Description: Solid-state monoblock power amplifier. Inputs: 1 single-ended (RCA), 1 balanced (XLR). Outputs: 2 pairs Furutech Torque Guard binding posts. Power output: 300W into 8 ohms (24.8dBW), 600W into 4 ohms (24.8dBW), 1kW into 2 ohms (24.0dBW), with AC line held constant. Class-A output power: 35W (15.44dBW). Maximum output voltage: 113V p–p, 40V RMS, into 8 ohms. Frequency response: 1Hz–650kHz, –3dB. Voltage gain: 29dB at 1kHz, balanced and single-ended. Input impedance: 82k ohms, single-ended and balanced. Input sensitivity (for nominal output): 1.74V.…
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Sidebar 3: Associated Equipment
Analog source: Linn Sondek LP12 turntable with Lingo power supply, Linn Ekos tonearm, Linn Arkiv B cartridge, Channel D Seta L phono preamplifier.
Digital sources: Roon Nucleus+ music server; Ayre Acoustics C-5xeMP universal player; PS Audio PerfectWave DirectStream and Weiss DAC502 D/A processors, Ayre Acoustics QA-9 A/D converter.
Power amplifiers: Parasound Halo JC 1+ and Lamm Industries M1.2 Reference (both monoblocks).
Loudspeakers: Vimberg Mino.
Cables: Digital: AudioQuest Vodka (Ethernet), AudioQuest Coffee (USB), DH Labs (1m, AES/…
Sidebar 4: Measurements
I tested the Classé Delta Mono with my Audio Precision SYS2722 system (see the January 2008 "As We See It"). I preconditioned the amplifier by operating it at one-third the specified power into 8 ohms for an hour. At the end of that time, the chassis was cool, at 76.9°F (24.9°C), though the grille over the rear-mounted fan vent was warmer, at 105.0°F (40.6°C).
The Classé's voltage gain into 8 ohms measured 28.7dB from both the balanced and unbalanced inputs and the amplifier preserved absolute polarity (ie, was noninverting) with both input signals. At 86k…
I've been wrestling with my elders about new ways to measure loudspeakers, lobbying for methods that might correlate more directly with a listener's experience. And wouldn't you know? Right in the middle of this Socratic dialogue, I put the fresh-from-UPS, $1000/pair, Tannoy Revolution XT 6s into my reference system, plunking them down on my 24" Sound Anchor Reference stands in the same spot my Harbeth P3ESRs had been sitting. And I freaked! I was using the Rogue RP-7 preamp and the Rogue Stereo 100 (100Wpc) amplifier, and I could never adequately describe how bad the shiny white Tannoys…
During my second cup of coffee, while listening to Ito Ema play Bach's Goldberg Variations (CD, MA recordings MO24A), I heard a dip around 120Hz and some boosted energy just above the 1.8kHz crossover point. The 120Hz dip made the left side of Ito's piano seem less corporeal than I prefer. The 2kHz boost made the upper registers sound lively and direct.
With both the Rogue Stereo 100 and now the Schiit Aegir, I would have to describe the Revolution XT 6's sound as pure and focused but slightly soft. Orchestral soundstages were accurately mapped. There were multitudes of fine detail, but…
Sidebar 1: Specifications
Description: Bottom-ported, reflex-loaded, standmount loudspeaker. Drive-units: One 6" dual-concentric multifiber-cone woofer with coaxially mounted, waveguide-loaded 1" PEI dome tweeter. Crossover frequency: 1.8kHz. Crossover type: 2nd order low pass, 1st order high pass. Nominal impedance: 8 ohms. Sensitivity: 89dB/2.83V/m. Recommended amplifier power: 25–120Wpc. Peak power handling: 240W.
Dimensions: 15.8" (400mm) H × 8.7" (221mm) W × 11.9" (302mm) D. Weight: 16.4lb (7.5kg). Cabinet volume: 0.38 cu. ft. (10.8 liters).
Finish: Piano white, piano black…
Sidebar 2: Associated Equipment
Analog sources: Dr. Feickert Analogue Blackbird turntable with Jelco TK-850L tonearm and Koetsu Rosewood Signature Platinum and My Sonic Lab Ultra Eminent Ex moving-coil cartridges; J.Sikora Initial turntable with TK-750M arm and Grado Labs Aeon3 moving-iron cartridge.
Digital sources: MacBook Air laptop, Mac mini running Audirvana Plus;
Mytek HiFi Brooklyn+, Chord Qutest D/A processors; Integra DPS-7.2 (used as CD transport).
Preamplification: Musical Surroundings Phonomena II+ and Parasound Halo JC 3+ phono preamplifiers; Rogue RP-7 line…
Sidebar 3: Measurements
I measured the Tannoy Revolution XT 6's farfield behavior with DRA Labs' MLSSA system and a calibrated DPA 4006 microphone. I used an Earthworks QTC-40 mike for the speaker's nearfield responses. Tannoy specifies the Revolution XT 6's sensitivity as "89dB," which I assume is for 1W at 1m. My estimate was 88.8dB(B)/2.83V/m, which is both within the margin of error and a little higher than average. Props to Tannoy for an honest sensitivity specification.
Although the Revolution XT 6's nominal impedance is specified as 8 ohms, the magnitude (fig.1, solid…
During the four years that I've reviewed for Stereophile, I've had the privilege of evaluating products from some of the world's best-known audiophile companies: Audio Research, Bel Canto, CH Precision, dCS, D'Agostino, Dynaudio, EMM Labs, Jadis, Krell, Nordost, and Wilson, among others. But one long-standing manufacturer whose exhibits at audio shows invariably inspire ecstatic reports, Germany's MBL, has remained outside my purview.
It thus came as a delightful surprise when MBL North America's Jeremy Bryan informed Jim Austin and me that the MBL N11 solid-state line preamplifier ($14,…
Because my two reference DACs, dCS's Rossini DAC/Clock combo and EMM Labs' DV2 integrated DAC, have very different sonic presentations that evoke different emotional responses, I used both in this review. For the Rossini, I chose Map 1, 2V output, and the recommended filters for each resolution; for the DV2, output was set to high. Both DACs' volume controls were turned all the way up to get them out of the way. A Nordost Valhalla 2 USB cable carried signal from the Roon Nucleus+ to the DACs; from there, I went balanced Odin 2 to the N11, then balanced out to my D'Agostino Progression…