Audio Research has launched a new two-channel power amplifier called the D-80, which builds on the design principles of the Reference product line. The amplifier combines pentode operation, automatic bias control, and balanced signal transmission with a practical output power of 70 watts per channel. The D-80 is available in two colors.
The Audio Research D-80 features a fully symmetrical and differential design. The signal path remains consistently balanced from the input to the speaker terminals. Pentode operation allows for higher output power while, according to the designers, guaranteeing a controlled and structured sound. Audio Research deliberately dispensed with switchable operating modes and complex additional features to focus on stability, reproducibility, and sonic consistency.
The design similarities with the Audio Research Reference 80S are most evident in the power supply and output stage design, although the D-80 is built in a more economical enclosure. The price is therefore lower.
The Audio Research D-80 is manufactured entirely in the USA. Each unit undergoes multiple test cycles and is finally individually tested against the manufacturer's reference system. According to the designers, this meticulous process guarantees that the stated performance data is not only achieved on paper but also consistently achieved in practice.
Tube placement and power reserves
Each channel utilizes a pair of matched KT150 power tubes, supplemented by two 6H30 tubes in the driver and amplification stages. The KT150 is known for its exceptional power handling and guarantees stable power delivery, even with complex loads. The nominal output power of 70 watts per channel is available across the entire relevant frequency range (which extends from 7 Hz to 68 kHz at -3 dB level), with additional dynamic headroom for transient peak loads.
In practice, this design allows operation with a wide range of high-quality speakers without pushing the amplifier to its limits.
Connection concept and system integration
The D-80 is specifically designed for use with balanced preamplifiers and features only XLR inputs. This approach minimizes interference and is compatible with modern high-end preamplifiers that use fully balanced connections. Separate outputs are available for 4 ohms, 8 ohms, and 16 ohms speakers, allowing precise matching to different speaker impedances.
Automatic bias control
A key feature of the Audio Research D-80 is its continuously operating automatic bias control. This monitors the operating point of the output tubes in real time and automatically compensates for changes caused by mains voltage fluctuations or tube aging. This eliminates the need for manual adjustment by the user, ensuring the power amplifier operates under optimal conditions at all times. This feature underscores the practical goal of the D-80: making classic tube technology usable without additional maintenance.
Price: $15,000
