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Audio Note CD-4.1x CD player Measurements

Sidebar 3: Measurements

I used Stereophile's loan sample of the top-of-the-line Audio Precision SYS2722 system to measure the Audio Note CD-4.1x (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.

The Audio Note player's error correction was excellent, there being no audible glitches in its output with the Pierre Verany test CD until the gaps in the data spiral reached 2mm in length. The player muted its output when the gap reached 2.4mm. The CD-4.1x's maximum output level at 1kHz was 2.45V, an…

The Entry Level #19

It was unusually warm for early spring, without a cloud in the big, blue sky to tame the sun's dazzling light—far too beautiful a day to be indoors, but Uncle Omar and I had already planned a little listening session, and I was determined to show him that high-end cables would make a difference in his system. I wasn't necessarily feeling bullish about the task, though. It had taken me a couple of years to convince Omar that he should replace his old boom-box speakers with something better, and it was only dumb luck that finally made it happen: I was with him when he found a gently used pair…

The Entry Level #19 Page 2

As Omar sat in the sweet spot, I quickly swapped the RadioShack zip cords for Kimber 4PRs, made sure the pluses and minuses were properly matched, took my seat, and started "One Armed Scissor" from the beginning. Again, I wondered: What if we don't hear an improvement? I shouldn't have worried. The 4PR's sound quality was just as immediately obvious as its build quality. Five seconds into the song, Omar and I turned to one another. I smiled and nodded. Omar looked pale. He blinked. He frowned. He said, "Wow."

Most apparent to Omar was an increase in overall clarity and low-level detail…

The Entry Level #19 Sidebar Contacts

Sidebar Contacts

Kimber Kable, 2752 South 1900 West, Ogden, UT 84401. Tel: (801) 621-5530. Fax: (801) 627-6980. Web: www.kimber.com/

Polk Audio, 5601 Metro Drive, Baltimore, MD 21215. Tel: (800) 377-7665, (410) 358-3600. Fax: (410) 764-5470. Web: www.polkaudio.com

Timbre Sound, LLC, dba Thinksound, 350 Route 108, Suite 204, Somersworth, NH 03878. Web: www.thinksound.com

Meridian Digital Media System, July 2012

Jon Iverson wrote about the MDMS in July 2012 (Vol.35 No.7):

It's been more than five years since the original Sooloos Music Server hit the market, and four since I reviewed it, in the September 2008 issue. The system became a favorite of mine, and was named Stereophile's Product of the Year for 2008. A lot has changed since then: the hardware, the software, the price, the company's ownership—even the product's name. One question remains: Is it still the best overall music server on the market?

What's in a name? After only a few years in business, New York–based Sooloos was…

NAD M51 Direct Digital D/A converter

Who wants only a digital-to-analog converter when you can have a DAC with benefits? How about if those benefits also come with some high-resolution attitude?

That's what I pondered while setting up the NAD M51 ($2000). Sure, it's a basic DAC, but it also has extras—like HDMI inputs, remote-controlled volume, a polarity switch, and one of my favorite features on any DAC: a display that tells you which sampling rate the thing is locked to.

The honey badger of DACs?
Then there's that attitude: The NAD resamples everything you throw in its direction and converts it to a pulse-…

NAD M51 Direct Digital D/A converter Page 2

What was weird was that, while setting levels, as I switched back and forth between DACs with the pink noise running, there was a slight difference in the character of the sound. After I'd adjusted the NAD's volume trim, the SPL meter read "0dB" for each DAC, but something subtler was going on—the tonal quality of the pink noise shifted just a little in the room. Later, I figured out what this meant musically.

All My Lovely Goners, the latest release from Winterpills, is a great Americana record (CD, Signature Sounds SIG 2044): folky, rocky pop that strikes me as the kind of album I…

NAD M51 Direct Digital D/A converter Specifications

Sidebar 1: Specifications

Description: Remote-controlled digital-to-analog converter. Digital inputs: AES/EBU (XLR), S/PDIF coaxial & optical, 2 HDMI (stereo only), USB 2.0; all support up to 24-bit/192kHz. Digital output: HDMI. Analog outputs: left & right RCA (unbalanced), left & right XLR (balanced). Output impedance: 47 ohms (unbalanced), 110 ohms (balanced). Output level: 2V RMS. Frequency response: ±0.5dB (ref. 20Hz–96kHz at 192kHz sample rate. Signal/noise: >125dB (ref. 0dBFS 2V out). Channel separation: >115dB (ref. 0dBFS volume –1dB). AC supply: 100–240V, 50–…

NAD M51 Direct Digital D/A converter Associated Equipment

Sidebar 2: Associated Equipment

Digital Sources: Apple MacBook Pro computer (2.66GHz Intel Core 2 Duo, 4GB RAM, 320GB HDD) running OS 10.6.7, iTunes 10.6, Sonic Studio Amarra 2.3, Songbird 1.9.3, XLD; Western Digital NAS Device (2TB); Oppo BDP-83 universal Blu-ray player; Meridian Digital Media System (Sooloos Control 15 & TwinStore x3); Apple iPad 2 and 3, Apple iPod Touch 1G; Benchmark DAC1 USB, Ayre Acoustics QB-9, T+A Music Player D/A converters.
Preamplifier: Marantz AV7005 (Pure Direct Mode).
Power Amplifier: Classé CAM 350 monoblocks (2).
Loudspeakers: MartinLogan…

NAD M51 Direct Digital D/A converter Measurements

Sidebar 3: Measurements

I used Stereophile's loan sample of the top-of-the-line Audio Precision SYS2722 system to measure the NAD M51 (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.

Both the M51's S/PDIF and USB inputs successfully locked to data with sample rates of up to 192kHz, including 88.2 and 176.4kHz. Although the TosLink format is specified to work only up to 96kHz, the M51's TosLink input did lock to 192kHz data. The Mac's USB Prober utility revealed the M51's product ID to be "NAD USB…