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As I wrote in our first video report from the 2018 CES, held January 9-12 in Las Vegas, NV, for our video coverage we purchased Sennheiser's "Ambeo" binaural system, which mounts microphones on the outer surfaces of a pair of earbuds. In this report, John Atkinson listens to some of his recordings in the DeVore Fidelity and dCS/D'Agostino rooms and offers his thoughts on what he had just heard. He also talks to exhibitors about their thoughts on the show and offers some final comments before heading to a bar for a well-earned beer. But first, John Quick of dCS and Rob Darling of Roon Labs…
Although PS Audio's Stellar M700 monoblock power amplifier ($2998/pair) is a brand-new design from a team led by engineer Darren Myers, it draws on the company's extensive experience with class-D amplification. Sam Tellig and Kalman Rubinson reviewed PSA's HCA-2 power amp in, respectively, the October and December 2002 issues, and I reviewed their GCC-100 integrated amp in January 2006. The Stellar M700's input stage is the latest version of PS Audio's Gain Cell, which they describe as a "proprietary, fully differential, zero feedback, discrete, class-A MOSFET circuit.
In the Stellar M700…
The Stellar M700 had very little sound of its own, and nothing that I could describe as a distinct class-D character. It just sounded like, well, a really good amplifier: clean, transparent, detailed, and, within the constraints of the rest of the system and the recording itself, providing faithful reproductions of the recordings.
The word that occurred to me when I first heard the M700 was smooth—an easy-on-the-ears quality that encouraged extended listening sessions. The sound of tube amplifiers is often described as smooth, and tubelike wouldn't be entirely inappropriate as a…
Sidebar 1: Specifications
Description: Solid-state, class-D, monoblock power amplifier. Inputs: 1 pair balanced (XLR), 1 pair single-ended (RCA), DC trigger. Outputs: 2 pairs five-way binding posts. Output power (120VAC mains, 1kHz, 1% THD): 350W minimum into 8 ohms (25.4dBW), 700W minimum into 4 ohms (25.4dBW), stable for musical transients into 2 ohms. Frequency response (2V RMS into 4 ohms): 10Hz–20kHz, ±0.5dB; 10Hz–50kHz, ±3.0dB. Voltage gain: 30.5dB, ±0.5dB. Sensitivity: 1.6V. Input impedance: single-ended, 50k ohms; balanced, 100k ohms. Output impedance: <0.007 ohm, 50Hz, 2.8V…
For all its faults—complex grammar, inconsistent rules of pronunciation, burdensomely endless vocabulary—English has proven itself a commendably plastic language. This is good for audio enthusiasts, in the US and elsewhere, whose choices in playback gear continue to evolve not only in substance and function but in name: Unlike many of the people who speak it, English can keep pace with the changes.
Consider: Less than three years ago, when I began working full-time as one of Stereophile's editors, product descriptions were still simple things, even in the world of digital audio. Seldom…
Sidebar 2: Associated Equipment
Digital Source: PS Audio DirectStream Memory Player & DirectStream DAC.
Analog Source: Acoustic Signature WOW XXL turntable & TA-2000 tonearm, Soundsmith Zephyr MIMC cartridge.
Preamplifier: Convergent Audio Technology SL-1 Renaissance Black Path Edition.
Power Amplifiers: McIntosh Laboratory MC275LE, Theta Digital Prometheus monoblocks.
Loudspeakers: Monitor Audio Platinum PL300 II.
Cables: Interconnect, speaker, AC: Nordost Valhalla 2.
Accessories: PS Audio PerfectWave Power Plant 5 power conditioner, Nordost QB8 AC power…
Streaming music from Tidal—or Qobuz, or Internet Radio, or suchlike—required me to use the RC S app, which was reasonably clear and straightforward if graphically unsophisticated: All I had to do was select, from the bottom of the RC S screen, the Sources icon, then select Tidal—and off I went. My only frustration—and, again, I'm new to this, so perhaps the wrinkle I'm about to describe is common to all such things—was that, every time I recalled my phone from sleep mode, I had to wait several seconds while the app reloaded. Several seconds: who has that kind of time?
How good was Tidal…
Sidebar 3: Measurements
I measured the PS Audio Stellar M700 with my Audio Precision SYS2722 system (see the January 2008 "As We See It"). Before performing any tests of an amplifier, I usually precondition it by running it at one-third the clipping power into 8 ohms for an hour. As the Stellar M700 has a class-D output stage, this was not necessary. But I did take the temperature of its case: the top panel was slightly warm, at 80°F (30°C). The voltage gain into 8 ohms was 30.5dB for both the balanced and unbalanced inputs, and the M700 preserved absolute polarity (ie, was non-inverting…
Sidebar 1: Specifications
Description: "Red Book" CD player with DAC and network streamer/file player. Tube complement: one AVM803. Formats supported: AAC, AIFF, ALAC, CD, CD-R, CD-RW, FLAC, MP3, OGG Vorbis, WAV, WMA. Digital inputs: 1 Ethernet, 1 USB Type B, 2 USB Type A (1 for music files, 1 for firmware updates), 4 S/PDIF (2 RCA, 2 TosLink), 1 AES/EBU (XLR). Digital outputs: 2 S/PDIF (1 RCA, 1 TosLink). Analog outputs: 1 balanced (XLR), 1 single-ended (RCA). Frequency response (CD): 20Hz–20kHz. Output voltage: 2.5V. Signal/noise: >110dB. Crosstalk attenuation: >120dB. THD: <0…
Sidebar 2: Associated Equipment
Analog Sources: Garrard 301, Thorens TD 124 turntables; Audio-Creative GrooveMaster II, EMT 997, Swissonor TA10 tonearms; EMT TSD 15, Ortofon SPU #1S pickup heads; Denon DL-103 cartridge, with/without MusiKraft body.
Digital Sources: AudioQuest DragonFly, Halide Design DAC HD USB DACs; Apple iMac computer (late 2015) running OS 10.12.1 & Roon v.1.3, build 269; Sony SCD-777 SACD/CD player.
Preamplification: Auditorium 23 Hommage T1 & T2 step-up transformers; EMIA Phono transformer (copper); Shindo Laboratory Monbrison (2017) preamplifier.…