Carver AV-705X (1996)
A five-channel home-theater amp that quietly cheats the FTC rulebook — and sounds all the better for it.
Overview
The spec sheet says 125 watts per channel into 8 ohms, all five driven, 20 Hz to 20 kHz at 0.08% THD. That's the number Carver had to print to clear FTC rules and qualify for THX certification, which the AV-705X carries. But the power supply and output stages were built to deliver 200 watts into 8 ohms when the energy sits predominantly in a single channel — and unlike the short-burst trickery of dynamic headroom, the amp will hold that 200-watt figure into any one channel all day and all night. Carver called the scheme Power Steering, and it debuted in this amplifier, part of the Premiere line.
The logic behind it is almost embarrassingly sensible. Multichannel home-theater amps had been built like stereo amps with extra channels bolted on, but the demands are different: in a Dolby Pro Logic rig the decoder steers the dominant energy to one channel at a time and cancels it out of the opposing ones, so all five channels almost never need maximum power simultaneously. Power Steering capitalizes on that by diverting supply energy from the channels that don't need it to the ones that do. Audio (September 1996, p.66) put Edward J. Foster on the review, and his bench numbers told the story plainly: at 1 kHz and 1% THD+N, the amp delivered 145 watts per channel with all five channels driven, 200 watts per channel with two driven, and 255 watts with just one — a climb from 21.6 dBW to 23.0 dBW to 24.1 dBW on the decibel scale. Into 4-ohm loads it pushed past 300 watts per channel with two channels driven and 390 watts with one before clipping. Not bad for a 125-watt amplifier, as Foster put it.
The build is genuinely unusual for the price. Each of the five channels lives on its own glass-epoxy circuit board with its own heat sink, its own fuse, and its own DC-offset, shorted-load, and high-temperature sensing. Each channel also gets its own power-on delay, and when all five relays come on at once the amplifier announces the fact with a mighty thwack. Modular construction keeps the signal path short: the input and output connectors and the input-level control are soldered directly to the circuit board and protrude through openings in the back panel, so there's no internal wiring in the signal path at all. The RCA inputs are gold plated; the outputs are base-metal binding posts that take up to 10-gauge bare wire or single banana plugs — functional, internationally safety-compliant, and not everyone's favorite.
Inside, apart from a coupling capacitor between the level control and the Texas Instruments Excalibur operating-point controller IC, the amplifier is direct-coupled, fully balanced, and discrete throughout. There are only two gain stages, each running true Class A. The output stage is a triple-Darlington, complementary-symmetry emitter follower using parallel-connected pairs of triple-diffused planar transistors rated at a 60-ampere output capability, with a safe operating area large enough to handle 600 watts per channel. The output devices drive the loudspeaker directly, without the usual series inductor — a choice that helps keep output impedance from rising with frequency, and one that demands exceptionally wide open-loop bandwidth and careful layout to stay stable. Carver's answer on the layout side is a double-stage ground-management system isolating the input from the nearby output connectors; the company claimed it solved ground loops, separation loss, and parasitic oscillation outright, and that the amp would run cleanly with no negative feedback at all.
The chassis is sturdy sheet metal with an extruded aluminum front panel, and it measures 5¾ inches high, 19 inches wide, and 18¾ inches deep with handles and feet fitted — 42 pounds in total. The front panel sprouts removable wings and handles, but Carver didn't suggest rack-mounting from the wings; the intent was shelf placement, and pulling the wings lets the amp slip into a 17-inch opening. It wants at least 3 inches of clearance above and an inch on each side for cooling. A power rocker sits at the upper left with a green LED beneath it; red per-channel LEDs light at turn-on before the delay relays click in, then quench and serve as clipping indicators once the amp is running.
Foster's listening notes described reserves that seemed endless on action soundtracks and a clean, silky-smooth, extended sound on music, and he figured the amp would serve surround-music systems as well as it served contemporary home theater. His verdict carried a caveat about whether Power Steering would prove as worthwhile with discrete multichannel formats as with steered Pro Logic, but even factoring the feature out entirely he called the AV-705X a great amplifier — and at $1,199, a terrific bargain.
That price is the thing collectors keep coming back to. Five channels of genuinely robust, fully discrete, Class A-driven amplification with per-channel modular construction and monitoring circuitry is not a combination that turns up cheaply, and the Power Steering behavior gives the amp a real advantage driving inefficient surround speakers in a Pro Logic setup. The caveats are period-typical: those base-metal binding posts draw complaints, the relay thwack on power-up is not subtle, and the amp needs breathing room. Buyers should confirm all five channels are healthy and that the protection relays engage cleanly, since each channel's independent sensing and fusing is both the design's strength and its service complexity. For a home-theater amp of the mid-nineties, it remains one of the more interesting designs to actually own and listen to.
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