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US$342 looks like a strong buy for this amp if it’s complete and working properly. The HP100 originally sold in the roughly US$600 to US$1,300 range depending on version and market, so this asking price sits well below typical used expectations and is closer to bargain territory than merely fair.
What makes it worth chasing is the Stello house sound: a respected, no-drama headphone/preamp with plenty of drive, useful as a serious desktop control center rather than just a throwaway headphone stage. At this price, the main thing to verify is basic functionality and any included power supply, remote, or original box if applicable; on a well-kept example, this is the kind of used buy that makes sense for someone who wants good performance without paying flagship money.
Independent perspective — not a price guarantee. Always verify condition, accessories and provenance before purchase.
Stello is a hi-fi brand from South Korea, launched by April Music, a company founded in 1998 in Seoul. April Music, known for its skilled engineering team that includes musicians, established Stello as one of its three core lines—alongside the digital-focused Aura and power amplification-oriented Eximus—initially targeting personal audio enthusiasts. The brand debuted with the acclaimed HP100 (also known as H100) headphone amplifier and preamp, building a foundation in compact, high-quality components assembled in Korea with some enclosures sourced from California.
Stello specializes in digital audio essentials and amplification, including standout products like the CDT100 and DA100 DACs, USB DACs such as the U3, CD transports like the CDT200, and integrated amplifiers like the Ai500. Its 100 Series emphasizes lifestyle-sized designs that bridge traditional hi-fi with PC-based music playback, delivering transparent, open sound through reliable engineering. The lineup avoids speakers or turntables, focusing instead on sources, DACs, and amps that integrate seamlessly into modern setups.
Positioned as an affordable high-end contender, Stello earns praise for punching above its price with extraordinary build quality and musicality, often rivaling pricier rivals. It challenges preconceptions about Korean audio—proving South Korea's prowess beyond consumer electronics—while serving as a gateway for discerning buyers seeking value-driven performance without boutique excess. April Music's OEM work for other high-end marques underscores its technical credibility in the global market.
See all Stello listings on RADAR.
