Halcro. What does that name conjure up in your mind? In mine it is “expensive”, “state-of-the-art” and “luxury”.

Before going back to my hotel room after a long day of talking and listening to stereo systems, I was winding down in the large, dimly lit Halcro/Wilson ballroom at the Rocky Mountain Audio Fest listening to the $500,000 stereo system the companies had set up there. The big room was festooned with overstuffed coaches and chairs, lovely potted palms and plants and best of all, a well-stocked open bar serving very nice wines by a tuxedoed attendant. The soft jazz music was soothing after nearly 48 non-stop hours of telling industry people about the new Stereomojo site that had just launched. I hadn’t stopped to eat anything in that time. My hotel room was a place for reviewing notes I’d scribbled, going through the hundreds of pieces of sales brochures and price lists and mapping out the strategy for the next day’s must-see demos – not sleeping. Since Stereomojo had been created to specialize in equipment priced generally under $10,000, I was sure this mecca of multibuck machinery would afford me a respite from review seekers.

I was almost startled when a sophisticated gentleman in an expensive suit came over and asked me if I was James Darby of Stereomojo. I smiled and said I was. He introduced himself as a VP of Halcro and asked if he could talk to me about reviewing one of their products. I asked if he know what Stereomojo was all about to which he said he did. I motioned toward the half-a-million display before us and said “Then you know that Halcro is probably the antithesis of what we do. It’s a household name. We concentrate on lesser-known manufacturers. Halcro is known for its very high-end, expensive amplifiers. We focus on gear under $10k. I’m sorry, I just don’t think we are a good match.” I shrugged and sipped my vintage Cabernet.

Bruce Ball continued, “Did you know that we make an incredible sounding 400 watt-per-channel power amp priced less than $5,000?”

I said, “You’re kidding. I had no idea”.

He leaned towards me and whispered in my ear, “Neither does anyone else. It’s been out for a year and nobody knows it exists. That is why we want you to review it”.

For twenty minutes, I continued to resist. I feared reviewing a Halcro might be considered selling out our primary mission. Finally, he sold me on the idea. But then, that’s why he’s VP of sales, I suppose.


Halcro History

Here’s a bit of trivia: From where does the company name Halcro originate? I confess, when I first read the name, I thought it was Halco – you know, some guy named Hal started a co-mpany. That’s not it. I’ll save the interesting answer for later.

Another VP I talked to about the MC20 is Jesse Walsh. Jesse is VP of North American Operations. I’ll share the backstory he related to me.

Halcro is the brainchild of Bruce Candy. Perhaps you know people who are ultra sensitive to the odor of certain women’s perfumes or the redolence of mildew. Those two things can make me nauseous. For Bruce, it is audio distortion. He loathes it as much as he loves music. It seems every amplifier he ever heard was awash in that evil nemesis.  Like so many other genius inventors, he knew he could build an amplifier he could stand to listen to, so he set about to do it. After all, he holds Ph.D.'s in mathematics and physics. You have heard the expression that “almost” only works in horseshoes and hand grenades? Halcro’s parent company holds 75% of the world’s market in explosive detection devices. Therefore, “almost” is not in Dr. Candy’s vocabulary. Alas, the good doctor could not build a perfectly distortionless amp. He could only get the signal to a purity of 99.9996%! He missed perfection by .0004 percent. What a loser, huh.

The result was the dm58 monoblock that was immediately hailed world over as a breakthrough product that set a new standard for amps and audio playback in general. Headlines blared “The Best Amplifier Ever”. Of course, as things seem to go, the next month’s issues proclaimed the same thing about the something else. At $25,000 the pair, the dm58 put out only 200 wpc. Bruce’s newer amp, the MC20 discussed here, generates a crushing 400 watts per channel for 1/5 the price. And no, it is not a spin off brand name – it says “Halcro Logic” right on the luxurious silver front panel.

So what’s the catch? This seems to good to be true and we know what that usually means. Is this $5,000 beast the equal of the older “bests”?


The Catch


Let us answer that up front; No, the MC20 is not the equal of any of the dm series, nor is it intended to be. There is no claim of 99.9996% purity. The specs do claim:


· THD: <0.007% at 1kHz at all

powers up to 400W into 4ohms

· < 0.03% at 7kHz at all powers up

to 400W

· Noise:  <30nV/sqrt(Hz) @ 1kHz

referred to input· FCC Part 15


That is still pretty quiet, folks. Particularly for a Class D amp.

