Instrument amplifier
An instrument amplifier is an electronic amplifier that converts the often barely audible or purely electronic signal from musical instruments such as an electric guitar, an electric bass, or an electric keyboard into an electronic signal capable of driving a loudspeaker that can be heard by the...
manufactured by Vox
Vox (musical equipment)
Vox is a musical equipment manufacturer which is most famous for making the Vox AC30 guitar amplifier, the Vox Continental electric organ, and a series of innovative but commercially unsuccessful electric guitars and bass guitars...
and known for its "jangly" high-end sound. First introduced in 1958 due to the growing demand for higher-wattage amplifiers, it became an iconic amplifier for British musicians and soon for others.
History
The Vox AC30 was originally introduced in 1958 as “big brother” for the fifteen wattWatt
The watt is a derived unit of power in the International System of Units , named after the Scottish engineer James Watt . The unit, defined as one joule per second, measures the rate of energy conversion.-Definition:...
(15 W) AC15 model, Vox's original flagship amplifier. The AC15 was powered by a pair of EL84 tubes, an EF86-driven "Normal" channel and ECC83-driven "Vib-Trem" channel, and rectified by an EZ81. The Original AC30, or AC30/4, had only a single 12 inch Goodmans 60 watt speaker as opposed to the later, conventional twin 12” speaker configuration. AC30/4 sported two channels with two inputs – hence the “4” in the model name. There was only a single tone control in it as well. The power amplifier circuit had EL34 tubes and the preamplifier used an EF86, which was a pretty unreliable tube and could fail due to vibration. The amplifier had a tube rectifier.
This first generation of AC30s were housed in "TV-front" cabinets, much like the early to mid 50s tweed Fender
Fender
Fender Musical Instruments Corporation, commonly referred to as simply Fender, of Scottsdale, Arizona is a manufacturer of stringed instruments and amplifiers, such as solid-body electric guitars, including the Stratocaster and the Telecaster...
amps. However, the Voxes sported a thin white covering ("Rexine") with a small printed diamond pattern and larger diamond pattern grill cloth. The EL34 powered AC30 was short lived, and was soon powered by a quartet of EL84 (6BQ5) power tubes, making it truly a doubling of the AC15. Vox initially offered a 1X12" version and subsequently introduced the 2X12" AC30 Twin, which solved the volume problem at larger venues. The first AC30 Twins used Goodmans Audiom 60s 15 Watt Speakers, followed by Celestion
Celestion
Celestion is a British maker of loudspeakers.-History:The work of what would become Celestion started in Hampton Wick in 1924. Celestion Radio Company and Celestion Limited were formed in 1927, and two years later the company moved across the Thames to Kingston. The company grew rapidly, but was...
G12 alnico
Alnico
Alnico is an acronym referring to iron alloys which in addition to iron are composed primarily of aluminium , nickel and cobalt , hence al-ni-co, with the addition of copper, and sometimes titanium. Alnico alloys are ferromagnetic, with a high coercivity and are used to make permanent magnets...
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.
To cure the unreliability issues Vox introduced another version of AC30 in 1961 that substituted the EF86 with ECC83 (12AX7) tubes. Its circuit had three channels, each with two inputs, and was therefore named AC30/6. The amplifiers were also available in three different “voicing” styles (Normal, Brilliant, and Bass) that were accomplished by slight circuit modifications.
About this time, the "Top Boost" (or "Brilliance") feature was Vox's optional addition of a rear panel-mounted circuit
Electronic circuit
An electronic circuit is composed of individual electronic components, such as resistors, transistors, capacitors, inductors and diodes, connected by conductive wires or traces through which electric current can flow...
that introduced an extra gain stage and tone controls for bass and treble (as opposed to the single "tone" control of early AC30s). The unit became so popular that its features were soon implemented to 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 3 tone controls. People began to refer to these amplifiers as AC30TBs.. Around the same time, Vox also introduced Treble and Bass versions of the AC30 without the Top Boost unit. Instead, the circuits of the Treble and Bass versions were slightly modified to emphasize those frequencies.
