Most audio manufacturers build their amps as if it's 1975. Surprisingly, most of their circuit topologies haven't changed much since then. Those circuits worked great three decades ago, when most amplifiers were stereo and sat in open-sided racks or on the floor. In 2007, though, home theater and custom installation have radically changed our expectations of an amplifier.

Amps used for home theaters typically have five or seven channels, so they provide 2.5 to 3.5 times as much power as—and generate far more heat than—their predecessors did. Amplifiers in custom home theaters are almost always tucked into equipment cabinets—which should be well-ventilated and cool, but often aren't. And the proliferation of channels has bloated some of these amps to impractically huge dimensions; some measure nearly two feet deep and weigh more than 120 pounds.

There are amplifier designs that provide just as much power from more compact, cooler-running chassis, but they have yet to gain wide acceptance in home theaters. Tradition-bound amp makers tell me it's because the more advanced designs don't sound as good, but they offer no evidence whatsoever to back their contention. Proof that they're wrong is ample. Famed high-end amp designer Jeff Rowland has adopted Bang & Olufsen's ICEpower digital technology for his entire line of amplifiers. The incredible new $130,000 Steinway Music System uses all-digital amplification. And AudioControl has been selling great-sounding, cool-running Class H amps for years—the latest of which is the Savoy, which delivers seven channels of amplification, each rated at 150 watts.

Class H amplifiers include a circuit that watches the incoming audio signal and adjusts the amplifier's power supply to suit the need. Conventional amps create a lot of heat because the power supply's full current runs through the output transistors all the time, and whatever power doesn't run down the speaker cables is converted to heat, which must be dissipated by the amplifier's heat sinks. Class H throttles down the power supply when its full oomph isn't needed, so much less heat is generated.

Indeed, I find that after I run the Savoy at high volume for an hour, the top is barely warm; under these conditions, a conventional amp would be too hot to touch. I daresay that using a Savoy instead of a traditional Class AB amplifier could eliminate the need to put fans in your equipment closet—and might eliminate a lot of noise in the process. One vent at the top of the closet and another at the bottom may suffice.

Once your installer sticks the Savoy into that closet, there's little chance it will ever need to come back out. Given the number of speakers and the long, complicated wire runs in a custom-installed home theater, it's easy for even the most experienced technicians to short out an amplifier channel accidentally. Much as you can best judge the character of a person by how she performs under stress, you can measure the assiduousness of an amp designer by how his products perform under stress. The Savoy performs flawlessly under stress. I find that as with other AudioControl amps I have tested, I can short the terminals repeatedly without damaging the amp. The shorted channel mutes while the others keep playing. Remove the short and the sound resumes. Many other amplifiers shut down all channels when one is shorted or overloaded, and must be restarted from the front panel or by flipping a circuit breaker or replacing a fuse in the back.

According to AudioControl, the same automatic shutdown procedure occurs if a channel is overloaded—i.e., played especially loud when connected to a low-impedance speaker. Given that the amplifier generates so little heat, and that (as you'll read shortly) it seems perfectly happy driving low-impedance speakers, I think it unlikely the Savoy could be overloaded in anything but a tremendous, 25-seat home theater with terribly inefficient speakers.

Despite its advanced technology, the Savoy sounds comparable to other mid-priced seven-channel amps in my possession—a little brighter than both of the amps I have on hand, a characteristic that lend it a crisp, clean presence that helps especially to bring out the detail in movie soundtracks. Even when I connect a pair of Triad Gold/6 LCR in-wall speakers—whose dual 8.5-inch woofers and low 3.2-ohm minimum impedance present a daunting challenge for an amplifier—the Savoy impresses me with its tight, precise, punchy bass. I wouldn't necessarily say it sounds better than the top competitors in its price range, but it's at least the equal of any of them.

This is the way a multichannel amp should be built in 2007. If you really want an impressive stack of conventional amps, and don't mind investing in the equipment necessary to keep them running cool, knock yourself out. But if I were installing home theaters for a living, I'd be installing this amp.

DESCRIPTION
Seven-channel amplifier for home theater use

POWER RATING
150 watts per channel

CONNECTIONS
XLR balanced and RCA unbalanced audio inputs for each channel, seven sets of five-way binding posts for speaker cables, block connector for 12-volt trigger input and output

DIMENSIONS
5.75 x 17 x 17.5 inches (hwd)

PRICE/CONTACT
PRICE: $2,499
CONTACT: 425.775.8461, www.audiocontrol.com