Halcro AmplifiersMC-20 Two ChannelusedHalcro MC-20 400W/8 ohm Balanced 2-Channel AmpFLASH SALE: Halcro Logic MC-20, Stereo 2 Channel Balanced Amp; Silver face, 400 watts into 4 Ohms & 400 into 8 Ohms like new only $1,695 ! Please see best for best description and condition. ...1695.00

Halcro MC-20 400W/8 ohm Balanced 2-Channel Amp

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FLASH SALE:

Halcro Logic MC-20, Stereo 2 Channel Balanced Amp; Silver face, 400 watts into 4 Ohms & 400 into 8 Ohms
like new only $1,695 ! Please see best for best description  and condition. Clean, big, and powerful sound.

                                    
Known to be a powerhouse sounding amp with effortless sound.   

We are rating this as 8 of out 10 condition, but it's probably a 9. You can choose balanced input or select to use single ended rca input, it's your choice.

Sounds great and you will likely agree. 

Local clients can audition it.

Weinhart Design has two Halcro service company's but Halcro is re establishing the Company.

We guarantee the amplifiers to be as advertised and here to help if and when needed but these are very reliable.

 

SOLID STATE POWER AMP REVIEWS

Halcro Logic MC20 power amplifier


Art Dudley  |  Apr 16, 2006
Within a few years of entering the US market, Australian audio manufacturer Bruce Halcro Candy cemented his place in audio history by designing a amplifier that Paul Bolin said (in the October 2002 Stereophile) "could well justify the creation of a 'Class A+' amplifier category in 'Recommended Components'," and the low distortion characteristics of which prompted editor John Atkinson, a man who has elevated the craft of understatement to a high art, to reach for the word astonishing. That was the Halcro dm58 monoblock ($29,990/pair), which has only recently been superseded by the Halcro dm78.

406halcro.jpg

In that one stroke, Candy became the unluckiest designer on earth, in the same sense that the great San Francisco band Moby Grape ran out of luck when their record label, Columbia, released eight songs from their debut album as four different singles—on the same day. What could you possibly do for an encore?

In the case of Moby Grape, while the merits of their subsequent albums are open to debate (I rather like Wow), there's little question that their wad had in fact been shot. On the other hand, Bruce Candy focused his talents in a new direction, on a very different and altogether less expensive sort of product.

The result of his recent work, the Halcro Logic series of amplifiers, has at least one thing in common with the company's more expensive Reference series: Both lines are the intended embodiments of Candy's complete and utter loathing of distortion, and his desire to shrink and then kill it, Grover Norquist style. Stereophile's readers have already heard how he did that the first time around; today, some five years after the release of the groundbreaking dm58, Candy is making something very different and very new: a class-D amplifier.

You say distortion like it's a bad thing
Well, class-D isn't entirely new, having been toyed with as early as the 1950s. Nor does the D in class-D stand for digital: After classes A through C had been described and created, D was simply the next letter up for grabs (footnote 1).

Even so, and notwithstanding the fact that a class-D amp doesn't necessarily have a digitized throughput, it does behave in a digital manner: Its output devices, typically in complementary pairs, are used purely as switching devices, and so their output signal, if left unmodulated (I'll come back to that), is either a 1 or a 0—meaning the device is either fully on or fully off. Think of it this way: Driven by the raw output of a class-D amp, a loudspeaker driver would either come flying out of the enclosure toward the listener's nose, or struggle equally hard to escape its moorings in the other direction, with nothing in between.

Coaxing the driver into moving in and out is what you want the amplifier to do, of course, but preferably with more in the way of finesse—and, ideally, in mimicry of the continuum that is sound. So you have to put something in front of the class-D output section to control, with near-infinite speed and accuracy, the ratio of time that those output devices spend between being on and being off—which is to say, you have to modulate the output. Most designers of class-D amps do that with an analog technique that has a digital-sounding name: pulse-width modulation.

That's easy: Add a fixed, very-high-frequency carrier signal from a triangular wave oscillator to the input, alongside the audio signal, and make an active circuit—you could even use a tube, I suppose—to compare the two and to then send the difference between them to the switching output devices. Let a higher-amplitude portion of the audio signal equal a wider, positive-going pulse, a low-amplitude part of the wave equal a wider, negative-going pulse, and so forth. Now you've given the output devices an analog blueprint to follow, and their own output is amplified sound—or at least it will be, once you perform the final trick of filtering out that triangular wave's harmonics and a few other nasties.

