Now I'm happy just to stay at home, listening to music through my favorite class-A…
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Winter has returned to Cherry Valley, New York, and I'm reminded of a bad habit that I used to conceal: On cold mornings I started my car well before driving off, then actually weighted down the accelerator pedal—with the heavy socket tray from my toolbox—in an effort to keep the idle high, and thus more quickly warm the windshield and the interior. Whether my lazy trick had the desired effect is a matter of some debate, but I wish now that I hadn't been so wasteful and so casually fouled the air.
In bluegrass-guitar circles, we speak of a select few people as tone players: musicians such as David Grier, Russ Barenberg—and, above all, Tony Rice—who are better than most at pulling rich, complex tone from their instruments. In that vein, the A21ai must surely be considered a tone amp—which is rare in my experience of solid-state products. It reproduced André Gertler's fiddle in the Berg Violin Concerto (LP, Columbia 33C 1030) with superb depth of color and texture, as it did the very nice ride-tom and floor-tom sound from drummer Shawn Pelton throughout Richie Havens's Nobody Left to…
Sidebar 1: Specifications
Description: Solid-state integrated amplifier. Inputs: 4 line-level, 1 phono. Maximum output power: 25Wpc into 8 ohms, 1kHz (14dBW). Line input impedance: 47k ohms. Line input sensitivity: 170mV for maximum output. Phono input impedances: 47k ohms (MM), 100 ohms (MC). Frequency response: 20Hz–20kHz, ±0.5dB. Signal/noise: >83dB (no reference level given).
Dimensions: 17" (430mm) W by 3.5" (92mm) H by 13.7" (350mm) D. Weight: 24.2 lbs (11kg).
Serial Number Of Unit Reviewed: 20349.
Price: $2995. Approximate number of US dealers: 10.
Manufacturer: J.E…
Sidebar 2: Associated Equipment
Analog Sources: Linn LP12, two Thorens TD-124 Mk.II turntables; Naim Aro, EMT 997 tonearms; Miyabi Mono & 47, EMT OFD 25 & OFD 65, Shindo SPU, Ortofon SPU Synergy A cartridges.
Digital Source: Sony SCD-777ES SACD/CD player.
Preamplification: Auditorium 23 Hommage T1 step-up transformer; Shindo Masseto & Fi preamplifiers.
Power Amplifiers: Shindo Corton-Charlemagne & Haut-Brion, Fi, Quad II.
Loudspeakers: Audio Note AN-E/SPe HE, Quad ESL.
Cables: Interconnect: Audio Note AN-vx, Shindo Silver. Speaker: Auditorium 23, Naim NACA-…
Sidebar 3: Measurements
I primarily used Stereophile's loaner sample of the top-of-the-line Audio Precision SYS2722 system (see the January 2008 "As We See It" and www.ap.com) to examine the measured behavior of the Sugden A21ai Series 2; for some tests, I also used my vintage Audio Precision System One Dual Domain.
My first test of an amplifier is to run it for 60 minutes at one-third its specified power into 8 ohms, which is thermally the worst case for an amplifier with a class-B or -AB output stage. But a class-A amplifier is at its most efficient when delivering maximum…
It was love at first sight when I saw a Jamo Reference R 909 loudspeaker in sparkling red lacquer on the floor of the 2007 Consumer Electronics Show. It made no sound, but it was beautiful, and I wanted it. It summoned up all my latent predilections for snazzy colors, striking shapes, and dipole speakers. But, as with many passing encounters in life, nothing came of it.
At the 2008 CES, another Jamo, the more modest Studio S 606, caught my eye, and I contacted Jamo USA. While I had Klipsch's then PR contact, Keith Claytor, on the line, I recalled the R 909 and thought, Hey, why…
3) The effects of a dipole's rear radiation on the speaker's frequency response and the size of its soundstage are at the mercy of room dimensions, room surface treatments, and speaker positions. This is the responsibility of the user, and accounts for the poor showing of the R 907s in that Manhattan hotel room. Normal listening rooms such as mine will be much more hospitable. It should be noted, though, that the R 907's tweeter has a sophisticated rear enclosure; only the woofer and midrange function as dipole drive-units.
Now that I've got the two of you alone . . .
The Reference…
Sidebar 1: Specifications
Description: Three-way, floorstanding dipole loudspeaker. Drive-units: 1" (25mm) fabric-dome tweeter, 5.5" (140mm) midrange unit, two 12" (305mm) woofers. Crossover frequencies: 250Hz, 2.5kHz. Frequency range: 35Hz–30kHz. Low-frequency extension: –6dB at 29Hz. Impedance: 4 ohms. Sensitivity: 89dB/2.83V/m.
Dimensions: 46.8" (1189mm) H by 17.3" (440mm) W by 19.2" (487mm) D, including base. Weight: 115.5 lbs (52.4kg) each, including base.
Finish: Piano black, high-gloss red.
Serial Numbers Of Units Reviewed: 0007, 0016.
Price: $10,000/pair. Approximate…
Sidebar 2: Associated Equipment
Digital Sources: Sony SCD-XA9000ES, APL-modified Philips SACD1000 SACD/CD players; modified Oppo DV-980H universal player.
Preamplifiers: Parasound Halo P7, Meridian Reference 861.
Power Amplifiers: Bel Canto REF1000 monoblocks, Classé CA-3200.
Subwoofer: JL Audio Fathom f113.
Cables: Interconnect: Crystal Cable Cinemax multichannel, AudioQuest Cheetah balanced. Speaker: AudioQuest Mont Blanc biwire. AC: JPS Aluminata.
Accessories: APC S-15, Environmental Potentials EP-2450 power conditioners; Echo Buster room treatments.—Kalman Rubinson
Sidebar 3: Measurements
The Jamo Reference R 907's voltage sensitivity is specified as 89dB/2.83V/m. My B-weighted estimate on the speaker's tweeter axis, with the grille removed, came in close to this, at 88dB(B)/2.83V/m. The speaker's impedance magnitude and electrical phase are shown in fig.1. Other than a dip to 3 ohms in the midbass, with a rather severe capacitive phase angle just below that region, the speaker is an easy load for the partnering amplifier to drive, with an impedance that remains greater than 7 ohms above 200Hz. (The shape of this trace will give a somewhat tilted-…