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The asking price is right in line with market for this model, landing just under the US$1,000 median and comfortably inside the recent US$900–US$1,250 interquartile range. At US$995, it reads as a fair buy rather than a steal, with no premium to justify unless the unit is exceptionally clean or serviced.
That matters because the M-504 is a respected vintage stereo power amp: plenty of current, a solid build, and a sound many buyers still like for its punch and drive. If the cosmetics are good and it’s been stable in use, this is the kind of listing that can make sense for a listener who wants classic high-current Onkyo muscle without chasing a bargain-basement example.
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.
