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Ayre Acoustics QB-9 USB DAC Getting Those Last Few Drops

Sidebar 3: Hitting It On The One: Getting Those Last Few Drops Out Of Digital Files

John Atkinson's "Music Served: Extracting Music from Your PC" is a must-read; start there. While you don't need the latest or most powerful computer to use as a server, you do, as JA observed, want a quiet one. My iBook did yeoman duty in this regard—from my listening position, I was never aware of its fan even turning on.

In future, however, I believe I'll take JA's suggestion to use a Mac mini; I discovered how much better my iBook sounds when I maxed out its RAM at 2GB. I can jam 6GB into the…

Ayre Acoustics QB-9 USB DAC Measurements

Sidebar 4: Measurements

I examined the measured behavior of the Ayre Acoustics QB-9 (footnote 1) using the Audio Precision SYS2722 system (see www.ap.com and "As We See It" in the January 2008 issue), as well as, for some tests, my Audio Precision System One Dual Domain. I drove the QB-9 with the USB 2.0 output of my Intel MacBook running OS10.4.11 for the testing, playing back WAV files using Bias Peak 6.2. Unlike iTunes, Peak interacts with the OSX CoreAudio engine to ensure that audio at the correct sample rate is sent out through the USB and FireWire ports; nevertheless, I double-…

Zu Essence loudspeaker

For 15 years, lovers of low-power amplifiers have clamored for more and better high-efficiency loudspeakers (footnote 1). For 15 years, their choices have remained limited to products with varying combinations of colored sound, poor spatial performance, basslessness, high cost, and cosmetics that range from the weak to the repulsive.

The genre has, so far, failed to attract the lions of the loudspeaker industry. Yes, the Klipsch and Tannoy lines still include some high-efficiency models—living fossils, mostly, from an era when all amps were low-power amps—and, among smaller…

Zu Essence loudspeaker Page 2

The latter is important in light of the high-frequency driver chosen for the Essence: a 2.5" aluminum-alloy ribbon manufactured by Tang Band of Taiwan. The TB tweeter has a powerful neodymium magnet—metal tools must be used with caution, if at all, in the vicinity of the Essence's baffle—and a matching transformer brings the ribbon's impedance in line with that of the 10.3" main driver. The tweeter is driven through a second-order high-pass filter, and is blended into the main driver's output beginning at about 10kHz; the output of the full-range driver, which is wired directly to the input…

Klipsch Palladium P-17B loudspeaker Associated Equipment

Sidebar 2: Associated Equipment

Digital Sources: Theta Digital Miles CD player (S/PDIF output); Benchmark DAC1 & DAC1 HDR D/A converters; Sony Vaio laptop running Sony Soundforge 9; M Audio Fast Track Ultra USB interface.
Power Amplifiers: Pass Labs Aleph 3 & XA 30.5, Rogue Audio M180.
Integrated Amplifiers: Simaudio Moon i3.3, Manley Labs Stingray iTube.
Loudspeakers: Revel Performa F30 & Ultima Gem, Totem Acoustic Forest.
Cables: Digital: Stereovox HDVX coaxial. Interconnect: Sain Line Systems Pure Balanced & Pure. Speaker: Kimber Kable BiFocal XL. AC: Sain…

Klipsch Palladium P-17B loudspeaker Measurements

Sidebar 3: Measurements

My estimate of the Palladium P-17B's voltage sensitivity was a little lower than the specified 94dB/2.83V/m, at 90.7dB(B). However, this is still significantly higher than average; the P-17B will work well with relatively low-powered amplifiers. Its impedance (fig.1) varies widely: averaging 14 ohms above 1kHz, it drops below 3 ohms between 128 and 265Hz, with a minimum value of 2.6 ohms at 170Hz. There is also an amplifier-frightening combination of 4.5 ohms and –50° electrical phase at 104Hz, a frequency where music has high energy levels. So while the Klipsch…

Recording of May 2010: <I>American VI: Ain't No Grave</I>

Johnny Cash: American VI: Ain't No Grave
Lost Highways/American Recordings B0013954-02 (CD). 2010. Rick Rubin, prod.; David Ferguson, eng.; Greg Fidelman, Jimmy Tittle, Paul Fig, Dan Leffler, asst. engs. AAD.? TT: 32:23
Performance ****½
Sonics ***½

A second career is a luxury that few artists ever consider, let alone attempt—yet that is essentially what Johnny Cash had via the six records he made at the end of his life with producer Rick Rubin.

Following at least one previous "final" volume, American VI: Ain't No Grave may truly be the last word to come from this…

The Holy Trinity

In an e-mail exchange with Stephen Mejias about why the mere mention of cassette decks on www.stereophile.com can so easily inflame our readers (and John Atkinson), I began to develop the idea that the brains of audiophiles and music lovers are governed by three complementary needs, or desires, that define who we are. I joked to SM that these desires, which apparently shift over time, constitute the Holy Trinity of Audiophiledom. They are, respectively, the love, desire, and need for:

1) Music
2) Quality audio reproduction
3) Ease of access to music

Well, SM took me…

Musical Fidelity AMS Primo line preamplifier

Musical Fidelity's Tri-Vista kWP, introduced in 2003, was an impressive, high-tech, "statement" audiophile preamplifier. Its outboard power supply weighed almost 56 lbs—more than most power amplifiers—and its hybrid circuitry included miniature military-grade vacuum tubes. As I said in my review of it in the January 2004 Stereophile, the kWP's chassis and innards were overbuilt, the measured performance impressive, and any sonic signature imposed on the signal was subtle and, essentially, inconsequential.

But while the kWP's fit and finish were jewel-like, its appearance was…

Musical Fidelity AMS Primo line preamplifier Page 2

The overall sound was harmonically rich without turning overripe. Attacks were surprisingly lightning-fast and ultraclean for an all-tube product. But sustain was where the magic lived: sounds just sailed generously on and on, their full harmonic envelope unfurled, slowly decaying into the sunset of background ambience before finally, cleanly disappearing altogether. Musical events effortlessly appeared, lingered, and dissolved, one after the other, meeting along the way no grain, glaze, or grit-induced resistance.

No syrup
I couldn't characterize the Primo's sound as "warm" or "…