Harry Joyce was a British electronics engineer who learned military-specification wiring techniques from American technicians during World War II. He went on to become one of the most influential figures in guitar amplifier history, introducing point-to-point military-spec construction to the world of guitar amplification. In the 1960s and 1970s, Dave Reeves contracted Joyce to hand-wire chassis for Hiwatt amplifiers, and Joyce's meticulous craftsmanship — with clearly labeled components, right-angled wiring, and tied-off leads — became the foundation of Hiwatt's legendary reputation for reliability and tone. He famously insisted on limiting production to 40 amps per month to maintain quality.

After parting ways with Hiwatt in 1976 and spending years building electronics for the British Ministry of Defence, Joyce launched his own amplifier line in 1993. The HJ Custom series — available in 30, 50, and 100 watt configurations — built upon his earlier Mullard-circuit designs with improvements including an extra gain stage, redesigned transformers, and an effects loop. The first three amps he produced went to Robert Plant's band. Rich Robinson of The Black Crowes and Brad Whitford of Aerosmith also became users of his amps. Joyce hand-built amplifiers until his retirement in 2000; he passed away in January 2002.

In 2015, Harry Joyce USA relaunched the brand out of Sarasota, Florida, producing hand-built, point-to-point wired amplifiers in the tradition of the originals. The lineup includes Custom and Classic series heads in 30, 50, 100, and 200 watt versions, all built with marine-grade birch plywood cabinets, EL34 power tubes, and selectable output impedance. The amps feature dual-channel designs with Normal and Brilliant inputs, continuing Joyce's legacy of uncompromising build quality and high-headroom tone.