Integrated amplifiers — Audio Research I/50

The I/50 is an accomplished push-pull tube integrated amplifier from Audio Research, structurally a classic design with a pair of 6550 output tubes per channel, with three 6922 dual triodes handling input and driver duties. The I/50 brings Audio Research's most storied American engineering to a serious, classic push-pull integrated-amplification format.

Key specs that matter

Input sensitivity is 1,250mV, with input impedance at 100,000 ohms balanced or 47,000 ohms single-ended. Output power is 2x50W into both 8 and 4 ohms. Frequency response spans 7Hz to 30,000Hz within plus-or-minus 3dB. Total harmonic distortion plus noise is 1%. At 430 x 180 x 340mm and 18.1kg, the I/50 maintains a manageable push-pull tube-integrated-amplifier chassis, with matched-tube sets typically supplied to ensure consistent performance across channels.

Sound and use context

Expect the exceptionally rich, harmonically engaging character 6550-tube push-pull amplification is broadly celebrated for, with the three 6922 dual-triode input-and-driver stages contributing to a refined tonal balance consistent with Audio Research's storied tube-amplifier heritage.

Pairing

The consistent 2x50W output across both 8 and 4 ohms makes the I/50 compatible with a wide range of loudspeaker impedances.

Alternatives

Audio Research's own broader integrated-amplifier catalogue offers related alternatives at different power levels within the same considered tube engineering philosophy.