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Marchand Electronics EC626 Power Amplifier

Single-Ended, Solid State, Monobloc Power Amps

[Marchand EC626]
Marchand EC626 Photo courtesy Marchand Electronics
[Italian version]

Product: Model EC626 SE MOSFET Power Amplifier
Manufacturer: Marchand Electronics, Inc.
Approx. price: $995 each ($695 for each kit)
Reviewer: Richard George - TNT USA
Reviewed: January, 2004

After unpacking the box from Marchand Electronics several months ago, I found myself staring at the new pair of EC626 monoblocs. Outwardly, they didn't look much different from another pair of solid state monoblocs that passed through here some time ago. Things are not always as they seem. These amplifiers are simple in appearance without gaudy adornment that is often inflicted on equipment in a similar price range. The massive, simple build, huge heatsinks, and large, premium quality binding posts give the impression of a no-nonsense amplifier designed to deliver massive amounts of effortless power. But, as I said, things aren't always as they seem. The model name on the fronts of the amps, displayed on a plaque in bold, raised letters, give the first clue that something is seriously different about this pair of solid state monoblocs - Eclipse SE MOSFET. SE? As in "single-ended"?

Certainly single-ended amplifiers have been around a long time, as they were the first amplifier design back at the birth of electronic signal amplification. Utilizing a single vacuum tube for output, these primitive first amplifiers had very little power; early examples seldom exceeding one watt. The search for more power brought about push-pull topology using arrays of tubes in pairs. As amplifier power grew greater, speakers that were smaller, but less efficient, could be developed. Smaller speakers were more practical for ordinary people to use compared to the horn-loaded behemoths they succeeded.

The advent of transistors allowed engineers to achieve greater power with lower measured distortion than ever before. But a funny thing happened as solid state achieved dominance in the audio industry: some audiophiles didn't like the way they sounded. This vocal minority claimed solid state equipment was harsh, bright, and brittle sounding, that regardless of claimed distortion measurements, solid state amplification sounded less like music than their vacuum tube forebears.

Over the past 20 years, single-ended, vacuum-tube amplifiers combined with high-efficiency, horn-loaded loudspeakers have achieved a powerful following. During this time, the question has sometimes been asked, is the difference in sound quality between SET amps and solid state due more to the topology of push-pull and high negative feedback v. single-ended and low negative feedback, or is the difference more related to the solid state vs. hollow state amplification device?

While Marchand Electronics is not the first to try to answer this question with a timely product, they are currently producing one of the more affordable examples. The Eclipse power amplifiers are offered in two versions, the inductor-coupled Eclipse EC616, and the capacitor-coupled EC626. The EC626 is the subject of this review.

What Is the Eclipse EC626?

The basic topology description of the EC626 initially sounds like any of a hundred different single-ended, vacuum-tube amplifiers currently on the market. It is a pure Class A, single-ended design that uses minimalist circuitry in a simplified design, and it uses no global negative feedback so as to produce the least alteration of the audio signal. However, instead of a directly-heated triode for amplification, the EC626 uses a single MOSFET. The EC626 is capacitor coupled and uses 40,000uF filter capacitors. Being less efficient than the inductor coupled EC616, the EC626 has a much larger heatsink. Each monobloc of an Eclipse EC626 stereo pair is built as a mirror image of the other. This means that, when placed next to each other, the single heatsink on each monobloc is facing away from the other.

The Eclipse EC626 amps measure 20cm long, 33cm deep, and 13cm high (8" x 13" x 5") and weigh 6.8kg (15 pounds). Unlike the open design of the EC616 (which resembles a valve amp with exposed transformers, MOSFET, and filter caps), the components of the EC626 are enclosed within a black, crinkle-finish box with the heatsink for the single MOSFET on one side. In outward appearance, the Eclipse EC626 looks very similar to some of the high-powered solid state offerings by Marchand Electronics. The power switch and name tag are located on the front of the amp; one RCA connector, IEC power connector, a fuse, and the speaker binding posts are on the back. The binding posts are high quality, massive, 5-way units that are large enough to accommodate any modern, anaconda-sized speaker cables. Each amp sits on four rubber feet.

[Eclipse Rear Panel]
The back panel of the Eclipse, showing the RCA and IEC connectors and the premium quality binding posts.

Internally, the Eclipse is a very simple and cleanly constructed unit that uses a toroidal power transformer and two small circuit boards. The massive heatsink is really two heatsinks: the single MOSFET is attached to the front heatsink; a pair of Arcol wire-wound resistors is attached to the rear heatsink. The entire case, including the solid frame, covers, and heatsink, are made of aluminum. Build quality of the samples was very good.

