Listening
I used the AK100 for six weeks of listening, mostly on the move but also for headphone…
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My Sennheiser HD650 'phones have a nominal impedance of 220 ohms, which might suggest that they would be a much better match for the AK100. However, the downside of this high load impedance is reduced sensitivity: the AK100 couldn't drive the Sennheisers to anything like a loud enough level. With an impedance that varies between 70 and 95 ohms, the closed-back Sony MDR-7506 should work well with the AK100. Certainly, the AK100 had no problem driving the MDR-7506s to high levels.
Sidebar 1: Specifications
Description: Battery-powered portable media player & D/A processor with 2.4" touchscreen (320x240 pixels), 32GB internal memory, and two Micro-SD card slots. Digital inputs: 1 S/PDIF TosLink on 3.5mm jack. Digital output: S/PDIF TosLink on 3.5mm jack. Analog output: 1 pair unbalanced on 3.5mm stereo jack. Resolutions and sample rates supported: 16-bit, 44.1, 48, 88.2, 96, 176.4, 192kHz (internal); 16/24-bit, 44.1, 48, 88.2, 96kHz (TosLink). File formats supported: WAV, FLAC, Ogg, APE, AAC, ALAC, AIFF, MP3. Frequency response: 20Hz–20kHz, ±0.02dB. Channel…
Sidebar 2: Associated Equipment
Digital Sources: Apple iPod Classic 160GB, Ayre Acoustics C-5xeMP universal player; Apple 2.7GHz i7 Mac mini running OS10.7, iTunes 10, Pure Music 1.86; Schiit Bifrost, Arcam FMJ D33 D/A converters.
Preamplification: Pass Labs XP-30 line preamplifier.
Headphone amplifier: Ray Samuels Audio Emmeline The Hornet.
Headphones: Sennheiser HD650, Sony MDR-7506, JH Labs JH16 Pro, Ultimate Ears 18 Pro.
Power Amplifiers: Classé CT-M600, Lamm M1.2 Reference, MBL 9007 (all monoblocks).
Loudspeakers: Vandersteen Treo, BBC LS3/5a, Boston Acoustics…
Sidebar 3: Measurements
I examined the Astell&Kern AK100's electrical performance with 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"); for some tests, I also used my vintage Audio Precision System One Dual Domain. I made sure the AK100's battery was fully charged before performing the tests. For source signals, I both used WAV files stored in the player's flash memory and fed it S/PDIF datastreams via its TosLink input. The TosLink input successfully locked to data with sample rates of 44.1, 48, 88.…
John Atkinson is a road warrior: When he attended the DC area’s Capital Audiofest in July of last year, he drove there in his vintage Mercedes-Benz coupe, all the way from his home in Brooklyn. He did the same in 2011, too.
Because I regard night driving with the same revulsion that Dothraki horsemen reserve for travel by sea, and because any round trip between upstate New York and our nation’s capital is bound to include at least some driving after dark, I took the train. It was easy and fun—and if your area is served by an Amtrak line that can get you to Washington DC’s Union Station,…
I can see already that this show has something in common with my favorite audio designers, audio dealers, audio writers, and audio enthusiasts: Capital Audiofest is an event with a distinct point of view. That this point of view mirrors my own enthusiasm for vintage gear in particular and relatively affordable, anti-(high-end) establishment gear in general, is icing on the cake.
That said, it turns out I began my first day at CAF with a somewhat conservative system: a pair of GT Audio Works GTA2 loudspeakers ($6495/pair, above) driven by a pair of very powerful Arion class-D monoblocks ($…
Among the people I telephoned during my first month on the job at The Absolute Sound—we're talking January of 1985—was Frank Van Alstine, the pioneering designer and builder of affordable-perfectionist electronics. Twenty-eight years and six months later I finally got to meet him—and I was happy to hear he has zero intention of retiring: good news, considering the altogether fine sound being made by the new Audio by Van Alstine Transcendence Nine vacuum tube preamp ($1395), used in concert with AVA's hybrid FET Valve 600R amplifier ($3499) and a pair of Philharmonic Audio's two-way…
It's my favorite part of every hi-fi show: the one big room, usually on one of the lower floors, where smaller companies exhibit such things as phono accessories, hi-fi furniture, publications, and, best of all, records. At Capital Audiofest, the Magnolia Ballroom on the Sheraton Hotel's fourth floor was home to all that, including a larger and altogether more impressive selection of used and collectable vinyl than I've seen at any other show in recent memory.
New LPs were available at the booth of specialty label Cuneiform Records, who announced the imminent release of a live recording…
There was this guy in the room shared by Joseph Audio, VAS, and VPI (above), and I guess he'd been there for a little while before I came in: big guy, sort of athletic-looking. Jeff Joseph had apparently just played one of his CDs for him, and the guy was stunned. You could tell he wasn't just being polite: "That was . . . really good!" Irrespective of the name over the door, I think we all live for moments like that.
I've admired for years the vintage-inspired designs of John Wolff and Classic Audio Loudspeakers; at Capital Audiofest, their lens-loaded Hartsfield loudspeaker,…
On Saturday evening, right after Capital Audiofest closed for the day, everyone seemed to converge upon the hotel bar at the same time: myself, Gary Gill (Capital Audiofest), Mat Weisfeld (VPI Industries), Clarence Wheat (Hifilogic), Dave Cope (Audio Note UK), Robin Wyatt (Robyatt Audio), Myles Astor (Positive Feedback Online), Brian Zolner (Bricasti Designs), Jonathan Horwich (International Phonographic), and numberless others. It was the first time since the Heathrow Airport show of 1996 that I'd witnessed such a convivial mob—competition be damned.
While I was speaking with Gary Gill,…