In the late 60’s 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
Dallas Arbiter
Dallas Arbiter is a company formed by the merger of John E. Dallas and Sons musical instrument company and Arbiter Electronics. Dallas Arbiter Ltd. produced a number of guitar effects which changed the ordinary sound of the electric guitar into something more noticeable...
" period, the tube rectifiers of AC30s were replaced by silicon
Silicon
Silicon is a chemical element with the symbol Si and atomic number 14. A tetravalent metalloid, it is less reactive than its chemical analog carbon, the nonmetal directly above it in the periodic table, but more reactive than germanium, the metalloid directly below it in the table...
rectifiers, which became standard on later AC30TB models. In the late 1970s Vox also introduced a solid-state
Solid state (electronics)
Solid-state electronics are those circuits or devices built entirely from solid materials and in which the electrons, or other charge carriers, are confined entirely within the solid material...
AC30 (AC30SS), 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” (1991), production of the AC30 has practically never ceased: Newer AC30s are reissues of the various top boost AC30/6 (AC30TB) 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
Korg
is a Japanese multinational corporation that manufactures electronic musical instruments, audio processors and guitar pedals, recording equipment, and electronic tuners...
in the early 1990s, who then manufactured a reissue of the early '60s AC30 Top Boost, correcting previous inconsistencies 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
Great Britain
Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...
. These were available with a choice of Celestion
Celestion
Celestion is a British maker of loudspeakers.-History:The work of what would become Celestion started in Hampton Wick in 1924. Celestion Radio Company and Celestion Limited were formed in 1927, and two years later the company moved across the Thames to Kingston. The company grew rapidly, but was...
"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.
AC30 Handwired
Introduced in 2010, the amp featured Hand-wired turret board construction (against cheaper PCB construction), Birch-ply cabinets featuring solid bracing and a natural high frequency diffuser (verses MDF cabinets and no high frequency diffuser); All-tube design (different from the Custom series tube pre/power amp but solid-state rectifier); ECC83/12AX7 preamp tubes (x3) EL84 power tube quartet; (AC30 models); EL84 Duet (AC15 models); GZ34 rectifier (AC30 models); EZ81 rectifier (AC15 models); came factory-fitted with matched Ruby Tubes to provide extended dynamic range; maintained the traditional VOX two-channel design (Top Boost and Normal. High and Low inputs for each channel); the Normal channel features an additional BRIGHT switch; The top boost channel features a HOT/COOL switch to achieve even more gain. A Master Volume/BYPASS switch completely bypasses the Master Volume section allowing incredible levels of gain and sustain to be achieved. OP mode switch cut the amp’s Output Power level in half (30 > 15 on the AC30, 15 > 7.5 on the AC15) allowing higher levels of saturation to be achieved at lower volumes). A Vintage fawn-colored vinyl covering, reminiscent of the 1960 classic AC30 and was avaible with either Celestion Alnico Blue or Celestion G12M Greenback speakers. A VFS1 footswitch controls the Top Boost channel's HOT/COOL switch was also included.AC30 Custom Series
At the 2010 Winter NAMM expo Vox introduced the Custom series; these models were updates to the 2004 Custom Classic series amplifiers and featured 2 channels (Normal and Top Boost) with 2 inputs for each channel (High and Low), more akin to the original AC30/4 released in 1958. Available with either Greenback speakers (C2) or Alnico Blue Speakers (C2x), and was also available as the AC15. Later limited edition models include the AC30C2RD, which is identical to the C2 but featured a red finish, and the AC30C2 Black Comet; featuring a patterned finish. The amp featured an option known as "Jumping" where the High-Normal channel could be linked to the Low-Top Boost channel with a patch lead, whilst the guitar is plugged into the High-Top Boost channel, allowing both channels to sound and create a fuller, thicker overdrive sound. The amp also featured a solid-state rectifier to increase reliability. Controls include a Normal volume, Top Boost Volume, Treble and Bass controls, Reverb Tone and Level controls, Tremolo Speed and Depth controls, a Tone Cut control (to add further control over the higher-frequencies), a Master Volume, and a Standby and Power Switch. A true bypass effects loop, extension cab output and external cab output were also included; as well as an input for the external foot-switch (to control Reverb and Tremolo). The amps are produced in China. The amps were released to be a critical success, garnering awards such as Music Radar's "Guitarist Choice" award.AC30 Custom Classic Series
