John Atkinson

John Atkinson  |  Apr 25, 2011  |  0 comments
A computer is not optimized for the uninterrupted streaming of audio data. It has rapidly become established wisdom, therefore, that the optimal means of extracting audio data from a computer's USB port is to operate that port in what is called "asynchronous isochronous" mode. This lets the receiving device, such as a digital-to-analog converter (DAC), control the flow of data from the PC. In theory, asynchronous USB operation (not to be confused with the asynchronous sample-rate conversion used in some DACs) reduces jitter to unmeasurable levels, depending on the accuracy of the receiver's fixed-frequency oscillator, which is used to clock the data to the DAC. By contrast, in the alternative and almost ubiquitous USB operating mode, called "adaptive isochronous," while the sample rate of the output data, averaged over a longish period, will indeed be the specified 44.1 or 48kHz, there will be short-term fluctuations, or jitter, due to the oscillator having to change its frequency every millisecond to match the uncertain rate of data flow from the PC.
John Atkinson  |  Dec 23, 2010  |  0 comments
The weekly Vote! Page is one of the most popular features of the Stereophile website, and the August 22 question, "Should Stereophile review more or fewer computer-audio products?", generated a record number of responses. No less than 88% of those responding asked for more coverage of products that allow a computer to be a legitimate source of music in a high-end context. Just 7% of readers wanted less coverage.
John Atkinson  |  Jun 14, 2010  |  0 comments
I have built up a large collection of CDs since the medium's launch more than a quarter century ago, along with a modest number of SACDs and a small number of DVD-As. But I find these days that, unless I'm getting down to some serious listening and can give the music my uninterrupted attention, I use iTunes to feed computer files to my high-end rig (footnote 1). I've mostly been using the superb-sounding combination of dCS Puccini U-Clock and Puccini player/DAC that I reviewed last December to take a USB feed from a Mac mini, but I've also been using the Bel Canto USB Link 24/96 and Stello U2 USB-S/PDIF converters, particularly for headphone listening, when I use one of those two format converters with a Benchmark DAC1 D/A headphone amplifier.
John Atkinson  |  May 24, 2010  |  0 comments
As someone who wrestled endlessly with the nine-pin serial ports and the RS-232 protocol with which early PCs came fitted (footnote 1), I welcomed the Universal Serial Bus (USB) interface when I first encountered it a decade ago, on the original Apple iMac. Plug it in. Don't worry. Be happy. The computer peripherals work as they should, which was often not the case with RS-232. It was a given, therefore, that the then-new USB port would be seen as a natural means of exporting audio data from a PC (footnote 2), but the first generation of USB-connected audio devices offered disappointing performance.
John Atkinson  |  Jan 24, 2010  |  0 comments
With all the current fuss about getting audio data from a computer to a standalone D/A processor via S/PDIF, USB, FireWire, WiFi, or Ethernet (footnote 1), it has been overlooked that the oldest way to get audio from a PC is to use a high-performance soundcard plugged into the host machine's motherboard. I remember how excited I was when I installed a Sound Blaster Pro 16 board in the 486-based Dell running Windows 3.1 that I was using in the early Clinton era, plugged its analog output into my high-end rig, and played back 16-bit/44.1kHz files.
John Atkinson  |  May 15, 2009  |  0 comments
The speed with which audiophiles have adopted a computer of some sort as their primary source of recorded music might be thought breathtaking. But with the ubiquitous Apple iPod painlessly persuading people to get used to the idea of storing their music libraries on computer hard drives, the next logical step was to access those libraries in listening rooms as well as on the move. A few months back, I wrote a basic guide to the various strategies for getting the best sound from a computer: "Music Served: Extracting Music from your PC." Since then, Minnesota manufacturer Bel Canto Design has released a product that aims to simplify matters even further.
John Atkinson  |  May 08, 2005  |  1 comments
Usually, a Stereophile "Follow-Up" follows up (duh!) a full review of the component in question. This review, however, is intended to flesh out a cryptic comment made by Wes Phillips in April's "As We See It": "When Apple introduced its AirPort Express wireless multimedia link," Wes wrote, "it even included a digital port so that an audiophile—such as Stereophile's editor—could network his system, using the AE to feed his Mark Levinson No.30.6 outboard D/A converter. 'Sounds okay,' deadpans JA."
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