Digital Sources: Apple MacBook Pro computer (2.66GHz Intel Core 2 Duo, 4GB RAM, 320GB HDD) running OS 10.6.7, iTunes 11.1.3, Sonic Studios Amarra 2.5, Songbird 1.9.3, or XLD; Western Digital NAS Device (2TB); Oppo BDP-103 universal Blu-ray player; Meridian Digital Media System (formerly Sooloos) (one Control 15, three TwinStores); Apple iPad Air, Mini; Apple iPod Touch 1G; Apple iPhone 4S; Benchmark DAC2 HGC, AudioQuest DragonFly 1.2 USB DACs.
Preamplifier: Marantz AV7005 in Pure Direct Mode.
Power Amplifier: Classé CAM 350 monoblocks (2).
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Sidebar 2: Associated Equipment
Sidebar 3: Measurements
I used Stereophile's loan sample of the top-of-the-line Audio Precision SYS2722 system (see www.ap.com and the January 2008 "As We See It") to examine the Channel Islands Audio Transient Mk.II's measured behavior. I used my 2012 Apple MacBook Pro running on battery power to examine the processor's performance via its USB port. For all tests, the Transient was powered from its VDC5 Mk.II supply.
Apple's USB prober utility identified the Transient as the "CIAudio USB Audio 2.0" and confirmed that it operated in the optimal isochronous asynchronous mode with…
Manufacturer's Comment
Editor: First, I'd like to thank the gang at Stereophile for reviewing our unique product.
As mentioned in Jon Iverson's review, we wanted this product to be completely portable, and to provide the industry-standard 2V analog output while running from USB power. There are only a small number of DAC integrated circuits with this capability that have the digital filtering and output stage built in. Being that there isn't much surrounding circuitry to work our "magic," we chose the IC that we felt offered the best musicality (not specs). In the end, I feel we…
Back in the summer of 2009, USB-connected D/A processors that could operate at sample rates greater than 48kHz were rare. Ayre Acoustics had just released its groundbreaking QB-9, one of the first DACs to use Gordon Rankin's Streamlength code for Texas Instruments' TAS1020 USB 1.1 receiver chip. Streamlength allowed the chip to operate in the sonically beneficial asynchronous mode, where the PC sourcing the audio data is slaved to the DAC. But high-performance, USB-connected DACs like the Ayre were also relatively expensive back then, so in the January 2010 issue of Stereophile I reviewed a…
The midrange receded slightly with upsampling engaged, as Michael Lavorgna described in his review. The voices in the Bachian arrangement of Noël Coward's "I'll See You Again," from The King's Singers Sing Flanders & Swann and Noël Coward (24/192 ALAC file from 1977 LP, EMI EMC 3196), acquired a touch more palpability. However, the recording lost a little bit of "air" around the singers' images, and the inevitable ticks in this needle drop sounded slightly softer. Augustin Dumay's performance of Beethoven's Violin Sonata 3 in E-flat, from his complete set of the sonatas accompanied by…
Sidebar 1: Specifications
Description: Upsampling, stereo D/A processor/headphone amplifier with independent volume controls for line-level and headphone outputs. Digital inputs: 1 S/PDIF (coax), 1 S/PDIF (TosLink), 1 USB 2.0 (type B). Analog outputs: 1 pair balanced (XLR), 1 pair unbalanced (RCA), 1 headphone output on ¼" (6.3mm) stereo phono jack. Compatible sample rates: 44.1–192kHz, all inputs. Frequency response: 10Hz–48kHz, –3dB, with 192kHz data. Channel separation: not specified. Signal/noise: 120dB ref. 0dBFS, A-weighted. THD+noise: >0.000316% (–110dB) at 0dBFS. Maximum…
Sidebar 2: Associated Equipment
Analog Source: Linn Sondek LP12 turntable with Lingo power supply, Linn Ekos tonearm, Linn Arkiv B phono cartridge.
Digital Sources: Marantz Reference NA-11S1 media player; Ayre Acoustics C-5xeMP universal player; Apple 2.7GHz i7 Mac mini laptop running OS10.7, iTunes 10, Pure Music 1.89, Audirvana Plus 1.5.10, JRiver Media Center 19 for Mac; NAD M51, Channel Islands Transient Mk.II, Auralic Vega D/A converters; Ayre Acoustics QA-9 USB A/D converter.
Preamplification: Channel D Seta L phono preamplifier, Pass Labs XP-30 line preamplifier.
Power…
Sidebar 3: Measurements
I used Stereophile's loan sample of the top-of-the-line Audio Precision SYS2722 system (see www.ap.com and the January 2008 "As We See It") to examine the ASUS Xonar Essence One Muses Edition's measured behavior. I used my 2012-vintage Apple MacBook Pro running on battery power to examine the processor's performance via its USB port. Apple's USB Prober utility confirmed that the USB port operated in isochronous asynchronous mode and reported the processor's product string as "ASUS Xonar Essence One\000" from "ASUSTek Computer Inc." Peculiarly, the Mac's AudioMIDI…
Responses to the 1985 "Carver Challenge" (from February 1986, Vol.9 No.1):
Publisher's note: We anticipated a far stronger response to Bob Carver's duplication of the sound of our chosen reference amplifier (Vol.8 No.6), but the two comments below were the only official replies we received. On the other hand, many people in the industry spoke to us off the record, some in admiration, some in envy, some with a kind of disgust. I'm sure other amplifiers will come along that seem to defy duplication; perhaps Bob will be up to another challenge in a year or so.—Larry Archibald
From…
AudioQuest DragonFly v1.2, from March 2014 (Vol.37 No.3):
I did all of the headphone comparisons in the March 2014 issue of Stereophile sitting at my desk, staring at my laptop, and using the latest version of AudioQuest's popular DragonFly USB DAC–headphone amplifier. Aside from some small, tidy certification markings on its backside, the DragonFly v1.2 is identical in size, shape, and functionality to the original model—and, at $149, costs $100 less. Like the original, the v1.2 handles file resolutions up to 24-bit/96kHz, making the device virtually plug-and-play for both PC and Mac…