Audio Research Reference 330M Monoblock Power Amplifier

Save on an open box silver finish 330M keep in mind this price per unit

330-Watt Reference Vacuum Tube Power Amplifier | The Grid HiFi

330 Watts. All-Tube. Unmistakably Audio Research.

The Audio Research Reference 330M brings together the power of a large-scale reference amplifier and the musical character of an all-tube signal path. Delivering 330 watts from a single monoblock, it is designed for listeners who want the dynamic range, bass control, and expressive detail demanded by ambitious loudspeaker systems.

Six KT170 output tubes form the heart of the amplifier. An ECC83 input stage, tube-based power-supply regulation, and a fully balanced architecture complete a design that draws on more than five decades of Audio Research engineering.

The Reference 330M is built to make a serious loudspeaker system come alive—whether the recording calls for the intimacy of a solo voice or the full force of an orchestra.

Six KT170 Tubes. One Powerful Monoblock.

Each Reference 330M uses three matched pairs of KT170 output tubes to deliver 330 watts of power to a single loudspeaker channel.

The amplifier's signal path begins with an ECC83 tube and incorporates a 6H30 gain-stage tube. A separate 6550 and 6H30 serve the regulated power supply.

This architecture combines high output capability with the all-tube approach central to Audio Research's Reference amplifiers. A stereo system requires two Reference 330M amplifiers—one for the left channel and one for the right.

Designed for Demanding Loudspeakers

High-power tube amplification is about more than achieving impressive volume.

The Reference 330M is designed to reproduce large dynamic swings while maintaining control and musical detail. Its dedicated 4-ohm and 8-ohm speaker output taps allow the amplifier to be connected according to the loudspeaker manufacturer's requirements and the system designer's recommendations.

Audio Research also provides both balanced XLR and single-ended RCA inputs, making the amplifier compatible with a broad range of reference preamplifiers.

For a system built around revealing, full-range loudspeakers, the 330M offers the output capability of a substantial monoblock without departing from vacuum tube amplification.

Automatic Bias. More Music, Less Maintenance.

The Reference 330M incorporates automatic tube biasing, continuously managing the output-tube operating conditions without requiring routine manual adjustments.

Audio Research specifies an output-tube life of approximately 3,000 hours. A built-in tube-hour meter helps owners track operating time, while tube monitoring provides additional visibility into the amplifier's operation.

These features make ownership more approachable without eliminating the care and eventual tube replacement that come with a high-performance vacuum tube amplifier.

A Reference Amplifier That Fits Into a Complete System

The Reference 330M includes practical controls that make a pair of large tube amplifiers easier to live with:

• 12V trigger connectivity allows compatible equipment or a control system to manage amplifier power.

• RS-232 control supports integration with a larger audio or automation system.

• Defeatable auto-off can shut the amplifier down after two hours without a detected signal.

• Adjustable fan speed provides control over the amplifier's cooling behavior.

• Selectable meter lighting and meter action allow the front-panel display to suit the listening environment.

Standby mode provides an additional power-management option. These are useful details in a dedicated listening room, where the system may include multiple source components and separate amplifiers.

A Statement in Industrial Design

The Reference 330M makes its engineering part of the visual experience. Its prominent front-panel meter, exposed vacuum tubes, and substantial chassis give it the presence expected of a flagship-class power amplifier.

The meter illumination can be dimmed or switched off, and the needle's movement can be disabled for listeners who prefer a quieter visual presentation.

At approximately 101 pounds per amplifier, the Reference 330M also demands an equipment rack or amplifier platform selected for its size, weight, ventilation, and service access.

Key Features

• 330 watts of monoblock vacuum tube amplification

• Six KT170 output tubes arranged as three matched pairs

• All-tube signal path

• Fully balanced amplifier architecture

• Balanced XLR and single-ended RCA inputs

• Dedicated 4-ohm and 8-ohm speaker output taps

• Automatic output-tube biasing

• Approximately 3,000-hour manufacturer-stated output-tube life

• Tube monitoring and tube-hour meter

• 12V trigger and RS-232 control

• Defeatable two-hour automatic shutoff

• Adjustable fan speed

• Controllable meter illumination and needle movement

• Standby power-saving mode

Technical Specifications

Build Your Reference System at The Grid HiFi

An amplifier of this caliber deserves careful system matching.

At The Grid HiFi in Houston, we can help integrate a pair of Reference 330M amplifiers with an Audio Research Reference preamplifier, suitable loudspeakers, and the source components that complete your listening system.

We'll also address amplifier placement, equipment support, ventilation, cabling, and system control—details that matter when installing two substantial vacuum tube monoblocks.

Contact The Grid HiFi to discuss the Audio Research Reference 330M and design your reference two-channel system.