Classé CA-200 stereo power amplifier
Classé Audio, based in Québec, currently offers a sizeable amplifier range, with the output powers more closely spaced than is usual. Krell, for example, offers units that tend to increment the maximum power, hence maximum loudness, in 3dB steps, the idea being that 3dB is the smallest sensible step in volume-related power capacity. By contrast, Classé offers the CA-100, -150, -200, -300, and -400 In addition, each can be used a monoblock, providing a second tier at 200W, 325W, 500W, 900W, and 1300W, all into a nominal 8 ohm load. To add to the choices, there are also two six-channel power-amp chassis, offering 6x75W and 6x150W. [TJN reviewed the CAV-150 in the Winter 1996 and Spring 1997 issues of Stereophile Guide to Home Theater.—Ed.]
If Classé achieves relatively consistent sound quality over this range, it does mean that you can precisely pick your price option with stereo high-current capability, or higher-power monoblock options. The CA-200, for example, rated at 200W into 8 ohms, will operate down to 2 ohms at a maximum rated power of 500Wpc (short term). The smaller CA-100, employed as a monoblock pair, also offers a rated 200W into 8 ohms, but with a limit of 350Wpc into 4 ohms. The installed cost for these two possibilities is quite similar; it's your choice.
The subject of this review, the $2995 CA-200 is neatly presented with an option of a soft silver aluminum faceplate or the usual satin black; its deeply finned heatsinks are placed tidily on the rear panel, leaving a clean exterior outline. The penalty is a rather cramped lineup for the bare-metal binding posts offered for speaker cable connection. These use large nuts and washers; some very large spade lugs, such as on the older van den Hul Revelation series, may give trouble due to the limited space. Classé incorporates good overload protection systems in the CA-200; if connections do go wrong, there should be no long-term problems.
Balanced and normal operation can be selected at the flick of a switch. Line input is via gold-plated phono sockets and Neutrik XLRs, mains power input via a 13A IEC-style detachable cord, with an adjacent AC power fuse for ultimate protection. The strongly made chassis stands on rubber cone feet.
A high input impedance of 75k ohms is quoted, an easy load with a rated sensitivity of 1.3V. Idle power is 200W; the CA-200 will draw over 1000W in full song. It's claimed to double its rated power into 4 ohms, while the bridge rating indicates that 700Wpc in stereo mode will be possible on short-term program into 2 ohms. This, and the very low 0.017 ohm quoted output impedance, suggest good load-driving ability. The generous-sized, well-shielded power-supply toroidal transformer accounts for a large part of the CA-200's 60-lb weight.
Classé embraces a design philosophy that doesn't take sides on device technology or implementation. Technology decisions are made strictly on an engineering basis, on their appropriateness for a given task.
At the input, good linearity, high input impedance, and low noise are pluses, and J-FETS are a logical choice for the differential balanced input section. Intermediate circuitry, including the voltage amplifier, uses low-saturation, high-current, bipolar transistors, while the circuit mix is enlivened by the use of MOSFETs for the output stage pre-drivers, their high gate-input impedance reducing the nonlinear loading of the output stage on the critical voltage amplifier.
At this price level and power, a pure class-A output stage is out of the question; the CA-200 runs fairly cool in class-A/B, enjoying an economical level of idle power. FET-based output stages are questionable in this size due to stability considerations and the need for extra-large heatsinking, so the CA-200 uses stable, efficient bipolar transistors. Four paralleled complementary pairs of high-current, plastic-encapsulated output transistors are used per channel; these are worked a little harder than the larger multiple average seen in the bigger Krell or Levinson designs.
In the main, the circuitry is contained on one double-sided printed circuit board; disassembly for service is relatively easy. The transformer has double secondary windings feeding separate rectifier and reservoir pairs per channel. Older Classé amplifiers used selected quality, single-unit power-reservoir capacitors. In the CA-200, a distributed power reservoir design replaces each capacitor unit with six smaller 4700µF devices connected in parallel. This technique is claimed to deliver a lower ESR (electrical series resistance) over a wider frequency range, particularly at high frequencies. The CA-200 contains a total of 24 such capacitors.
Overall, build quality is fine, with good engineering and safety practice evident.
My review sample was a well-burned-in demonstrator and required little warmup. When it was used regularly, stable sound was obtained after 15 to 20 minutes.
