Accuphase C-17 (1984)

Name: Accuphase C-17
Brand: Accuphase

MC head amplifier released in September 1984, designed to preserve the unique characteristics of moving coil cartridges.

Overview

The Accuphase C-17 is an MC head amplifier manufactured by Accuphase Laboratory, Inc. in Japan and released in September 1984. It is designed to amplify signals from moving coil phono cartridges with minimal coloration. The unit was developed to directly convey the inherent qualities of the cartridge, featuring a dual-mono design with independent circuitry for each channel. Housed in separate aluminum enclosures, the left and right amplifier sections are isolated to prevent induction noise and vibration-induced resonance.

Specifications

Gain	0 dB (MM), +26 dB, +32 dB
Frequency characteristic	20 Hz ~ 20 kHz +0 -0.2 dB; 2 Hz ~ 100 kHz +0 -3.0 dB
Input impedance	10 Ω, 30 Ω, 100 Ω (switching type)
Output impedance	50 Ω
Minimum load impedance	10k Ω
Rated output voltage	2.0 mV
Total harmonic distortion factor	0.005% (20 Hz to 20 kHz at maximum input)
S/N (input conversion noise)	+26 dB position: 72dB (A-weighted), -152dBV (input short); +32 dB position: 66dB (A-weighted), -152dBV (input short)
Power consumption	30W
Power supply voltage	AC100V/117V/220V/240V, 50Hz/60Hz
External dimensions	Width 194 x Height 142 x Depth 371 mm
Weight	8.1kg
Semiconductor count	Transistor: 71; FET: 4; IC: 8; Diode: 64

Design

All amplification stages use cascode push-pull circuits operating in Class A, with dual-mono topology ensuring complete separation between channels. Each channel has its own dedicated power transformer and constant-voltage power supply, housed within the same aluminum enclosure as the amplifier circuit to reduce wiring length and interference. The MC input impedance is switchable between 10 Ω, 30 Ω, and 100 Ω. Low-noise components are used throughout, and noise resistance is enhanced by reducing impedance in the NFB loop and applying feedback to the base of the constant current source rather than directly to the differential stage’s negative input.

Context

The C-17 was released in September 1984 during a peak period for Japanese high-end audio equipment. It is part of Accuphase’s lineup of MC head amplifiers, designed to preserve the tonal authenticity of moving coil cartridges.

Market

Original price was ¥195,000. Current secondary market listings show prices ranging from ~$1,980 to $2,632. Units may exhibit cosmetic aging such as faceplate yellowing and typically require servicing of aged capacitors and connections.

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