Audio Research I/70
The I/70 brings the joy of tube audio playback to those seeking an elevated level of musical performance, combining Audio Research separates in a single elegant, compact package.
The I/70’s visual design takes cues directly from the REF330M. Black or silver anodized top and bottom plinths mate with a fully enclosed transformer array topped with machined aluminum, mesh, and badging inspired by the 330M. A full mesh wrap around the bottom chassis and an additional bottom plinth complete the I/70’s upscale look.
The beauty continues inside. The same output transformer used in the famed Reference 75 amplifier, combined with four KT120 output tubes, produce 70 watts per channel. There is dynamic swing, a sense of command, control and resolution that were previously unimagined in this category. Auto-bias ensures maximum performance daily with no extra effort from the listener.
The I/70 sounds like a big amp. Go ahead, use it with your favorite floor-standing speakers and hear what a great tube system can bring to your music.
The I/70 integrated amp has independent tube preamplifier and tube amplifier sections, providing flexibility with a set of stereo preamplifier outputs. While we suspect very few listeners will pair it with an external power amp, many will need this feature to feed powered subwoofers that offer only low-level inputs.
The active preamplifier section offers a wide range of gain settings, now with a 75-step volume control. This is especially helpful with recordings that are cut at a low gain setting for wide dynamic range.
The headphone output is driven by the KT120 output tubes. It was designed for high quality headphones, able to provide the best possible personal listening experience.
The DAC card’s AKM Velvet Sound DAC chip provides high resolution formats over USB, Optical, Coax, and Bluetooth. All are upsampled. The result is fine resolution, great transparency, and tonal purity that is rarely heard outside of the finest separate DACs.
There are three sets of single-ended inputs and one set of Balanced XLR inputs. The optional phono card has both MC and MM gain settings, controlled via the I/70 remote. MC loading is also adjustable, from 50 to 1k ohms.
The I/70 delivers the punch, detail and musicality that evoke the performance of our larger separates. It continues the Audio Research heritage, built by hand in our Minnesota facility, twice tested, and individually auditioned in our reference system.
SPECIFICATIONS
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Power output |
2 × 70 W continuous into 8 Ω / 4 Ω (20 Hz–20 kHz) |
|
Power bandwidth |
~10 Hz – 22 kHz (-3 dB) |
|
Frequency response (-3 dB) |
~7 Hz – 30 kHz |
|
THD |
< 1% at rated power · < 0.1% at 1 W |
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Input sensitivity |
~1.25 V RMS for rated output |
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Input impedance |
~48 kΩ (single-ended) |
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Inputs |
3 × RCA single-ended |
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Optional modules |
Optional DAC module (USB, coaxial, optical, Bluetooth) |
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Outputs |
Speaker outputs with 4 Ω / 8 Ω taps |
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Headphone output |
Yes (front panel) |
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Tube complement |
2 matched pairs KT120 (output) · 3 × 6922 (driver/input) |
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Biasing |
Automatic bias |
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Display / UI |
Front panel LED indicators |
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Remote control |
Included |
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Power requirements |
105–130 VAC / 210–250 VAC |
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Power consumption |
~350 W max |
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Dimensions (W × H × D) |
420 × 180 × 340 mm |
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Net weight |
~19 kg |