In 2004, Vox introduced a new series of amplifier called the AC30 Custom Classic. It claims to combine attributes of the original AC30 with what Vox sales literature refers to as a "boutique" of features. Specifications of the AC30CC series are two Inputs (Top Boost & Normal), an Input Link Switch for blending channels, a Normal Volume knob, a Brilliance Switch, a Top Boost Volume knob, a Treble knob, an EQ Standard/Custom Switch, Bass and Reverb Controls (Tone, Mix, and a Dwell Switch), Tremolo Speed & Depth knobs, a Tone Cut knob, a Master Volume knob, a Standby and a Power Switch, switchable cathode bias (Output Bias switch: "50 Hot": 33W at full power, "82 Warm": 22W at low power), switchable filter values (vintage/modern), and a true bypass effects loop. Newer AC30CC (or “Custom Classic”) reissues (CC1, CC2X CCH head) are produced in ChinaChina
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
. All AC30CC series amps, although believed to be 30 watts, are in fact 40 watts in power handling.
AC30BM
Recently, Vox released a limited edition version of the amp, the AC30BM, based on the tone of one of the amp's most prominent and consistent endorsers, Brian MayBrian May
Brian Harold May, CBE is an English musician and astrophysicist most widely known as the guitarist and a songwriter of the rock band Queen...
of Queen
Queen (band)
Queen are a British rock band formed in London in 1971, originally consisting of Freddie Mercury , Brian May , John Deacon , and Roger Taylor...
. The amp is limited to only a few hundred examples worldwide, in a 'never-to-be-repeated' run. As the amp is designed to replicate May's tone, there are no controls on the amp except for a single volume control, though a switch enables the user to halve the number of output valves (therefore reducing the output to 15 watts as well as the volume, making it more suitable for home use), and there is a boost function operated from the included footswitch.
JMI returns
As of 2006, a company having licensed the name JMI (Jennings Musical InstrumentsJennings Musical Instruments
Jennings Musical Instruments is a manufacturer of musical instruments, notably the original owner of the Vox brand. The company was founded by Thomas Walter Jennings.-History:...
) began manufacturing period correct, British made AC30 "copy" amplifiers, available in both black and beige. Since this incarnation of JMI has never owned the Vox brand, their official website lists the disclaimer "JMI amplification are in no way affiliated with Vox amplification (Korg)", and the models are listed as 30/6 (6 input) and 30/4 (4 inputs, sans "Brilliant" channel). As originally the case in the 1960s, Top Boost is offered as a retrofit upgrade and is not standard, and the original configuration 4/6 inputs are offered, with options for Green/Blue speakers, the blue speakers being similar in appearance to the Celestion alnico speaker but made by Fane
Fane
Fane may refer to:* Fane, Papua New Guinea, village associated with Simona Noorenbergh* Fane * Fane River in Ireland...
with fiberglass voice coils which allow them a much higher 100 watt power rating. JMI later changed their alnico speakers to ones made by Tayden.
AC30VR
Another recent addition is the VOX AC30VR (Valve Reactor). According to the Vox website, this version of the AC30 includes both "solid-state" and "tube" technology. Originally designed for the Valvetronix modelling amplifiers, the Valve Reactor circuit places a 12AX7 vacuum tube (or “valve”) into the power stage, which is a tube configured to act as a small power amplifier. Too small to be used as an amplifier on its own, the output of this Valve Reactor circuit is fed to a solid state power amp that boosts the output signal.Other AC30 Clones
Other popular AC30 clones include: Majic Amplification, Hayseed & JMJ. They have various combinations of the EF86, Top Boost and Normal channel circuits. Recently, the company Bugera has released a clone of the AC30, the Bugera BC30. However, it is also similar to the Matchless DC30(which, in itself started as a clone of the AC30).Electronics
Though widely believed to be a Class-A amplifierElectronic amplifier
An electronic amplifier is a device for increasing the power of a signal.It does this by taking energy from a power supply and controlling the output to match the input signal shape but with a larger amplitude...
