Audio by Van Alstine DVA M225 Monoblock Power Amplifier

Sometimes reviewers need to pay close attention to all the details in the material their editors send them for a review. When Robert Harley suggested that I review a pair of Van Alstine M225 monoblock power amplifiers, my instant reaction was “Yes.” Frank Van Alstine has quietly been making outstanding audio designs for around half a century, and I hadn’t had the chance to fully audition any of his work in years. 

But, urgh, in a world where the main goal of high-end design has sometimes seemed to be to create power amps that are bigger than speakers, that break the 300-pound limit, and that cost well over $30,000 a pair, I expected more of the same (and promptly resumed my weight-lifting exercises).

Well, all kidding aside, sometimes it really does pay to read the manufacturer’s literature. The two power amps arrived stacked in the hands of a deliveryman, who showed no signs of strain. Moreover, I learned that each M225 costs $1699, or almost exactly $3400 a pair—high-end prices, but scarcely highway robbery, and cheap for a cutting-edge design.

It was their size and weight, however, that were truly striking. They were almost tiny by today’s standards—and even by those of the 1960s. They were only 9″ wide, 10″ deep, and 4″ high, and their shipping weight was all of 17 pounds. Moreover, they were anything but compromises in terms of power. Van Alstine rates them at 225 watts into 8 ohms, and over 300 watts into 4 ohms. In practice, I quickly found that they deliver real power even into demanding loads. In fact, they are an almost ideal way of teasing fellow audiophiles. You can always ask them if they still have one of those “old-fashioned,” large power amplifiers.

Moreover, while they operate in Class A at lower levels, they shift into Class AB at higher levels, and run relatively cool even at high playback. With no heating or placement issues, they virtually disappear behind floorstanding speakers, which means that you use long XLR cables and short speaker cables—a combination I find is generally more neutral and provides better performance. (They only have XLR inputs, but a neutral-sounding DVA R2X adapter is available for $279 to convert to RCA from XLR for audiophiles who have preamps with RCA outputs only.)

Far more importantly, their sound quality is really excellent, with some of the best soundstaging I’ve ever heard. You’ll forget about their size and weight the moment you listen to them. These are great-sounding amplifiers, even in a world where virtually all of today’s power amps are among the most neutral and least-colored components in the audio chain.

The Technical Details

I realize that many TAS readers have moderate to no interest in circuit details or technology, but this is a truly innovative design that draws heavily on Van Alstine’s long history of working with solid-state circuits. It is a pure differential amplifier, which the manufacturer’s website says “uses a new and unique version of our award-winning SET amplifier design. These are Class AB amps that operate as Class A amps at normal listening levels. The SET name stands for our unique Single Ended Transistor voltage-amplifier design. This is our newest design with a simple but amazingly effective bipolar transistor front end followed by a very fast and rugged power MOSFET current-amplifier section. The frequency response is within 3dB from under 10Hz to over 100kHz. Our SET amplifiers are uniquely DC stable. This means they will not generate speaker-damaging DC-drift, even when driven past clipping. The combination of our design ideas allows the amplifiers to run cooler, last longer, and be amazingly fault tolerant. The DVA M225 has four double-die MOSFET output transistors. There is plenty of power for any rational loudspeaker.

“All of our SET power amplifiers, including the new DVA M225, have regulated power supplies for all areas of the amplifier, including the output transistors. The regulated power supplies provide unequaled bass control and micro-dynamics. In the DVA M225 there are no unregulated power supplies—anywhere!”

Well, there may be just a bit of hype in these statements, so I asked Frank Van Alstine, a designer with half a century of experience in amplifier design, to give me the full background on the circuit, and I suspect his response will be a great deal more reassuring as to how the design effort on the M225 could end up doing more with less: “Our M225 amplifiers actually started life here in the early 1980s! Back then we designed a complete replacement audio set for the unreliable Dynaco ST-120 amplifier, salvaging only its case, power transformer, and some of the big power-supply capacitors. Our MOSFET 120 was a good sounding amplifier for its days and was bullet-proof reliable. Power was limited by its power transformer and layout, and when more power and performance were demanded, we tooled our own chassis and designed more powerful amplifiers with more conventional bipolar power supplies. 

