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At £297, this used Phase Linear 4000 preamplifier is a strong bargain, sitting well below the 25th percentile of £445 and nearly half the median of £593 from recent GBP listings. The price is exceptionally low for a functioning unit, especially since the listing condition is unknown but the asking price assumes minimal risk for the buyer.
The Phase Linear 4000 is a revered 1970s preamp renowned for its Autocorrelation circuit, which delivers ultra-low distortion (under 0.03% at 1V) and exceptional clarity. It’s a rare find in the UK market, and at this price, even if it needs a full cleanup or capacitor replacement, the upside is massive. If it works as stated, this is a clear buying opportunity for any vintage hi-fi enthusiast.
Independent perspective — not a price guarantee. Always verify condition, accessories and provenance before purchase.
Phase Linear was founded by Bob Carver in his home in Edmonds, Washington, around mid-1969, with the company officially launched in 1970 from a small building at 405 Highway Way. Operating as an American manufacturer during the golden age of high-fidelity audio, Phase Linear quickly established itself as an innovator in power amplification. The company remained independent until 1979, when Pioneer Electronics Corporation acquired it, though Phase Linear continued operating under its own brand until manufacturing ceased in 1983.
The brand built its reputation primarily on high-powered amplifiers, most notably the Phase Linear 700, unveiled in 1970 and delivering an impressive 350 watts per channel—a significant achievement for the era. This inaugural design became the company's flagship offering and exemplified their engineering philosophy of combining substantial output with reliable construction. Phase Linear's amplifiers became synonymous with driving demanding speaker loads and delivering the dynamic power that serious audiophiles sought during the 1970s and early 1980s.
Phase Linear occupies a distinctive position in audio history as a vintage collectible brand rather than a contemporary manufacturer. Among enthusiasts and restoration communities, the company is remembered fondly for solid build quality and components that continue functioning reliably decades after production ended. Today, Phase Linear equipment appeals primarily to vintage audio collectors and restoration hobbyists who value the brand's engineering heritage and the warm, characterful sound signature associated with classic 1970s amplification.
See all Phase Linear listings on RADAR.