, the AC30 is in fact a class AB1 amp with cathode bias. It utilizes a quartet of EL-84 output tubes. The high bias condition is believed by some to be the source of the amplifier's famous immediate response and "jangly" high-end, though the lack of negative feedback, minimal preamp circuit, simple low loss tone stack, and the use of cathode biasing on the output stage play at least as large a role, if not larger. Its Celestion "Blue" speakers are integral to the AC30, and also contribute much to the sound of the unit. The two 12" 15-watt speakers, often overdriven and at the brink of their power handling capability, provide a cutting mid-range speaker sound that is immediate and sharp and a distinction from the Marshall
Marshall Amplification
Marshall Amplification is a British company, founded by drummer Jim Marshall, that designs and manufactures music amplifiers, brands personal headphones/earphones , and, after acquiring Natal Drums, drums and bongos. Marshall amplifiers, and specifically their guitar amplifiers, are among the most...
or Fender
Fender
Fender Musical Instruments Corporation, commonly referred to as simply Fender, of Scottsdale, Arizona is a manufacturer of stringed instruments and amplifiers, such as solid-body electric guitars, including the Stratocaster and the Telecaster...
-style amplifier.
Notable users
- Brian MayBrian MayBrian Harold May, CBE is an English musician and astrophysicist most widely known as the guitarist and a songwriter of the rock band Queen...
- Hank MarvinHank MarvinHank Brian Marvin is an English guitarist, best known as the lead guitarist for The Shadows. The group, which primarily performed instrumentals, was formed as a backing band for vocalist Cliff Richard...
- The BeatlesThe BeatlesThe Beatles were an English rock band, active throughout the 1960s and one of the most commercially successful and critically acclaimed acts in the history of popular music. Formed in Liverpool, by 1962 the group consisted of John Lennon , Paul McCartney , George Harrison and Ringo Starr...
- Tom PettyTom PettyThomas Earl "Tom" Petty is an American singer-songwriter and multi-instrumentalist. He is the frontman of Tom Petty and the Heartbreakers and was a founding member of the late 1980s supergroup Traveling Wilburys and Mudcrutch. He has also performed under the pseudonyms of Charlie T...
- The EdgeThe EdgeDavid Howell Evans , more widely known by his stage name The Edge , is a musician best known as the guitarist, backing vocalist, and keyboardist of the Irish rock band U2. A member of the group since its inception, he has recorded 12 studio albums with the band and has released one solo record...
- Rory GallagherRory GallagherWilliam Rory Gallagher, ; 2 March 1948 – 14 June 1995, was an Irish blues-rock multi-instrumentalist, songwriter, and bandleader. Born in Ballyshannon, County Donegal, Ireland, and raised in Cork, Gallagher recorded solo albums throughout the 1970s and 1980s, after forming the band Taste...
- Jonny GreenwoodJonny GreenwoodJonathan Richard Guy "Jonny" Greenwood is an English musician and composer, best known as a member of the English rock band Radiohead. Greenwood is a multi-instrumentalist, but serves mainly as lead guitarist and keyboard player. In addition to guitar and keyboard, he plays viola, harmonica,...
- Robert SmithRobert Smith (musician)Robert James Smith is an English musician. He is the lead singer, guitar player and principal songwriter of the rock band The Cure, and its only constant member since its founding in 1976...
- Black Francis
- Jimmy Eat WorldJimmy Eat WorldJimmy Eat World is an American alternative rock band from Mesa, Arizona, that formed in 1993. The band is composed of lead vocalist and guitarist Jim Adkins, guitarist and backing vocalist Tom Linton, bassist Rick Burch and drummer Zach Lind....