Audio Research's Latest Stereo Amp and DAC

by The Audio Beat | November 11, 2016

udio Research has released a new digital-to-analog converter and power amp, both in its lower-priced Foundation series and designed by the same team responsible for the company's Reference products.

The 75Wpc VT80 amplifier (top, $8000) uses two 6H30 driver tubes and four KT120 output tubes, although the amplifier can also accommodate 6550, KT88, KT90 and KT150 output tubes. At the heart of the VT80 are features new to Audio Research amplifiers. The first is a proprietary auto-bias circuit that automatically adjusts bias for each output tube. The circuit accounts for tube wear and AC fluctuations in real time and does not compromise performance. The second new feature is an individual fuse for each output tube, so in the case of a tube fault, a fuse blows. The VT80 has both single-ended RCA and balanced XLR inputs, along with 4- and 8-ohm outputs. A tube-hour meter makes assessing tube life easy, and an auto-off function triggers when no input signal is encountered for four hours.

The fully balanced DAC9 digital-to-analog converter ($7500) features a vacuum-tube analog section, dual stereo DACs running in mono to increase dynamic range and lower the noise floor, native DSD file decoding, and upsampling for all for all inputs up to 352.8kHz or 384kHz for PCM music files. The DAC9 uses two different TCXO crystal master oscillators, each automatically selected for different sampling rates, ensuring proper integer decoding without interpolation distortion. Selectable digital filters with both fast and slow roll-off are also available, so the user can tailor the sound to personal taste. The DAC9 includes both balanced XLR and single-ended RCA analog outputs. Galvanically isolated digital inputs include USB 2.0, RCA, AES/EBU, BNC and TosLink.