Accuphase A-20V (1995)

Name: Accuphase A-20V
Brand: Accuphase

Pure Class-A stereo power amplifier with dual-mono design and MOS-FET output stage, released in June 1995.

Overview

The Accuphase A-20V is a pure Class-A stereo power amplifier manufactured in Japan by Accuphase Laboratory, Inc. Released in June 1995, it belongs to the "V" series lineup, which includes the A-20V, A-30V, A-50V, and A-100V. Positioned as a "low-power, high-current" amplifier, it delivers 20 watts per channel into 8Ω in stereo mode and can be bridged for monaural operation, providing up to 160 watts into 4Ω. The amplifier features both balanced and unbalanced inputs and supports speaker loads from 2Ω to 16Ω in stereo and 4Ω to 16Ω in monaural mode.

Specifications

Power Output (Stereo, 8Ω)	20 watts per channel
Power Output (Stereo, 4Ω)	40W/ch
Power Output (Stereo, 2Ω)	80W/ch
Power Output (Monaural, 8Ω)	80W
Power Output (Monaural, 4Ω)	160W
Frequency Response (Rated Output)	20Hz to 20,000Hz, +0 -0.2dB
Frequency Response (1W Output)	0.5Hz to 160,000Hz, +0 -3.0dB
Total Harmonic Distortion (Stereo, 4–16Ω)	0.02%
Total Harmonic Distortion (Stereo, 2Ω)	0.05%
IM Distortion	0.003%
Damping Factor (Stereo)	120
Damping Factor (Monaural)	60
Gain	28.0 dB
Input Sensitivity (Stereo, 8Ω, Rated Output)	0.50V
Input Sensitivity (Stereo, 8Ω, 1W Output)	0.11V
Input Sensitivity (Monaural, 8Ω, Rated Output)	1.00V
Signal to Noise Ratio (A-weighted)	110dB
Input Impedance (Balanced)	40kΩ
Input Impedance (Unbalanced)	20kΩ
Dimensions (WHD)	475 x 170 x 426 mm
Net Weight	22.6 kg
Power Supply	AC100V, 50Hz/60Hz
Power Consumption (No Input)	160W
Power Consumption (8Ω Rated Output)	180W

Design

The A-20V operates in pure Class-A with a dual-mono construction, ensuring independent amplification for each channel. It uses a current feedback circuit design with discrete components and a Power MOS-FET output stage in a 3-parallel push-pull configuration. The power supply features a large 400VA transformer, supporting stable high-current delivery. The front panel includes a distinctive champagne/gold faceplate with dual analog power meters of logarithmic compression type, displaying from -40dB to +3dB in NORMAL mode and -60dB to -17dB in -20dB mode.

Context

The A-20V is part of Accuphase's "V" series, a lineup emphasizing high-current delivery despite modest rated power. Accuphase Laboratory, Inc. was founded in late 1972 by Jiro Kasuga, a former Kenwood engineer. The amplifier reflects the company's focus on precision engineering and high-fidelity performance.