Unison Research S6 Tube integrated amplifier taken in trade. New retail $5,600. This is among the most musically satisfying single pieces of gear we've had the pleasure of representing in the last decade with a performance level that can't be beat for much less than twice the price.
Face Plate is not perfect with minor blemishes resulting in the 7/10 rating.
Pure Class A output power of 30/35 watts per channel using 6 EL 34 tubes. Simple and easy bias via buttons and meters ton either side of the transformer. A very solid 55 lbs. 5 Line inputs and one tape output. Steadily updated and improved over the years.
Great reviews as selectively noted below.
From Tone Magazine: The S6 is perfection
for a listener in a modest room with a high quality pair of small speakers. In room two, (which is 13 x 15 feet) mating the S6 with either the Harbeth Compact 7ES-3s, Dynaudio C1’s or the Penaudio Cenyas makes for a symbiotic relationship far greater than the sum of its parts. Combining the S6s liquid midrange with the imaging of these speakers in a small room makes for an immersive listening experience that’s tough to argue with. It’s almost like a giant pair of Stax headphones.
Add a source or two, your favorite pair of speakers and call it a day. .... you’ll be hard pressed to find the finesse, both electronically and aesthetically that the S6 offers. This amplifier is more than just a nice tube integrated; it is a work of audio art. It’s an amplifier that should be put on a pedestal with a wonderful painting above it.
If 30-35 watts per channel is enough to rock your world and you’ve been itching for something special, audition the Unison Research S6. I think you will agree that this is a unique product.
From What HiFi: 5 Star Rated
Our Verdict In the right system the S6 is capable of sonic magic. Hear it working properly and we defy anyone not to fall for its charms. It’s the S6’s speed that grabs our attention first. It tracks a signal with a impressive lack of inertia, which translates into a wondrous ability to render the nuances of Nina Simone’s voice on I Loves You Porgy
with a delicacy we rarely come across.
Richness, power and tenderness: it’s all here, in generous portions. In the midrange and treble the S6 is the real deal.
It’s agile and insightful, delivering the low-level details that define the texture of instruments and voices brilliantly. Not only that it keeps every musical strand in place even with demanding recordings such as Beethoven’s Fifth.
From techradar reviews:
During those all-important few minutes when we first got the amp up and running, we had an immediate 'I like it' moment – being smitten with its combination of smooth, lush warmth and crisp incisive clarity. It definitely delivers that airy, three-dimensional quality Class A amps are famous for.
If you're new to valves and wonder what all the fuss is about, Unison's Research's S6 would be the perfect introduction. It sounds absolutely gorgeous, delivering that sweet glowing richness that tubes are famous for, without loss of bite or immediacy.
Indeed, it's the combination of silky smoothness and crisp immediacy that is so alluring. Power output is limited, but the S6 is one of those tube amps that's very good at covering its tracks.
Listening to it, you're rarely aware of its 'limitations'. It recreates the music with little sense of strain and sounds as though it has power to spare.