Once the amplifiers were warmed up, my concerns about their capabilities were put to rest in fairly short order. So long as I was not trying to blast the speakers at larger-than-life volume levels, the Zestos drove the Maggies with surprising ease. I have written in the past that the 20.7s will certainly sound good with quality amplifiers in the 200-watt range, but really come alive with more powerful amps. I still believe this to be true. Nevertheless, the Eros 300s’ performance belied their nominal rating of 150 watts a side—they powered the Maggies with the ease of 300–400Wpc amplifiers. I cannot say if this prowess is a product of its Class A design, but I am guessing this gain strategy has a lot to do with it.
Moreover, the 300s deliver in spades the full musical magic of which tubes are capable. Voices and virtually all musical instruments reproduced by the 300s possess a richness of tonal color that, to these ears, solid-state has yet to deliver. This is not intended to imply that these are throwback tube amps, slow and syrupy. They are not. They are modern state-of-the-art-sounding amplifiers across every important criterion—fast, transparent, and fully extended at both frequency extremes. In fact, their tight control of the bass might lead one to (erroneously) believe that some transistors are hidden inside. But this lower-octave control and slam is combined with a bull-bodied roundness—especially on double bass and drums—that eludes many solid-state amps.
When I started my listening evaluation, the first pleasant surprise came with some material that was not terribly taxing for the amps: a very nice LP reissue of Boss Tenor with Gene Ammons on tenor sax [Alto]. Played at lifelike levels, Ammons’ sax was three-dimensional and golden in tone while the rhythm section (bass, drums, and conga) was swinging. Every instrument was crystal clear and the stand-up bass, unlike some of Rudy Van Gelder’s other recordings, remained taut and controlled without devolving into pluminess. Power-wise, there was no sense of the 300s straining or running at the limit. I was just hearing really great music playback.
Turning to more demanding material, I took an old favorite for a spin on my Kuzma Stabi M: Martinon and the Paris Conservatory Orchestra playing works of Ibert, Bizet, and Saint-Saens [London]. Those of you who have the LP know it to be one of London’s finest, with great dynamic range, sweet strings, and huge stage width and depth. The Zesto Eros 300s loved this recording. Sounding fast, delicate, and surprisingly powerful, the amps placed the orchestra in an enveloping, three-dimensional space that transformed most of my listening room into a hall. The jet-black background was in stark contrast to the sometimes startling appearance of whistles and horns in Ibert’s playful “Divertissement.” Even “Danse Macabre,” a piece I have heard so many times that I usually skip it on most recordings, had a new-found charm and excitement when heard through the Zestos. The strings were luscious and even the grave-dancing skeletons seemed more energetic than usual. The bass drum whacks were powerful and filled the room.
But, on this recording at least, the full beauty and capability of the Eros 300s were revealed in Bizet’s “Jeux d’Enfants,” a fanciful homage to the world of children’s toys. As noted, violins were lovely throughout this recording, sounding neither metallic nor screechy. Compared with the high energy of “Danse Macabre,” the lyrical passages of “Jeux d’Enfants” showcased the Zestos’ ability to change pace and mood at a moment’s notice, conveying all of the subtlety and joy of Bizet’s light-hearted fare.
At this point in the review process I became curious as to how the Zestos compared to higher-power amplifiers. I remember the wide-open sound of the Aavik Acoustics U-300 integrated amplifier that was recently in my system. That solid-state amplifier, rated at 600 watts per channel into 4 ohms, rocked the house and never sounded ruffled. Unfortunately, manufacturers want their review gear returned and that amp no longer resides chez moi. Based upon recent memory, I would say that the U-300 (retail price: $30,000) presented a slightly larger soundstage and somewhat more slam at higher volume levels than the Zestos. On the other hand, the Zestos offered a somewhat richer tonal palette and a more three-dimensional presentation.
I was also able to compare the 300s with my VTL 750s, admittedly amps engineered and built years ago and not representative of the latest in design or technology. (To my knowledge, VTL’s most recent offerings in this 600-plus-watt power range cost more than three times the price of the Zesto Eros 300s.) I was interested in determining if the VTL’s power advantage was beneficial. The same musical selections played through the 750s sounded very good, but immediately it was apparent that the Zesto Eros 300s displayed more transparency, quieter background, and a more three-dimensional presentation than the VTLs. On the other hand, at high to unnaturally high listening levels, the larger tube amps sounded slightly more relaxed and produced a fractionally larger soundstage. This is not a criticism of the Zestos; they conveyed a very convincing sense of space. But quadrupling the output power led to a slightly more spacious presentation (if the recording captured this)—not four times as large, of course, but still the increased sense of space was noticeable.
Putting all of this into perspective, the 300s were undeniably superior to the larger tube amplifiers in many important ways: greater transparency, more body to instruments and voices, very lively with no tendency to sound dark(ish), and blacker of background. The 300s gave up only a slight sense of ease at the highest volume levels and a small but noticeable sense of space on large orchestral recordings. To be fair to the Zestos, and figuratively putting the large Magneplanars aside for a moment, most real-world loudspeakers, regardless of size and cost, are more efficient and hence considerably easier to drive than my Maggies. I am making a (hopefully) well-educated guess that with most speakers owned by most music enthusiasts the Zesto Eros will be exemplary for all musical styles at all listening levels, with no shortage of power or slam.