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For a single-ended triode the A08s was actually fairly good but nowhere near as capable of the separation the other three delivered. Again the A08s excelled at tonal colors with all the brass instruments blossoming incredibly textured but it lacked in bite and ability to reproduce the sudden level changes and dynamics this piece showcases. The F5 and Genesis GR360 sounded like twin brothers on this track. I could not tell them apart blind and considering that the F5 is Srajan's reference in this department, it speaks very highly of the Genesis by offering the same speed and responsiveness with far greater power. The Gryphon Diablo was even faster, its rise times sharper. Microdynamic realism is what this amplifier lives for. The music jumps at you, explodes and bristles. On this track, the Diablo again was my favorite but not by much over the F5 and GR360 twins, with the Diablo at times having just a touch of excess trumpet bite (realistic as that's what the instruments actually sounds like but even in a treated small room, it could be a little much at times).


The next two tracks "Sweet Georgia Brown" and the "dynamic test" yielded similar results for the same reasons. Both require massive macrodynamics capabilities, with "Sweet Georgia Brown" adding the complexity of a jazz big band and the dynamic test actually capturing the full range of an unrestrained drum solo. The Yamamoto on both tests ran out of steam early. It could play louder than anyone sane would want to sustain but distortion kicked in quickly to mask the message and dynamics. It was loud but lacked resolution and sounded flat. 97dB/watt is actually not that efficient for a 2-watt amplifier and these tracks showed that I was asking too much from the Yamamoto.


The F5 did very well for its puny 25 watts considering that I listened to these tracks at the highest level I could stand to really push the gear and room to the practical limits. Listening to the F5 alone would never have you believe that it was holding anything back in terms of dynamic but the Genesis and the Diablo both proved that the F5 also ran out of steam although only marginally. The Genesis and Diablo had similar dynamic capabilities, with the Diablo showing more separation power at loud levels where it was easier to differentiate the various players in the big band but on the other hand it had a little less coherence than the Genesis.
By that I mean that the band sounded more like playing as one over the Genesis. I am not sure which is closer to reality but I preferred the Genesis better by a hair on "Sweet Georgia Brown", the Diablo on the drum solo where the explosiveness of the Gryphon netted that last touch of realism. All I can say is that this last test felt brutal. A full drum set unleashed in a 300 square-foot room, even treated, is like a sucker punch to the stomach. Proud of its professional driver heritage, the Zu Essence broke no sweat. Try that with a Fostex for a chuckle.

Another telling track is simply called "bass resonance" and showcases a solo upright very closely miked. You can hear the pluck on the strings and all the harmonics and body resonances. I don't know just how deep in the bass this goes, likely deeper than the Essence is flat. The Yamamoto stopped before the Essence and had the least amount of extension or control. This was no surprise as it was the kind of track you'd pick to make a SET sound bad. The F5 went deep and sounded full, the Diablo went deeper but sounded a lot leaner as though some of the wooden harmonics had been restrained. Finally the Genesis offered the Gryphon's depth and the F5's body for hands down the best performance on this track.


The track that seemed to bring all of it together was Johnny Frigo's "I love Paris". This tremendously fast-paced jazz cut is full of diabolical transients, impacts, percussions and a huge diversity of instruments and tonal colors. It progresses from an almost muted dialog between violins to an all-out saxophone, piano and drum kit mélange before bringing in the whole jazz band. On tonal colors the A08s again had no rival although the F5 came so close that I can understand why Srajan loves this amplifier. On transients the Gryphon was king but the F5 again trailed it by just a split fraction. On bass weight the Genesis was best yet the F5 and its slightly emphasized upper bass was no slouch either. The A08s lacked depth and control by comparison and the Diablo sounded a little leaner (and probably prefers being associated with speakers more endowed than the Essence).


After the hundreds of tracks listened to, I came to really understand why the F5 is so spectacular. It has a balance of qualities that seems completely unreasonable at its price. If you can live with 25 watts into 8 ohms, I doubt $3,000 can do better. Keep in mind that power is not about how loud an amplifier will play (the hi-gain 2-watt A08s played more than loud enough) but how the system reproduces dynamics both micro and macro realistically. In this test the 97dB Essence did manage to get the F5 to run out of steam but only on tremendously dynamic parts at very high levels.

The Yamamoto A08s showed superb colors and unmatched vocals but also limitations on massive orchestral parts and dynamically complex music. In all fairness, a 97dB/watt speaker is probably not sufficient to do it full justice and if I were to rely on the A08s alone, I would look at 101dB speakers or higher, perhaps with active bass and ideally use it high-passed above 80Hz to relieve it from the most strenuous frequencies. If ultimate dynamic realism is not your priority, the A08s and Essence are all SET lovers have promised. There is a presence and naturalness to the music that nothing can match as long as you're not asking for thunder and lightning or 1812 explosions. For a lot more dosh, the Diablo and Genesis GR360 build upon the F5 and add the ease and stupendous dynamic prowess only high power and high current bring. They weren’t exact twins but it did take intense analytical listening to really nail the differences. The most obvious was that the Genesis will not stage as deeply and separate front-to-back planes as clearly. The second was that the Gryphon was just a little more brutal in its transient response and more explosive but the Genesis responded with more bass weight and a slightly warmer balance that was just a little more forgiving.

With speakers like the Essence offering a good dose of Zu's legendary tonal density yet with a far more open and extended treble, the Gryphon in the end was the most complete, exciting and in short best amplifier of the lot but I have little doubt that with Genesis' own speakers and their metallic midrange drivers, the GR360 would be better. Since I don't have €11,500 laying around, the F5 for a fraction of the cost delivers all the musical enjoyment I need and I can always pull out the A08s for long opera sessions when the family is away.


I don't know how much of the results in this comparison were influenced by the Wyred4Sound STP SE and how much ‘blame’ it carries that the Gryphon sounded more dynamic and resolved than the other three amplifiers. The only way to know would be to replicate the test with a preamplifier like the new SMc VRE-1b or Gryphon's own Mirage but I won’t be the one doing it. One thing I have learnt in this experience is that moving around four amplifiers—two of which weigh in excess of 80lbs—is not something I want to ever do again. Not even for our readers, sorry.


All in all this exercise gave me even more insights into these four machines and I can proudly stand behind each one of their awards. In their respective categories and price ranges they are amongst the best you can find. The question readers always seem to want answered is, which was best? I really don't know. It depends on your taste, gear and the music you listen to. If I were to keep only one it would be the FirstWatt F5. For the money it does almost everything as well as the very best and is quite forgiving indeed. If money were no object, the Diablo is one of a kind although it will require even more careful matching to reach its full potential.
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