Unison Research ABSOLUTE 845 Class A Dual Mono Stereo Tube Integrated Amplifier at Vinyl Sound Buffalo, NY USA

The ABSOLUTE 845 is a dual mono Class A stereo integrated valve amplifier from Unison Research (Treviso, Italy), available at Vinyl Sound in Buffalo, NY, USA. First selected as the Best Product of 1994 by The Absolute Sound magazine, the ABSOLUTE 845 holds one of the most enduring records of critical recognition in audio history. Its dual mono architecture uses four 845 directly-heated triodes alongside six ECC82 and two ECC83 tubes in a parallel single-ended Class A output stage, delivering 40 watts per channel across a frequency response of 20 Hz to 30 kHz. With a weight of 199 lbs and dimensions of 31.7 x 23.8 x 11 inches, the ABSOLUTE 845 is both a physical monument to Italian audio craftsmanship and a sonic benchmark that has remained at the summit of its category for over three decades.

A Thirty-Year Audio Landmark

When The Absolute Sound named the ABSOLUTE 845 the Best Product of 1994, no one could have anticipated that the amplifier would still be in production -- let alone still ranked at the top of its class -- more than thirty years later. The ABSOLUTE 845 was designed by Unison Research founder Giovanni Maria Sacchetti and was among the earliest stereo amplifiers built around the 845 direct-heated triode in an audio application. Its single-ended parallel Class A output topology was, and remains, a statement of engineering commitment: a refusal to compromise the purity of the 845's harmonic signature by introducing crossover artifacts, switching, or feedback structures beyond the 10 dB applied for frequency stability. The five line inputs and two tape loops ensure connectivity with any high-end source or preamplifier, and the dual tape outputs facilitate recording integration.

845 Triode Topology and Dual Mono Construction

The ABSOLUTE 845's dual mono architecture means that each stereo channel has its own completely independent power supply, signal path, and output stage -- there is no shared power rail between left and right channels, eliminating crosstalk at the most fundamental level. Four 845 triodes operate in parallel pairs per channel in a pure Class A single-ended configuration, contributing to the amplifier's characteristic harmonic richness and three-dimensional imaging. Six ECC82 tubes handle the voltage amplification and driver stages, while two ECC83 tubes provide initial gain. The output transformer taps cover 4-ohm and 8-ohm loudspeaker connections with bi-wiring capability, and the input impedance of 47k ohms is compatible with any line-level source.

Key Features

• The Absolute Sound Best Product of 1994: One of the longest-standing awards in audio history, recognized by the leading American audiophile publication over thirty years after its initial award.
• Dual Mono Class A Architecture: Fully independent left and right channel power supplies and signal paths eliminate inter-channel crosstalk at the circuit level.
• Four 845 Directly-Heated Triodes: The 845's warm, harmonically rich character in a parallel single-ended configuration delivers 40 watts per channel of pure Class A power.
• 40 W/Channel Output: Sufficient power for a wide range of loudspeakers, particularly high-sensitivity designs including all three MAX series and the MALIBRAN loudspeakers.
• Five Line Inputs, Two Tape Loops: Comprehensive analog connectivity for multi-source high-end systems with tape recording facilities.
• Bi-Wiring Speaker Outputs: Dual binding posts on each channel accommodate bi-wire and bi-amp loudspeaker configurations.
• Italian Craftsmanship: Designed and produced entirely in Treviso, Italy, under the direction of Unison Research founder Giovanni Maria Sacchetti.

Technical Specifications

Awards and Critical Recognition

• The Absolute Sound -- Best Product of 1994 (American audiophile magazine)

Frequently Asked Questions

What is the Unison Research ABSOLUTE 845?

The Unison Research ABSOLUTE 845 is a dual mono Class A stereo integrated valve amplifier from Treviso, Italy, producing 40 watts per channel through four 845 directly-heated triodes in a parallel single-ended output stage. It spans 20 Hz to 30 kHz and provides five line inputs, two tape loops, and bi-wiring speaker outputs. It was named Best Product of 1994 by The Absolute Sound and is one of the longest-tenured reference-class integrated amplifiers in high-end audio.

How does the ABSOLUTE 845 compare to the Unison Research Simply 845?

The ABSOLUTE 845 and Simply 845 are both 845-based integrated amplifiers but differ substantially in scale and topology. The ABSOLUTE 845 is a dual mono design using four 845 tubes and six ECC82 plus two ECC83 tubes, producing 40 watts per channel at a weight of 199 lbs. The Simply 845 uses two 845 tubes with four ECC82 tubes in a single-chassis configuration producing 23 watts per channel at 30.5 kg. The ABSOLUTE 845 is the flagship integrated -- with greater power, more comprehensive connectivity (five line inputs versus four in the Simply 845), and the dual mono architecture -- while the Simply 845 is the more accessible entry into 845 triode amplification.

Why has the ABSOLUTE 845 remained in production for over thirty years?

The ABSOLUTE 845 endures because its fundamental engineering choices -- the 845 directly-heated triode, pure Class A single-ended topology, dual mono power supply isolation, and hand-wound output transformers -- produce a sonic character that successive generations of amplifier technology have not displaced. The 845's harmonic structure, with its dominance of low-order even harmonics, is considered by many audiophiles to most closely approximate the natural tonal body of acoustic instruments. Unison Research has continued to refine the ABSOLUTE 845's build quality and component selection while preserving its original circuit architecture.

What loudspeakers pair best with the ABSOLUTE 845?

The ABSOLUTE 845's 40 watts per channel suits loudspeakers of 89 dB sensitivity or higher in most room sizes. Within the Unison Research range, the MAX 2 (96 dB), MAX 1 (94 dB), MAX MINI (93 dB), and MALIBRAN (89 dB) are all well-matched. High-sensitivity designs from other manufacturers -- including horn-loaded loudspeakers from brands such as Klipsch, Zu Audio, or DeVore Fidelity -- are also commonly paired with 845-based amplifiers of this power level.

Where can I buy the Unison Research ABSOLUTE 845 in Buffalo, NY or the USA?

The Unison Research ABSOLUTE 845 is available at Vinyl Sound in Buffalo, NY, USA. Vinyl Sound is an authorized Unison Research dealer serving western New York and the United States. Contact the Vinyl Sound team for current stock, audition availability, and loudspeaker matching recommendations.