Introduction

The A-80 is Accuphase’s flagship Class-A stereo amplifier, evolved from the company’s 50th-anniversary A-300 monoblock. By paralleling ten push-pull MOS-FETs per channel, it delivers ultra-linear output with musical authority—65 W into 8 Ω, 130 W into 4 Ω, 260 W into 2 Ω, and an astonishing 520 W into 1 Ω—while preserving the finest micro-dynamics.

Design

• 10-Parallel Push-Pull MOS-FET Output Stage
  A massive Class-A section employs ten MOS-FETs per channel in a push-pull arrangement for exceptionally low distortion and high slew rate.
• Fully Discrete Signal Path
  The input stage uses a discrete, instrumentation-amplifier topology with current-feedback architecture to achieve ultra-low noise.
• Robust Power Supply
  A large toroidal transformer feeds 120,000 µF of filtering capacitance, ensuring stable voltage under heavy musical peaks.

Application

Use the A-80 to drive demanding loudspeakers in two-channel or multi-channel systems. Its high damping factor (>1,000) gives precise control over bass drivers, while its head-room and Class-A purity let you hear every nuance—from the quietest whisper to full orchestral crescendos.

Technology Overview

• MCS+ Circuitry
  Accuphase’s proprietary “Multiple Circuit Summation” design maintains waveform integrity by minimizing feedback loops and optimizing gain distribution.
• Balanced Remote Sensing
  Long speaker cables and bi-amping are accommodated with remote-sensing inputs that compensate for voltage drop.
• Advanced Noise Reduction
  Cutting-edge layout and shielding keep mechanical, power-supply, and signal-processing sections completely isolated for an ultra-quiet background.

Key Features

• Class-A operation throughout gain stages
• 65 W/8 Ω, 130 W/4 Ω, 260 W/2 Ω, 520 W/1 Ω continuous output
• 10-parallel, push-pull MOS-FET output per channel
• Instrumentation-amplifier-style, fully discrete input stage
• Current-feedback topology for wide bandwidth
• High damping factor (>1,000) for tight bass control
• Large toroidal power transformer with 120,000 µF filtering
• MCS+ low-feedback circuitry
• Balanced remote-sensing speaker inputs
• Rigid, vibration-damped chassis

‍