

Make music come alive in a way you will never forget.
The Reference 330M puts you right there, and does not let you forget that you are listening to a living performance captured in time, just waiting to be unearthed with no potential left unrealized.
The beauty, the emotion, the dynamics, the life are all there to conjure total immersion, whenever you want it.
A hand built masterpiece
The Reference 330M is the finest amplifier ever created by Audio Research, with the ability to control any loudspeaker with a vice-like grip and startling dynamic life. It is the culmination of everything we have learned over 50+ years.
It is a statement that music is king, always ready to sweep you away. Infusing new technology and circuits with the finest vacuum-tube architecture, the 330M elevates music reproduction to the highest plateau with an all-tube signal path.




From its ECC83 input to its KT170 output, with tube regulation in the power supply, the 330M proves that you can enjoy the ease of high power along with a delicacy and purity usually associated with low-power amplifiers. Tonal saturation and density accompany a specificity of recording space beyond anything we have built.
Liquidity and artistry abound, yet with blade-like edge precision when called for. Extension at both frequency extremes is state of the art even for solid state amplification. Statement-level loudspeakers capable of meaningful infrasonic bass output will be fully commanded down through their lowest octave without a hint of retreat. Stones unturned: None.
This is our heritage, the legacy created by our founder, William Zane Johnson.

REF 330M DEBUT: MUNICH HIGH END 2024
FEATURES
• The 330M was designed to provide ultimate performance without worry.
• Auto bias assures rock-steady consistency, minute-by-minute, day in and day out.
• Output tube life is 3,000 hours, providing many years of listening pleasure.
• A fully-balanced design, the addition of single-ended inputs allows its compatibility with virtually any source.
• 12 volt triggers allow the 330M to be turned on remotely, just by powering up your Reference preamp or a master control.
• RS232 control.
• Auto-off control will turn 330M off if no signal is sensed in two hours (defeatable).
• Fan speed control.
• Tube hour meter.
• 4-8 ohm speaker outputs.
• Tube monitor.
• Meter light control allows dimming or off.
• Meter action switch allows meter needle to be turned off.
• The 330M was designed to provide ultimate performance without worry.
• Auto bias assures rock-steady consistency, minute-by-minute, day in and day out.
• Output tube life is 3,000 hours, providing many years of listening pleasure.
• A fully-balanced design, the addition of single-ended inputs allows its compatibility with virtually any source.
• 12 volt triggers allow the 330M to be turned on remotely, just by powering up your Reference preamp or a master control.
• RS232 control.
• Auto-off control will turn 330M off if no signal is sensed in two hours (defeatable).•
Fan speed control.
• Tube hour meter.
• 4-8 ohm speaker outputs.
• Tube monitor.
• Meter light control allows dimming or off.
• Meter action switch allows meter needle to be turned off.
TECHNICAL SPECIFICATIONS
Power Output | 330W @ 1kHz 0.92% THD +N 10Hz - 80kHz Unweighted 1W @ 1kHz 0.013% THD+N 10Hz - 80kHz Unweighted |
Frequency Response | (-3dB points at 1 watt) 0.5Hz to 110kHz |
Input Sensitivity | 2.48V RMS Balanced for rated output; 1.23V RMS Single Ended for rated output 135mV RMS Balanced for 1W output; 70mV RMS Single Ended for 1W output |
Gain | 26.3dB Balanced Input into 8 ohms 34dB Single Ended Input into 8 ohms |
Input Impedance | 168.5k ohms Balanced, 19.5k ohms Single Ended |
Output Polarity | Non-inverting. Balanced input pin 2+ (IEC-268) |
Output Taps | 4 ohms, 8 ohms |
Output Regulation | 0.82dB 8-ohm load to open circuit |
Output Impedance | 0.812 ohms |
Damping Factor | 10 at 8 ohms |
Noise | Input shorted. Noise level referenced to 1W into 8 ohms Balanced: -80dBV 10Hz-80kHz Unweighted; -91dBV A-weighted ; Single Ended: -75dBV 10Hz-80kHz Unweighted; -86.5dBV A-weighted |
Power Requirements | 105-130VAC 60Hz (210-250VAC 50Hz) 987w at rated output; 386w at idle, 1.1w power off |
Tube Complement | 6 matched KT170 V1-V6 Power Output; (1) x 6H30 V7 Gain Stage; (1) x 12AX7/ECC83 V8 Gain Stage; (1) x 6550 and (1) x 6H30 V9, V10 voltage regulator |
Dimensions | width 18.5” (47 cm) 19.0” (48.26 cm) inc faceplate height 10.5” (26 cm) depth 21.5” (54.6 cm) with handles & connectors 24.25” (61.6 cm) |
Shipping Dimensions | 31 x 27 x 20 (in). 787 x 686 x 508 (mm). |
Weight | 101 lbs 46 kg, Shipping 118 lbs, 54 kg (per monoblock) |


