Audio Research I/55 Integrated Amplifier

The I/55 is a successor to Audio Research's I/50 integrated amplifier, carrying over technology developed for the larger I/70 while keeping the I/50's compact size and power.

It is an all-tube design with two matched pairs of 6550 power tubes and 6922 input tubes, adding auto-bias that the I/50 lacked, with an independent active tube preamp section, an AKM Velvet Sound DAC with USB, optical, coaxial, and Bluetooth inputs, and an optional phono card with adjustable MC loading.

Specifications

• Power: 50W continuous (20Hz to 20kHz), approximately 1% THD at rated output, under 0.1% at 1W
• Tubes: two matched pairs 6550WE output, three 6922 input/driver
• Inputs: 4 total, 1 balanced XLR plus 3 single-ended RCA; pre-out; 8/4 ohm taps
• Headphone output: yes, driven by the 6550s
• Optional phono card: MC/MM gain, loading 50 to 1000 ohms
• Built-in DAC: USB, optical, coax, Bluetooth
• Dimensions: 16.5 in W x 7.25 in H x 13.5 in D
• Weight: 40 lbs