Audio Research Reference 330M Monoblock Amplifiers – First Look
All Image Credit: Audio Research
The American Hi-Fi brand Acoustic Research from Minnesota has just announced a new flagship monoblock power amplifier, the Reference 330M. This latest flagship amplifier is a high-performance power amplifier that builds on many years of expertise in tube amplifier design and delivers 330 watts of power.
The amplifier features a fully-balanced hybrid design that combines tube and solid-state elements in the input and power supply circuitry while maintaining an all-tube signal path. The all-tube signal path uses six KT170 tubes in the output stage that operate in push-pull Pentode only mode, 1x ECC83 and 1x 6H30 in the input stage and 1x 6550 and 1x 6H30 in the power supply.
The ECC83 input tube has a buffered output, the buffering is accomplished using a special bipolar transistors that has tube-like qualities. The second stage uses the 6H30 tube as a differential pair biased using a double-diffused metal-oxide semiconductor (DMOS) power MOSFET current source, with the 6H30 plates bootstrapped by the output stage. The six KT170 output tubes are driven by Silicon Carbide (SiC) JFETs that are bootstrapped by the output and support the automatic biasing of each output tube to an ideal quiescent current, with each tube having its own servo to maximize driver headroom.
The power supply features solid state regulation for the front end and tube regulation (6H30 and 6550) for the output tube screens and driver stage. It also has a Pi filter that uses a large choke, helping to reduce output stage supply ripple.
The Reference 330M features 4-layer circuit boards produced in-house, with every component’s solder point applied by hand by Audio Research crafts people. It includes proprietary auto-bias and valve monitoring systems to help extend valve lifespan and features Audio Research’s GhostMeter VU display, which appears to float in front of the KT170 valves within a dual-layer glass window.
The rear panel includes; balanced XLR and single-ended RCA inputs, 8Ω and 4Ω output taps, 12V Trigger, RS-232 control, tube hour meter and fan speed adjustment.
Features At A Glance:
- Auto bias
- Output tube life 3,000 hours
- Fully-balanced design with both XLR and RCA inputs
- 12 volt triggers
- RS232 control
- Auto-off control
- Fan speed control
- Tube hour meter
- 4 and 8 ohm speaker outputs
- Tube monitor
- Meter light control allows dimming or off
- Meter action switch allows meter needle to be turned off
Specifications:
- Power output: 330W
- Tube biasing: Auto-Bias
- Inputs: 1 x XLR, 1 x RCA
- Output taps: 4 ohms, 8 ohms
- Valves – output stage: 6x KT170
- Valves – input stage: 1x ECC83, 1x 6H30
- Valves – power supply: 1x 6550, 1x 6H30
- Inputs: balanced XLR and single-ended RCA
- Control ports: 12V triggers, RS-232 remote control
- Weight: 101lbs (45.8Kg)
- Finish: Black or natural (silver)
MSRP – Price on application – (pair):
- US: $90,000.00 approx.
- UK: £92,000.00 approx.
For more information visit the Audio Research web site.
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