Accuphase AC-1 (1979)
Low-output moving-coil phono cartridge with line contact stylus, released in October 1979.
Overview
The Accuphase AC-1 is a moving-coil (MC) phono cartridge manufactured by Accuphase Laboratory, Inc. and released in October 1979. Designed with a line contact stylus and nude diamond tip, it was engineered for high-resolution analog playback with extended high-frequency response up to 60 kHz. The cartridge features moderate compliance and a rigid cantilever constructed from a German-made aluminum-magnesium alloy, with beryllium applied along 60% of its length to enhance rigidity and transient response.
Specifications
| Output Voltage | 0.3 mV (5cm/sec., 1 kHz) |
| Frequency Response | 20 Hz to 20 kHz ± 1 dB |
| Channel Separation | 30 dB (1kHz) |
| Tracking Force Range | 1.5 to 2.5g |
| Cartridge Weight | 6.5 g |
| Stylus Type | Line contact stylus, 0.3 x 0.7 mil nude diamond |
| Compliance | 15 x 10⁻⁶ cm/dyne (horizontal and vertical) |
| Internal Impedance | 4 Ω |
| Recommended Load Impedance (Head Amp) | 50 Ω or more |
| Recommended Load Impedance (Transformer) | 3 Ω or more |
| Dead Weight | 9.5 g |
Design
The AC-1 uses a moving-coil design with a samarium cobalt magnet, its DC magnetic field adjusted to 65% of saturation for optimal linearity. The armature core is made of high-quality permalloy, and the coil is wound with 0.035 mm φ high-purity copper wire. The cantilever combines a German aluminum-magnesium alloy with beryllium reinforcement over 60% of its length to extend high-frequency reproduction. A dumped damper system and Q-damping are used to correct saddle-shaped frequency dips between 5 kHz and 10 kHz. The body is made of aluminum die-cast; according to audio-database.com, the body material is solid boron. The contact surface with the headshell is precision-flattened. The vibration system is fixed, requiring full cartridge replacement for stylus renewal.
Market
The original price of the Accuphase AC-1 was ¥38,000. Stylus replacement requires body replacement at a cost of ¥25,000. It is recommended to have the stylus inspected before use on valuable records, and cartridges stored for long periods may require time to recondition.
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