“Ahhh”, you say. “THAT’S the catch! It’s a digital amp”! Not really. Much has been written about Class D amps (we did a huge “Emerging Technologies” shootout that included several Class D amps), so I won’t go into it much here. Suffice it to say that while there is an element of 1s and 0s at play, Class D is still analog. It is just that with a D, the analog, push-pull amp is a full power all the time, but it is switched on and off by those 1s and 0s so fast as to be almost infinite. That is why Class D's are referred to as switching amps.  Cool. And they are cool – literally. These amps use power very efficiently so there is very little residual heat – a big plus for those of us in tropical climbs.


The problem is, all that switching creates noise and – oh no! – distortion! Since Bruce lives by the motto “Distortion must die”, he donned his Starship Trouper outfit and created Lyrus – his proprietary circuitry to obliterate the malodorous fiend.

Yeah, that’s great. So how did Dr. Candy accomplish such low distortion figures? Here is what he says:

“Class-D amplifiers convert an input signal to a power 1-bit digital output signal, that is the output signal is either a 1 (say +70V) or a 0 (say -70V). The rate at which the output switches is much higher than audio frequencies (say 500kHz). This rate is controlled by a reference clock signal. The ratio between the average time spent at +70V and -70V varies in proportion to the input signal. That is if the input signal is say more than 0V, then the output correspondingly spends more time on average at +70V than -70V and so on.

This ratio is also controlled by the clock signal. The 500kHz switching signal is removed by analogue filters so that only the average signal passes to the loudspeaker, and as stated, this is controlled to be in proportion to the corresponding input signal.

Class-D amplifiers (analogue) suffer from intrinsic distortion, that is, even with "perfect electronic components" the circuits mathematically generate distortion. This intrinsic distortion increases rapidly with both increasing power and frequency. Thus at high powers, class-D amplifiers hitherto are substantially inferior to well designed traditional class-A or -AB or -B amplifiers.

The Lyrus circuits contain patented distortion canceling circuitry so that at high powers the Lyrus™ class-D amplifiers are on a par with well designed traditional class-A or -AB or -B amplifiers. Technically the intrinsic distortion can be attributed to an intrinsic time distortion (advanced phase) which varies in a non-linear manner with signal level (level squared law). The Lyrus circuits introduce a compensating time variation to the reference clock signal which controls when the output signal switches.

More technically, the clock signal is a triangular-wave which acts as a reference to the pulse-width modulator and the symmetry of the triangular-wave is varied by the input signal to produce the required corresponding phase compensation.

The Lyrus amplifiers produce about 1/5th to 1/10th of the distortion of typical well designed competitors at high powers.”

Like I said, the man hates distortion.


Physical Description

Another hallmark of Class D is potential small size and weight as seen in Dusty Vawter’s Channel Island amps. But the Candy man’s MC20 weighs almost 50 pounds and the size is 7x17x16 inches. Not small, not light.


Like a big Mercedes, the Halcro oozes quality and luxury. The front panel has a small line of gold that creases it horizontally that does nothing more than break up the visual monotony of the silver slab and adds a bit of tasty sumptuousness without implying lavishness or opulence. Classy.


The backside is all business – XLR's for fully balanced operation or RCA's if you must.  I ran the amp in both modes, but preferred the sound in the balanced configuration through Cardas Neutral reference XLR's. Speaker posts are first class as well. There is one connection port that you will not find on any other stereo amp. We’ll reveal that in a moment.


The Halcro employs a series of protection circuits that make it electronically bulletproof. The amp also acts like a state of the art line cleaning device that renders that incoming juice worthy to ignite the amp’s fire.


There are several other quality touches as well. Even the shipping cartons are an engineering marvel. The users manual is a leatherette 3-ring binder with the pages on very heavy paper. The Halcro name is proudly stamped on the cover.



