Accuphase E-307 Stereo Integrated Amplifier (2000)
A high-end pre-main amplifier that refines the E-306V with discrete current feedback topology and independent pre/power sections.
Overview
Accuphase Laboratory, Inc. of Yokohama, Japan released the Accuphase E-307 Stereo Integrated Amplifier in December 2000. It is a pre-main amplifier built as an evolution of the E-306V, with accumulated design improvements for higher performance. A separate switch lets you use the preamplifier and power amplifier sections independently, and the unit has both main and preamp input/output terminals. With an optional board, it takes digital input and analog record playback. The phono stage handles moving magnet (MM) and moving coil (MC) cartridges, and there is a preamplifier output.
Specifications
| Power Output | 140W/ch into 4Ω, 120W/ch into 6Ω, 100W/ch into 8Ω (20Hz–20kHz, both channels driven) |
| Total Harmonic Distortion | 0.01% (4Ω–16Ω load) |
| IM Distortion | 0.01% |
| Frequency Response | 20Hz–20kHz ±0.2dB (rated output); 2Hz–150kHz ±3.0dB (1W output) |
| Damping Factor | 100 (8Ω load, 50Hz) |
| Inputs | Phono MC ×1, Phono MM ×1, Line ×4, Tape ×2 |
| Outputs | Pre Out ×1, Tape Out ×2, Headphone ×1 |
| Input Sensitivity / Impedance | High Level: 113mV/20kΩ; Balanced: 113mV/40kΩ; Main: 1.13V/20kΩ |
| Output Level / Impedance | Pre out: 1.13V/50Ω |
| Gain | High Level → Pre out: 20dB; Main → Output: 28dB |
| S/N Ratio | High Level: 104dB (A-weighted); Balanced: 88dB; Main: 122dB |
| Tone Control | Bass ±10dB at 300Hz (50Hz); Treble ±10dB at 3kHz (20kHz) |
| Loudness Compensator | +6dB at 100Hz (Volume -30dB) |
| Attenuator | -20dB |
| Power Meter | Logarithmic peak level display with dB scale and 8Ω load reference |
| Load Impedance | 4Ω–16Ω |
| Headphone Output | 4Ω–100Ω |
| Power Supply | AC 120V/60Hz, 220V/50Hz, or 240V/50Hz |
| Power Consumption | 50W (idle); 240W (compliance); 385W (8Ω rated output) |
| Dimensions | 475mm W × 170mm H × 424mm D |
| Weight | 21.4 kg (47.2 lbs) |
| Remote Control | Included RC-20 (IR, 2×AA batteries) |
| Original Price | ¥280,000 |
Design
The E-307 uses current feedback amplifier circuits in both the preamp and power amplifier sections. Construction is fully discrete dual mono, with a DC configuration - no capacitors in the signal path. The line amplifier is a pure complementary push-pull circuit built from discrete components. The output stage uses parallel push-pull high-power transistors with excellent high-frequency characteristics, mounted on a large heatsink for efficient thermal management. The preamp section gets a dedicated power supply, and the internal layout physically separates the preamp and power amp sections. Logic-controlled relays with gold-plated cross-bar twin contacts keep the signal paths short. The tone control is an additive active filter design, and dual speaker terminals allow flexible wiring. A 500 VA power transformer and two 22,000 μF filter capacitors provide stable power delivery. The unit also includes a high-quality phono equalizer amplifier, a high-precision loudness control, and a subsonic filter.
Context
Accuphase lists the E-307 in its Classic Models Reference line. It was developed to refine the earlier E-306V by applying accumulated design technology.
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Service Manuals, Schematics & Catalogs
- Service Manual — audiocircuit
- Service Manual — elektrotanya.com
- Catalog — archive.org
- Catalog (1991) — archive.org
- Catalog (1992) — archive.org