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Because 8x oversampling puts very stringent demands on aperture timing and sample-and-hold settling speed (the time required for a switched voltage to overshoot the mark and return to its new setting), the DAS-R1 employs four D/A converters in what Sony calls a staggered overlap configuration. The 352.8kHz samples for each channel are switched alternately between two of the converters, so that each gets twice as much processing time as it would otherwise. The outputs from both converters are then averaged, as are noise and (in theory) distortion, resulting in 3dB reductions in both. In…
Sidebar 1: Gordon Holt's System
Equipment used for my tests included the Ortofon MC-3000 cartridge in the Versa Dynamics 2.0 arm and turntable, Vendetta Research SCP-2 head amp, a Mod Squad Prism CD player, Revox A-77 15ips open-reel tape deck, the Threshold FET-10L line controller, Audio Research M200 power amplifiers, and Sound Lab A-3 full-range electrostatic speakers. Audio interconnects were Monster 1000s, and speaker cables were AudioQuest Greens.
The listening room is extensively treated with ASC Tube Traps, for standing-wave control. Program material was some of my own…
Sidebar 2: Measurements
The R1 fared very well on both the CBS CD-1 and Pierre Verany PV.788031/788032 test discs.
The CBS has several series of 1kHz tones of diminishing level, down to –90dB and below, with and without dither added. Nearly every player I have tried them on has produced severe harmonics and/or buzzing from the undithered –80 and –90 tracks, and most were incapable of producing a recognizable pitch from the –100dB dithered signal; it became undifferentiated hiss. With the R1, the undithered –80 track had perceptible even-harmonic content and the –90 track had…
Sidebar 2: Specifications
Description: Two-piece CD player with separate D/A processor. Controls: CDP-R1: AC Power, Drawer Open/Close, Play, Pause, Track Advance/Retreat. DAS-R1: AC Power, Source selector (CD, Aux 1, Aux 2). Infra-red remote control.
Dimensions: Each unit 18.5" W by 5" H by 16" D. Weight: CDP-R1, 38 lbs; DAS-R1, 38 lbs.
Price: $8000 (1988); no longer available (2017). Approximate number of dealers: 20.
Manufacturer: Sony Corp., Park Ridge, NJ 07656 (1988); Sony Electronics, Inc., 16530 Via Esprillo, San Diego, CA 92127-1708 (2017). Tel: (858) 942-2400. Web:…
Merriam-Webster's 11th Collegiate Dictionary defines tot as "1: a small child: TODDLER; 2: a small drink or allowance of liquor: SHOT." Torus Power used it to name their compact line of toroidal power conditioners. Although small in size, weight, and price, the TOT AVR includes the Automatic Voltage Regulation referred to in its name, as well as noise filtering and smart Ethernet control, and is available with series-mode surge suppression (SMSS) circuit protection.
Kevin Main, president of Torus Power, joined me for lunch in Las Vegas during the 2016 Consumer Electronics Show, to tell…
Sidebar 1: Specifications
Description: AC power isolation transformer and voltage regulator with six AC outlets. Nominal input voltage: 120V. Undervoltage limit: 85V (US). Overvoltage limit: 135V (US). Input frequency: 60Hz, ±3Hz. Input fuse: 10A, 250V. Output voltages: 120V, ±5V (US). Maximum continuous current output: 10A. Power VA/maximum continuous load: 1200VA (US). Output impedance: <'2 ohms. Efficiency at 1200VA: <1200VA resistive load, >99.6%; reactive load, >99.6%. Noise reduction: Narrow Bandwidth Technology (NBT) circuit using transformer as low-pass filter…
Sidebar 2: Associated Equipment
Analog Sources: Linn Sondek LP12 & Lingo turntable & power supply, Linn Ittok tonearm, Spectral cartridge; Day-Sequerra 25th Anniversary FM Reference tuner.
Digital Sources: Bryston BCD-1 CD player, Bryston BDP-2 media player with IAD soundboard; Bryston BDA-3 DAC; Oppo BPD-103 universal Blu-ray player; Sony SCD-C555ES SACD/CD player; Lenovo P50 laptop computer running Windows 10 Pro (64-bit), Bryston USB driver, JRiver Media Center 22.
Preamplifiers: Bryston BP-26, Mark Levinson No.526.
Power Amplifiers: Mark Levinson No.334 (stereo)…
Saturday March 4, 1–5pm, Suncoast Audio in Sarasota, Florida (7353 International Place, Unit 309, Sarasota) will be hosting its grand opening. Suncoast Audio will be showcasing the latest products from Magico, Focal, Vandersteen, Raidho, Avantgarde, VPI, Soulution, Ayre, Berkeley, Aurender, Esoteric, Chord, Lampizator, AudioQuest, Aavik, Ansuz, Siltech, and many more.
Saturday, March 4, from 5–9pm, Musical Artisans (8335 Keeler Avenue, Skokie, IL 60076) will host their winter open-house event, introducing Nagra Audio and the Helix 1 turntable by Mark Döhmann to the Chicago area…
New England Audio Resource's NEAR-50M is a cyborg: metal innards in a wooden body. It represents NEAR's top statement in the firm's Metal Diaphragm Technology speaker line, which features the "NEAR-Perfect" driver cone. Metal—in this case an anodized aluminum alloy—is much more rigid than paper or plastic. Hence, a driver with a metal cone acts more nearly as a true piston. When it comes to loudspeaker cones, breaking up is not hard to do. When that happens, the cone flexes in a complex pattern, generating harmonic distortion. A typical plastic or paper 8" woofer may experience its first…
Sidebar 1: Measurements
Looking first at the NEAR-50M's electrical impedance and phase (fig.1), the valley at 30Hz reveals the port tuning. Overall, the impedance is more like that of a 5 ohm than an 8 ohm speaker, with a precipitous drop almost to 2 ohms centered at 8kHz. (I assume the specified impedance minimum of 5 ohms is a typographical mistake.) The '50M will be a hard speaker to drive; I find it surprising that DO and other reviewers have used tube amplifiers with it, which will tend to reduce energy around this mid-treble minimum due to the interaction between the amplifier's…