The iconic amplifier which started Onix Audio back in 1984 and changed the culture of listening to music. Created for real lovers of the original OA21 amplifiers. Now 35 years later it's emulating to next level of OA21. It's time for LEGACY for another 35 years coming. Our classic OA21 design has the same unique sense of fashion associated with it. No matter what part of the planet you live in you will love it from the moment you will have it. Every unit will have a serial number for each of the last 35 years from 1984 to 2019 . You may request a certain number. The serial number will be a bonded plate on the base of the unit and engraved on the PCB. Pure class of Hi-Fi audio.