Tweek Geek
Unison Research S6 Integrated Amplifier
Our Take
First, bass. You will not believe the amount of grip this amp has on speakers. My Aurai Z165's are playing into the mid to high 30's, at low levels, and with a tremendous amount of speed, clarity and control. This is most unexpected. It is no-joke solid state like control in the bass region.
The midrange is everything you would expect from an EL34 based amp. Dimensional, layered, and just wonderful. Guitars and vocals have a reach out and touch intimacy, not a hint of harshness even on my old 80's recordings.
The highs are equally wonderful, and smooth with an airy extension.
Overall the S6 is a remarkable performer. It's quick, smooth, holographic and has a high engagement factor. You will find yourself listening more often and longer.
The S6
The Unison Research S6 has been a mainstay of Unison's product lineup for quite some time. Steadily updated and improved over the years to the point where it is easily one of the most respected integrated amplifiers in the world. Hand made in Italy, it should be no surprise that the build quality, and performance are hallmarks of this amplifier and of Unison Research as a whole.
The S6 is a 30 watt EL34 based power amplifier with the output configuration being Single Ended Ultra-parallel. This compact amplifier is able to drive almost all speakers on the market, including low sensitivity. We do recommend careful matching of speakers and ancillary components nonetheless.
Reviews
Inside
The stages consist of two triode preamps directly coupled, while the output stage uses three pentodes for each channel type in configuration EL34 Single Ended Ultra-parallel.
The output transformer, are a Unison Research tradition, and have been specifically designed and hand made their laboratories. The power transformer is able to seamlessly provide all the energy needed to operate the amplifier in under nearly any load.
Aesthetics
The Unison Research, as tradition has always placed great importance and attention to the aesthetics of its products. The originality of form and choice of materials is to demonstrate the artistry and expertise of their design team. The S6 is another expression of art for which the Unison Research is known worldwide and are justifiably proud.
The wooden components of the amplifier are handcrafted using blocks of precious woods.
The rotary controls are non-magnetic stainless steel, turned and precision machined.
The design of each tube amplifier must also take account of the dissipation of heat produced by the valves. The S6 in this regard has been resolved with an attractive layout of the arc power tubes and a baseplate with non-magnetic stainless steel as a heat reflector. A wire grille protects chrome valves allowing adequate ventilation without compromising the view of the valves.
Sonic Characteristics
A careful calibration and fine tuning for maximum sound quality of the S6 was performed over several months of listening tests, using a variety of sources and speakers.
The largest and most important result of this calibration process was to determine the value of feedback. This allowed them to achieve maximum sound quality, high capacity for detail reproduction, without altering or compromising lightness, transparency and heat.
Specifications
Output Stage: single-ended parallel, ultralinear
Class: pure A class
Output Power: 30/35 Watt/channel
Frequency Response: 20 – 50000 Hz
Output Impedance: 6 Ohm
Input Impedance: 47 kOhm
Inputs: 5 line
Outputs: 1 tape, loudspeakers
Power Consumption: 265VA max
Dimensions : 35 cm x 21cm x 49 cm (L x H x D )
Net Weight: 55 lbs
