Mat Weisfeld and Harry Weisfeld of VPI…
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Friday May 20, from 2-10pm, Hi-Fi Sales (1732 Route 70 East, Cherry Hill, NJ 08003) is hosting an event in which audiophiles can get their first look at VPI's brand new ADS (Analog Drive System) speed controller (projected price: $800-$1000), the first product of the company's newly forged partnership with electronics designer Mike Bettinger. Attendees will also have a chance to compare VPI's magnetic-drive and direct-drive turntable technologies, in the form of two otherwise-identical VPI Avenger turntables—a first for their direct-drive system.
May 21, 2–6pm, Bill McKiegan, President of Sales at Dan D'Agostino Master Audio Systems, will be presenting a day of listening at Audio Concepts (11661 Preston Rd #280, Dallas, TX 75230) in Dallas, Texas. The featured system will include the new Momentum M400 mono amplifiers, Momentum Preamplifier, and Momentum Phonostage (above), driving Wilson Alexx loudspeaker and using the AMG Viella 12 turntable.
Also on display will be the Momentum MLife integrated amplifier, which has been recently upgraded to include Tidal streaming.
I was lying on a mattress on the floor of an empty apartment on Manhattan's Upper West Side. Not as grim as it sounds—it's a nice apartment, and the mattress was new, and had just been delivered—but it was hot (no air-conditioning), and my family and my furniture were still in my condo up in Maine, and I was lonely. I needed some cheering up. Which is how I rationalized the decision to buy an Explorer2, Meridian Audio's tiny, inexpensive ($299) digital-to-analog converter.
Thanks to Amazon Prime, 24 hours later I was sitting on a newly delivered bar stool—still no other furniture—…
MQA also uses a clever approach to nondestructive compression (in interviews, Stuart has used the phrase analog-lossless) in which timing-relevant data from the higher sampling frequencies—including the range above the range of human hearing, where music still has energy—are folded back into the first 44,100 samples and reversibly buried below the noise floor. In this way, MQA claims to deliver music with studio-master quality in packages small enough to conveniently download and stream, and in a form its exponents say sounds better than a CD even if you don't have an MQA decoder.
If MQA…
Sidebar 1: Specifications
Description: Single-box, USB bus–powered, MQA-capable digital/analog converter and headphone amplifier. Input: mini USB-B. Output: line-level and headphone via separate 3.5mm minijacks. Maximum word length: 24 bits. Maximum sampling rate: 192kHz. Maximum line-level output voltage: 2V RMS. Headphone output impedance: 0.47 ohm.
Dimensions: 4" (102mm) L by 1.25" (32mm) W by 0.7" (18mm) D. Weight: 1.76oz (50gm).
Serial number of unit reviewed: E201EP.
Price: $299. Approximate number of dealers: 136. Warranty: 2 years parts & labor.
Manufacturer:…
Jim Austin briefly discusses MQA in his review of the Explorer2 in this issue, but a more complete description of MQA can be found in an article posted on Stereophile's website at the end of 2014.
MQA involves two fundamental concepts, discussed in a paper presented to the Audio Engineering Society in October 2014 (footnote 1), the first responsible for a potential improvement in sound quality, the second responsible for a large reduction in the bandwidth required for storage and streaming of high-resolution files:
MQA can compensate for the time-domain errors of both the…
Sidebar 2: Associated Equipment
Digital Sources: MacBook Pro computer (early 2015); Benchmark DAC 1, PS Audio DirectStream DACs; Apogee Groove, Meridian Explorer USB DACs; Ayre Acoustics CX-7eMP CD player.
Analog Sources: Thorens TD 124 turntable reconditioned by Schopper AG; Oswalds Mill Audio slate plinth; Ortofon RMG-212 tonearm (rebuilt); Schick 12" tonearm; Ortofon 90th Anniversary SPU cartridge; Sony XDR-F1HD AM/FM/HD tuner.
Preamplification: Auditorium 23 standard step-up transformer; PS Audio NuWave Phono Converter phono stage/analog-to-digital converter, EAR phono stage.…
Manufacturer's Comment
Editor: Thank you for the chance to respond.
In fig.3, the green/gray curves show the observed spectrum with no decoder. The noted small rise of noise in the treble is in fact a manifestation of the (noise-shaped) MQA signaling, rather than buried higher-frequency information. This signaling is at this level for wide compatibility and is completely removed by the decoder; the buried information from the higher octave is at a lower level.
The level at which MQA buries information from higher octaves is not predetermined; it's responsive to the…
Sidebar 3: Measurements
I measured the Meridian Explorer2 with my Audio Precision SYS2722 system (see the January 2008 "As We See It"). Source materials were WAV and AIFF test-tone files, played with Pure Music 3.0 on my MacBook Pro running on battery power. As with the original Explorer, I performed a complete set of measurements from both the line-level and headphone outputs, but most of what I describe here is the Explorer's performance from its line output; I comment on the headphone output only when it differed. I also comment on the Explorer2's measurements only when they differ…
The inaugural Canlanta is being held this Saturday, May 21, 10am–6pm, in Atlanta, Georgia at the Marriott Century City. Twenty vendors will have the latest in latest in DACs, amplifiers, and headphones on display. Exhibitors will include Noble, Questyle, Oppo, Sennheiser, Kimber Kable, Empire Ears, Violectric, Meze, and Cavalli. National retailers include HeadphoneAudiophile and Sight+Sound Gallery.
Tyll Hertsens, editor-in-chief of Stereophile's sister site InnerFidelity.com, will deliver the keynote speech and hold two "table sessions" in which he'll talk with show attendees. Oppo,…