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This is a buyer’s market for this piece, and US$1,200 lands above the US$1,000 median and even above the US$1,250 75th percentile, so it’s only slightly ambitious rather than a bargain or outright stretch. In this market, I’d treat it as a buy only if the condition is genuinely strong and the unit is complete.
The M-504 is well-regarded because it’s a muscular, old-school stereo amp with plenty of drive and a sound that still appeals to listeners who want grip and scale over modern fuss. If it’s clean, unmodified, and functions properly, the appeal is real; the upside is especially good if it includes the original cosmetics, documentation, or has recent service history. At this price, though, I’d want proof it’s healthy, since age-related service can matter more than the badge.
Independent perspective — not a price guarantee. Always verify condition, accessories and provenance before purchase.
Onkyo traces its roots to postwar Japan, founded in 1946 in Osaka by Takeshi Goda, an engineer at Matsushita Electric who envisioned high-quality Japanese loudspeakers. Initially established as Osaka Denki Onkyo K.K., the company began production in 1948 with the acclaimed ED-100 speaker featuring a 25 cm driver, quickly building a reputation through LP concerts and innovative designs that resonated with audiophiles.
The brand excels in premium home audio, renowned for AV receivers, hi-fi amplifiers, and surround sound speakers that deliver exceptional clarity and power. Its portfolio spans turntables, DACs, headphones, and cables, bolstered by acquisitions like Pioneer's home electronics division in 2015, enabling cutting-edge integrations such as internet radio and high-resolution streaming.
Onkyo holds a solid mid-tier position in the hi-fi market, prized by discerning buyers for reliable performance and value rather than ultra-high-end exotica. Despite bankruptcy challenges in the late 2010s, its revival under new ownership preserves a legacy of technological innovation and pure sound enjoyment, appealing to both vintage enthusiasts and modern home cinema setups.
See all Onkyo listings on RADAR.
