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Note says - "Works" sound comes through IN -> Aux 1, Out -> LR/RR, others not fully tested. Everything scratchy. Item looks great, sounds great with static controls, scratchiness is only when adjusting settings. Probably does need a little bit of internal clean up.
Are you looking for a working vintage preamp or a restoration project? At US$350, this is a strong deal: it sits below the supplied 25th-percentile comparable price of US$362, well under the US$481 median and US$590 75th percentile. For a recognizable Phase Linear 4000, that is bargain territory if it powers up and the core functions operate.
The appeal is its unusually ambitious feature set: effective auto-correlator noise reduction, dynamic expansion, selectable tone shaping, joystick balance, and SQ quadraphonic decoding. It is also an interesting, distinctive piece of American hi-fi history rather than a generic line stage. The catch is age-related complexity: board connectors and solder joints can cause noise or intermittent operation, and restoration is labor-intensive. At this price, though, those risks are reasonable—just verify both channels, phono, controls, noise-reduction circuitry, and all inputs before treating it as a finished keeper.
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.
