Accuphase C-2400 (2003)
Stereo control amplifier released in August 2003 with AAVA volume control and optional phono stage compatibility.
Overview
The Accuphase C-2400 is a stereo control amplifier manufactured by Accuphase and released in August 2003. It features the company's proprietary Analog Vari-gain Amplifier (AAVA) volume control system, which uses 16 weighted V-I conversion amplifiers and current switches to eliminate mechanical contact. The design separates amplifier circuits and power supplies left and right to prevent interference. It supports optional analog playback via the AD-2800 phono equalizer unit and is also compatible with the AD-290/AD-290V phono stages from other Accuphase models.
Specifications
| Production Year | August 2003 |
| Original Price | ¥ 580,000 |
| Frequency Response (Balanced/Unbalanced) | 3 Hz ~ 200 kHz +0 -3.0 dB; 20 Hz ~ 20 kHz +0 -0.2 dB |
| Total Harmonic Distortion | 0.005% (at all input terminals) |
| Signal-to-Noise Ratio (Balanced) | 111 dB (IHF-A, input short, rated output) |
| Input Sensitivity / Impedance (Balanced) | 252 mV / 40 kΩ (rated output) |
| Rated Output / Impedance (Balanced/Unbalanced) | 2 V / 50 Ω |
| Gain Switch | 12 dB, 18 dB, or 24 dB selectable |
| Tone Control (Bass) | ±10 dB at 50 Hz, turnover 300 Hz |
| Tone Control (Treble) | ±10 dB at 20 kHz, turnover 3 kHz |
| Subsonic Filter | 10 Hz: -18 dB/oct |
| Power Consumption | 33 W |
| Dimensions (W×H×D) | 465 × 150 × 403 mm |
| Weight | 17.6 kg |
Design
The C-2400 uses Accuphase’s AAVA analog volume control, integrating the amplifier and volume regulator to eliminate mechanical wear. Sixteen V-I conversion amplifiers and current switches, controlled by a CPU, determine volume by combining current signals, which are then converted back to voltage. The tone control uses an additive active filter method, maintaining a flat signal path while adjusting response. Input/output switching uses logic relays for a direct signal path. The amplifier circuit is split into five unit amplifiers (input buffer, AAVA, balanced output), physically separated left and right on the motherboard. Power transformers and smoothing circuits are also isolated per channel. The unit includes a headphone amplifier, phase switch, attenuator (-20 dB), and EXT-PRE function for external preamp integration. The AD-2800 phono stage connects via a DIN connector, features Teflon-based circuitry in an aluminum case, and offers two-stage gain switching (MM/MC) and three-stage MC impedance selection (10 Ω, 30 Ω, 100 Ω).
Context
The C-2400 inherits design technology from the C-2800 and shares phono stage compatibility with the AD-2800, AD-290, and AD-290V units used in the C-2800, C-290, and C-290V models. It is listed as a preamplifier in the Accuphase lineup.
Market
Current market prices include €10,750 (Kleinanzeigen, Feb 26, 2026), €6,250 (Marktplaats, Mar 5, 2026), SEK 40,000 (Hifitorget, Nov 15, 2025), CZK 239,000 (Bazos Czechia, Jan 23, 2026), and €4,280 (Audio-markt, May 1, 2024). A bundled listing for C-2400 with P-6100 and DP-400 reached CZK 275,000 (Bazos Czechia, Jan 14, 2026).
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