UNISON RESEARCH S6 BLACK EDITION

Black Edition version, featuring the following upgrades: Selected Golden Lion KT77 tubes for superior tonal performance - Integrated DAC with optical, S/PDIF, and USB inputs - Upgraded internal circuit boards for enhanced audio quality - Fully manual bias adjustment for increased power and detail - Input section now uses relays with ground termination on unused inputs - Higher output power (approximately 5–10W more than the standard version)

The Unison Research S6 Black Edition is a tube integrated amplifier that represents a refined evolution of the highly acclaimed S6 model. This Black Edition is a significant leap forward, both technically and aesthetically, the result of a deep revision of circuits, power supplies, components, and overall design. Output power has been increased to 40 watts per channel—a 15% boost over the standard version—and the output stage has been redesigned with the removal of the Auto-Bias system. This choice improves sound quality by eliminating passive components that introduce distortion, resulting in better frequency response, particularly in the lower ranges.

At the heart of this amplifier are the prestigious KT77 Genalex Gold Lion tubes, selected for their exceptional tonal and structural characteristics. Unlike the more common EL34, KT77 tubes deliver a more linear, detailed, and three-dimensional sound with extended high and low frequency response, reproducing music in a natural, fluid, and coloration-free manner. The ECC83 and ECC82 preamp tubes, also carefully selected, help build a wide, coherent soundstage while maintaining the clarity and transparency that define Unison Research products.

The entire power supply section has been redesigned to provide an independent line for each tube, minimizing stage-to-stage interference and ensuring uncompromised stability. The combined use of electrolytic and polypropylene capacitors ensures faster transient response, improved dynamics, and greater definition across the entire frequency spectrum.

Signal path engineering has been approached with obsessive attention to detail. The input selection system, for example, incorporates Return GND technology derived from Unison’s flagship models. This isolates incoming signals to minimize crosstalk and preserve sonic purity. The use of shielded micro-relays with silver-gold-plated contacts, along with high-grade coaxial internal cabling, further reflects the commitment to excellence down to the smallest components.

The digital section of the S6 Black Edition is modern and comprehensive, featuring three inputs—USB, optical SPDIF, and coaxial SPDIF—capable of supporting formats up to 384 kHz and DSD 256. Digital conversion is handled by the Sabre ES908K2M chip, one of the most highly regarded DACs available, ensuring an extremely precise and musical digital playback. A stereo subwoofer output is also provided, unfiltered and taken directly from the amplifier’s output stage to maintain consistent tonal character when integrating an external subwoofer.

The aesthetic design is the result of meticulous craftsmanship. The glossy lacquered wood front panel is hand-finished through a complex process, while the black gunmetal finishes, treated with cataphoresis, offer both a contemporary look and exceptional durability. The result is an amplifier that seamlessly blends the traditions of tube design with the best of modern audio technology, offering refined, dynamic, and transparent sound in an object of striking elegance and character.

Technical Specifications:

• Dual Mono circuit topology for optimal channel separation
• 6 KT77 Genalex Gold Lion power tubes for smooth, natural, and detailed sound
• ECC83 Genalex Gold Lion tubes in the signal stage for a wide, articulate soundstage
• 40W per channel in pure Class A, delivering refined and dynamic musical reproduction
• Cathode Capacitor Less technology, eliminating cathode capacitors for faster, clearer response with no coloration
• 4 RCA analog inputs
• Stereo subwoofer output, unfiltered and derived from the amplifier’s output for perfect tonal integration
• Integrated digital section with 3 inputs: USB (up to 384 kHz), optical and coaxial SPDIF (up to 192 kHz), compatible with DSD up to 256
• Sabre ES908K2M DAC, among the most advanced in its class, for top-tier D/A conversion quality
• Dimensions: 35 cm (W) x 22 cm (H) x 50 cm (D)
• Weight: 35 kg