November 2008

Denon Professional DN-C640 Network CD Player
Has some limitations, yet deserves serious consideration.
Review By Clarke Robinson
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  As much as we all hoped (or feared) that the compact disc would be replaced by one of the new high-resolution formats, but it looks as if America 's music consumers have spoken, and they are choosing digital downloads in ever-increasing numbers. The CD may be on its way out, but it is still the most popular medium for music distribution for the time being (almost 6x that of digital download sales in 2007), so you're still going to need one for the foreseeable future. However, a new question is emerging among audiophiles faced with growing collections of music files on their hard drives: how do I play all that stuff on my "real" audio system?

In this month's chapter of my informal series, "The Last CD Player You Will Ever Buy", I take a look at the DN-C640 Network CD Player from Denon Professional, a player sturdy enough to last a lifetime, but is "future proofed" (if there is such a thing) by its ability to be connected to a computer network. Sound interesting? I thought so, and Denon Professional's PR agents were nice enough to respond to my request for a review sample.

Fit/Finish
Being a pro unit, the DN-C640 is designed to handle a good deal more abuse than it would ever experience in an audiophile system. The slot-loading player has no flimsy plastic CD drawer, the front panel appears to be cut from a 5/16-inch slab of aluminum, and the buttons and knobs have a solidity to them that appears would last millions of cycles. The DN-C640 was intended for use in radio stations, dance clubs, shopping malls playing background music, etc... situations where the unit would be played 24/7 for months at a time.

The transport (which seems to be an off-the-shelf Tohei unit) is designed for high-reliability... all its parts that I could see after popping the top were metal, and the unit as a whole includes a two year warranty. I couldn't think of a way to effectively test the unit's longevity other than playing it on "repeat" for a few weeks straight, which it did without breaking a sweat.

Features
The DN-C640 has many features that seldom (if ever) appear on consumer-level CD players. These range from the amusing (fade in/fade out, adjustable in half-second increments up to 10 seconds in length) to the irrelevant (pitch shift, which speeds up or slows down the playback, thus adjusting the pitch in half-step increments). Still, none of these detract from the usability of the player except to add a few buttons to the front fascia and the remote. The cue feature (common to pro players, unheard of in consumer units), on the other hand, is mildly annoying until you modify its behavior in the player's preferences.

Network Able
There are other, cheaper options on the market if all you want is a rock-solid disc spinner (Denon's own DN-C615 and DN-C635 among them). The real reason to consider the DN-C640 is its network abilities, which I am geeky enough to be thoroughly excited by. 

Running an Ethernet cable from the port on the rear of the DN-C640 to a network router automatically assigns a dynamic IP address to the player. Cool network feature #1: typing that IP address into any web browser on your network brings up the players own web-based interface, which can be used to control every aspect of the player: from major functions like play, stop and pause to obscure preferences like fade in/out duration and what the cue button does.

Cool network feature #2: once you have the player up in browser, you can assign any shared directory on your network to the DN-C640. It didn't work if the remote directory was on a computer connected wirelessly to the network, but worked flawlessly with those connected by Ethernet cable. All of the supported audio files (mp3, wav, & wma) in that directory can be played via the front panel display or the web-based interface. The manual doesn't go out of its way to make this task easy for the networking newbie, but if you know enough to set up a home router, you can probably pull it off without too much trouble.

I ran the web-based interface off a laptop connected wirelessly to my network (I suppose you could do the same from a PDA or iPhone). While the on-screen display is far more usable than the front panel of any CD player I know of, it is quite primitive compared to most any PC-based music application you may be familiar with, like iTunes or Winamp. The main control screen only shows 20 tracks at a time, with only "next" and "previous" buttons for navigation. If you have 800 files in your shared directory, you'll have to click "next" 20 times before you see any tracks that start with the letter "M". Playlists can be created and saved locally, but the unit lacks any kind of searching, shuffle play, or sorting (by artist, genre, etc.). Potentially even more crippling, the player cannot "see" more than 999 files in a directory. While that is certainly more than you're likely to listen to in any one session (or any one week) it is a limitation for those looking to use the DN-C640 as the main interface between their computer and audio system.

Sound
The DN-C640 boasts one set of balanced outputs and two sets of unbalanced (one with fixed output, the other variable by the unit's front panel jog wheel). I only tried the fixed outputs, but found their sound remarkably good: clean & airy, with excellent detail retrieval and accurate tonality. Compared to the best digital player I had on hand, my aging (but highly regarded in it's day) Perpetual Technologies P-3A, the Denon boasted a top-end that was smoother and more extended, with more lifelike instrument timbres in the midrange, and bass that was slightly better defined and punchier. Differences were subtle, to be sure (as they are between any two digital source components) but still...very impressive performance for a unit packed with this much functionality.

There are two digital outputs: one coaxial and one XLR. When I first tried them, they were so noisy as to be unusable. After pointing this out to my contacts at Denon, I was informed that a firmware update had been released that cures the problem. Normally these are shipped out for free on CD-ROM, but I was in a hurry to make my deadline so I downloaded the files and burned my own CD. With the CD in hand, updating the firmware couldn't be easier: just insert the disc into the player, the screen reads "FW Update", click "enter", and you're done in a minute or two. It did indeed fix the problem, although I occasionally heard the same noise when the player was stopped, music was perfectly clean with every DAC I tried.

