The Virtuoso was one of the five Vox solid state guitar

Standardization and Modular Design
By the time JMI had introduced their new solid state amp line in 1967, Thomas Organ in America was exerting a major influence over the electronic designs and construction techniques employed on British Vox amplifiers. First and foremost, Thomas was encouraging JMI to phase out hand wired tube amps in favor of solid state circuitry built on printed circuit boards.

Thomas Organ also encouraged JMI to incorporate modular construction and standardization techniques. To this end, JMI designed a pair of preamp and control modules. A standardized guitar preamp and control module, detailed on JMI service schematic OS/136, would be shared by the Virtuoso, Conqueror, Defiant and Supreme solid state guitar amplifiers. JMI would also design and construct a second, standardized preamp and control module that would be used by three models of bass guitar amplifiers.

JMI created seven new solid state amplifiers from a pair of modular preamps and four power amp sections. The Virtuoso included a 20 watt RMS power amp module, detailed on JMI repair schematic OS/132. The Conqueror and Dynamic Bass would include the 30 watt RMS module, the Defiant and Foundation Bass the 50 watt module and the Supreme and Super Foundation the 100 watt RMS module.

Features
The Virtuoso, like the Conqueror, Defiant and Supreme, featured a Normal and a Brilliant channel. Like the larger American Vox amps, reverb was selectable between either channel but tremolo was only offered in the Normal channel. The Normal channel featured a "Top Boost" switch while MRB (Mid Range Boost) and a variable distortion (fuzz) was offered in the Brilliant channel.

The 1967 JMI price list indicated that the Virtuoso had a list price of £110.5.0. In USD, the Virtuoso would have retailed for about $400, about the same as a 1967 era Vox V1081 Berkeley II amp from Thomas Organ.