I had the Mark Levinson No.30 and the No.30.5 at the same time, so I was able to make direct comparisons, and also to listen to each one at length. Both processors were driven by the Mark Levinson No.31 Reference CD Transport via an AES/EBU link (AudioQuest's new Diamond x3 analog cable, which works very well as a digital cable). The processors fed a Sonic Frontiers SFL-2 line-stage preamp, which in turn drove a pair of Audio Research VT150 tubed monoblock power amplifiers. The loudspeakers were Genesis II.5s, with the Genesis servo amplifier powering the woofers…
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Sidebar 2: Specifications
Description: 24-bit digital/analog converter. Inputs: five AES/EBU on XLR connectors, two Toslink (EIAJ) optical inputs, one AT&T ST-type optical input. Digital outputs: two AES/EBU on XLR jack, one optical on Toslink jack. Analog outputs: one unbalanced stereo pair on RCA jacks, two balanced stereo pairs on XLR jacks. D/A conversion: two custom 20-bit DACs. Digital filter: 8x-oversampling. Analog filter: Bessel-tuned low-pass, linear phase to 40kHz. Frequency response: 10Hz–20kHz, +0dB, –0.2dB. THD: 0.003% at 1kHz, 0dB, A-weighted. Dynamic range: 98dB or…
Someone, I forget who it was, once wrote a perceptive essay on how in any field of human endeavor, apparent perfection is attained only when that field is in the process of being superseded. The Palace at Versailles was built when the power of the French monarchy was well into decline; Wagner's "music of the future" was in fact the end of a particular line of development; the nuvistor was developed almost simultaneously with the silicon transistor which would render tubes almost obsolete; and six years after the commercial introduction of Compact Disc, with record shops increasingly filling…
"The arm also had a sliding collar on the tube. This was not to adjust the tracking force, but to adjust the inertia of the system, the same as with these two lateral masses. Not only does everything have a center of gravity, it also has an ellipsoid of inertia."
I obviously looked puzzled.
"To determine the ellipsoid of inertia, you put an axis anywhere through the center of gravity of the system, and calculate the moment of inertia around this axis. You find the two points on your chosen axis, either side of the center of gravity, where the moments are equal. You then choose…
"In terms of mathematics, to have the center of gravity very near to the point of rotation gives you a lot of advantages. In one sentence, forces acting on the system are not applied through a couple, but only as pure forces. There are no distances involved. That is to say, the system is as simple as possible."
The Audiomeca J1 is one of the more elegant turntable designs I have seen, being constructed from a black methacrylic sheet. In common with the Oracle, it dispenses with the traditional box construction for the plinth.
"Most turntable bases are like the sounding box of a…
You'd probably be surprised to learn that headphones are the most common means for listening to music. No, I didn't get that from a book, but from personal observation. I'm referring here to personal portable stereo listening—the ubiquitous Jogman with which a whole generation has retreated into its own private world, isolated from traffic noise, muggers, and, at home, housemates or parents screaming "Turn it down!"
Audiophiles discovered the benefits of headphone listening years ago. I still remember my first set of Koss Stereophones—nirvana for a college student in a tiny, shared dorm…
The bass response of the Pro Classic (and of headphones in general) was restricted to that which was fed directly to the ears. This restricted the sensation of real weight that comes from feeling the bass as well as hearing it. The ear is notoriously insensitive to bass—with loudspeakers that have the appropriate extension, there's an important tactile contribution from the skin's reaction to powerful bass wavefronts reverberating through the listening space. Even with modest loudspeakers, there can be more to this than you might expect. This can be a mixed blessing: the listening room's…
Sidebar 1: A Caution
All of the headphones discussed here were comfortable to wear using eyeglasses—at least the eyeglasses I tried. But there are so many varieties of frames that I urge you to try before you buy with your glasses, if you plan to wear them with the headphones.
Similarly, all of these 'phones are of the open-back, circumaural variety: Circumaural means that they surround, rather than sit, on the external ear; open-back means that others sitting in the same general area as the headphone wearer will hear a rather scratchy, bassless rendition of whatever the listener…
Sidebar 2: System
Unless otherwise noted, the Stax headphones auditioned here were driven from the analog output of a Krell Reference 64 D/A processor. The transport was a Krell DT-10, connected to the processor by ST optical link with ST sync lock. The interconnects between the processor and headphone interface units were AudioQuest Lapis Hyperlitz, alternated with TARA Labs RSC where noted.
Comparison products included the Sennheiser Orpheus HE 90, the Koss ESP/950, and Sennheiser's own HD-580 driven by the HeadRoom Supreme dedicated headphone amplifier.—Thomas J. Norton
Sidebar 3: Specifications
Description: Electrostatic headphones with SRM-Xh direct-drive amplifier. Open-back design. Transducer principle: electrostatic, push-pull. Frequency response: 8Hz–35kHz (no tolerance specified). Sensitivity: 108dB/1mW input. THD: 0.001% at 95dB. Bias voltage: 580VDC. Inputs (SRM-Xh): 1 pair, analog.
Weight (headset): 15.1oz.
Serial number of sample tested: 33973.
Price :(SR-Lambda Pro Classic headset and SRM-Xh amplifier), $849.95; headset alone costs $474.95 (1994). Approximate number of dealers: 150.
Manufacturer: Stax, Japan. Web: www.stax.co…