The headphone output, equipped with its own volume pot, is excellent. Typical of a pro unit, it seems optimized for higher-impedance headphones (like my 300 ohm Sennheiser HD-580s) but still performed well with my 32 ohm, current-hungry Grado SR-225s. In each case, performance of the on-board headphone amp was clean, accurate, and punchy…making for listening that was both engaging and useful as a sonic reference.

Conclusions
The DN-C640 is easy to recommend based on its sound quality alone, however there are numerous units around its $900 retail price that are similarly excellent. It is the unit's network connectivity options that make it unique. While these are not features that are required by the vast majority of the music-loving populace, this player can fill a badly needed niche for those who want to spin discs and occasionally play digital files directly off their hard drive with a single unit. 

The DN-C640's few caveats will be more serious to some than to others. Not much can be done about the unit's cosmetics, but if a noisy digital out can be fixed with a firmware update, I assume the clunkier aspects of the unit's UI can as well. That said, if you can live with the unit's looks and don't need it to access a huge library of music files on your computer, the Denon deserves your serious consideration. I know of no other player that does everything the DN-C640 does at all, let alone well, so it can be placed with confidence at the top of a very short audition list.

Associated Equipment
Ascend Sierra-1 stand-mounted loudspeakers
Hawthorne Audio Sterling Duets
Sony SCD-CE595 SACD Player
Perpetual Technologies P-3A DAC
Parasound Model 2100 Preamplifier
Parasound Model 2125 Amplifier
Listening room is approximately 13 feet wide and 25 feet long. Acoustic treatments include wall-wall carpet, curtains, and a large overstuffed sofa.

Specifications
Type: Networked CD Player
Frequency Response: 10Hz to 20kHz (+1dB)
Dynamic Range: 98dB
Signal-to-noise Ratio: 104dB (1kHz, 0dB playback, A filter)
Channel Separation: 96dB (1kHz, 0dB playback, A filter)
Total Harmonic Distortion: 0.004% (1kHz, 0dB playback, A filter)

Analog Output
Unbalanced Output (RCA): 2.0 Vrms at 0dB disc, 10 kohms
Variable Range: 4.0 Vrms at 0dB disc, volume max.
Balanced Output (XLR): +18dBu at 0dB disc, 600 ohms
Variable Range: +24dBu to +0 dBu at 0dB disc

Digital Output
Unbalanced Output (RCA): 0.5 Vp-p, 75 ohms
Balanced Output (XLR): 3.5 Vp-p, 110 ohms
Signal Format (Selectable): SPDIF (IEC958 type II) - Consumer, AES/EBU (IEC958 type I) - Professional

Other Specification
Headphone Output (1/4"): 20mW, 33 ohms
Variable Pitch Control: +12% maximum
Frame Search Accuracy: 1/75 second (CD-DA or WAV)

Signal System
Sampling Frequency: 44.1kHz at Normal Pitch
Sample Rate Converter Settings: Auto, 32kHz, 44.1kHz, 48kHz
Quantization: 16-bit Linear

Audio Outputs
2 Analog Unbalanced Outputs: RCA L/R Fixed Level, RCA L/R Variable Level
1 Analog Balanced Output: XLR L/R Output with Trim Control
2 Digital Outputs: RCA S/PDIF Format, XLR AES/EBU Format
1 Headphone Output: 1/4" Headphone Output (front panel mounted, w/ level control)

Control
Ethernet (LAN): RJ-45, 10BASE-T/100BASE-TX
Serial Remote: RS232C, D-Sub 9-pin
Parallel Remote: D-Sub 25-pin
IR Control Input: IR Sensor

Power Supply, USA and Canada models: 120V AC +10%, 60Hz
Power Consumption: 25W (USA and Canada Models)

Installation
19-inch, 1U rack space
Maximum Dimensions: 19" (W) x 1.7" (H) x 12.8" (D)
Weight: 4.3 kg, 9.5 lbs.
Accessory: IR Remote Included

Environmental Conditions
Operating Temperature: +5°C to +35°C
Operating Humidity: 25% to 85%, non-condensing

Media Specifications
Compatible Disc Type: Standard Compact Discs (12 cm), CD-DA, CD-R/RW, DVD-R/RW, DVD+R/RW
Compatible Audio Formats: CD-DA (.cda), WAVE (.wav), MPEG-1/2 Layer III (.mp3), MPEG-1 Layer II (.mpg), Windows Media Audio (.wma)
Max. Files (LAN or Disc): 999
Max. Directories (LAN or Disc): 254
Compatible Text: CD-Text, ID3 v1/v2

Price: $699 (street)

Company Information
D&M Professional
A Division of Marantz America, Inc.
1100 Maplewood Drive
Itasca, IL 60143

Voice: (630) 741-0330
Fax: (630) 741-0652
E-mail: marketing@d-mpro.com
Website: www.d-mpro.com