Some solid-state power amplifiers give an impression of neutrality (for solid-state, that is), but are found wanting when compared with other amplifiers, including tube models. Though I didn't find the CA-200 to be highly neutral, I hasten to add that it was sufficiently neutral to not upset the tonal balance of any good system.
Interestingly, it seemed to straddle the region between tube and solid-state. There was a softer, richer quality over the broad midrange that spoke of vacuum devices, this quality associated with a certain sweet "sparkle" in the treble, again tubelike. Yet in the bass there were the kind of control and power—and the load-drive ability to go with it—associated with good solid-state.
Time and again I was struck by the CA-200's relaxed, laid-back character—a sound that built effortlessly to big climaxes, achieved with beautiful power and no sense of strain or aggression. Here the Classé closely approached the big Jeff Rowland Design Group models.
Soundstages were nicely focused, with good breadth, and were imbued with a fine spread of low-level detail and related recorded ambience. Perspectives were well-proportioned, evenly layered, with good image depth. Transparency was very good, if not up to the almost crystal-clear standard of the new Krell FPB-300 or the Conrad-Johnson Premier Eleven A.
There was a creamy tonality through the midrange, with no perceptible hardness or thinning of timbre at all. Such approval was, however, countered by the view that the balance might be a little too laid-back. (Lest you feel that a "pure" tonality automatically leads to the impression of weaker dynamics, just try the Conrad-Johnson Premier Eight A!)
The bass was a strong point—lusty and well-defined, the CA-200 taking good control of the speaker load. The bass was well-extended, with clean playing of tunes and a powerful sustain where required—for example, on cathedral organ material.
The treble also had a tubelike quality; that is, some sheen or emphasis was audible, though not necessarily with attendant distortion such as roughness or grain. Interestingly, this aspect of the treble, heard as almost a touch of extra breathiness on vocals, was essentially below the identifiable threshold when driven via the balanced inputs. Further checks indicated that with unbalanced signal sources, the treble quality was somewhat dependent on the source; in a particularly well-matched system, this factor may have a significant influence on the overall sound quality.
As well as the improvement in treble with balanced input drive, there was an increase in midrange clarity and bass definition. Interestingly, at the same time the pace and rhythm seemed to be slightly reduced. This is unfortunate; despite the generally small difference between normal and balanced drive, this amplifier belongs to the group in which smoothness and a relaxed approach override considerations of rhythm, dynamics, and listener involvement.
Such subjective aspects vary greatly between systems and individual listener perceptions. In absolute terms, the CA-200 was unexceptional as far as listener involvement was concerned; it sounded dynamically "quiet" when compared with a Premier Eleven A, for example, and even more so than a good single-ended tube amplifier. "Bland" is perhaps too pejorative a word in this context, although it's hard to find a better term. However, this amplifier sounded more powerful than its rating suggested. It was hard to reach clipping; when I did, the CA-200's recovery from gross overload was graceful, fast, and clean.
The CA-200 favored the Spendor and Quad speakers and, not surprisingly, the Classé DAC 1 (though I was less keen on the Classé transport). Apogees, Magneplanars, and Thiels come to mind as alternative speakers that might suit this amplifier well.
The CA-200 failed to fully convey the speed, dynamics, and rhythm of the Krell KPS-20i/l CD player, nor did it bring out these qualities in the equally agile Wilson WITT speakers. Conversely, it did compare well with many established mainline power amplifiers from such major brands as Mark Levinson, Jeff Rowland, PS Audio, Audio Research (excepting the VT150SE), and the Conrad-Johnson solid-state designs.
Hand on heart, I have to say that I was not totally knocked out by the Classé CA-200. Still, I judged it to be a very worthy performer. In the CA-200's favor is its ability to do almost everything pretty well: drive capability, healthy maximum power, a smooth and sweetly balanced neutrality, fine stereo, strong bass, and an airy, sparkling treble. Clarity and transparency are also high on the list, together with those spacious, well-dimensioned stereo images. It will acquit itself well on quieter, more restrained systems; on my Krell/Naim/Wilson/Linn system it sounded a little too restrained to get top billing. These days, the best power amplifiers are very good indeed; competition is tough.
The CA-200 is a well-built, well-engineered, load-tolerant amplifier with a nice sound; it offers generally good sonic as well as engineering value. At its realistic price, all of this certainly qualifies it for a Class B ranking in Stereophile's "Recommended Components"—in context, a good result for price and specification.