“There this little uni-polar design rested for nearly 40 years. It came awake here when a client brought a still working MOSFET 120 amp to sell for him. We hooked it up to our best current system and were surprised at how nice it sounded. Evidently, our limitations with source and speakers were limiting our evaluation back then. 

“My engineer grabbed our old schematic and took it home to study. He found lots of flaws and just for fun did a completely modernized design upgrade with all modern active devices fed by adjustable regulated power supplies and everything properly biased. This included the best new Exicon power MOSFET output transistors. He installed these proto-circuits in a spare chassis, and we powered it up in my reference system. 

“It made our day! Really transparent, engaging, and dynamic, a musical delight. I immediately designed new circuit boards for it and put together all the other needed parts and designed a new chassis and announced the new DVA SET 120 60Wpc power amplifier. 

“My EE determined that the design was scale invariant. We could make a much more powerful amplifier simply by upping the voltage, current capability, and some of the values of the parts to scale the design up to 200Wpc, our DVA SET 400 stereo amplifier. This amp is just as engaging and natural sounding and has been a big seller for us. Again, great reviews. 

“Now a what-if happened. What happens if we can eliminate essentially all the residual harmonic distortion, even that which we can’t measure, along with most of the noise? This requires a differential balanced design. We can do that! 

“The mirror-imaged audio boards are small. They do not need the higher power-supply voltage of conventional big amplifiers, so the amplifier could be scaled down in size to fit on your shelf, pick up, move, and ship easily, and be done at an affordable price. One more new chassis designed and fabricated, one more new audio board pair and power supply designed and all put together, creating our new and unique DVA M225 balanced mono 225W amplifier.”

Let me be clear, I’m not saying in any way that M225s are the design approach to a great power amplifier. I have a half century of experience with tube, hybrid, solid-state, and digital designs. I heard truly excellent results from each option—and mediocre results, as well. I do, however, feel that you should know the design goals and concept behind a product—especially one this innovative and one that, as I’m about to describe, sounds good.

The M225’s Sound Quality

It is sound quality that counts from the audiophile’s perspective, and the M225 does have rivals, and power-amp sound quality must be kept in careful perspective. Accordingly, I should preface my description of the M225’s sonics with a couple of points about amplifier reviewing and selection where I differ from many of my colleagues and many audiophiles. 

To start, the design of power amplifiers has scarcely advanced to the point where they all sound alike, but one needs to be very careful in judging the overall impact of the different nuances in the sound of really good power amplifiers on any given system. 

First, the colorations in the components in the front end, in interconnects and speaker cables, in speakers, and in the interface between the speaker position, listening-room acoustics, and listening position normally generate more coloration than the better power amplifiers. 

Second, the sonic nuances in a given power amplifier in a given system depend to some degree on the speaker load and character, and the speaker cable. Finding the best synergy even between these three components is difficult at best, and the subtler sonic merits of a given power amp will vary accordingly. 

Third, much depends on your taste in music and your listening experience. Everyone has his own “absolute sound” as a goal, but that goal differs from audiophile to audiophile, reviewer to reviewer, and designer to designer. 

Finally, I have never had the kind of emotional epiphany that some audiophiles, reviewers, and designer have had with good-sounding components, and I’m extremely doubtful about reviews that tell me that a given power amplifier reveals dramatic new aspects of the music. You do often hear a better soundstage, better dynamics, better transparency, better bass power, more coherent musicality across the entire frequency spectrum from a given power amp, and sometimes you hear it consistently across the full range of musical sound qualities. 

But one needs to be careful. Every good amplifier sounds different enough in small ways that one may be more revealing than another, but the sonic differences in truly high-end power amps are limited. My experience has been that suddenly hearing a dramatic improvement in performance in a new amp in one aspect of sound can easily, over time, be revealed as voicing one aspect of sound quality at the expense of another. Moreover, the fact that an amplifier sounds great in a given system often does not mean that it is exceptional in a wide range of different systems or that other audiophiles will hear the same benefits. In practice, the better the amplifiers you compare, the more these issues matter.

