Jansen is a New Zealand audio company with origins in late-1950s Auckland, where Bruce Eady and Jack Collins began assembling small valve amplifier combos for the country's emerging rock and roll scene. Manufactured by Beverley Bruce & Goldie Ltd. and distributed under the Jansen name, the line expanded from a purpose-built Grey Lynn factory into electric guitars, basses, and electric organs, becoming the dominant homegrown gear brand in New Zealand through the 1960s and into the 1970s.

The company is best known for its valve amplifier series — early models like the five-watt I-A33 through the 25-watt silver-panel I-A715 — and for the higher-powered 100 and 150 watt heads that became staples of louder rock acts on both sides of the Tasman. After winding down guitar manufacturing in 1972, Jansen pivoted toward solid-state PA gear, with the PA-80 and PA-150 systems finding wide use in venues and touring rigs. MOSFET-based designs followed in the late 1970s, and Jansen-branded amplifier production continued into the late 1990s.

Jansen amplifiers and guitars were closely associated with New Zealand artists such as Peter Posa and Ray Columbus & The Invaders, and the brand's high-wattage heads were adopted by the Dave Miller Set in Australia. The Jansen Audio business continues today as a professional audio distributor based in Auckland, handling lines including Allen & Heath, Audio-Technica, Audient, and Martin Audio alongside its own legacy guitar and amplifier heritage.

Jansen has 2 products cataloged on Equipboard, including Bass Combo Amplifiers and Combo Guitar Amplifiers. Their gear is featured by 1 artist, with the strongest followings in Rock and Pop. Notable users include Elizabeth Stokes.