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GKC Research & Development Model 655 Monitor Amplifier
Monitor Audio 6 views

GKC Research & Development Model 655 Monitor Amplifier

USD$60
Location
US
Seller
teddyburr
Source
eBay US
Posted
22 Aug 2026
Last seen
2d ago

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Our Thoughts RADAR AI

At US$60, this sits far below the typical used market for this kind of gear, and well under the US$125 25th percentile in your comps, so it reads as a strong bargain rather than a borderline buy. Against a median of US$428, the asking price leaves plenty of room for normal vintage-audio risk and still looks very attractive if the unit is genuinely complete and functioning.

The appeal here is the chance to get a rare Monitor Audio research-piece amplifier at an entry-level price, which makes it a very easy add for a collector or experimenter. If it powers up quietly, switches cleanly, and isn’t missing any critical parts or documentation, this is the sort of oddball used-audio find that can be a lot of fun for very little money.

Independent perspective — not a price guarantee. Always verify condition, accessories and provenance before purchase.

About Monitor Audio

Monitor Audio, a British hi-fi mainstay, traces its origins to 1972 when founder Mo Iqbal established the company in a modest factory near Cambridge, England. Starting with hands-on loudspeaker assembly in a garage-like setting, it quickly professionalized, moving to Rayleigh, Essex, in 1976 for in-house manufacturing. This heritage of meticulous British engineering has endured through expansions, including a 2004 shift of production to China while retaining design leadership in Essex, alongside strategic acquisitions like Roksan in 2016 and Blok in 2019.

The brand excels in loudspeakers across diverse categories, from high-fidelity two-channel stereo models to advanced home cinema systems, architectural installations, outdoor speakers, and lifestyle solutions. Signature innovations like the patented C-CAM Gold Dome tweeters, introduced in the 1980s and continually refined, define its sound. Complementing these are amplifiers, streamers, and integrated audio systems, reflecting a broad portfolio that prioritizes proprietary driver technologies and precise enclosure design over peripheral gear like turntables or headphones.

Positioned as a mid-to-high-end powerhouse, Monitor Audio commands respect for delivering audiophile-grade performance at accessible price points, blending relentless innovation with timeless British craftsmanship. Over five decades, it has solidified its status as a global juggernaut, appealing to discerning buyers seeking refined, dynamic sound without boutique exclusivity or vintage nostalgia.

See all Monitor Audio listings on RADAR.

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