models incorporate the classic EF86 pre-amp tube, which although subject to failure in the late '50s had been re-introduced and improved. The classic EF86 pre-amp tube is remarkable for its high gain and for the notable harmonic overtones it produces and feeds to the power tubes when driven into distortion, providing the creamy distinctive VOX sound of the early hand made amplifiers produced by Jennings of Dartford. Clapton, Cream, Pink Floyd and Queen are ambassadors to the success of the early AC30s. The Heritage series 50th anniversary model stands alone as either the AC15 or AC30 with this distinct circuitry not found in the current VOX line-up. AC30BM In 2006, 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 May of Queen. The amp is limited to only 500 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 Instruments) 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 International with fiberglass voice coils, which allow them a much higher 100 watt power rating. JMI later changed 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