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Unison Research S6 Black Edition integrated amplifier Measurements

Sidebar 3: Measurements

I performed a full set of measurements on the Unison Research S6 Black Edition using my Audio Precision SYS2722 system. I carefully installed the tubes and after leaving the amplifier powered up for 30 minutes, checked that the bias for each of the six KT77 output tubes was correctly set. I rechecked the bias every 30 minutes during the testing.

Looking first at the S6 Black Edition's unbalanced line inputs, the input impedance measured 39k ohms at 20Hz and 1kHz and 36k ohms at 20kHz. The amplifier inverted absolute polarity at both the loudspeaker and…

Unison Research S6 Black Edition integrated amplifier More Measurements

To examine the performance of the S6 Black Edition's digital inputs, I used the coaxial and optical S/PDIF inputs—the optical input only accepted data sampled at rates up to 96kHz—and USB data sourced from my MacBook Pro. The USB Prober utility identified the S6 Black Edition as "UNISON USB DAC 2" from "UNISON RESEARCH," with the serial number string "0 (none)," and indicated that the USB port operated in the optimal isochronous asynchronous mode. Apple's AudioMIDI utility showed that the Unison Research accepted 16-bit and 32-bit integer data via USB sampled at all rates from 44.1kHz to…

Room Correction, Swiss Precision, and Serious Scale: Von Schweikert, WestminsterLab, Rockna, LUMIN

New York–based dealer New Life Audio teamed up with California distributor Hear This—representing WestminsterLab and Von Schweikert Audio—to build a system around those two brands. On a Bach Violin Concerto, played with characteristic sweetness—if not period authenticity—by Belgian violinist Arthur Grumiaux, both tone and texture came through with striking fidelity.

At my request, we transitioned from Grumiaux in 16-bit/44.1kHz to Isabelle Faust in 24-bit/96kHz. I didn't scribble down what we played, but I suspect it was either the Ligeti or Britten Violin Concerto. Colors and textures…

Pearl Acoustics: Luster at the End of the Hall

“Do you know where the room with Pearl Acoustics Sibelius loudspeakers is?” That question, which greeted Jim Austin and me as we navigated the stairs, grew increasingly common as AXPONA unfolded.

Pearl wasn’t listed in the official show guide, but word of mouth made the English company impossible to ignore. Its room, tucked away at one end of the fourth floor, became a destination—helped, perhaps, by the firm’s devoted YouTube following. While we were setting up for our video shoot, a Pearl owner popped in to say hello. I believe he was an oboist with the Metropolitan Opera Orchestra:…

Wattson’s Madison Amplifier Debuts with CH Precision DNA, Magico Brawn

At Munich High End 2024, my biggest discovery was Switzerland’s Wattson Audio. It’s easy to hear a sonic kinship between Wattson and its new owner, CH Precision—an affinity that helped explain CH’s acquisition of the company last year.

At AXPONA, Wattson introduced its new Madison amplifier ($6495), a fully discrete, class-AB, dual-mono design rated at 50Wpc into 8 ohms. Configurable for stereo, mono, or biamp use, it was paired with the Madison LE Streamer ($4995), launched in 2023.

Kevin Wolff, CH Precision’s director of global sales and US distributor for Wattson Audio, and…

Friends with (Sonic) Benefits: Stenheim, VTL, Grand Prix, Kuzma, Nordost, and dCS

Stenheim, VTL, and Nordost returned as AXPONA system partners, joined this year by several notable additions. The analog front end featured Grand Prix Audio’s Monaco 3.0 turntable ($56,250) with Fuel Station battery power supply ($15,250), Kuzma’s Safir 9 tonearm ($23,140), and a Lyra Etna cartridge ($8995). Nordost showcased four rare Odin Gold power cords ($43,999), alongside its familiar Odin 2 and Valhalla 2 cables and a broad range of accessories. Digital duties had shifted from last year’s dCS Rossini Apex to the full Vivaldi Apex stack: DAC ($46,500), Upsampler ($27,000), and Master…

Analog Corner #225: Why, in 2014, Does Vinyl Continue to Grow?

Michael Fremer advocating vinyl and analog on MTV in 1993.

Vinyl sales in America rose 30% in 2013, according to Nielsen SoundScan, which keeps a tally of recorded media sales. Because Nielsen SoundScan only skims the surface of the record retailing picture, missing considerable "nook and cranny" sales, the real number is probably far greater. The SoundScan numbers also omit sales of used vinyl, which are considerable.

By the time you read this, I will have posted on Analogplanet.com worldwide record-pressing totals, from information I've obtained direct from the pressing plants.…

Analog Corner #225: Why, in 2014, Does Vinyl Continue to Grow? Page 2

Keeping the analog flame alive? A very young Chad Kassem of Acoustic Sounds (left) and an equally young Michael Fremer at a 1997 audio show.

Having predicted it on The Today Show in the early 1990s, during a segment on how to transfer LPs to cassette (!), and having advocated vinyl and analog on MTV in 1993 (footnote 2), and on The Howard Stern Show in 2001, etc., I am not confounded by the LP's resurgence, nor do I wonder what's going on here. Thanks to reader tips, I've been monitoring the intensity of the backlash to the vinyl resurgence for years, and it seems to be directly…

Sweet Puppies Powered by Boulder: Wilson’s Legends Get a New Leash on Sound, Aided by Quintessence, Clearaudio, dCS, and Innuos

In the Renaissance Hotel’s Connection room, Quintessence Audio of Morton Grove, Illinois presented Boulder’s new 1151 power amplifiers ($48,000/pair as monoblocks, see Stereophile’s June issue), a 1110 preamp ($24,000), and a 1108 phono preamp ($24,000), all making their AXPONA debut.

They were paired with Wilson Audio’s WATT/Puppy loudspeakers ($39,500/pair); Clearaudio’s Reference Jubilee turntable ($30,000) fitted with a Hana Umami Red MC cartridge ($3950); a dCS Rossini APEX streaming DAC ($32,800) and a Rossini Master Clock ($11,500); Innuos’s ZEN Next-Gen streamer-server…

Brama Drama: Vinnie Rossi and Rockport Bring the Thunder Along With Innuos, Mola Mola, Stillpoints, and AudioQuest

It had been too long since I’d heard Vinnie Rossi’s gear, so I was pleased to encounter the brand’s Brama Gen2 preamplifier ($38,995), Brama Gen2 monoblocks ($59,995/pair), and Rossi himself. The system also featured Rockport Technologies’ new Lynx loudspeakers ($78,000/pair in Satin Titanium Metallic) and the Mola Mola Tambaqui DAC ($13,500). I was curious to hear how it all came together sonically.

I heard three tracks: one by Abdullah Ibrahim; Dominique Fils-Aimé’s “Where There Is Smoke” (mercifully birdless); and Reference Recordings’ Danse macabre by Saint-Saëns, performed…