It's an efficient amplifier, because those switching devices don't require any bias current. It's also a compact amplifier, for the same reason and because MOSFETs that are up to the task can be made very small. But is it a clean amplifier? I'm sure the boys at Stereo Review would have thought so, but let me remind you: Bruce Halcro Candy hates, and I mean really hates, distortion. And in addition to the switching noise that you'd imagine is part and parcel of a system such as this (think of a class-D amp as an audio-frequency switch-mode power supply), he's identified a distortion that, in his words, is mathematically intrinsic to a class-D amplifier with pulse-width modulation: The shape of the triangular carrier wave becomes distorted—is actually rendered asymmetrical—while the amplifier is in use, resulting in a nonlinear phase advance in the final output. Which ain't good.

So Candy, in his quest to cancel out every last iota of distortion, developed a circuit that actively modulates the carrier wave and corrects its symmetry during amplification. The Halcro company has appended the trade name Lyrus to this distortion-canceling circuitry, but you could also call the technique carrier-symmetry modulation: That, in fact, is what Bruce Candy called it in a paper he delivered to the AES convention in 2004, a copy of which I've been trying, with only limited success, to fathom.

MC, phone home
The Logic MC20 ($4990) is Halcro's entry-level Lyrus amp; in fact, it's Halcro's least expensive amplifier, period. In addition to the unique class-D circuitry described above, the 400Wpc MC20 offers a choice between unbalanced and true balanced inputs, an apparently sophisticated switch-mode power supply, and current-sensing and thermal-protection circuits that keep the MC20 from going postal on itself or the user's loudspeakers.

In the unlikely event that a glitch does occur, the MC20 and its owner can fall back on Plan B, which is called HRAS—for Halcro Reliability Assurance Service. Every Halcro Logic component has RS-232 and Ethernet sockets on its rear panel and is supplied with a CD of HRAS software, complete with high-level user interface, ready to be installed on the Windows XP-based PC of choice. With the amp connected to the computer, the HRAS software loaded, and the computer logged on to the Internet, a malfunctioning MC20 can literally call the nearest Halcro distributor, report the fault, and have a new board or perhaps a whole new amplifier delivered by air freight before the owner knows there's anything wrong. As a parent, I can't help being reminded of the time my daughter had a tiff with a playmate at the other child's house, called me using their phone, and cried, "Daddy, come get me now!" (footnote 2) (And as someone who has recently had to jump through flaming hoops of bureaucracy to get his Sony SACD player through the front door of a factory service facility, I can't help being very impressed.)

Overall, in a technical sense, I'm hard-pressed to think of anything that differs more from my low-output, tube-powered, single-ended, class-A monoblock amplifiers (the Lamm ML2.1s) than this high-output, solid-state, push-pull, class-D stereo amplifier. More to the point, Halcro's US high-end representative, the thoroughly genial Philip O'Hanlon, was well aware of that fact when he suggested that I give the Halcro a spin in my system and write this review. Talk about courage.

 



Footnote 1: It's a good thing audio engineers don't use the Etruscan alphabet for naming their operating classes; otherwise, the fourth class of operation would have to be called Class F, which would elicit much snickering from the back of the room.

Footnote 2: But this is a slippery slope: Could an HRAS-enabled amp harvest the user's credit-card number from an unsecure page and buy a new preamp for itself? Could it notify the federal government if the user plays politically unacceptable music (I'm thinking Phil Ochs here), or call the local drug squad if it senses that "Interstellar Overdrive" has been repeated too many times in a single listening session? The implications are staggering.

SOLID STATE POWER AMP REVIEWS

Halcro Logic MC20 power amplifier Page 2

 

 


The Logic MC20 arrived on a disagreeable day, so I was glad to see that Halcro double-boxes their amps, and that their packing materials and other ancillaries are of apparently high quality. One curious thing I did notice during setup was that the MC20 has the most resonant enclosure of any contemporary amp I've tried. If you run your finger along the cooling vents on its top surface, the way a child might pass a stick over the tines of a wrought-iron fence, you'll hear quite a loud sound. The first time I produced the noise by accident, I thought the phone was ringing elsewhere in the house.

