Halcro MC50 Multi-channel Power Amplifier 
Home Theater Power Amplifiers Multi-Channel Amplifiers
Written by Brian Kahn   
Friday, 01 September 2006

Introduction
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.

Set-up
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.

Music and Movies
After letting the amplifier break in for a few days, I began my critical listening with Shawn Mullins’ Soul’s Core (Sony). The detail in the vocals on the song “Anchored in You” was quite good, clearly reproducing the raspiness in Mullins’ voice while at the same time giving the voice a solid position in the sound stage. The sound stage was slightly further back than I am used to, but it was appropriately large, with a good sense of space and placement of the individual sources.

Continuing with male vocalists, I listened to Elvis Presley’s Elvis is Back (DCC). Elvis’ rendition of “Fever” has always been a favorite of mine. The Halcro continued with an incredible amount of detail, both in the reproduction of vocals and instruments and also the sense of space. The positioning of each of the sound sources was well defined within the sound stage. I could easily hear someone keeping time in the background and imperfections in the recording.

Picking up the pace, I played System of a Down’s album Toxicity (Sony). The song “Chop Suey!” is a frenetically-paced, energetic song. The MC50 had no problems delineating between all the components of the aural assault that comprises this track. I am used to listening to this track with amplification coming from my recently discontinued Krell 300 iL. The Halcro was just as detailed but seemed to be less forward, favoring polite finesse over force.

I wanted to see how the Halcro did with bass, so I spun up Crystal Method’s Vegas (Outpost Records) and went straight to one of my favorite tracks, “Busy Child.” This track features a deep and powerful synthesizer soundtrack. Listening to this track reinforced my prior impressions. The Halcro was extremely detailed and was powerful enough to reproduce any signal I fed it at volumes much higher than I would normally listen to, without any signs of harshness or compression. Despite having plenty of power, the overall character of the Halcro remained polite.

I then switched to movies and watched “The Chronicles of Narnia: The Lion, The Witch and The Wardrobe” (Disney Home Entertainment), which I had just watched for another review. I paid particular attention to the intelligibility of vocals. The Halcro did an excellent job. All of the vocals were easy to understand, solid and full-bodied. In the final battle sequence, it was easy to keep track of distinct sounds as they moved from channel to channel without changing character.

Another classic demo movie that I had recently watched was “The Fifth Element” (Columbia/TriStar Home Entertainment), so I replayed some of the scenes that were fresh in my memory. As before, the vocals were extremely intelligible and had plenty of detail, conveying the nuances of each particular voice, as well as differentiating between background voices. The sonic character remained consistent from channel to channel without any noticeable change. Due to the unit’s relatively light weight, I was a bit skeptical of the MC50’s ability to handle an all-out multi-channel sonic assault. I need not have worried. I listened to the now infamous battle scene several times at volumes ranging from low to annoying-the-neighbors loud. The character and detail remained consistent at all listening levels without any signs of compression or harshness.

Lastly I listened to the DTS version of the Eagles’ Hell Freezes Over (DTS), which I also had out from my last review and was still fresh in my memory. I listened to this disc through both the Monster THX Select speaker system and my reference Canton Ergo system. One of the areas on this disc that I listen to closely for overall system control is the drumbeat on “Hotel California.” While the drums were noticeably different between the two speakers, the Halcro amplifier demonstrated good control over both. I felt that I was close to getting most, if not all, of the detail that the speakers were capable of. The imaging and sound staging was as solid as with any other amplifier and I felt that the individual images were etched with great precision, making each image on the stage sound a bit smaller.

The Downside
The Halcro MC50 is hard to criticize when it comes to performance. The sound is clean, detailed and neutral. My only criticisms of the unit are related to set-up. The binding posts had plastic shrouds with openings that allow the speaker cables to be inserted from one angle only. These covers can make the insertion of certain cables difficult. The covers can be circumvented by the use of banana plugs if your speaker cables are so equipped.

Conclusion
Halcro’s MC series provides listeners with another option in well-made high-quality multi-channel amplifiers. I believe that the MC50 will develop a strong following for use in 5.1 music systems due to its finesse and detail. Each channel of the amplifier is capable of extreme accuracy and the precision to capture the slightest nuances of the recording. The Halcro MC50 will please those listeners who demand detail and neutrality for music and film playback in a high performance theater.

Halcro is no flash in the pan. The gear has the chops to hang on stage with the likes of Classe’, Krell, Mark Levinson, Meridian, Linn and the other big boys that grace the shelves of the world’s best home theaters. Hype like “the best amplifier in the world” is very dangerous when considering the subjective differences among the top-performing amps on the market. To my ears, you can hear that the Halcro MC50 lives up to the hype and surpasses even lofty expectations for build, design and, most importantly, sound.
Manufacturer Halcro
Model MC50 Multi-channel Power Amplifier
Reviewer Brian Kahn





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