business increased, Marshall asked the three to work for him in his shop, as he had more space and capital to expand. The original idea was talked about late one Friday night in early 1963 in a Wimpy bar in Ealing in West London by three amateur radio enthusiasts after they had been to their weekly Greenford radio club meeting, Dudley Craven's call sign was G3PUN, Ken Bran's was G3UDC, and Ken Underwood's was G3SDW. As of Dudley's death in 1998 and Bran's death in 2018, the only original individual is Ken Underwood. The first six production units were assembled in the garden sheds of Bran, Craven, and Underwood in the same year, in Heston, Hanwell and Hayes, all in West London. They were almost copies of the Bassman circuit, with American military-surplus 5881 power valves, a relative of the 6L6. Few speakers then were able to handle more than 15 watts, which meant that an amplifier approaching 50 watts had to use multiple speakers to handle the power. For their Bassman, Fender used four ten-inch Jensen speakers in the same cabinet as the amplifier, but Marshall chose to separate the amplifier from the speakers, and placed four 12-inch Celestion speakers in a separate closed-back cabinet instead of Fender's four 10-inch Jensens in an open-back combo. Other crucial differences included the use of higher-gain ECC83 valves throughout the preamplifier, and the introduction of a capacitor/resistor filter after the volume control. These circuit changes gave the amp more gain so that it broke into overdrive sooner on the volume control than the Bassman, and boosted the treble frequencies. This new amplifier, tentatively called the "Mark II", was eventually named the "JTM 45", after Jim and his son Terry Marshall and the maximum wattage of the amplifier. Jimi Hendrix, Eric Clapton, and other blues rock-based bands from the late 1960s such as Free used Marshall stacks both in the studio and live on stage making them among the most sought after and most popular amplifiers in the industry. Distribution deal Marshall entered into a 15-year distribution deal with British company Rose-Morris during 1965, which gave him the capital to expand his manufacturing operations, though it would prove to be costly. In retrospect, Marshall admitted the Rose-Morris deal was "the biggest mistake I ever made. Rose-Morris hadn't a clue, really. For export, they added 55% onto my price, which pretty much priced us