Power Amplifiers

Emotiva XPA-3 Three-Channel Power Amplifier

ARTICLE INDEX

Design and Setup

The XPA series are fully discrete, dual differential, high current, short signal path Class A/B design amplifiers. The XPA's modular design share the same glass epoxy pc boards, 1% resistors and metal film capacitors, and all XPA series amps use large toroidal transformers. The primary differences between the XPA two, three and five channel amplifiers are transformer size, secondary capacitance and number of output devices per channel. The XPA-3 has an 850VA transformer with 60,000uF of secondary capacitance, and six output devices per channel. Translated into plain English, that's a whole lotta power.

Many typical home theater receivers rate their power at something like 100 watts, but on closer inspection the specs show 100 watts when driving less than all channels (typically one or two channels), and usually a short burst rather than continuous power. Emotiva goes to the opposite extreme; the XPA manual states that "all Emotiva amplifiers are rated for continuous power, tested with all channels driven simultaneously." The XPA-3 is rated at 200 watts RMS @ 8 ohms, and 300 watts RMS @ 4 ohms (0.1% THD), with all channels driven. Emotiva publishes detailed graphs on its website, showing amplifier bench tests using an Audio Precision test analyzer (the same brand used by SECRETS Editor-in-Chief, it costs about $40,000).

The main purpose of the XPA-3 is to take over a receiver's amplifier for the front three (L/C/R) channels. Since most content (film soundtrack or multi-channel music) comes from the front of the soundstage, this is where the greatest demands will be made on a receiver's amplifier section. The XPA-3 is connected to the pre-amp outs on the receiver for the front channels, allowing the receiver's entire amp section to power the less used surround channels. Theoretically, substituting the XPA-3 for a low-powered receiver's amp section will result in dramatic sound improvement, while adding the XPA-3 to a more robustly powered receiver will make for more modest gains. However, as described below, I found that even when pairing the XPA-3 with a beefy-powered THX Ultra2 certified receiver, the Emotiva can make a big difference when driving low sensitivity or 4 ohm speakers.

The XPA-3 is bigger and heavier than most home theater receivers. It weighs 57 pounds, and at 17 x 7.75 x 19 inches (W/H/D) is a tight fit in a standard 19" rack. The front of the unit has a single glowing power button, along with three LED channel status lights. In standby mode (there is a master power switch on the back of the amp), the power button glows orange. When powered up using either the front button or via 12V remote trigger input, the status lights flash red, then sequentially turn to blue as the internal circuits confirm that the amp is operating normally. The channel status LED's can be turned off via a switch on the back panel, but the power light is not dimmable. Since the amp sat behind a perforated metal door of my rack, the blue power status LED was never a distraction.

The back panel of the XPA-3 will be familiar to anyone with an XPA series amplifier. The right side has the master power switch and a detachable IEC mains connector that runs on 115V or 230V automatically, without user adjustments. There are separate inputs for each channel, both single-ended RCA and balanced XLR. Each channel has a switch depending on whether balanced or unbalanced inputs are being used. Below the inputs are five-way binding posts for speaker terminals. The left side of the back panel has a jack for remote trigger, and the XPA-3 packaging included the necessary mini-jack cable. I used the 12V trigger on my Integra DTR 8.9 receiver, which worked flawlessly powering the Emotiva whenever I turned the receiver on or off.