Onkyo unveils a DIY headphone amplifier kit for hobbyists
Onkyo has launched a DIY headphone amplifier kit for hobbyists. The kit is available in Japan for 44,000 Yen (~$300) from the Kyoritsu Electronics Shop. Each unit is made to order and can be ordered from September 3, 2025 to October 3, 2025.
Onkyo was founded in 1946 and has been making audio devices such as these Puella Magi Madoka Magica AOW01 true wireless earbuds. The company has been awarded patents for its audio technologies, including those used in audio amplifiers. Onkyo incorporates these patented technologies (Japanese patent No. 7206472, US patent No. US10862437B2) into the modular components of its TRHPA-KIT01 kit.
The result is a DIY project that can be enjoyed for its ultra-low distortion, which the company says is on par with its commercially-produced amplifiers. Owners can also read about the design of this kit in the September 2025 issue of Transitor Technology published by CQ Publishing in Japan.
The acrylic case allows its owners to see the internal components, which can be further modified by individuals with a knack for modifying audio electronics. The amp accepts 3.5 mm or BNC audio inputs, and has one 3.5 mm audio output for headphones. The unit is powered by a USB-C power source capable of providing at least 2.4 amps (3.0 amps recommended).
The Onkyo DIY ultra-low distortion headphone amplifier measures 157 x 90 x 59 mm (6.2 x 3.5 x 2.3 in.) and weighs 0.72 kg (1.59 lbs.). Readers outside Japan who want a more accessible headphone amp kit might consider this one on Amazon US. Onkyo's home audio components can also be purchased from its store on Amazon US.
