Audio Research
Audio Research I/55 Integrated Amplifier
Audio Research I/55 Integrated Amplifier
The I/55 imports the functionality of the I/70 into a chassis that maintains the look and power output of the I/50 it succeeds. Its all-tube amplification circuit uses two matched pairs of 6550 power tubes fed by 6922 input tubes to deliver 50 watts per channel, now with auto-bias to keep the output tubes in their optimal range for life. Two LexieTubes display input selection and volume, an active preamplifier section feeds stereo preamp outputs, the headphone output is driven by the 6550 output tubes, and optional cards add an AKM Velvet Sound DAC or MM/MC phono stage.
Specifications
| Dimensions | 16.5 in W x 7.25 in H x 13.5 in D, 40 lbs |
|---|---|
| Display | Two LexieTubes for input and volume |
| Inputs | 4 balanced, 4 single-ended; optional DAC and MM/MC phono cards |
| Output taps | 8 and 4 ohms |
| Power output | 50 watts per channel continuous, 20Hz to 20kHz |
| Tube biasing | Auto-bias |
| Tube complement | Two matched pairs 6550WE output, three 6922 (one input, two driver) |
Options & Upgrades
| DAC card AKM Velvet Sound DAC; user-installable |
+$1,000 |
|---|---|
| MM/MC phono card User-installable |
+$1,000 |
| Both DAC and phono cards, factory preinstalled | +$1,500 |
Prices shown are for the base configuration. Ask us about options and factory upgrades when you visit.
Call or visit the showroom about availability. Contact our team for pricing, a demonstration, or system design — get in touch.
Or call (512) 883-0844
Pricing on request. Call or visit the showroom about availability.

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