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Frederic Beudot
Financial Interests: click here
Digital Source: Esoteric X-03SE
Analog Source: Acoustic Solid Classic Wood, AS WTB211, Grado Reference Sonata 1, Denon DL103, Esoteric E03, Nagra BPS [on loan]
Preamplifier: Wyred4Sound STP SE
Amplifier: Genesis Reference 360, Yamamoto A08s, First Watt F5, Gryphon Diablo [on loan]
Speakers: Zu Essence
Cables: ASI Liveline interconnects & speaker cables
Power Cords: Zu Mother, Zu Bok, ASI Liveline power
Powerline conditioning: Isotek Nova [on loan]
Sundry accessories: Isolpads under electronics, ASI resonators and sugar cubes, ASI Heartsong racks
Room size: 21' x 13’ x 7.5'
Review component retails:
See review

The idea for this article came as I was putting the final touches to my Gryphon Diablo review. While swapping amplifiers for a final comparison, I suddenly realized that there were four Blue Moon amplifiers staring at me on the floor in front of my system, two bestowed by Srajan, two by myself.*

I remember thinking how that had to be a fairly rare occurrence. Then the idea to write an article comparing and contrasting those four awardees came to me. Obviously once I actually thought about it more I realized just how complex an adventure this was going to become yet I was excited about the project. I moved on knowing very well that it would not be perfect yet I was hoping to gain some insights from the experience.

One of the keys to a meaningful comparison like this is to keep as much constant from one audition to the next and ideally only change one component. All in all I managed to keep the system very constant throughout the audition period but for a few details. One added variable were the power cords. I do not own four identical cords and all four amplifiers require long warm-up periods, forcing me to leave them on together during the test. I still managed to use four cords by the same manufacturer - two Zu Mother and two Zu Bok. Although there are differences between these cords, I don't feel the differences I’m about to report on with the amps are associated in any significant way.


* The FirstWatt amplifier with the award was actually the current-gain only F4. In hindsight and for its rather more universal relevance, the F5 would have been the even more deserving could there be only one award for this unusual amplifier range. Having reviewed each of its models, we indeed were very conservative and only bestowed one. Frederic's inclusion of the F5 here (reviewed/owned by him, me and reader Michele Surdi) is very much to the point then. - Ed.

More problematic to manage was the use of amplifier stands and vibration controls because some of the amplifiers tested are fairly heavy. Here I used pragmatism. Two of the amps sounded clearly better on the ASI HeartSong rack and they alternated on that stand when in use. One amplifier preferred being on the floor with Isolpad blocks under its feet so that’s how I tested it. The last one has its own built-in amp stand so I saw no reason not to use it.

Finally the question of the reviewing process arose. Anybody who's done a face-to-face amplifier comparison knows that it is a demanding exercise especially when moving gear around is required. So imagine the logistics with four. My first thought was to just write about my listening impressions of the four amplifiers on which I have clocked in hundred of hours each. I know them well enough to give what I believe is an accurate description of their respective gestalts. Yet I was not completely convinced this was the way to go at least not exclusively.

Those four amplifiers are all award recipients. These distinctions were granted by two listeners whose tastes and biases are extremely close. I therefore expected the amplifiers to all be excellent and differences to be at best subtle and the overall presentations very close. I thus needed a more targeted and intense effort to ferret out small but meaningful differences. That could potentially become a long and arduous process and looked like a daunting task.

That's when Joel on staff unknowingly came to my rescue. On his forum he mentioned a Chesky record he's been using to assess gear and systems. Seeing light at the end of my tunnel, I promptly ordered a copy of Chesky's Ultimate Demonstration Disk from Amazon. There are dozens of such audiophile discs available, all filled with very well recorded music capable of demonstrating the qualities and weaknesses of a system. What I like about Chesky's is two-fold. First and foremost I love their recording philosophy. They are not after the most upfront analytical perspective and favor a very natural organic blooming sound (very resolved but that’s not their only goal) using a minimal number of microphones for simplicity over complex mastering.

The second thing I like about this disc is that each of the fourteen test tracks is preceded by a spoken introduction which accurately describes what one should strive to hear. After four years at the reviewing game there was nothing unexpected yet it helped to focus when going through a complex exercise. And complex it ended up being even more so than expected as I ended up doing two massive listening sessions, one vertical and one horizontal. In the first I listened to all fourteen tracks in a row with the same amplifier and did that four times on the same day once with each machine. In the second and far more back-breaking one, I listened to one track at a time through each of the four amplifiers before moving to the next track and starting all over again.

Without further ado, here are the protagonists and their results.