Unison Research S9 Integrated Valve Amplifier

Unison Research S9 Integrated Valve Amplifier

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Key info

Unison Research S9 valve amplifier is an advance in modern all-tube design integrated amps and uses the new SV-572 tube to offer superb musical performance across the full audio spectrum.

When partnered with loudspeakers of suitable quality it will provide a convincing listening experience to satisfy the most demanding audiophile or music lover.

Organic Sound

The Unison S9 great strength is that’s it’s a very organic-sounding amp. Few amplifiers combine such resolution with such a self-effacing sound. Highs are sweet and beautifully layered, producing a shimmering treble few rivals get close to. The sheer quality of the S9 makes itself felt when you go back to more conventional alternatives.


The output power valves of this amplifier are the SV572 from the russian Svetlana. The main characteristics of SV 572 are: Directly heated thoriated tungsten filament for soft glow and warm sound. Hard glass envelope with white ceramic base.

Low microphonic construction with ceramic internal spacers. Graphite plate with titanium coating for extremely high power capability and a small physical size. The bias of output stage is manual controlled for each tube and it has obtained by aid of a precision analogic mA meter.

Output Performance

The output transformers have been studied, designed and produced in the factory to exalt at maximum the exceptional sound characteristics of the SV572. The total negative feedback of S9 is very low, about 9dB, nonetheless is bandwidth is from 30Hz to 50kHz with extremely low THD.

The anodic power supply, more than 1kV, has supported with 8.000 uF capacitors filters. The filaments of each power valves has supplied by a dedicated power supply with Shotky diodes.

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