Introduction

The AD-2900 is Accuphase’s dedicated phono equalizer module, designed to slide into the expansion slot of compatible preamplifiers (e.g., C-2900). It elevates vinyl playback to reference-level quality, supporting both low-output moving-coil and moving-magnet cartridges with class-leading noise performance and precision RIAA equalization.

Design

Featuring completely discrete signal paths, the AD-2900’s first stage employs junction FETs for MM cartridges and bipolar transistors for MC cartridges, achieving ultra-low noise. The subsequent differential-style RIAA equalizer uses glass-cloth fluorocarbon resin circuit boards with fully separated left and right channels. All circuitry resides in a robust, shielded aluminum module to reject external interference.

Application

Simply install the AD-2900 into your preamplifier’s expansion slot and select between two tonearm inputs (AD1 and AD2) via the front-panel INPUT selector. Memory settings store optimal gain and loading for each cartridge, allowing quick, repeatable setup changes without external adjustments.

Technology Overview

• Independent MC/MM Head-Amp Circuits
  Polarity-matched FET and transistor stages optimize impedance and gain for each cartridge type.
• Differential RIAA Equalization
  Fully balanced passive network delivers precise ±0.1 dB RIAA accuracy across the audio band.
• Channel-Sealed PCB Construction
  Left and right channel boards use high-purity substrates to maintain crosstalk below audible thresholds.
• Front-Panel Control & Memory
  On-the-fly switching between tonearms and automatic recall of loaded settings streamline listening sessions.

Key Features

• Slide-in module for C-Series preamplifiers
• Dual phono inputs (AD1, AD2) for two tonearms
• Separate ultra-low-noise head-amp circuits for MC and MM
• Differential-style, fully balanced RIAA equalizer
• Glass-cloth fluorocarbon resin PCBs with isolated L/R channels
• Front-panel INPUT selector with two dedicated memories
• RIAA accuracy within ±0.1 dB (20 Hz–20 kHz)
• Module weight: approximately 1.2 kg
• Shielded aluminum housing for EMI/RFI rejection

‍