Classé CAP-100 integrated amplifier
By Robert Harley   •   September, 1997 With the price of high-end audio increasingly reaching for the stratosphere, audiophiles appear to becoming much more value-conscious. This trend is reflected in the recent popularity of CD players over separate transports and processors, and particularly in the sudden resurgence in integrated amplifiers. An integrated amplifier makes a lot of sense: the buyer saves the cost of two chassis, two power cords, two owner's manuals, and an extra pair of interconnects. You also get a simpler system.

However, there have long been two problems with integrated amplifiers. First, serious designers have long focused their efforts on separates, not integrateds. The integrated amplifier has long been an afterthought of many manufacturers, introduced only to round out their lines with a budget product. Integrated amplifiers have traditionally been underpowered because they've been targeted at the entry-level market, not the serious audiophile. Second, integrated amplifiers have been regarded as a dead end on the upgrade path. Traditionally, if you wanted to improve your integrated-based system, you had to sell the thing and start over.

All that has changed with today's new breed of integrated amplifiers. High-end manufacturers are realizing the benefits of applying their full design skills to moderately priced, full-powered integrateds. In addition, today's integrated amplifiers often offer the flexibility of converting them into preamplifiers or power amplifiers when the user wants to upgrade. Without a doubt, the integrated amplifier has become a significant market category.

A good example of this trend is Classé Audio's new CAP-100 integrated amplifier. With 100Wpc, the CAP-100 provides enough power for most systems, yet retains a reasonable retail price. At $1995 retail (plus $200 for the optional phono board), the CAP-100 could be the basis of a solidly performing $6000 system.

Technology
The CAP-100 looks sleek, simple, and elegant. The amplifier's 3/8"-thick front panel is graced by three rounded machined knobs that control volume, balance, and input selection. This metalwork would be at home in a $10,000 product, and is particularly gratifying to find in a modestly priced integrated amplifier.

The Classé's sleek lines are maintained by a minimum of front-panel controls. In addition to the three low-profile knobs, four buttons turn on the power, engage muting, select the tape monitor, and convert the CAP-100 into a separate preamplifier and power amplifier. A remote control, also machined from aluminum, adjusts the volume and mutes the CAP-100's output. The remote has a solid feel, and matches the rounded edges of the amplifier's front panel.

Three line inputs are provided on RCA jacks (four line inputs without the optional phono board), plus one balanced input. A tape loop is also included. Loudspeaker connection is via five-way binding posts. All of the RCA jacks are gold-plated and mounted to the chassis—a higher-quality alternative to soldering RCA jacks directly to a circuit board. Oddly, no grounding post is provided for the phono input.

My review sample included the optional phono board ($200). Jumpers on the board adjust the gain and loading for moving-magnet or moving-coil cartridges: 42dB gain and 47k ohms impedance for MM cartridges, or 55dB gain and 150 ohms impedance for MC cartridges. With the AudioQuest AQ7000's 300µV output, the moving-coil setting worked, but barely; I would have liked another 6–10dB of gain.

The CAP-100 is built around a huge toroidal transformer located roughly in the chassis center. Seven 4700µF electrolytic capacitors per channel smooth the power-supply rails. The output stages, which flank the transformer, are bolted to the chassis bottom for heatsinking, and attached to roughly 5"-square heatsinks inside the chassis. The lack of external heatsinks contributes to the CAP-100's clean look, and also avoids sharp edges on the chassis.

The preamplifier section is a hybrid circuit based on the classic OP-27 op-amp and pairs of Motorola transistors. Volume control is handled by a motorized potentiometer sourced from Alps. The input selector knob operates relays on a board at the rear panel that determine which input is connected to the preamplifier board. The phono stage is also a hybrid circuit using OP-27 op-amps and discrete transistors.

The power-amplifier stage consists of a differential pair of JFETs (two devices in one package) at the input, bipolar transistors in the voltage gain stage, MOSFETs in the driver stage, and a single pair of Sanken transistors in the output stage (per channel). These output transistors are gain-matched by Classé before being installed in the CAP-100. The driver boards are mounted vertically next to the output stages, and shielded from external noise.

The CAP-100's parts and build qualities are exemplary. I particularly liked the machined faceplate, knobs, and remote control. Although the CAP-100 is a moderately priced integrated amplifier, you don't give up anything in the "look and feel" department.