Vox AC30 - History

History

The Vox AC30 was originally introduced in 1958 as “big brother” for the fifteen watt (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 in a "TV Front" cabinet as opposed to the later, conventional twin 12” speaker configuration. The AC30/4 sported two channels with two inputs – hence the “4” in the model name, and had a single tone control in it as well. The amplifier also had a GZ34 tube rectifier, and the power amplifier circuit had EL34 tubes. The preamplifier also carried over the EF86 pentode in its "Normal" channel which, coupled with the AC30's increased output over the AC-15, exposed a reliability issue. The high gain EF86 tube was susceptible to microphonics, or even failure, when exposed to the increased vibration present in this uprated amp.

This first generation of AC30s were housed in "TV-front" cabinets, much like the early to mid 50s tweed Fender 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 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.

To cure the unreliability issues Vox introduced another version of AC30 in 1961 that substituted an ECC83 (12AX7) for the EF86 tube. Its circuit had three channels, each with two inputs, and was therefore named AC30/6.

About this time, the "Top Boost" (or "Brilliance") feature was 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 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. 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.

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" 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 (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 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. 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.