Classe CP-800

 Classe CP-800D/A PREAMPLIFIER I was setting up for some musical demonstrations I was to present for a Music Matters evening at the ListenUp! store in Boulder, Colorado, in May 2011. For these events, an audio store invites manufacturers (and the occasional journalist) to demonstrate to local audiophiles the musical benefits of high-end audio playback. In Boulder, I was to share the storebig listening room with Dave Nau-ber, president of Classe Audio, who had set up a system with B&W Diamond 802 speakers, a Classe stereo amplifier, and a preproduction sample of Classenew CP-800 preamplifier ($5000), all hooked up with AudioQuest cable. I unpacked my MacBook, with which I was going to play the high-res-olution master files of some of my Stereophile recordings, and looked around for a DAC. There wasnone. I hadnrealized that the CP-800 is an example of a new breed of audio component: Not only is it a two-channel line preamplifier, it offers a complete set of digital inputs, including USB and an iPod connector. It can serve as a systemone-box heart, replacing the D/A processor and the cables connecting it to a conventional preamp. It even has a headphone output and a complete set of equalization features.
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Plugging my laptop USB output into the CP-800rear-panel USB port, I was good to go chcz ListenUp! I also vowed that the CP-800 would spend some quality time chcz Atkinson. What it does The CP-800 shares the curved aluminum front panel Classe has used for its Dclta-scrics products since the beginning ot the century. Tliis starts life as a flat extrusion with raised edges, and is gently bent into a U to form the front and side panels. Dominating the front panel is a large color LCD touchscreen that, in combination with the chunky metal remote, gives the user access to all functions via the usual hierarchical menu tree. Flanking the touchscreen, within its bezel, are the Menu (left) and Mute (right) buttons, these duplicated on the remote. A black horizontal styling strip conceals: the Standby On/Off button to the left of the screen and, to the right, die infrared remote receiver window; a USB Host connector for an iPod (Apple portable devices only; the CP-800remote can control the iPodtransport functions); and a V" headphone jack. The large black knob for the shaft encoder that controls volume is at the right end of the black strip. On the bottom of the rear panel are, from left to right: tliree pairs of unbalanced analog inputs on RCA jacks; two pairs of balanced analog inputs on XLR jacks; and two pairs of balanced outputs on XLRs, along with a single XLR output labeled Sub —all with their unbalanced counterparts on adjacent RCAs. The second pair of outputs can be assigned to double the main output pair, to permit biamping; alternatively, they can be used to provide stereo subwoofer outputs. The Sub output passes a mono low-frequency signal when enabled, but when the CP-800 is set up via the menu to manage bass, there is full control of crossover frequency and high-pass filter slope. From left to right along the top of the rear panel are: the On/Off switch, and the AC input on an IEC jack; a USB port for connecting to a computer for audio streaming; a single AES/EBU digital input; three electrical S/PDIF digital inputs on RCAs (all digital inputs arc galvanically isolated); four optical S/PDIF inputs on TosLinks; and various trigger and comms ports, including RS-232 and Ethernet. (On the review sample, the latter had still to be implemented.) Classe CP-800 Inside the CP-800, in front of the rear panel, a large, six-layer printed-circuit board runs the full width of the chassis. This carries the analog circuitry and the A/D, D/A, and DSP sections. Above this board and connected to it with two ribbon cables, a smaller, full-width, six-layer board carries the digital input circuitry. A small board behind the touchscreen, again connected to the main board with two ribbon cables, as well as to the screen with another ribbon, carries the CP-800microcontroller. Next to the controller board is the power supply. Tliis is a switching type, but unlike conventional switch-mode power supplies, which have a bad rap in high-end audio circles for their propensity to introduce noise and enharmonic spuriae, the CP-800supply uses Zero Volt Switching (ZVS), in which the primary switch operates when the incoming DC voltage is at a minimum, thus allowing the supply to have a low-noise RF footprint. In addition, the CP-800supply is fully power-factor corrected, meaning that the incoming AC voltage and current are sinusoidal and in phase. (A white paper on this and the other technologies featured in the CP-800 can be downloaded at http ://tinyurl.com/7mvqz3i.) The CP-800rear-panel USB port operates in asynchronous mode, in which