Audio Research I/55 Integrated Amplifier

Audio Research I/55 Integrated Amplifier

The Audio Research I/55 Integrated Amplifier is a refined evolution of one of the most respected tube amplifier designs in high-end audio. Building directly on the foundation of the I/50, the I/55 incorporates meaningful performance upgrades inspired by the flagship I/70—delivering greater flexibility, improved usability, and enhanced musical performance while maintaining the signature Audio Research sound.

The Audio Research I/55 Integrated Amplifier is designed to be tailored to your system with optional modular upgrades. The DAC card is available for an additional $1,000, and the phono card is also available for an additional $1,000. For those looking to maximize versatility and value, both the DAC and phono modules can be added together for $1,500, offering a complete analog and digital front-end solution on top of the I/55’s $6,500 base price.

At its core, the Audio Research I/55 is a fully tube-based integrated amplifier designed for listeners who value realism, dimensionality, and emotional engagement. It uses two matched pairs of 6550 output tubes along with 6922 input tubes to produce 50 watts per channel. This power output is carefully engineered to deliver a balanced combination of control, dynamics, and tonal richness—making the I/55 an ideal integrated amplifier for both modern and classic loudspeaker pairings.

One of the most important advancements in the I/55 is the addition of auto-bias technology. This feature continuously maintains the correct operating point for the output tubes, ensuring consistent performance and extending tube life without the need for manual adjustment. For consumers, this means a more user-friendly tube amplifier experience without sacrificing the purity and performance that tube enthusiasts expect from Audio Research.

The I/55 also introduces a more advanced internal architecture with independent tube preamplifier and power amplifier sections. This design provides greater system flexibility and improved performance, particularly in setups that benefit from external integration. The inclusion of preamplifier outputs allows the I/55 to easily pair with powered subwoofers, giving users the ability to build a more complete full-range system without compromising the integrity of the signal path.

Connectivity is another area where the Audio Research I/55 Integrated Amplifier excels. The amplifier features three single-ended inputs and one balanced XLR input, allowing seamless integration into a wide variety of high-end audio systems. For listeners seeking a more modern digital front end, the I/55 offers an optional DAC module featuring the AKM Velvet Sound DAC architecture. This optional digital section supports USB, optical, coaxial, and Bluetooth inputs, making it easy to connect today’s digital sources while maintaining audiophile-grade performance.

For vinyl enthusiasts, an optional phono stage is available with both moving magnet (MM) and moving coil (MC) compatibility, including adjustable loading for MC cartridges. This flexibility allows the I/55 to serve as the centerpiece of a high-performance analog system, eliminating the need for additional external components.

The I/55 also includes a headphone output driven directly by the 6550 output tubes, delivering a premium personal listening experience with the same warmth, detail, and dynamic expression found in its speaker output. This feature reinforces the amplifier’s versatility, making it equally suited for both dedicated listening rooms and more personal listening environments.

With its combination of 50 watts per channel of tube power, auto-bias operation, optional DAC and phono modules, and flexible connectivity, the Audio Research I/55 Integrated Amplifier stands as a complete solution for discerning listeners. It embodies the craftsmanship, innovation, and sonic excellence that define Audio Research—bringing high-end tube performance into a modern, accessible, and highly adaptable integrated amplifier design.

At The Grid, the Audio Research I/55 can be experienced the way it was meant to be heard—in a properly designed listening environment with expert guidance. Our team will help you configure the ideal setup, from source components to speaker pairing, ensuring you get the absolute best performance from your system. Contact us today or visit our Houston showroom to schedule a private listening session and explore the I/55 in person.