The chassis is a mix of castings, stampings, and machine work, most portions of which are reasonably light. (The prospective owner is not, in other words, being forced to pay for a foolishly massive, sculpted faceplate.) It's worth noting that the Halcro Logic MC20 was more difficult to take apart than most amps that come my way—you'd almost think they don't want me to electrocute myself. I persevered nonetheless, and my stubbornness was rewarded with a glimpse of several components whose function I couldn't even begin to identify, save for a large, mostly sealed-off power-supply module.

Even though the manual says that the MC20's break-in period is completed at the factory, I let it run in for about a week before taking any serious listening notes. For the most part, I used the MC20 with my Quad ESL-989 loudspeakers—the idea of a 400Wpc amplifier driving my Lowther horns was just too nutty to try—playing a variety of LPs and CDs at the generally sane listening levels I prefer.

And I must say
The Halcro Logic MC20 really did sound immediately, and significantly, different from most other amplifiers that I've experienced. I didn't have to strain at all to tell the MC20 apart from anything else in the house.

Its most obvious performance characteristic was something that I can describe only as an enormous sense of clarity. The sound of the MC20 was exceptionally, conspicuously uncolored and unsoiled by noise or textures that didn't belong there. On record after record, it placed musical sounds in front of me with a physically big but, at the same time, simple and unspectacular hear-through quality—transparency, if you prefer. It made a big, agreeable, convincingly whole mass of sound between the speakers, every time out.

Those qualities were all in good supply when I tried out André Previn and the London Symphony Orchestra's recording of Rachmaninoff's Symphony 1 (LP, EMI ASD3137), which is itself one of the very best, most transparent-sounding orchestral recordings to be made in the 1970s. The Halcro, while remaining tuneful throughout, with no detectable distortions of pitch relationships, made the timbral colors and spatial realism captured in that recording even more beautiful and impressive than I remembered. By comparison, my Lamm ML2.1 monoblocks provided more in the way of tactile qualities and overall presence and spatial depth, but exhibited less poise and calm in the loudest, most frenetic bits—as in the somewhat obvious (but nonetheless satisfying, and presciently cinematic) final movement.

Hearing the Rachmaninoff reminded me to pull out another of my favorite classical records, the Adrian Boult–New Philharmonia recording of Elgar's Dream of Gerontius (LP, EMI SLS 987), which was made not long thereafter by the same team of producer Christopher Bishop and engineer Christopher Parker (although the two recordings don't sound all that much like one another). The Halcro was poised and forceful—no signs of strain that I could hear—on the loudest passages, such as the insistent drumbeats in the demons' chorus and the tam-tam crash at the moment of judgment.

The Halcro was very good, too, at capturing sonic subtleties, such as the return of the clock motif in the harps late in the work—and musical subtleties as well, such as the (deliberately perverse, I think) bounciness of the fugue-like scoring for the choir that begins when the word dispossessed is passed around among different sections of the choir, and the return of the prayer motif halfway through tenor Nicolai Gedda's final, brilliant solo. There remained sonic differences between the Halcro and the Lamms, of the sort that will tip some listeners' preferences one way or the other—such as the Lamms' superior sense of spatial depth, especially inasmuch as the Lamms allow the choir to sound as if they're coming from an area several feet behind the soloists—but there was no mistaking the musical sense, and the consequent emotional satisfaction, that the Halcro delivered with that record.

After weeks of listening, while I found that the MC20 conveyed consistently less spatial depth than my reference amps, I became equally convinced that the Halcro nonetheless gave a very clear idea of spatial perspective between different sounds within the "stage." That became obvious during a furniture shuffle in my hi-fi room, when I found myself sitting closer to my Quads than usual. While listening to guitarist David Grier's brilliantly performed and equally well-recorded Panorama (CD, Rounder CD 0417), I was struck by how forthright, stable, and utterly believable the players' positions were on the stage relative to one another. Mike Compton's mandolin, in particular, was utterly there at stage right, and the quality of presence was so convincing that I could've sworn I sensed the interaction between Compton and Grier toward the end of the former's solo, when his single notes morph into syncopated chording and Grier's guitar echoes that from the background. Lovely.