Similar to SET amps, the EC626 produces a relatively modest power output of only 10 watts, slightly more than a 300B-based amp, but substantially less than a C633 or 845-based circuit. Because the EC626 operates in pure Class A mode, it runs at nearly maximum A/C power draw at all times. The need for the massive heatsinks becomes obvious, even with an amp that only delivers 10 watts of output.

[Inside the Eclipse]
Inside the Eclipse. This is as simple a solid state amplifier as you will find - note the single MOSFET.

How Do They Sound?

Several sets of speakers were used during this review, including B&W DM602, nOrh SM5.1, Reynaud Twins, Hornshoppe Horns, Omega TS-1, and Electro-voice based, DIY speakers. Generally speaking, the Marchand Eclipse amplifiers delivered excellent sound with most, but there were a few reservations.

The Marchand monoblocs drove the B&Ws beautifully, delivering exceptional clarity of sound and surprisingly deep, powerful, and well-controlled bass. However, since the B&Ws are only 90dB efficient, volume must be limited to a 'reasonable' level. Clipping can be induced if the volume is raised with too much enthusiasm. Similar observations applied to the nOrh SM5.1 speakers: bass was clean and well-controlled, and the clarity of mid-range and sharpness of imaging were superb with these speakers. At a claimed 88dB efficient, volume must be limited even more than with the B&Ws.

While the commercial 2-way speakers did quite well when powered by the Eclipse monoblocs, they were all let down by their relatively low efficiency and the limited, available power. The remaining speakers ranged from 92dB to 98dB efficiency. Additionally, the lack of crossover network (or extremely simplified crossover, in the case of the Electro-Voice) was very beneficial to amplifiers that had a maximum output of only 10 watts.

The next set of speakers tried with the EC626 monoblocs was a pair of Hornshoppe Horns, which are notoriously picky about amplifiers. The Horns, at 92dB efficiency, seemed much more efficient than the previous two speakers, because they are single driver speakers - no crossover network to soak up power. With most solid state amps, the Horns deliver sound that is grating, irritating, and fatiguing: the Horns require a supremely smooth and musical amplifier. Results with the Eclipse amplifiers were mixed. The Eclipse amps through the Horns were very clean sounding; there was no trace of grain in the mid and upper end. That is the good news. Unfortunately, the combination resulted in a somewhat thin sound, as though mid- and upper-bass were not being delivered with enough weight. Using a vacuum tube preamp with this combination resulted in very good sound quality, though still having a slightly thin presentation. There was a tradeoff, though, as detail and clarity were exceptional, surpassing any of the other commercial speakers used with the Eclipse monoblocs. Holographic imaging also was excellent. When combined with a Hornshoppe Hornline sub-woofer, crossed over at a relatively high 100Hz, the musical sound quality was very good, very involving, though some imaging seemed to be lost with the sub crossed over at such a high frequency. A loss of imaging is a small price to pay for improved tonal balance.

Switching to a pair of Omega TS-1 speakers (96dB efficiency) changed everything. The EC626 monoblocs delivered a surprising and delightful performance, sounding both smooth and detailed, precise, clear, and always musical. The Eclipses couldn't quite match the liquid-smooth mid- and high-frequency performance of a good 2A3-powered SET, but the Marchand amps more than compensated with an extended upper end that allowed the sparkle and brilliance of well-recorded treble to shine through, especially when compared to the performance of most SET amps. Low frequency control and clarity was also notably excellent. Quick, solid, bass transients were delightful. Complex and exotic percussion in Benise's Mediterranea had more punch and sharper sound than my SET amps, without any of the exaggerated, soggy bass so common in much of today's mass market solid state equipment. While this speaker and amp combination could not compete with the sheer, visceral impact of Benise live, the mood and emotional content of the music remained intact.

The mid-range performance of the Marchand amplifiers was also very impressive. Vocals, from the smooth tenor of John Gary to the ethereal beauty of Charlotte Church, sounded excellent with the Omega speakers. There is much to be said for the sound quality of single-driver, cross-overless speaker designs. An additional benefit, compared to the Fi X, 3-watt SET amp that I often use to drive the Omegas, was noticeably greater headroom, and the ability to reproduce complex music with greater instrument separation and clarity than has ever been possible with only three watts per channel.

