Analog Sources: Garrard 301 turntable; EMT 997, Wand Plus tonearms; Ortofon SPU Century & SPU A Wood, Shindo SPU pickup heads; Denon DL-103, EMT TSD 15 SPH cartridges.
Digital Sources: Apple MacBook Air laptop computer running Roon v.1.5, Hegel Music Systems Mohican CD player, Mytek Liberty D/A processor.
Preamplification: Auditorium 23 Hommage T1 & T2 step-up transformers, Shindo Laboratory Monbrison (2017) preamplifier.
Power Amplifiers: Air Tight ATM-300R, Shindo Laboratory Haut-Brion.
Loudspeakers: Altec Flamenco, DeVore…
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Sidebar 2: Associated Equipment
Sidebar 3: Measurements
I measured the Exposure XM5 integrated amplifier and D/A processor with my Audio Precision SYS2722 system (see the January 2008 "As We See It"). Usually before performing any testing, I run an amplifier for an hour at one-third power into 8 ohms, which is thermally the most stressful condition for a design with a class-AB output stage. With the Exposure XM5, however, I cut short this preconditioning after 15 minutes. The temperature of the amplifier's bottom panel, to which the output devices are fastened, had already reached 163.6°F (73.1°C), and I was concerned…
Manufacturer's Comment
Editor: Our sincere thanks to Art Dudley for the recent review of the Exposure XM5 Integrated Amplifier. The XM5 was designed for "real-world" buyers who want a unit that can do most things, without taking up the room needed by conventional hi-fi separates. These days, many urban dwellers don't have the space for a living room full of boxes. The XM5's half-width size allows it to be more flexible for positioning, while not compromising performance. The circuitry is based on the legendary Exposure 2010S2—which is the staple of our separates range—but it necessarily…
Every time I review a digital-to-analog converter, my memory drifts to the spring of 1983, when the first Compact Discs arrived at Tower Records in New York City. They appeared in the opera section. Sitting next to big, thick boxed sets of opera LPs, these new discs looked truly compact. A few months later, boxed sets of popular opera LPs, in almost untouched condition, began selling in the Tower Annex for $1/disc.
I was shocked. I could not believe people were actually trading these luxurious, linen-covered, rag-papered, thick-librettoed boxes for chintzy, verkakte plastic "jewel cases…
I judge each DAC on its own sonic merits, independent of its technology. However, I'm sympathetic to the chipless concept—a chip DAC sounds like the chips used in it, while an FPGA DAC has more potential for voicing and, later, for modification of that voicing via in-the-field firmware upgrades.
I compared the PS Audio's FPGA PerfectWave DirectStream to a DAC that uses a sigma-delta chip and sells for almost the same price: Mytek's Manhattan II ($5995), which uses the Sabre ES9038Pro chip. The two DACs differed greatly in their portrayals of space, texture, and musical momentum.
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Sidebar: PS Audio Digital Link Measurements
Intrigued by this 30-year-old D/A processor, I thought it would be interesting to run it through my standard set of measurements, using my Audio Precision SYS2722 system (see the January 2008 "As We See It").
The Digital Link's serial number on the pcb was 1172. Its single coaxial S/PDIF input would lock only to data sampled at 44.1 or 48kHz, an understandable limitation of its Yamaha S/PDIF receiver chip—back in 1989, there were no sources of data sampled with rates above 48kHz. A 1kHz digital signal at 0dBFS resulted in an output level…
I had never been alone with a Russian-manufactured 6C33C tube. At least not at night, in the dark. The first night Balanced Audio Technology's VK-56SE tubed amplifier was in my system, I sat on the floor studying the unusual shape and dark orange glow of its four 6C33C-B output tubes. I noticed their brightly lit, cathedral-like innards. My Russian neighbor told me they were used as regulator tubes in MiG jets during the Cold War. I could believe it—their exposed cathodes were the exact color of the Soviet flag. From more than a foot away, I could feel the heat from their high-amperage…
In preparation for this report, I read a review of the VK-56SE's ancestor, the VK-55SE, by one of my favorite-ever Stereophile writers: the late Wes Phillips, writing in the April 2010 issue. Wes described its sound: "As I listened to Arturo Delmoni's superb disc of solo violin works by Ysaÿe, Kreisler, and Bach (CD, John Marks JMR-14), the character of the BAT was immediately apparent: the sound was vivid, relaxed, and liquid." Those three adjectives also describe my early impressions of the VK-56SE.
A week later, I put on Björk Guðmundsdóttir and the Tríó Guðmundar Ingólfssonar…
Sidebar 1: Specifications
Description: Tubed, push-pull stereo power amplifier. Maximum output power: 55Wpc into 8 ohms (17.4dBW), 110W when bridged for mono operation. Frequency range: 8Hz–200kHz. Nominal voltage gain: 25dB into 8 ohms. Input impedance: 215k ohms. Input sensitivity: 1V. Power consumption: 400W at idle, 800W at full power. Output transformer taps: Low (2–4 ohms), Med (4–6 ohms), High (6–8 ohms). Tube complement: two 6H30, two 6SN7, two 6922, four 6C33C-B.
Dimensions: 17" (430mm) W by 8" (205mm) H by 16" (405mm) D. Weight: 52 lb (22.7kg).
Finishes: Black, Silver.…
Sidebar 2: Associated Equipment
Analog Sources: Dr. Feickert Analogue Blackbird turntable, Jelco TK-850L tonearm, My Sonic Lab Ultra Eminent Ex cartridge.
Digital Sources: Apple Mac mini computer running Audirvana Plus 3.2; Schiit Audio Yggdrasil, HoloAudio Spring "Kitsuné Tuned Edition" Level 3, Mytek Brooklyn+ & Manhattan II DACs, Chord Qutest, PS Audio DirectStream & Digital Link DACs.
Preamplification: Rogue Audio RP-7 line-level preamplifier.
Power Amplifiers: First Watt SIT-3, Pass Laboratories XA25, Rogue Audio Stereo 100.
Loudspeakers: Harbeth Monitor 30.2…