Conclusions
The Halcro Logic MC20 impressed me in almost every way: It's a magnificent-sounding amp. It may indeed be more timbrally neutral than my Lamm tube amps, and it was equally good in the area of image stability and precision, as well as in its ability to put across very-low-level detail—to not only let me hear subtle things that were otherwise buried in a recording, but to present them in a way that made sense alongside everything else, and that, under the best conditions (good music, good mood, good health, etc.), could result in an emotional or even physical response. That's worth noting, given that those performance aspects are already among the Lamm's most notorious strengths. And when it came to poise and lack of strain at the loudest end of the scale, the Halcro's superiority was as obvious as it was welcome.

Where the MC20 fell short of my reference was where most other amps seem to, as well: While the Halcro didn't sound mechanical per se, the Lamms allowed music to sound that much more human and organic: Lines of notes had a more natural flow through the Lamms—which also retained their edge in preserving that last, eerily convincing sense of texture in the sounds of instruments and voices.

But for $25,000 less, and given that it plays music superbly well in its own right, you can be more than forgiven for keeping the Halcro nearer the top of your must-hear list for 2006: Consider yourself urged. And while I haven't the slightest idea how to appraise the worth of its parts, it seems that the sheer sophistication of the technology behind the Halcro Logic MC20, let alone its very good performance, qualifies it as a good value.

Beyond that, I suppose everything's relative. There's a sizable Amish population in this part of upstate New York, and passing their one-horse buggies in my car is more or less a weekly occurrence. To them, my vehicle would be almost unimaginably powerful; to a car enthusiast, my 120hp Subaru is the anemic bottom of that company's line. And so it goes.


NEXT: Specifications »

SOLID STATE POWER AMP REVIEWS

Halcro Logic MC20 power amplifier Specifications

 

 


Sidebar 1: Specifications

Description: Solid-state two-channel amplifier. Maximum output power: 400Wpc continuous into 4 ohms (23dBW). Input impedance: 10k ohms, unbalanced, 20k ohms balanced. Output impedance: <0.08 ohm at 7kHz. Frequency response: 5Hz–45kHz, –3dB. THD: <0.007% at 1kHz up to 400Wpc, <0.03% at 7kHz up to 400Wpc.
Dimensions: 17" (435mm) W by 7" (180mm) H by 16" (410mm) D. Weight: 46.5 lbs (21.1kg).
Serial Number of Unit Reviewed: A0000483.
Price: $4990. Approximate number of dealers: 50.
Manufacturer: Halcro, Wayville SA 5034, Australia. US distributor: Halcro Audio USA, Howard Hughes Parkway, Las Vegas, NV 89119. Tel: (818) 230-2627. Web: www.halcro.com.


NEXT: Associated Equipment »

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Halcro Logic MC20 power amplifier Associated Equipment

 

 


Sidebar 2: Associated Equipment

Analog Sources: Linn LP12 turntable, Naim Armageddon power supply, Naim Aro tonearm; Miyabi 47, Linn Akiva, Incognito Shibui cartridges; Tamura TKS-83 moving-coil step-up transformer.
Digital Sources: Naim CD5xAyre CX-7e CD players; EMM Labs CDSD2/DCC2 SACD player.
Preamplification: Audio Note M3; Linn Linto phono preamplifier.
Power Amplifiers: Lamm ML2.1 monoblocks.
Loudspeakers: Quad ESL-989, Audio Note AN-E Lexus.
Cables: Interconnect: Audio Note AN-Vx, Nordost Valhalla. Speaker: Audio Note AN-SPe, Nordost Valhalla. AC: JPS Labs The Digital (CD players), Cardas Golden Reference (some other components).
Accessories: Mana Reference Table, Reference Wall Shelf (turntables); Ayre Myrtle Blocks (various other components).—Art Dudley


NEXT: Measurements »
COMPANY INFO
Halcro
US distributor: Halcro Audio USA
871 Grier Drive, Suite B-1
Las Vegas, NV 89119
(702) 270-9307
www.halcro.com
ARTICLE CONTENTS

 

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Halcro Logic MC20 power amplifier Measurements

 

 


Sidebar 3: Measurements

As with all amplifiers that use a switching output stage, examining the Halcro Logic MC20's performance on the test bench was complicated by the presence of RF energy in its output. Unless this energy is filtered, you can never be sure that you're not actually measuring the interaction between the RF content and the test gear instead of the absolute performance of the amplifier under test. (For a discussion of this subject, see my "Measurements" sidebar accompanying Robert Deutsch's review of the PS Audio GCC-100 amplifier in January.)

