April 2008 Reviewed by Howard Kneller	Halcro Logic MC50 Multichannel Amplifier

Description Model: Logic MC50 Price: $5990 USD Weight: 52 pounds Dimensions: 17"W x 7"H x 16"D Warranty: Five years parts and labor	Features Rack-mountable or freestanding Balanced and unbalanced inputs Lyrus class-D circuitry Remote trigger switch Full control via RS-232 or Ethernet connection Ability to inhibit individual amplifier modules Amplifier module will indicate over-temperature or over-current conditions Halcro Reliability Assurance Service (HRAS) software Five-way binding posts

Say "Halcro" in a crowd of audiophiles and you’ll get their attention. The company’s Reference products -- particularly their power amplifiers -- have been touted by some to be the best made. Pretty heady stuff for a company founded as recently as 1997.

Halcro’s top-of-the-line monoblock, the Reference dm88, retails for $39,990 per pair. Recently, however, Halcro has branched out to introduce a series of far more affordable home-theater products, including the Logic MC50 five-channel power amplifier ($5990). The first time I saw the Logics, I wondered if they could live up to the reputation of their Reference big brothers.

Description

Per Halcro’s website, the Logic MC50 delivers 200Wpc into 8 ohms or 350Wpc into 4 ohms, and can stand free or be mounted in a rack. On its rear panel are single-ended RCA and balanced XLR inputs, a remote trigger switch so that it turns off automatically when your processor does, and RS-232 and Ethernet sockets.

The MC50 also comes with the Halcro Reliability Assurance Service (HRAS) software, which you can download to your computer. Once installed, this software lets the MC50 monitor its own performance. If it detects an internal fault, it even e-mails you, your installer, or the nearest Halcro distributor. Worried that a Halcro support team would come busting through my door, tools in hand, in the middle of a Sunday-night movie session, I never activated HRAS. Fortunately, there was never any need for it. The MC50 comes standard with a curious power cord, with a little box on it marked "Noise Filter."

The MC50 is a class-D switching amplifier. Although class-D technology has been around for a while, it has primarily been used for car audio and subwoofers. Only recently has it been refined for use in high-end home theaters. Halcro claims that their class-D Lyrus amplifiers, as implemented in their Logic MC line, offer a number of advantages over other types of digital switching amplifiers.

First, the Lyrus reportedly produces extremely low levels of distortion. In the case of the MC50, Halcro claims that their proprietary Lyrus circuitry produces only 10-20% of the distortion produced at high power by competing class-D amps.

Second, because class-D amps use switching technology, their transistors are either on or off, which means they are therefore extremely efficient. As a result, the MC50 uses relatively little energy and throws off almost no heat -- something greatly appreciated by environmentalists, and audiophiles who don’t live in the far north.

Finally, because they don’t need massive heatsinks, class-D amps are generally small and light. At 52 pounds in a relatively svelte chassis, the MC50 is a pleasure to move around when need be, and will fit virtually any equipment rack -- something that can’t be said for many high-powered multichannel amps.

Sound

The sonic hallmark of the Logic MC50 was a shockingly clear transparency that was the precise opposite of "muddied" and "veiled." It was almost as if someone had taken a garden hose and washed off the sound of impurities. A second key trait was the extreme detail -- not your grandfather’s detail, but the type of resolution that made my next-door neighbor’s jaw drop to the floor and kept me up way past my bedtime replaying discs I’d thought I’d never listen to again. The MC50 combined this extreme clarity and extreme detail with getting all the other stuff right: soundstaging, imaging, inky-black backgrounds, dynamic range. Here’s what all that meant for actual music and movies.

I love 3 Guitars, an acoustic set with guitarists Larry Coryell, Badi Assad, and John Abercrombie [SACD, Chesky SACD289]. Assad plays nylon-string classical guitar, thumb piano, and copper flute, in addition to a bit of vocalizing and mouth and body percussion. The Logic MC50 brought out the strings on all the guitars in this disc with detail I’ve heard only from amps costing substantially more. I could detect the movements of each musician’s hands not only on the strings, but also on the rest of the instrument. Assad’s mouth and body percussion were rendered with such a high level of detail, clarity, and realism that she seemed to be physically in the room -- a sensation that’s all too rare, even with a lot of extremely expensive audio equipment.