As a final experiment, one last set of speakers was tried. The speakers were home-made, DIY, open-baffle speakers using a pair of vintage (1950s) Electro-Voice 12TRX drivers. The 12TRX is a 12-inch, coaxial driver that has a 12-inch paper cone, a felt-damped whizzer cone, a compression horn tweeter, and over 98dB efficiency. The cross-over network is handled by a single capacitor on the tweeter and an L-pad, for high frequency attenuation. The Electro-Voice drivers are notoriously revealing of the sonic shortcomings of many modern, solid state amplifiers. Expecting warts to be revealed, I was pleasantly surprised to find the Marchand Eclipse EC626 monoblocs sounded stunningly powerful and supremely musical when driving them - provided a valve preamp was used to control the Eclipses.

Complex musical passages, like some in Beethoven's Second Symphony, sounded very good with the Omega/Eclipse combination. However, the ability of the Eclipse/Electro-Voice combination to dissect the sounds within the recording and to clearly separate each instrument, while allowing the music to flow unimpeded was a revelation - the Eclipses provided extreme detail without loss of musical content. Switching to a Jacintha LP, Lush Life, brought Jacintha into the room, surrounded by her band. Listening to this combination was delightful and sometimes a little eerie as it raised the hair on the back of my neck. The Marchand EC626 Eclipse monobloc amplifiers are capable of superb music reproduction.

Three solid state and three vacuum tube preamps were tried with the Eclipse monoblocs. When combined with the Eclipse amps, the BV Audio P1 sounded somewhat bright and analytical; musical flow was replaced with sometimes excessively highlighted detail. Using the +6dB and +9.5dB gain settings of the IRD Purist resulted in a similarly analytical sound. However, when using the zero-gain setting of the Purist, no detail was lost, but the sound was more musical and less analytical. As an experiment, the preamp-out plugs of a vintage, Marantz 2245 receiver were used to control the Marchand amplifiers. While the sound was somewhat warmer and less analytical than the Purist or the P1, it also lacked a great deal of detail - it sounded as though a blanket had been dropped over the speakers. This was not an improvement.

[Eclipse Pair]
The Eclipse pair, setup for initial burn-in.

All three tube preamps, including a Decware ZTPre, a Mapletree Audio Design Octal-6, and a Conrad-Johnson PV-2a, had warmer, more musical sound than the solid state preamps. However, while the CJ was very satisfying musically, it was also very noisy, especially when used with the Electro-Voice speakers. The ZTPre had the lowest noise floor of the tube amps, almost as low as the Purist and the P1. It also had the most detailed sound with the greatest clarity of any of the valve preamps. Of all the preamps available, the Decware ZTPre had the best synergy with the Marchand EC626 amplifiers.

Positive Impressions

The high end extension of the Eclipse amplifiers is very good. When compared to other high end, solid state amplifiers, the treble extension is not exceptional, but when compared to many SET amps, particularly those using directly heated triodes, it does sound exceptional. It is rare to hear the high end sparkle with 300B amps, as they often sound somewhat dark.

Bass is clean and solid sounding; bass transients are quick and very well controlled. Many SET amps can't approach the bass quality of a good solid state amp. The Eclipse EC626 amplifiers manage to provide bass quality on par with good solid state amps (provided the listener observes the power limits of the Eclipse) - and that is a compliment!

The Marchand Eclipse monoblocs sound very detailed. Unlike many solid state amps that seem to have a multiple veils covering the sound and muting small details, the Marchand amps seem to deliver everything to the speakers that is on the recording. Perhaps it is the lack of global negative feedback, or perhaps it is the simplified circuitry, but the Eclipse amplifiers will allow most people who are used to common solid state, push-pull topology to hear sounds and instruments on their recordings that they never knew existed. This is a quality I have always admired about my Decware SE84C Select amplifier - but the Eclipse does it with almost 6 times more power.

The most important aspect of the Eclipse EC626 monobloc amplifiers is their ability, when properly set up and matched with appropriate components, to provide an involving musical experience. Some high-powered solid state amplifiers sound sterile and analytical no matter how they are setup. The Marchands do not suffer from that flaw.

Having only 10 watts each, it can be rather easy to drive these amplifiers into clipping. Fortunately, they clip softly, almost like a tube amp. As such, if you overdrive them (as I did a few times), the sound suffers drastically, but the speakers remain intact.

The Marchand Eclipse EC626 monoblocs have as their defining characteristic, simplicity of design. From a circuit that uses a minimum of parts, to an external design with little non-functional adornment, the Eclipse amps eschew complexity in favor of elegant simplicity and excellent build quality.

