The Audio Research Reference 20 is the company's current flagship line-stage preamplifier, built around an entirely new mechanical and electrical platform. Rather than being a conventional update to the previous Reference series, Audio Research redesigned the chassis, circuit mounting, power supply and critical signal-path components together.
The Reference 20 is a fully balanced tube line stage using six 6H30P dual-triodes in the audio circuit. A separate regulated power-supply section is housed within the same chassis, allowing the Reference 20 to retain a single-box design while providing the power-supply performance expected from Audio Research's Reference series.
New Reference Architecture
The chassis uses a multi-metal, layered construction designed to control mechanical resonance. Critical circuit boards are suspended and mass-loaded, isolating the audio circuitry from mechanical energy generated by the chassis and transformers.
This is a substantial departure from the stamped-metal construction used on earlier Audio Research preamplifiers. The mechanical design is intended to preserve low-level information and spatial detail while reducing the influence of vibration on the signal path.
Redesigned Power Supply
Audio Research completely redesigned the Reference 20's power supply. Advanced regulation and new-generation film capacitors reduce noise on the regulated rails by approximately an order of magnitude compared with the previous architecture.
The regulated high- and low-voltage supplies provide the tube circuitry with a stable operating environment while also contributing to the Reference 20's low noise floor and wide dynamic range.
Six 6H30P Tubes
The audio circuit uses six 6H30P dual-triode tubes. The 6H30P has been used extensively in Audio Research's higher-performance designs because of its high current capability and ability to drive the following stages with a low output impedance.
The Reference 20 uses a fully balanced circuit architecture, with 15dB of gain available through the balanced outputs and 9dB through the single-ended outputs.
Extensive Connectivity
Four balanced XLR inputs and four single-ended RCA inputs provide connectivity for a complete reference-level system. The Reference 20 also offers two balanced and two single-ended main outputs.
A dedicated buffered subwoofer output is provided as well. Its level follows the main output, making it possible to connect powered subwoofers without requiring an additional preamplifier or volume control.
The Reference 20 also provides both balanced and single-ended connections for maximum system flexibility.
Precision Volume Control
Volume is controlled through a precision resistor-based network with 104 steps. The large number of volume positions allows very fine adjustment while maintaining accurate channel tracking.
The Reference 20 also includes Audio Research's touchscreen interface, remote control and system control connections.
Key Features
• Flagship Reference-series tube line-stage preamplifier
• Completely new Reference-series architecture
• Fully balanced circuit design
• 6 × 6H30P dual-triode audio tubes
• 1 × 6550 and 1 × 6H30 tube in the power supply
• Multi-metal layered chassis construction
• Suspended, mass-loaded circuit boards
• Fully regulated power supply
• Four balanced XLR inputs
• Four single-ended RCA inputs
• Two balanced main outputs
• Two single-ended main outputs
• Dedicated buffered subwoofer output
• 15dB balanced gain
• 9dB single-ended gain
• Precision 104-step volume control
• Touchscreen control interface
• Remote control
• Single-chassis Reference-series design
• Hand-built in Minnesota