Unison Research S2K Valve Integrated Amplifier – Second Hand


Class A ultra linear design valve integrated amplifier.


Unison Research S2K Valve Integrated Amplifier

Unison Research Aria S2K is handcrafted in Italy, single ended class A integrated valve amplifier offering 15-watt per channel. The S2K is a supercharged unit using 2 x 12AU7A & 2 x KT-88 in a Single-Ended Ultra Linear Class A design. Pure silver is used for the S2K printed circuit board, and all hard wiring connections. The circuit has been designed to include the minimum possible number of passive components in the signal path and Unison Research output transformers are made from the very finest materials. The S2K has a solid hand rubbed cherry wood front panel and the control knobs are machined from solid stainless steel.

Single-ended transformer-coupled designs, both power and audio transformers are very important, and it’s obvious that Unison has not scrimped in that department. This amp is heavy (about 36 lbs), and most of its weight is at the rear. Its industrial design is top-drawer, and its build quality and fit and finish are excellent for the price.

The S2K’s chassis is deeper than it is wide. The rear two-thirds are taken up by an enclosure of black sheet-metal. In front of that, not centered but offset slightly to the right, are two 12AU7A input tubes; behind them are two Sovtek KT88 output tubes. A contoured stainless-steel apron surrounds the tubes, and bears script legends identifying which tubes go where. Considering the size difference between the input and output tubes, at first blush this gesture might seem silly. But if the amp gets separated from its tubes and manual, the legends will eliminate guesswork in buying replacement tubes. Read more at https://www.stereophile.com/thefifthelement/726/index.html



A pair a new matched KT88 tubes

A pair of 12AU7A

Remote control

IEC power cord

Note : 230V power supply 50Hz


Additional information

Weight 22 kg
Dimensions 50 × 50 × 40 cm


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