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Less activity is occurring in state-of-the-art audio converters because the market is much smaller for these. Analog Devices and Philips are sitting things out, while Burr-Brown appears to be concentrating on lower-cost chips for use in CD-R, MiniDisc, and A/V receivers. Most companies are busy working on converters for DSL rather than audio. DSL has some very tough requirements, and many of these are multibit delta-sigma structures. We will not reference these here.

I. Fujimori, et al, "A 5V Single-Chip Delta-Sigma Audio A/D Converter…

Finally, two papers I refer to directly in the text:

S. Norsworthy, D. Rich, "Idle-Channel Tones and Dithering in Delta-Sigma Modulators," presented at the 95th Convention of the Audio Engineering Society, Preprint 3711.

S. Norsworthy, "Effective Dithering of Sigma-Delta Modulators," ISCAS '92, IEEE Proceedings, Vol.3, May 1997, pp.1304-1307.—David Rich

I am a pianist, inventor, successful businessman, and a longtime subscriber to Stereophile, The Abso!ute Sound, Stereo Review, and Audio magazines. I have been an avid audio enthusiast for 55 years and have never been satisfied. I have, in fact, been very critical of the sound reproduced by CDs. Recently, however, I purchased a Sony SCD-777ES SACD player at a generous discount from Anthony, at The Good Guys in Canoga Park, California.

Mortgage your home, send your wife and children out to work, do what ever you have to do—the sound we have been…

Editor: It has recently come to our attention that some questions have been raised about the viability of the Direct Stream Digital (DSD) encoding process, particularly in comparison with multi-bit PCM.

This subject was covered in a November 2000 Stereophile article by David Rich, as well as in a paper presented by Stanley Lipshitz and John Vanderkooy at the 109th AES Convention in Los Angeles. Both Sony and Philips will also present some papers on this subject at the spring 2001 AES Convention in Amsterdam. In addition, James Angus, formerly of…

In the November Stereophile, David Rich raised some technical questions concerning the DSD encoding used in Sony's and Philips' Super Audio CD medium. Again, I had been puzzled. Basically, given its 1-bit format, the seventh-order noise-shaping employed, and the 64Fs (2.8224MHz) sampling rate, DSD should not be capable, in my opinion, of producing the increase in dynamic range and high-frequency extension claimed—nor, as Mr. Rich pointed out, should it be stable enough to do so without introducing spurious tones. Like Meridian's Bob Stuart in this…

Description: Two-way, reflex-loaded, stand-mounted, magnetically shielded loudspeaker. Drive-units: 1" silk-dome tweeter, 6.5" paper-cone woofer. Frequency range: 55Hz-20kHz. Impedance: 8 ohms nominal, 6 ohms minimum. Sensitivity: 88dB/W/m.
Dimensions: 15.5" H by 8.25" W by 11.75" D. Weight: 14 lbs each.
Finishes: Black; other finishes on request.
Serial numbers of units reviewed: 0757, 0760.
Price: $595/pair. Approximate number of dealers: 50.
Manufacturer: Acarian Systems, Ltd., Hunters Run, Suite 104, 181 Smithtown Blvd., Nesconset, NY 11767.…

Analog sources: VPI TNT IV turntable, Immedia RPM tonearm, Koetsu Urushi cartridge; Rega Planar 3 turntable, Syrinx PU-3 tonearm, Clearaudio Virtuoso Wood & Aurum Beta S cartridges.
Digital sources: California Audio Labs Icon Mk.II Power Boss, Creek CD53 Mk.II CD players; Pioneer DV-333 DVD-Video player.
Preamplification: Vendetta Research SCP-2D phono stage, Audio Valve Eklipse line stage.
Power amplifier: Audio Research VT100 Mk.II.
Integrated amplifier: Creek 5350SE.
Cables: Interconnect: MIT MI-350 CVTwin Terminator, MI-330SG,…

The Alón L'il Rascal Mk.II's voltage sensitivity was very slightly higher than specified, at 89dB(B)/2.83V/m, which is also 2dB above the average I found in my 1999 articles on speaker measurements. Its plot of impedance magnitude and phase (fig.1) revealed it to be an easy load for the partnering amplifier to drive, its impedance dropping below 8 ohms only in the lower midrange. Both sensitivity and impedance values indicate that the Rascal would be a good match for the inexpensive amplifiers with which it is likely to be used.

Fig.1 Alón Li'l…