Yet, all that said, the sound of the M225s did prove to be outstanding with a wide range of speakers and speaker cables. One key aspect was its neutrality in both my reference system and the reference systems of several of my friends, who use some very demanding Wilson and Magico speakers. 

The M225 may not have had the dynamic energy of far more powerful amplifiers in reproducing the lowest frequencies at extremely high volumes, but control of bass dynamics and detail were very good, and the deep bass matched the rest of the bass as naturally as the recording permitted. In fact, the tightness and detail of the deep bass often made the overall sound of the bass seem more musically natural than it was with amplifiers that delivered more sheer energy but tended to excite resonances in a given listening room. 

More isn’t always better in most real-world listening rooms, unless you absolutely must feel the furniture vibrating and low-level resonances from something in the room décor. Broadly speaking, the deepest bass of the M225 was as good as the speaker and the listening room permitted, even with truly demanding recordings of synthesizer, organ, and bass guitar. 

With speakers with anything approaching normal levels of efficiency, the midbass through the lower midrange was as consistently natural in dynamics, timbre, and detail as any power amplifier I’ve encountered. The M225s seemed exceptionally good in dealing with different speaker and cable loads, and in controlling the speaker even with very demanding recordings like the Oue/Minnesota Orchestra’s performance of Copland’s Fanfare for the Common Man (Reference Recordings RR-93CD), the bass tests on the Reference Music test disc that come with the PS Audio Audiophile’s Guide (Octave Records Oct-0004), and a selection of different recordings of Saint-Saëns Symphony No. 3 using the Qobuz streaming service.

Moreover, I did not detect any clear voicing or coloration in the rest of the musical spectrum from the midrange up through the audible limits of the treble. There was no point where the M225 seemed to emphasize or reduce some aspect of timbre, no sign of etching or hardening or softening of low- or high-level dynamics. No product can have perfectly neutral voicing or performance, but I’ve heard far more expensive power amplifiers that introduce more emphasis in the upper midrange, that did not resolve as much low-level detail, or did not provide quite as well-controlled high-level dynamics. 

I also must give the M225 full marks for some of the best soundstaging I’ve heard. I think if you can audition this power amp in a truly good system with proper setup—and with a recording that really does have natural depth, width, a detailed placement of voice, and instruments that are of natural size—you will find the M225 to be at the top level of performance for any power amplifier around. It also is an outstanding amplifier for hearing the real-world differences in the quality of soundstaging and musical detail between recordings, and between the various levels of resolution and method of recording and streaming. 

One particularly good such test is the Sigiswald Kuijken and La Petite Band recording of Vivaldi’s Le Quattro Stagioini (Accent SACD ACC24179)—a recording that seeks to recreate some of the original instrumentation and where every bit of added detail is aesthetically important in revealing how complex Vivaldi can really be. At the same time, try any natural jazz group, natural recording of country or rock, or naturally staged vocal group.

The only caution I’d give is that overproduced and manipulated recordings are revealed for what they are. You also may need to slightly adjust the balance control to truly hear the best soundstage. There are reasons that the late Dave Wilson described the balance control as the “soundstage control” in the days when he was reviewing for TAS.

Summing Up

Don’t let its size fool you. This is one of the best, most neutral, and most revealing power amplifiers around within its power limits at any price. Moreover, the M225 proved to be far less sensitive to the speaker cable used than some other amplifiers I’ve reviewed, and you may find any set of good balanced interconnects and ordinary speaker cables work very well. One caution, however— the M225 is designed to be used with balanced cables. If you have preamp that only has RCA output jacks, you’ll need to buy a DVA R2X unbalanced-to-balanced converter. This will cost another $279 but seemed very neutral and worked very well.

Specs & Pricing

Power: 225W into 8 ohms, 300W into 4 ohms
Inputs: Balanced on XLR jacks
Outputs: Five-way binding posts
Dimensions:  9″ x 4″ x 10″
Weight: 17 lbs. each
Price: $3398/pr.

AUDIO BY VAN ALSTINE
2665 Brittany Lane
Woodbury, MN 55125
frank@avahifi.com
(651) 330-9871