When I played Pink Floyd’s Dark Side of the Moon [SACD, Capital CDP 5 82136 2], the MC50 portrayed the voices that randomly appear throughout this album with such clarity that I could not only understand every word, I could hear the speaker’s breaths between them. The famous "Time," with its montage of clock, chime, and bell sounds, was reproduced with substantial details that were simply absent with most other amps I’ve heard. The effects that begin "Money" -- the clanging of coins, the dialing of a rotary-dial pay phone -- were sent from the front to the rear speakers and back with such detail and clarity that, for better or worse, it will let you know whether you have a five-channel rig of truly high fidelity, or a mere stereo system with tacked-on surrounds.

Movies were no less exciting. A reference DVD that I frequently use is Open Range, a western starring Kevin Costner and Robert Duvall. Recorded in DTS, the climactic gunfight (chapter 14) is a great test for any amp. It begins with a single bullet to the forehead that, through the Logic MC50, almost always had my guests literally jumping out of their chairs. The ensuing shoot-out is a sonic masterpiece, and as real as anything I’ve heard on any DVD. The MC50 made me feel as if I was in the middle of it. The gunshots were razor-sharp, clean and deep. And when bullets shattered window panes, the MC50 captured every last tiny detail.

I conducted extensive A/B comparisons of the Halcro Logic MC50 with a Theta Digital Dreadnaught II five-channel amplifier. While at 52 pounds the Halcro is a relative featherweight, the Dreadnaught is a 98-pound behemoth -- even its faceplate looks as if it’s been milled from a solid block of steel (it’s actually several pieces of alloy) and belongs on the front of a Sherman tank. The MC50’s faceplate is not cheaply made, but should you ever feel the need to throw the Halcro against a wall, you’ll need a new amp. Do the same with the Theta and you’ll need a new wall. Also, the Halcro produces very little heat; you could cook your breakfast on the Theta.

The sounds of these two amps were also very different. The Theta is darker, with a rawer, throatier bottom end -- when it roars, you and your neighbors better get out of its way. While some wouldn’t want to hear a film such as U-571 any other way, others -- such as I -- prefer the ever-so-slightly leaner but significantly more defined, detailed, and revealing sound of the Logic MC50.

Downside

The Logic MC50 is one of the more impressive pieces of home-theater gear around, but no product is perfect. Although class-D amplifiers generate much less heat than other types of amps, they can still reach temperatures that can damage their output transistors if run for long periods at high levels, and especially if installed in enclosed spaces. And while most amps are cooled by heatsinks, not fans, the MC50 has one of the latter, and it’s just barely audible in operation. (Halcro uses the fan in its five- and seven-channel Logic MC amps, but not in the two- and three-channel models.)

This minor problem bothered me only once. Chesky’s 3 Guitars SACD was recorded in a New York City church that has been converted to a recording studio, on a cold winter day that challenged the building’s antiquated heating system. An extremely resolving system will reproduce the humming of the church’s heaters, and the Logic MC50 did so wonderfully. However, the MC50’s cooling fan ever so subtly obscured the sound of the heater fans, possibly because it ran at the same frequency. But had I not played 3 Guitars, I might have overlooked this entirely.

Conclusion

A number of manufacturers now produce class-D switching amplifiers, and it’s likely that many more will in the near future. But you’ll find few home-theater amplifiers of any type that will sound better than Halcro’s Logic MC50. Go out and listen to one. Just be certain that the rest of your system can deliver the high-quality sound that this baby can dish out. If not, remember this warning: If you buy a Logic MC50, your system may be in for some other significant upgrades.

Manufacturer contact information:

Halcro International
118 Hayward Avenue
Torrensville, South Australia 5031
Phone: +61 8-8238-0807
Fax: +61 8-8238-0852

E-mail: admin@halcro.com
Website: www.halcro.com

Halcro Audio (USA)
871 Grier Drive, Suite B-1
Las Vegas, NV 89119
Phone: (702) 270-9307
Fax: (702) 891-8810

E-mail: USA@halcro.com

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