He served with the Royal Electrical and Mechanical Engineers during World War II, but he was discharged from the Army on medical grounds in 1942.
He also invented new products, the first being the Univox electronic organ, which was a huge success, and not only inspired the "Vox" brand name but was the springboard for his musical instrument amplifier manufacturing empire.
Dick Denney, was also experimenting with guitar amplification and succeeded in producing a 15 watt amplifier paired with a 12-inch (300 mm) speaker.
Displeased with the direction his old company was taking, Tom Jennings left JMI in 1967, roughly the same time that Marshall overtook Vox as the dominant force in the British guitar amplifier market.
Later, Dick Denney joined the new company which operated for several years, making an updated and rebadged version of the AC30, along with other amplifiers and a new range of organs.