Fig.1, for example, shows the waveform of a small-signal 10kHz squarewave as reproduced by the MC20. The risetime appears to be relatively long, but more important, the wave is obscured by a large UHF component with an approximate frequency of 500kHz. This can also be seen in the Halcro's reproduction of a 1kHz squarewave (fig.2). The frequency of the UHF content appears to be lower in this graph, but this is because the digital 'scope lacks an input low-pass filter and is therefore showing an aliased product. Switching into circuit a sixth-order low-pass filter set to 30kHz eliminated the switching noise, revealing a degree of overshoot and damped ringing (fig.3).

406Halfig01.jpg

Fig.1 Halcro Logic MC20, small-signal 10kHz squarewave into 8 ohms.

406Halfig02.jpg

Fig.2 Halcro Logic MC20, small-signal 1kHz squarewave into 8 ohms.

406Halfig03.jpg

Fig.3 Halcro Logic MC20, small-signal 1kHz squarewave into 8 ohms with sixth-order low-pass filter at 30kHz.

A switch-mode amplifier must have a passive low-pass filter between its output stage and the speaker terminals. The tuning of this filter can be critical, as a mismatch can lead to an ultrasonic response peak. When I measured the MC20's frequency response, I therefore examined its behavior into 32 and 16 ohms as well as into the more usual loads of 8, 4, and 2 ohms (fig.4). The MC20 does roll off above the audioband, but, as can be seen in fig.4, the rolloff starts earlier into the lower impedances, with the response into 2 ohms being 3dB down just above 20kHz. Into 8 ohms, the response is –3dB at a more reasonable 55kHz, while into 32 ohms there is the beginning of a peak developing at 70kHz, this correlating with the damped overshoot seen in fig.3.

406HALFIG04.jpg

Fig.4 Halcro Logic MC20, frequency response at 2.83V into (from top to bottom at 2kHz): 32 ohms, 16 ohms, simulated loudspeaker load, 8, 4, 2 ohms (0.5dB/vertical div., right channel dashed).

Fig.4 also shows the variation of response with our standard simulated speaker load, which is moderate at ±0.2dB, implying an output impedance only a little higher than is usual for a solid-state design, despite the presence of the MC20's output filter. I measured a value of 0.3 ohm at midrange and bass frequencies, this rising slightly, to 0.55 ohm, at 20kHz. The amplifier's unbalanced input impedance was slightly but usefully more than specified, at 13k ohms through the low treble, but it did drop to 9875 ohms at 20kHz. The balanced figure was lower than specified, at 14k ohms. The MC20 inverted signal polarity from both sets of inputs.

Measuring channel separation was complicated by the presence of ultrasonic noise. However, using the external low-pass filter, I measured midband figures approaching 100dB, which is excellent. Similarly for signal/noise measurements, I had to use the low-pass filter, which gave an audioband figure of 91.7dB ref. 2.83V into 8 ohms. Without the filter, this degraded to 58dB, due to leakthrough of the noise.

I couldn't use the active low-pass filter for high-power testing. When I plotted the percentage of THD+noise in the amplifier's output against power, therefore, the presence of the unfiltered ultrasonic noise interfered with the Audio Precision System One's autoranging, resulting in some broken traces at lower powers in fig.5. Also because of this noise, the THD+noise level shown below clipping is exaggerated. The clipping powers in this graph are 290W into 8 ohms (24.6dBW) and 540W into 4 ohms (24.3dBW), the latter significantly greater than the Halcro's 400W (23dBW) specification. The amplifier shut down above this level into 4 ohms; into 2 ohms, it went into protection at 183W (16.6dBW).

406HALFIG05.jpg

Fig.5 Halcro Logic MC20, distortion (%)vs 1kHz continuous output power into (from bottom to top at 100W): 8, 4, 2 ohms.

For reasons already explained, I used the 30kHz active low-pass filter to measure how THD+N changed with frequency, which is why fig.6 is plotted only up to 10kHz, the highest frequency at which the third harmonic will be allowed through by this filter. At most frequencies, there is no difference in the THD+N percentage taken into loads ranging from 2 to 8 ohms. There is a peculiar change centered on 90Hz, however, where the THD+N increases into lower impedances. I have no idea what this means, but as the level of spuriae is still below 0.04%, I don't think it significant.

