Audio Research I/70 integrated, LS-2 And LS-3 Preamplifier, S-100 And S-200 Solid-State Amps, And D-80 Tube Amp Assessment Review
Sonic ascension into pure musical bliss via tube and solid-state amplification.
HIGH END 2025 Audiophile Show Report By Steven R. Rochlin

  Audio Research is here at HIGH END 2025 show in Munich with many new products. Their new I/70 vacuum tube stereo integrated amplifier, LS-2 and LS-3 stereo preamplifiers, D-80 vacuum tube amplifier, plus the S-100 and S-200 solid-state amplifiers. The new I/70 ($9,950, with DAC or MM/MC Phono Card adding $1,000 each, or $1,500 for both) represents a major upgrade over its sibling. ARC wants Enjoy the Music.com to share with you that the I/50 provides a benefit in both performance and flexibility for the discerning listener. It has been meticulously engineered to serve as the heart of any high-fidelity audio system.

The amplifier uses auto-biasing for 6550 output tubes, ensuring that these crucial components perform optimally and enjoy a longer lifespan. A dedicated active tube preamplifier section drives the tube amplifier stage, which may create a rich and dynamic audio experience that brings music to life (and life into music). It offers single-ended (unbalanced) RCA preamplifier outputs for both the preamp and subwoofer, making it easy to integrate with additional audio components. The inclusion of balanced XLR inputs also allows for high-end balanced source components, providing enhanced versatility.

Audio Research Corporation's I/70 shares output transformers with the acclaimed Reference 75SE amplifier, ensuring exceptional sound quality. Additionally, the headphone circuit is driven by the same 6550 tubes, delivering an immersive listening experience for private sessions. Inspired by the Reference 330M, the I/70 is available in natural silver or black anodized finishes, making it as visually appealing as it is sonically impressive. A new machined metal remote adds both sophistication and ease of navigation.

Audio Research's new LS-2 stereo preamplifier ($8,450, plus $1,000 for the DAC or MM/MC Phono Card, or $1,500 for both) is crafted for those who demand uncompromising audio purity. It is a pure tube preamp that shuns solid-state devices to deliver a warm and authentic sound experience. Built around a vacuum tube signal path, the cathode follower design within the LS-2 preamplifier eliminates solid-state components from the signal chain. It's single gain stage operates in pure Class-A mode, ensuring that the sound remains rich and uncolored by feedback. The constant current cathode bias further enhances the overall stability and consistency.

A full touch-screen display provides intuitive control over balance, input labeling, and color settings. This modern interface elevates the user experience while keeping the classic tube audio charm intact. Equipped with both balanced XLR and unbalanced RCA inputs, the preamp seamlessly integrates with a variety of audio setups. The LS-2 can be enhanced with a user-installable DAC card (supporting USB, S/PDIF coax, and TosLink Optical inputs) as well as an optional MM/MC Phono card. These options allow for a customizable experience based on the listener's needs.

The LS-3 ($7,450, plus $1,000 for the DAC or MM/MC Phono Card, or $1,500 for both) could be a major breakthrough in solid-state audio preamplification, representing a significant advancement over earlier ARC models — despite sharing a similar external appearance to the LS-2. The Audio Research Corporation's LS-3 stereo preamp kicks off with a differential JFET-based input stage, which works to enhance signal integrity and reduce unwanted noise. Following this, a bipolar transistor-based voltage amplifier ensures robust and consistent performance. Employing a high-quality precision Class-A output stage, the LS-3 delivers should produce a warm and wonderfully dynamic sound that audiophiles will appreciate, ensuring that every note is rendered with clarity and depth.

The D-80 ($12,950) is a classically beautiful, high-performance stereo power amplifier built on the trusted Reference 80S platform. It replaces the previous VT80SE model and sets a new benchmark for vacuum-tube performance within its price range. ARC's D-80 employs a fully balanced, differential design that operates in Pentode mode (much like the celebrated 330M amplifier). This design choice should very much elevate audio quality, delivering clear, dynamic sound reproduction.

With an output of 80 Watts per channel, the amplifier uses two pairs of KT150 output tubes. To make operation easy, A sophisticated auto-biasing system automatically adjusts the output tubes for optimal performance and longevity. Additionally, the amplifier features versatile output terminals supporting 4, 8, and 16 Ohm loudspeaker configurations.

Moving to solid-state designs, yes my good friends here at Enjoy the Music.com ARC does also produce solid-state amps, Audio Research's S-100 ($9,450) is a stereo amplifier engineered to deliver a powerful 100 Watts per channel, driven by the expertise of Audio Research's newly formed solid-state engineering team. Its design focuses on capturing every musical nuance and emotion, from big to small, with standout features that music lovers enjoy. At its core, the ARC S-100 solid-state stereo amplifier employs a differential JFET-based input stage to cleanly reproduce audio. This is followed by a bipolar transistor-based voltage amplifier, culminating in Class AB output stages that should produce a nicely rich, accurate, dynamic sound profile.

With a fully balanced signal path — from input to output — the ARC S-100 minimizes interference and distortion. This meticulous attention to balance creates an immersive listening environment where every nuance can be truly heard. ARC's sister amplifier, the S200 ($12,950) is rated at 200 Wpc into 8 Ohms (400 Wpc @ 4 Ohms). 

Our Assessment Of The New Gear: ARC I/70, LS-2 & LS-3 Pre, S-100 & S-200, And D-80 Tube Amp
No matter the combination of products from Audio Research, together, enjoying music thanks to an Audio Research Corporation sound system brings joy to many music lovers worldwide. Be sure to visit our Review Magazine to learn more about luxurious audiophile equipment, plus we provide thought-provoking think pieces and much more! As always, in the end what really matters is that you... enjoy the music.

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