One thing a new owner will find in the carton is a CD. There is no music on it, but there is a Windows executable. Stick it in your PC and it will install the HRAS program. The Halcro Reliability Assurance Service. To quote from the manual, “HRAS monitors the performance of the system. It can be set up to alert your dealer, installer or yourself by E-mail if any amplification module fails, without disruption to your listening pleasure. An event log can also be maintained by HRAS for troubleshooting purposes”. Yep, if something goes south, the thing will E-mail you and any two other recipients you tell it to. This is where that other connector on the MC20’s back comes in – it’s an Ethernet jack. The PC software will also search, locate and identify every Halcro device in your system and automagically register it with Halcro.

Halcro even goes to the trouble of burning in the unit at the factory, saving you the two weeks it normally takes at 24 hours per day to reach potential.

This is where I tell you that the MC20 is part of Halcro’s home theater series which includes two pre-processors and four power amp configurations from two to seven channels; this being the 2-channel version. Now you know the other reason the Halcro VP had to twist my arm to get me to review this unit – Stereomojo doesn’t do Home Theater.

So. Is this slight exception (it is 2-channel) exceptional in sound?


Okay. No more drama;

The sound of the Halcro MC20 is extraordinary in its ability to produce the essence, heart and soul of music near flawlessly at this – or any other price.

Should we go through the litany of soundstage, detail, low-mid-high and all the rest, or does that one sentence do it for you? I suppose I should proceed because that’s why you pay me the big bucks. Wait. No you don’t. Aw, what the heck.

Whenever I am asked to review a power or preamp, I always insist that its mate is sent as well. That way, no one can claim that the other associated piece was not compatible or otherwise objectionable. It also assures that the product will receive a review that is fair for you, the reader. In this case, Halcro sent their SSP80 pre-processor which is a visual and sonic match for the MC20. Since the SSP80 is a surround sound piece, it will not be the subject of a review at Stereomojo. I will just say that at $8,000, this thing in direct, balanced stereo mode with no DSP or other processing in the circuit is exceptional as a preamp. It also includes one of the best sounding audio DACs I have every heard. The DAC alone is almost worth the eight grand. While I have been sorely tempted to stick it in the home theater system which is entirely separate from the stereo reference system, out of respect for Halcro and you the reader, I have not succumbed. Perhaps after this review I will ask Halcro permission to slip it in for a few days before it is returned.

Running into the even more extraordinary Sason LTD granite-enclosed speakers and Kimber Select BiFocal wires, the Halcro combo formed an image of sheer music. I must insert here that Steve Rothemel, the designer of the Sasons, is every bit the perfectionist and distortion loather that Bruce Candy is. This system just projects whatever the source creates in a space that is neither too big nor too small, dictated by the recording venue and how well the engineer captured it. And it is utterly quiet. No haze, no hash. Even the word “transparent” is inadequate because it implies that there is some barrier in place that is clear enough to see through. What we heard was not transparent, it was just there!

At 400 watts per channel, power is virtually limitless, but it never flexes its muscles ala the young Schawartzenegger, it never draws attention to itself at all. It never brags about its power.

If you think about it, it can be said that the high end is all about laziness. Most good components will present audio information and detail at one level or another. What people pay the large dollars for is the ability to hear them without having to work at it. In live music in a good venue, one does not have to strain to hear rosin on the bow or that triangle back in the percussion section. One does not have to exert effort to hear the nuances of a vocal performance or the articulation of the trumpeter. You never feel the urge to physically lean forward to differentiate the bass player’s lines from the kick drum.

One of my reference selections is Karen Carpenter singing Solitaire. She’s close mic’d so her unmatched rich alto timbre is right there in front of you. My niece, who just received her Ph.D, was visiting during the review process. When I played that cut for her she turned to me wide-eyed and exclaimed “My gosh, you can hear the saliva in her mouth”!

True. She’s no audiophile, but it was easy for her to recognize that rather odd detail. We put on Gnarls Barkley, cranked it up and rocked out. She turned to say something else to me and was surprised when the music was too loud for her to talk over. I hit mute and she said, “Wow. Was it that loud? It didn’t sound loud at all”! I explained to her that distortion adds a false senses of loudness, so when a signal is really clean, it can be loud but not perceived as such. I mentioned that rock guitar players today often use distortion inducing stomp boxes or even computer software to simulate distortion at low decibel levels. Then I took her into my home studio and played two signals at the exact level – one with a distortion VST add-on and one without. Of course, the nasty, distorted signal sounded much louder.


