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 made by Accuphase Laboratory, Inc. in Japan and released in September 1984. It amplifies signals from moving coil phono cartridges with minimal coloration. The idea was to pass along the cartridge's own qualities directly. It is a dual-mono design with independent circuitry for each channel. The left and right amplifier sections sit in separate aluminum enclosures, which keeps induction noise and vibration-induced resonance from crossing between them.

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 are cascode push-pull circuits running in Class A. The dual-mono topology keeps the channels completely separate. Each channel has its own power transformer and constant-voltage power supply, and both sit inside the same aluminum enclosure as the amplifier circuit. That shortens the wiring and cuts interference. The MC input impedance switches between 10 Ω, 30 Ω, and 100 Ω. Low-noise components are used throughout. Noise resistance is improved by reducing impedance in the NFB loop and applying feedback to the base of the constant current source, rather than to the differential stage’s negative input.

Context

The C-17 came out in September 1984, during a peak period for Japanese high-end audio equipment. It belongs to Accuphase’s lineup of MC head amplifiers, built to preserve the tonal character of moving coil cartridges.

Market

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