406HALFIG06.jpg

Fig.6 Halcro Logic MC20, THD+N (%)vs frequency at 4.7V into (from bottom to top at 100Hz): 8, 4, 2 ohms.

Without the low-pass filter, it was fruitless to look at the waveform of the spuriae to assess the dominant harmonic; all you can see is ultrasonic noise (fig.7). With the filter, the dominant harmonic, at least at midrange frequencies, is the subjectively benign third (fig.8). But at low frequencies, the increase in THD seen in fig.6 appears to be due to the appearance of the second harmonic (fig.9). Intermodulation distortion was also very low in level (fig.10), though the need to use the active low-pass filter for this measurement meant that I could not do this test at high output powers.

406Halfig07.jpg

Fig.7 Halcro Logic MC20, 1kHz waveform at 6W into 8 ohms (top), 0.2% THD+N; distortion and noise waveform with fundamental notched out (bottom, not to scale).

406Halfig08.jpg

Fig.8 Halcro Logic MC20, 1kHz waveform at 6W into 8 ohms (top), 0.0116% THD+N, with sixth-order low-pass filter at 30kHz; distortion and noise waveform with fundamental notched out (bottom, not to scale).

406HALFIG09.jpg

Fig.9 Halcro Logic MC20, spectrum of 50Hz sinewave, DC–1kHz, at 6W into 8 ohms, with sixth-order low-pass filter at 30kHz (linear frequency scale).

406HALFIG10.jpg

Fig.10 Halcro Logic MC20, HF intermodulation spectrum, DC–24kHz, 19+20kHz at 12W peak into 8 ohms (linear frequency scale).

The presence of the ultrasonic switching noise aside, the Halcro Logic MC20 offers good measured performance. It will work best with speakers having impedances between 4 and 16 ohms.—John Atkinson


NEXT: Jim Austin, June 2009 »

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Halcro Logic MC20 power amplifier Jim Austin, June 2009

 

 


Jim Austin wrote about the Halcro Logic MC20 in June 2009 (Vol.32 No.6):

The $4995 Halcro Logic MC20 is a lesson in stereotypes defied. It demonstrated that pretty much everything I ever assumed I knew about digital amplification is wrong.

My tastes as an audiophile lean toward the simple. The more direct and simple the connection between the original musical source and my eardrums, the happier I tend to be. I love the simplicity and elegance of analog transducers and step-up transformers converting mechanical vibrations into moving electrons in a way that I find direct and easy to comprehend: from music to electricity. I prefer fewer gain stages, generally, and few-way speakers with minimalist crossovers.

I'm no zealot—I enjoy digital, and I like a little bass and treble to go with my midrange, so I don't go in for low-powered single-ended-triode tube amps and single-driver speakers. But my biases, if not necessarily the products I own, tend toward the less complicated end of the audio-tech spectrum. This is an ideological as much as an aural preference, and thus subject to revision as I hear new gear. Still, you need to know: Going into this review, I preferred my music straight up, sans long ingredient lists and paper umbrellas.

Halcro Logic's MC20, the two-channel version of a series that also comes in multichannel varieties for home-theater enthusiasts, is a switching amplifier—a relatively new technology that no doubt has a very long parts list. And John Atkinson's measurements of it looked awfully scary, with a lot of ultra-high-frequency noise that alarmed me. My response is irrational, I know: the noise is way above the range of human hearing, and above what any loudspeaker I know of can produce. Still, the noise isn't a pleasant prospect. Add to that the MC20's astonishingly resonant case, which Art Dudley pointed out in his April 2006 review—tap it and you feel you could almost break a wineglass if you excited it at just the right frequency—and let's just say that I did not expect the MC20 to be to my taste.

But despite its parts count, measured HF noise, and very resonant case, the MC20 had a simple sound that was very easy on my ears. From the beginning of my extended audition—I kept the MC20 for months, using it with several different sources and two pairs of loudspeakers—I expected to hear something I didn't like. Like-minded audio friends and colleagues—my friend Bryan, who listens to tubes and vinyl almost exclusively, and a visiting speaker manufacturer who shares my taste for simple technology—encouraged me in my bias as I searched for a telltale sterility or an absence of emotional immediacy. I never found either.