Negative Impressions

For all the noteworthy and wonderful qualities of the Eclipse monoblocs, they have one serious drawback that must be taken into account prior to purchase. I used them in combination with numerous components I had available over the past several months. What I observed is that, if the combination was good, the sound quality was simply excellent. However, if the equipment combination was less than ideal, sound quality quickly suffered. I don't know why this was so, and it may not be such a problem with other setups in other listening rooms. Perhaps it was only an artifact of my listening room, which about to be renovated. Whatever the case, a buyer must not give up if the Eclipse amps don't sound excellent right away. Proper system synergy and setup will be very rewarding.

Still, with either of the two, high quality, solid state preamps that I tried, a BV Audio P1, and an IRD Purist (in all but the 'passive' mode) the Eclipse monoblocs sounded overly bright with detail bordering on the 'etched' sound typical of many solid state amps. Switching to any of the available tube preamps completely changed the character of the sound, and, in the case of my experiments, always for the better.

Unfortunately, I did not have any of Marchand Electronics' own passive preamps available to find out how well they work with the Eclipse monoblocs. However, since the best sound from any of the solid state preamps was the IRD Purist set at its zero gain setting (the equivalent of passive), a Marchand passive preamp may be anticipated to work very well with these amplifiers.

The Marchand Electronics EC626 monoblocs don't have the power to take on many typical 'high end' speakers. At only 10 watts, they are limited to speakers with efficiency of about 92dB/1 watt/1 meter or higher. This is the same complaint observed with most SET amplifiers.

When combined with some digital sources, such as the nOrh CD-1 used for this evaluation, some harshness can be heard. However, unlike typical push-pull solid state amplifier designs (and some tube amps as well), the harshness is subtle rather than overwhelming. Typically, very detailed amplifiers seem to pick out any harshness from the source and send it to the speakers. The EC626 is no exception. Considering the superb sound that LPs achieved with the Eclipse amps, using a superior digital source is necessity, but one that will be well worth the effort.

Due to their Class A operation, these amps run quite warm and require a location that will provide sufficient cooling. They are more typical of other Class A amps, rather than the Class AB solid state amps that they superficially resemble. However, unlike the extremely hot tubes of comparably powered SET amps, the observed maximum temperature of the heatsinks will not cause burns if touched.

[Cover off the Eclipse]
Overview of the Eclipse with the top cover removed. The clean, simple, solid construction is obvious, even in a low-resolution, digital photo.

Conclusions

Every audio design is a compromise. As such, a buyer must understand the nature of the compromise. The EC626 Eclipse amplifiers deliver extremely detailed sound, too detailed if the audio front end isn't up to the task. They can be unforgiving of poor synergy, resulting in sound that is less than pleasant. However, they are also capable of delivering a wonderful and very musical presentation, provided the rest of the system is properly matched. It is important to remember that this can be said of any and probably all high-end audio components - they must be properly matched for good synergy, and the system must be properly set up to achieve true, high-end sound.

What to think of the Marchand Electronics EC626 monoblocs. They are single-ended transistor amplifiers that provide most of the advantages of SET designs, while eliminating some of the disadvantages. They have a sound that is more immediate, more musical, and more involving than most typical solid state designs, but they are limited in speaker selection by having only a fraction of the power. They do have greater power than most SETs, and they do so without the fragile, glowing bottles of valve amps. To some this would be a great disadvantage, as the visual impact of glowing vacuum tubes has a visceral effect on many people. However, others have no desire to have equipment that contains high voltages and is controlled by antiquated tubes that could catastrophically fail, possibly damaging the amplifier.

The Eclipse Single-Ended MOSFET is a wonderful addition to the immense variety of equipment available to the audio enthusiast. It provides a new avenue to approach audio amplification at a price that, while not cheap, also is well below the stratospheric level attained by some other examples of single-ended, solid state amplifiers. By combining most of the sonic advantages of single-ended, tube amps with most of the ergonomic advantages of solid state devices, the EC626 strikes a useful blend of attributes that will be greatly appreciated by anyone who makes the effort to match the rest of the system to the Eclipse Monoblocs. In some ways, this has been a frustrating review, as I had to search for combinations that made the Eclipse amps shine. Now that I know what is needed and can really appreciate them, I will be quite saddened to see them go.

Many thanks to Phil Marchand of Marchand Electronics, for providing background information and the samples used in this review. Thanks also for his endless patience while this overlong review was being prepared.

Copyright 2004 Richard George - www.tnt-audio.com Photos by Richard George, except where noted.

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