The Jennings Organ Company was founded by Thomas Walter Jennings in Dartford Kent, England after World War II. Jennings's first successful product was the Univox, an early self-powered electronic keyboard similar to the Clavioline.
In 1956 Jennings was shown a prototype guitar amplifier made by Dick Denney, a big band guitarist and workmate from World War II. The company was renamed Jennings Musical Industries, or JMI, and in 1958 the 15-watt Vox AC15 amplifier was launched. It was popularised by The Shadows and other British rock 'n' roll musicians and became a commercial success.
In 1959, with sales under pressure from the more powerful Fender Twin and from The Shadows, who requested amplifiers with more power, Vox produced what was essentially a double-powered AC15 and named it the AC30. The AC30, fitted with alnico magnet-equipped Celestion "blue" loudspeakers and later Vox's special "Top Boost" circuitry, and like the AC15 utilizing valves (known in the US as tubes), helped to produce the sound of the British Invasion, being used by The Beatles, The Rolling Stones, The Kinks and the Yardbirds, among others. AC30s were later used by Brian May of Queen (who is known for having a wall of AC30s on stage), Paul Weller of The Jam (who also assembled a wall of AC30s), Rory Gallagher, The Edge of U2 and Radiohead guitarists Thom Yorke, Jonny Greenwood and Ed O'Brien. The Vox AC30 has been used by many other artists including Mark Knopfler, Hank Marvin who was instrumental in getting the AC30 made, Pete Townshend, Ritchie Blackmore, John Scofield, Snowy White, Will Sergeant, Tom Petty, The Echoes, Mike Campbell, Peter Buck, Justin Hayward, Mike Nesmith, Peter Tork, Noel Gallagher, Matthew Bellamy, Omar Rodriguez-Lopez, Dustin Kensrue, and many others.