|Halcro MC50 Multi-channel Power Amplifier|
|Home Theater Power Amplifiers Multi-Channel Amplifiers|
|Written by Brian Kahn|
|Friday, 01 September 2006|
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The Halcro brand name is famed in the world of audiophiles, most notably for offering amplifiers that have been lauded as “the best” by many in the know. In an effort to move past the constantly shrinking two-channel audiophile world, Halcro has expanded their product offerings to include a home theater line, consisting of multi-channel amplifiers and a preamplifier-processor (review pending). The amplifier line consists of two-, three-, five- and seven-channel units. The MC50 five-channel unit which retails for $5,990 is the one we’re reviewing here.
Halcro’s parent company Minelab makes technologically advanced metal detectors and land mine scanning equipment. In the security industry, it is imperative that every product be designed and built to astronomical standards, as lives are literally on the line. Without question, Halcro has adopted these same high standards for their audio gear. The build quality of the MC50 is spectacular, even in comparison to the best that more established audio companies have to offer. Under the hood, Halcro didn’t utilize traditional amplifier technology. Instead, Halcro opted to employ their high-speed-switching Lyrus Class D topology, which is a somewhat out-of-the-box move, but there are many advantages to be had with such a design, including benefits from heat production, size, output and beyond.
Halcro’s lead physicist Bruce Candy has modified the Class D circuitry to greatly reduce the distortion that is intrinsic in a traditional Class D circuit amplifier when operating at higher power. Candy wrote a paper to the Society for Industrial and Applied Mathematics, explaining how the Lyrus Class D circuit was modified to reduce distortion. In simple terms, the Lyrus circuit modifies the clock signal, which controls the pulse-width modulator in the output stage to produce the proper phase compensation to minimize distortion.
In addition to the Lyrus circuit’s unique application of its Class D architecture, the MC series of amplifiers also features Halcro’s Reliability Assurance Service (HRAS). This advanced alert system allows the amplifier to be connected to a computer system. HRAS allows the user to set the service up to notify their Halcro dealer of the detected fault, so that they can immediately begin the repair process.
The above features are packed into a 52.3-pound, 17-inch wide, seven-inch high and 16-inch deep attractively designed chassis. The brushed aluminum front panel is divided by a vertical accent a couple of inches from the left edge of the panel with a horizontal detail line across the bottom portion. When the amplifier is viewed from above, one can see that this accent is the front portion of an oval that is reminiscent of the vertical walls from Halcro’s monoblock amplifiers. The power button and a status light are to the left of the accent. To the right are five LEDs that provide the status of each channel. The back panel has balanced and single ended inputs, a switch to select which input is utilized and plastic-shielded binding posts for each channel. To the left of the amplifier channels are the communication card ports, with RS-232, remote trigger and Ethernet connections. On the right side of the panel are the master power switch, fuse and IEC standard power connector. The MC series can be rack-mounted and also comes with aluminum feet for stacking.
The MC50 is a powerhouse, putting out five channels of 350 watts into a four-ohm load. Total harmonic distortion is less than .007 percent at 1kHz, and less than .03 percent at 7kHz. The noise rating is provided in the unfamiliar (to me) format of less than 30nV/sqrt at 1 kHz. The efficiency rating is greater than 94 percent, which keeps the amplifier running cool.
The MC50 was quite simple to set up in both my reference stereo and theater systems. In my stereo system, I utilized my Krell 300iL as a preamplifier, driving the MC50 through its single-ended inputs. The MC50 powered a pair of MartinLogan Ascent’s. Installing the MC50 in my theater system was equally easy. I flipped the input switches from single-ended to balanced and was then able to utilize the balanced outputs of the Halcro SSP100 and Krell HTS 7.1 processors. The speakers utilized in my theater system with the MC50 included Canton Ergo series speakers and Monster THX Select speakers. The MC50’s binding posts have plastic shrouds, which I presume have something to do with EU or Australian safety regulations. These shrouds can make connecting some spade-equipped speaker cables difficult or impossible. I recommend that you either use banana plug-equipped cables or try the particular spade connections before purchasing your speaker cables.