On weekend mornings the first thing Linda and I do is play some classical music while we read the paper, drink coffee and talk. When I say classical, I mean the real classical school; Mozart, Bach, Vivaldi. This morning it was Handel. No Mahler at 7 a.m., please. Even though the music was at background level, we found ourselves at times not talking or reading, but listening to something particularly interesting in the music. In other words, the Halcro not only rocks, it conveys detail, nuance and musically when playing quietly. Many call it microdynamics, but those are found in loud music as well.

The MC20 was so revealing that even non-audiophile friends and visitors could hear the difference when I switched out a cable. By the way, I did try substituting an excellent $1,000 power cable for the stock one, but there was very little improvement. That is a tribute to the filtering circuits in the amp, because usually there is a marked improvement.

There was no perceived glare or edge. The Flim & the BB’s cut I use for dynamics propelled the 100db sudden “hits” like the sound of a .44 magnum being shot at close range. Or, exactly as they were intended to be by the musicians. There is a little piano and bass ostinato for a few measures, then a quick beat of silence followed by a crash of piano, drums and electric bass all struck at blastissimo. Very few systems render this impact as explosively as it was recorded. This one did without strain or protest. Just…”BAM!!”.

But James…what does that mean?

Glare and edge. What does that really mean? Let’s see if I can show you what it means to me graphically.

Here, “MOJO” represents the music (of course!) as produced by an excellent system. The “music” is three dimensional, clear and clean. Each letter (note and/or instrument) is clearly defined. The bumpy surface indicates texture. Music is not flat, it has dynamics, transients, harmonics, detail and emotion. The color, or lack of it, signifies just that – no added colorations. The soft, gray background portrays the ambient or reverberant field encompassing the performance.

This graphic represents “edge”. Surrounding each note, voice or instrument is an electronic, non-organic, non-musical artifact that does not belong there. The size, amount and rawness of the edge will vary from component to component. Here, the edge is intended to sound rather moderate. It does not pervade the whole image, just an edge around individual sounds. The reverberant field is still there and little effected, but usually a bit truncated. For me, still listenable, but it impedes the flow and beauty – the naturalness – of the performance.

Here the edge is more prominent. It diminishes the original sound. Beyond moderate and bordering on nasty. Not pleasant. This is usually found in lower quality (but not mid-fi and not always less expensive) solid state gear. It can come from an amp, a CD player, any part of an analog front end or even power chords, cables and lack of quality equipment racks. In fact, everything else in a system may lack this edge, but one component may be the culprit that introduces it.

Now this is what “glare” sounds like to me. It is an unnatural, bright sounding artifact that is less hashy-sounding than edge, more solid in substance, but it can take on anything from a steely quality to that of gelatin. You notice that the ambient field is now reddish. That is because I’ve found that glare often invades that territory and colors it as well. Tubes as well as solid state can generate glare. Perhaps bad electric current can, too. Mismatches in impedance can cause it to some degree, though usually the opposite is true. Glare, to me, is rather fatiguing - not something to which I like to listen for long periods. This graphic portrays quite a bit of glare. Just looking at it makes me shudder.

Now this is what you get with really poor components. It usually takes more than one bad one to achieve this monstrosity. Notice the music is now smeared, blurred and indistinct. It is also flat and lacks both dimension and texture. The color takes on the cast of fecal matter. The soundstage (if it exists at all) is clipped, grainy and colored. This, my friends, is what the vast majority of our fellow Americans listen to in their homes every day. This is what my 2005 $2,000 Denon Home Theater receiver sounds like to me when I attempt to listen to music only through it – something I abandoned long ago.


Has this been helpful? Drop me a quick line (use “Contact” on the Home Page) and let me know. If so, maybe I can illustrate other “audiophile” terminology in future reviews.


Bruce Ball, the Halcro VP who talked me into reviewing this (bless you Bruce), mentioned that the designer is a tube geek who wanted to impart the good qualities of tubes while excoriating the less pleasant.

I won’t go so far to say it has the luscious warmth of good tubes, rather it lacks the coldness of even good solid state. I did put the nice Triode TRV-4SE tube preamp in front of it for a while. The Halcro seemed to say, “Hey, that’s nice. Here’s what the Triode really sounds like”.