the flow of data is controlled by the DAC clock, not the computer. But the CP-800operating mode, which Classe calls Optimal Asynchronous with Single Clock Substrate, differs from topologies used in competing products. Usually, the microcontroller in the asynchronous USB receiver cliip controls the master clock. In the CP-800, a high-precision clock signal is buffered by a high-speed Field-Programmable Gate Array (FPGA) cliip placed next to the DACs and mastcr-clock oscillators. This is said to result in increased clock purity and more accurate D/A conversion. Additionally, when the CP-800 is processing data encoded at 44.1kHz and its multiples, the 48kHz master clock is turned off, and vice versa, to avoid cross contamination. In Analog Bypass mode, analog signals are fed straight to the volume control and output circuits and the digital clocks are turned off. (The volume control is implemented with two two-channel Burr-Brown PGA2310 programmablc-gain chips, one per channel used as a differential volume control.) However, the tone or equalization controls are implemented using two Analog Devices DSP chips. So if the user wants to use these controls, the analog input signals are converted to 24-bit digital data with a Cirrus Logic 5381 A/D cliip. Digital data are turned back to analog using two Wolfson WM8741 DAC chips, each of these a high-performance, multi-bit, sigma-dclta, two-charmcl type capable of operating with 32-bit data. Each DAC chip operates in differential mode, one per channel, and runs at a constant rate of 176.4 or 192kHz. The voltage-output DACs arc followed by a fourth-order reconstruction filter with a 100kHz passband. Operation Wliile the CP-800 offers myriad customizing options via its touchscreen menu, the default settings out of the box proved to be all that I needed. Pressing any part of the touchscreenHome screen or the Source Select button on the remote allows you to choose a digital or analog input. The chosen source is then displayed on the bottom left of the Home screen. If digital, the Home screen displays the currcnt sample rate in small print at the bottom. Large numerals in the top half of the screen indicate the current volume setting. Pressing Menu allows you to adjust balance, switch to dual-mono, and activate the tone controls. Pressing Menu, then System Set-Up brings up a screen where you can program the parametric equalization, tone control, input-volume offset and maximum, bass management, and DC trigger and display options. You can also define up to six custom configurations that can be recalled at the touch of a button, as well as program the eight function keys on the remote. If you enable EQ or the tone controls, the words ,”,”or ”appear at the bottom right of the Home screen. The menu offers more options and functions than can be described in a review; everything is fully described in the excellent manual, wliich can be downloaded from http:// tinyurl.com/7rg72w3.1 commend Classe for including, as well as conventional tone controls, a Tilt control that allows the entire response be hinged up or down by up to 6dB at each end of the spectrum. Introduced at the end of the 1970s in analog guise, by Quad Electroacoustics in their Model 44 preamplifier, this kind ot control is the only one I have found useful for adjusting recorded balances to sound neutral. Made in China Back in 2005 I visited the Classe factory, in a Montreal suburb, and was impressed with what I saw. Here was a major high-end audio brand that still manufactured its products in North America. It was thus with some sadness that I learned last year that the CT-M600 and CA-M600 amplifiers, which I positively reviewed in March 2011, were among the last products Classe was to make in Canada. Like B&W, Classe is owned by the B&W Group, whose products, along with RotcPs, arc distributed in North America by the Canadian Equity International conglomerate. In fill 2011 the B&W Group moved Classeproduction to the facility it owns in China, which already was responsible for manufacturing Rotel gear as well as 600 and CM series B&W models. My review sample of the CP-800 is one of the first to come from the Chinese factory. In a frank discussion at the 2012 Consumer Electronics Show, Classed Dave Naubcr outlined for me the reasons for offshoring manufacturing. With many of the components used in Classe products already made in the Far East, it made sense to move actual manufacture there. Thereno real difference, Nauber said, between, say, installing a Chinese-made transformer in an amplifier in Montreal and in China. To guarantee quality, the important thing is that the Chinese facility be not an independent contractor, but vertically integrated with the ownerother brands. Most important, the creation of the intellectual property embodied in Classeproducts —the R&D and design —remain in Canada.1  Classe CP-800Sound Quality Tonally, as a line preamplifier in Analog Bypass mode, the CP-800 fell into the camp of the clean and clear rather than the mellow and euphonically colored. In that respect it was somewhat similar to the Parasound Halo JC 2 ($4000), which I reviewed in March 2008: A wealth of recorded detail was laid bare without being spotlit. In level-matched comparisons with the Ayrc Acoustics K-5xcMP ($3500; I reviewed it in June 2011), the Ayrc sounded slightly veiled, though there was a robustness to its soundstaging that resulted in more fully flcshcd-out images within that soundstage. Using as a source my newly repaired Mark Levinson No.30.6 D/A processor, I selected the CP-800EQ section but set it to do nothing. This way, ana_log signals were digitized, then converted back to analog. Though the extra processing added a very slight hardness to the sound in absolute terms, this will be offset by the tonal changes that are then possible. For most of my auditioning of the CP-800 I fed it digital data, cither via USB from my 2.7GHz i7 Mac mini, or via AES/EBU from my Ayre C-5xeMP disc player. There was a delightful delicacy to the sound, without any significant difference audible between the USB and AES/EBU modes. Leonard Cohenhusky baritone in his reading of Joni MitchellJungle Line,”from Herbie HancockRiver: The Joni Letters (Apple Lossless 24/96, Verve/HDtracks), sounded as natural as I can recall, without any emphasis of sibilancc. The drum opening of ,”from Lyle LovettLive in Texas (Apple Lossless file ripped from CD, Curb MCAD-11964), effectively lit up the surrounding ambience, while the horn interjections punched holes in the appropriate places in space. With the levels matched using the CP-800Input Off_set Level control to within 0.1 dB, the kick drum on this album didnhave as much LF authority as the No.30.6analog output. The older mcgabuck processor, however, couldnquite match the Classedelicacy in the treble. The complex mix of Afterlife,”from Paul Simon So Beautiful or So What? (24/96 Apple Lossless file, Hear Music/HDtracks, transcoded to USB to AES/EBU using Empirical Audio Off-Ramp4), sounded muddier with the Levinson, even though the bass guitar had cleaner leading edges to its tone. Against the Debussy A more relevant comparison for the CP-800performance as a D/A processor was with the dCS Debussy ($10,999, re_viewed in January 2011), again with levels at 1kHz matched to within 0.1 dB. (Comparisons were rendered easier by the fact that the transport controls on the CP-800remote functioned with iTunes on the Mac mini.) The Debussy was used with its apodizing filter selected, which is how I feel it performs at its best. While there was no real difference in the processors’tre_ble characters, with the Debussy I got a better sense of the surrounding space of Chad KassemBlue Heaven Studios in Mooche,”from the Jerome Harris Quintet (Editor s Choice, CD/Apple Lossless file, Stcrcophilc STPH016-2). The Classe, however, offered slightly more lower-midrange energy in the sound of JeromeTaylor acoustic bass guitar. Lossless file, Verve Forecast B0011631-02), the dCS gave his frantic strumming a little more propulsive drive, wliile the Classe was slightly better at bringing out the jangly quality of his open-strung acoustic guitar. With the solo cello at the songbeginning, it was a wash. Only with 192kHz-sampled tracks, such as from the Ray Brown TrioSoular Energy (24/192 Apple Lossless file ripped from DVD-Audio, HiRez Music HRM2011), did the dCS pull ahead, presumably because the USB data were being downsampled by Pure Music to 96kHz to feed the CP-800. Summing Up Classe AudioCP-800 is that rare component: a multi_function device that, despite its versatility and extensive use of new technologies, doesnappear to compromise the quality of the sound. Yes, its D/A section is surpassed in both measured and audible performance by expensive state-of-the-art processors such as the dCS Debussy, wliich also has a 192kHz-capable USB input. However, it must be remem_bered that the dCS costs more than twice as much, and while its volume control is truly transparent, it lacks both analog inputs and the CP-800extensive DSP functions. Six months after starting this review, I am well aware that the CP-800 offers more functions than I have come to grips with. Performance as a headphone amplifier? As an iPod dock? Providing bass management for a sub/ satellite system? Sorry. While I can confirm that those functions do work, I have not yet formed opinions of how well. But even without my testing those functions, I highly recommend the CP-800 as a straight, future-proof, two-channel D/A preamplifier. It offers more than its purchaser expects, at a price lower than any would expect to pay.

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