Accuphase C-275 (1995)

At 21.7kg, it sits on the rack like an anchor for the whole system.

Overview

The Accuphase C-275 is a precision stereo control amplifier, released in October 1995. It is built without compromise. Owners report a machine that feels overbuilt, with every toggle, relay and circuit path designed to eliminate signal degradation before it starts. It is a line-stage amplifier first. Phono capability comes only through the optional AD-275V phono equalizer unit, sold separately. That fits the design approach - no shared circuits, no shortcuts. The core architecture borrows heavily from the flagship C-290V, adapting its balanced transmission and current feedback topology into a slightly more accessible form. "Accessible" is relative when the original price hit ¥530,000.

The specs matter, but how they're achieved matters more. The entire signal path, from input relays to output stage, uses discrete components and a current feedback amplifier circuit, which Accuphase pursued for transient accuracy. The line amplifier is a pure complementary push-pull configuration built entirely from discrete parts rather than op-amps. It works via balanced transmission across Teflon-based printed circuit boards. The Teflon is meant to minimize dielectric absorption and maintain signal integrity across a very wide bandwidth. The internal layout is complete mono construction: separate power transformers, filter capacitors and regulated power supplies for left and right channels, all in an 8 mm thick hard aluminum frame. That frame handles shielding, channel separation and mechanical rigidity.

The remote-controlled volume uses a low-distortion resistor array driven by a motorized clutch system. It is meant to preserve the analog signal path while allowing precise, repeatable adjustments. Inputs are switched by logic-controlled relays - industrial-grade, gold-plated crossbar types - set up to keep the signal path as short as possible. These are not consumer-grade parts. They were chosen for longevity and contact stability. The unit also has a dedicated headphone amplifier circuit rather than a simple output tap. It ships without phono capability, but adding the AD-275V via DIN connector gives full MM/MC support with switchable gain (60dB or 66dB) and impedance settings (10Ω, 30Ω, 100Ω).

Specifications

Key Features

Current Feedback Amplifier Circuit with Discrete Push-Pull Topology

The C-275's line amplifier section uses a current feedback design, a departure from the more common voltage feedback in many preamps. According to available documentation, this approach gives better transient response and stability across wide bandwidths, which may explain the extended frequency response beyond 300 kHz. The signal path is a pure complementary push-pull configuration built entirely from discrete transistors. There are no integrated circuits, which keeps control over every stage of amplification. Combined with balanced transmission, this discrete construction aims for a neutral yet dynamic presentation, particularly with complex, rhythmically demanding material.

Balanced Transmission with Teflon-Based Circuit Boards

Balanced transmission runs across both line and phono stages. The internal signal paths sit on printed circuit boards made from Teflon (glass cloth fluorine resin), a material known for low dielectric loss and high insulation resistance. The optional AD-275V phono unit uses the same material. Balanced transmission sends inverted and non-inverted signals simultaneously and rejects common-mode noise. That is especially useful in high-gain MC stages or with long cable runs.

Complete Mono Construction with Dual Power Supplies

The C-275 isolates its channels completely. Each channel has its own power transformer, filter capacitors and regulated power supply, which eliminates crosstalk and power supply interaction. The design notes call this a "perfect monophonic structure." It sits inside an 8 mm thick hard aluminum chassis that doubles as mechanical support and RF shielding. The preamp behaves more like two independent monoblocks than a stereo unit, which is a approach typically reserved for much higher-end gear.

Logic-Controlled Relays for Minimal Signal Path

Signal routing is handled by closed-type communication relays with gold-plated crossbar twin contacts, selected for durability and low contact resistance. The relays are logic-controlled to give the shortest possible signal path between input and output, which minimizes capacitance and inductance. Unlike stepped attenuators or digital volume controls, this relay-based system adds no extra components to the signal chain when not in use. The volume control itself is a low-distortion resistor array, motorized through a clutch mechanism linked to the RC-10 remote commander.

Dedicated Headphone Amplifier Circuit

The C-275 has a built-in headphone amplifier rather than a passive tap from the main output. It is designed to drive loads from 4 Ω to 100 Ω. It is a fully active circuit, which suggests Accuphase intended the unit to work as a complete listening hub, not just a preamp for powered systems.

Phase Switch, Compensator, and Subsonic Filter

The front panel has an output phase switch to invert polarity, handy for aligning speakers or sources. A three-position compensator provides loudness correction for low-volume listening: +3dB at 100Hz, +6dB at 100Hz, or a combination of +6dB at both 100Hz and 20kHz. A subsonic filter at 25 Hz with a -12dB/octave slope helps eliminate rumble from turntables without affecting musical bass.

Modular Phono Support via AD-275V

The C-275 ships as a line-only amplifier. It can be expanded with the AD-275V phono equalizer unit via a dedicated DIN connection. That keeps RIAA equalization circuitry out of the main chassis, preserving signal purity for line sources. The AD-275V provides switchable gain (60dB or 66dB) and MC input impedance (10Ω, 30Ω, 100Ω), so it works with a wide range of moving coil cartridges. It is not compatible with other models.

Collectibility & Value

The C-275 appeals to collectors who put build quality and circuit purity ahead of convenience. A used unit in "Excellent" condition was listed for $2,900 approximately four years ago. A C-275 paired with the AD-275 phono unit fetched an auction bid of ¥340,000 in December 2025. Owners consistently praise the sound, and one listing simply says, "The sound from the C-275 is fantastic." The brand's reputation for sturdy construction and high-quality parts contributes to long-term reliability, though no widespread failure modes or maintenance issues are documented. It is a 1995 design with no digital inputs or modern connectivity.

eBay Listings

Accuphase C-275 Preamplifier with AD-275 Phono Equalizer Ful

$3,900

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Service Manuals, Schematics & Catalogs

• Catalog (1990) — archive.org

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