The sound became bit creamy and languorous, the soundstage diminished just a tad and instruments were not as delineated in the image. Strings became a bit more lush and vocals took on a more golden aspect. Acoustic instruments in particular sounded a bit more woody. There was no drastic deterioration, but there was a change, as if another singer had taken the stage. I believe with a lesser amp and speakers, those qualities may not have been as easy to discern. Perhaps I am lazy, too.

I usually never refer to other reviews, in fact I try to avoid reading any reviews on a component under review here, but since Jesse practically recited it to me that night at RMAF, I read it after my listening process was finished. In it, Art Dudley compared the MC20 to his $30,000 Lamm monoblocks. Mr. Dudley concluded that the MC20 was equal or better in some areas, but lacked the last “eerily convincing sense of texture” for which the Lamms are “notorious”. He also points out that the Lamm’s last sense of texture costs you an additional $25,000. The only reason I mention Mr. Dudley’s comment is because the Lamms are tube amps and I am commenting here on the designer’s fondness for tubes and the sound I perceived. Bottom line, if YOU are a tube addict and long for more than 25 wpc without spending $30,000, the MC20 is definitely worth investigating.

Even though the DAC in the Halcro pre I mentioned is exemplary with CD and DVD-A, when I fired up the TW Acustic (yes that is spelled correctly) Raven One table, the musical level went up. I have already received several emails, mostly from the Pacific Rim, either asking about it or telling me how hot this table is in the region.


The MC20, aided by the wonderful Roksan Caspian Reference phono pre, embraced the increased musical acumen of LPs like a long lost golden retriever. The LA 4’s “Pavane Pour Une Infante Defunte” on EASTWEST Nautilus Direct to Disk was never more clean and convincing on the superlative guitar work of the late Laurendo Almeada.


Ennio Morricone is becoming increasingly recognized as a master of composing movie soundtracks and “The Mission” as one of his best works. The LP cut “On Earth As It Is In Heaven”  is a very complex track  with two different choirs singing in counterpoint, a full orchestra, oboe solo, and array of African percussion and very deep and distant drum thwacks. The soundstage is very large in all directions and layered with lots of ambience. The Halcro handled all of those factors flawlessly.


I listened to hundreds of CDs, SACD's, DVD_As and LPs through the Halcro. Never did it make a discouraging sound. It never faltered even during Florida’s regular power surges and outages in severe weather.

So then, is this power amp perfect? Of course not. No amp is. Even if a thousand people pronounced something “perfect”, there would be another thousand whose taste and sensibilities would somehow be offended by its sound. I believe it is not my job to pronounce something good or bad, but rather to report on how it sounds in relation to a myriad of other components I have heard, owned or currently have as part of a reference system, report as accurately and clearly as possible without unnecessary hyperbole or excessive “audiophilespeak” and to make recommendations based on my years of experience as an audiophile and professional musician. Does that make sense?


Reading “Publishers Listening Materials and Biases” (http://www.stereomojo.com/Articles.htm) may shed some light on what I have just said.


Having said that, since there is no distinct coloration or euphonic, romantic lushness, some may find the sound of the MC20 on the dry side. A bit cool and a bit dry. Compared to most tube amps, those are good descriptors of the MC20's sound. Like wines, it depends on your palette. In this case, your audio palette. The Halcro defines the smallest details in a solid perspective. Some may find this to be too much, preferring a smoother, more constrained approach.

I compared the Halcro mates to the outstanding LSA Reference MK III integrated amplifier. The LSA is a hybrid tube/ss design with 150 wpc that goes for about $6,000. The Halcro combo was just a smidge better, but in fairness, LSA makes a better version of this integrated that would be a closer comparison in price.


In short, the Halcro MC20 power amplifier sounds like the first  “MOJO” graphic above. It pushes all my buttons. It is a sensory wonderland. It lets me not just hear the music, but experience it. I think there is a very strong chance it will for you, too. Halcro warrantees the MC20 for 3 years.

Oh. The trivia question: Where did the Halcro company name originate?

Halcro is Bruce Candy’s middle name – Bruce Halcro Candy.