UNISON RESEARCH SINFONIA

Pre owned. In good condition. Shows signs of wear. Comes with  remote control, without original packaging.

Unison Sinfonia is a stereo integrated tube amplifier that authentically embodies the tradition and philosophy of the Italian brand, combining a vintage-inspired aesthetic with a warm, enveloping, and refined sound character. Designed entirely in a dual-mono configuration, it effectively consists of two identical and completely independent amplifiers housed within a single chassis, each with its own power transformer, dedicated circuits, and separate output stage. This approach drastically reduces channel interference and contributes to a purer and more stable sound reproduction. All amplification stages are strictly tube-based and operate in pure single-ended Class A, a technical choice that favors natural timbre and musicality.

The design closely recalls the renowned Performance model, from which it inherits its flowing aesthetic language and many technical solutions, while positioning itself slightly below in terms of output power. Sinfonia delivers approximately 25 watts per channel. The design remains faithful to the Unison Research style, featuring elegant retro lines and carefully selected materials, the result of a fully handcrafted manufacturing process carried out in the brand’s Italian facilities. Every stage, from design and assembly to final testing, is followed with meticulous attention to ensure exceptional quality control, both sonically and aesthetically.

The preamplification and driver stages use ECC83 and ECC82 triodes connected in parallel and properly biased to reduce output impedance, improve linearity, and optimize the signal-to-noise ratio, with virtually no odd-order harmonic distortion. The power supply employs two separate toroidal transformers, one per channel, designed to minimize magnetic flux leakage, while the output stage uses two KT88 tubes in an ultralinear parallel single-ended configuration, made possible by dedicated output transformers that allow the tubes to operate in a manner similar to triodes. A bias control circuit ensures continuous compensation for parameter drift over time, guaranteeing consistent performance even after years of use, confirming a design built to last.

Attention to detail extends to every component, from gold-plated input contacts to non-inductive resistors, from filter capacitors to pure ceramic tube sockets, as well as the non-magnetic stainless steel top plate that aids heat dissipation together with the side heat sinks. The solid wood elements, used for both the amplifier and the infrared remote control, serve not only an aesthetic purpose but also help dampen unwanted resonances. The control knobs, machined from solid non-magnetic stainless steel, provide a sense of solidity and ensure smooth, precise operation.

Once powered on, Sinfonia reveals all its charm through the warm glow of its tubes, which illuminate brightly after just a few minutes, creating a captivating atmosphere perfectly in line with its sonic character. Sonically, it displays a distinctly tube-like personality—smooth and refined—capable of highlighting the quality of the best recordings without ever becoming fatiguing, softening rough edges and delivering a consistently pleasurable listening experience. Dynamics are surprisingly lively and controlled, with a solid, punchy low end despite the moderate power rating, and a well-focused stereo image rich in detail and depth. When paired with reasonably sensitive loudspeakers, Sinfonia expresses its full potential, offering a rare balance of musicality, aesthetics, and artisanal craftsmanship that makes it a truly timeless amplifier.

Technical specifications:

• Type: dual-mono integrated tube amplifier
• Output stage: ultralinear parallel single-ended Class A
• Output power: 25 W per channel
• Inputs: 4 line inputs; 1 tape input
• Input impedance: 47 kOhm
• Outputs: 1 tape output; 1 subwoofer output
• Output impedance: 4 – 8 Ohm
• Feedback factor: 14 dB
• Frequency response: 20 – 30,000 Hz
• Tubes: 4 x 6550/KT88; 2 x ECC82; 2 x ECC83
• Remote control: IR for input selection and volume control
• Power consumption: 500 W max
• Dimensions: 44 x 21 x 42 cm
• Weight: 25 kg