Art Dudley said that the Halcro sounded like no other amplifier he'd ever heard. My less experienced ears detected no such radical departure from my own past experience—only from my expectations. But it was almost as if Halcro had set out to confound the expectations they knew such a product would engender. First, imagine the fatiguing, bright sound of ringing casework. Or imagine what John Atkinson's graph of the MC20's small-signal 10kHz squarewave into 8 ohms might sound like were the overlying mess in the audible range (see fig.1 of the original review).

Then imagine the precise, subjective opposite—not a hole where the high frequencies ought to be, but a sound that lacks even a trace of glare or HF electronic hash. That's what the Halcro Logic MC20 sounded like. All the HF information was there, but it was always easy to listen to, never fatiguing. There was a touch of darkness and a dryness that I, who can't tolerate a bright, "high-tech" sound, found very pleasing. It was almost as if, somehow, the MC20 very slightly accentuated the somewhat dry acoustic of my listening room. It was almost as if Halcro Logic had set out to confound the biases of simpleminded audiophiles—audiophiles like me.—Jim Austin


NEXT: Jim Austin's Review System »
 

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Halcro Logic MC20 power amplifier Jim Austin's Review System

 

 


Sidebar: Jim Austin's Associated Equipment

Analog Source: Rega P7 turntable & RB-700 tonearm, Zu Audio DL-103 phono cartridge.
Digital Sources: Marantz SA-7S1 SACD/CD player, Benchmark DAC1 D/A converter.
Preamplification: EAR 834P phono preamplifier, Balanced Audio Technology VK-52SE line-level preamplifier.
Power Amplifier: Balanced Audio Technology VK-55SE.
Cables: Digital: Stereovox HDXV. Interconnect: Q-Audio Tao (unbalanced), Mogami (balanced). Speaker: Chord Odyssey. AC: Belden, PS Audio Statement.
Accessories: Generic steel equipment rack with wooden shelves, Wiremold power strip.—Jim Austin
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We prefer this method of payment and also makes shipping to addresses other than billing agreeable. VISA, MC and Papal are gladly accepted within the U.S. and Canada as long as the charge is approved and shipping to the billing address is to the one on record and plus 3% to cover card service costs. 

Please call me directly in my world class showroom in Los Angeles weekdays @ 310-472-8880 or any reasonable time on my cell including weekends @ 310-927-2260 and I can answer your questions and help you with all of your new and pre owned needs.

* * * We are always interested in purchasing quality Audio and Video items, LP collections and quality trades are welcomed. * * *

Please feel free to view our other used items for sale on Audiogon or come to our website to view our new products and see the exciting new lines we have to offer you like Bowers & Wilkins, Bryston, Aqua Acoustics, Rel Acoustics, Synergistic Research, Roon Labs, Pro-ject, Van Den Hul, Marantz and many others.

We are proud to be the dealers representing the new Diamond B&W Reference Speakers.

It is best to call David and visit: www.weinhartdesign.com with questions or come to our Los Angeles Showroom 310-472-8880 or on my cell after hours and weekends 310-927-2260 any time from 10AM - 7PM PST.

Weinhart Design has lots of other items new and used and if you’re in Los Angeles or visiting please accept my invitation to experience our World Class Audio Showroom and please visit our web site @ www.weinhartdesign.co

We accept payments by Bank Wire Transfers without fees and is the only form of payment on all sales out of the U.S. and Canada. 

We prefer this method of payment and also makes shipping to addresses other than billing agreeable. VISA, MC and Papal are gladly accepted within the U.S. and Canada as long as the charge is approved and shipping to the billing address is to the one on record and plus 3% to cover card service costs. 

Please call me directly in my world class showroom in Los Angeles weekdays @ 310-472-8880 or any reasonable time on my cell including weekends @ 310-927-2260 and I can answer your questions and help you with all of your new and pre owned needs. 

 

Changing the Way You Listen,

 

The Audio and Video Experts...

David Weinhart  and the Weinhart Design Audio team

President & CEO [email protected] 

Visit our Weinhart Design Audiogon The AV Experts STORE:

2337 Roscomare Road, Studio #1

Los Angeles, California 90077 

(Showroom) 310-472-8880 

(Cell) 310-927-2260 10AM-7PM West coast time

www.weinhartdesign.com 

🎶 🎵 🎶 

 

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