Esoteric

The Esoteric A-03

The Details:

An amplifier circuit with wide range, high speed, and powerful drive
A pure class A implementation with low distortion and high linearity is used for the amplifier circuit. This design always ensures an idling current that can output a minimum of 100 watts RMS into 4 ohms and a minimum of 50 watts RMS with an 8 ohm load.

Obsessive use of high-grade components everywhere
Esoteric has gone to extremes to use the highest quality components to maintain signal clarity and minimize transmission loss. They have used ultra high-grade components such as an electrolytic capacitor and a high frequency/low impedance transistor. These components were selected based on property examination and trial listening. It is an Esoteric requirement that all critical components undergo exhaustive listening tests before any final section is made.

Can be used as a mono power amplifier with a bridged connection
By using the A-03 as a monaural power amplifier in bridged (BTL), mode, a minimum output of 200 watts at 8 ohms (1 kHz, 8 ?) can be achieved (400 watts at 4 ohms in BTL mode).

Advanced power supply with dedicated L/R dual mono architecture
The new A-03 employs dedicated dual mono technology that established Esoteric's reputation for high-end design implementation. Equipped with independent power sections featuring dedicated toroidal transformers for the left and right channels, this amplifier also boasts enhanced mechanical strength and rigidity. Separate dedicated compartments for the power transformer, the power circuits and the voltage and current amplifier stages, all help to prevent electrical interference between components.

What do the pros say, from Sound Stage:

My first impression of the A-03 was of how attractive it is. The photos I'd seen of it had not done it justice -- this amplifier is stunning .

The A-03 has large, independent toroidal transformers, one per channel..this enhances the amp's ability to "supply current to each channel's speakers, while preventing interference between channels. By using an independent transformer and power circuit for the voltage amplifier stage, which drives the current amplifier stage, the effect of variations of voltage is suppressed and the current amplifier receives a stable power supply. Separating each circuit block into power circuits and providing independent transformers reduces cross-channel interference and enables both robustness and delicacy of expression within the music."

System
The Esoteric A-03 was connected to my Rockport Technologies Mira loudspeakers and the preamp section of my Simaudio Moon Evolution 600i integrated amplifier. Also in the signal chain were a Bel Canto DAC3 DAC, and an Apple MacBook Pro laptop computer used as a music server. Speaker cables and interconnects were Analysis Plus Solo Crystal Oval.

Sound
There are moments in audiophile time when the way a particular song sounds at a particular moment sticks with you forever..With the A-03 in the chain, my Rockport Technologies Miras provided an equal sensation. The strings of the guitar were incredibly focused. Each pluck of the pick was ultraprecise, and resonated out from the image of the guitar as if from an actual instrument in my room. The sound had the palpability of a physical object occupying three-dimensional space. This was a rare moment, and an accomplishment by my audio system that I will remember long after the A-03 has been returned to Esoteric. To say that the A-03 got the best from my speakers is an understatement. In fact, I now have newfound respect for the amplifier's importance in the audio chain -- I always knew it was critical, but I hadn't realized it could define the sound of the system, just as we expect speakers do. The exceptional synergy of the combination of A-03 and Rockport Miras created a sublime sound in my room..the A-03 was a completely different listening experience from any I had had before. It was as if the A-03 -- and its mere 50Wpc -- had breathed more life into the orchestra, and I was hearing an inspired, once-in-a-lifetime performance that was filled with passion -- a performance I won't soon forget.

For an audio product to be truly high end, it must first sound great; second, it must be rugged and reliable; and third, the execution of the design, from the build quality right down to the finish, must be impeccable. The Esoteric A-03 is such a product.

However, there's one other thing. If I'm going to buy a product, it's vital that its manufacturer have a reputation as impeccable as the one Esoteric has earned. I'm reminded of a recent editorial Jeff Fritz wrote on Ultra Audio , in which he paraphrased Warren Buffett: "It's far better to buy a wonderful audio component at a fair price than a fair component at a wonderful price." I believe that the Esoteric A-03 is that sort of wonderful audio component.

If you're in the market for a new stereo amplifier and can afford an A-03, you may find it to be the last amplifier you ever buy. I fell in love with this amp from the moment I pulled it out of its box. The Esoteric A-03 is the best stereo amplifier I have ever heard in my room, and I was thoroughly impressed with it in ways I hadn't expected. 

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Esoteric A-100

Awarded Product of The Year 2009 by The Absolute Sound. The 3 stage A-100 tube amplifier that can be used as a direct stereo power amplifier or as an integrated (line level), power amplifier. This new hybrid technology incorporates proprietary circuitry and "cutting edge" tube technology. The A-100 provides a min imum of 90 watts (Minimim 45 wrms), power output from 4, KT-88's in UL-push/pull operation driven with a direct-coupled cathode follower. The cathode follower and voltage amplification stage is directly coupled to form a triple stage combining a variable self-biasing system and a zero voltage control system. is included.

And how does it sound, this from SoundStage:

The A-100 had a seemingly endless reserve of power and never felt as if it was going to run out of juice, even though its rated power output was under 50 watts.

While treble and midrange reproduction were excellent, bass reproduction was simply outstanding. One weakness of tube-powered amps has been soft or flabby bass.

And so it went with my listening, the A-100 not only contradicting its tube-based circuitry but also readjusting my understanding of my system and reproduction as a whole. This was a special performance by a special piece of audio equipment.

This from The Absolute Sound:

Only a handful of amplifiers on this planet are as revealing as the Esoteric A-100 of a recording's origin and acoustic signature. Those of you, who like me, crave tube magic in the form of vivid harmonic colors, palpable image outlines, and a spacious soundstage, may rest assured that the A-100 delivers the goodies. In fact, I don't know of a more synergistic match for Esoteric's exceptional MG-20 loudspeaker than the A-100. Yet it goes further than any other medium- or high-powered tube amplifier I've auditioned to-date. The A-100 amplifier breaks through the traditional barriers of tube amplification: low-distortion harmonic textures, transient speed, and resolution are integral to its reproduction of music. Now you can have your sonic cake and eat it too! I submit to you that the A-100 represents the state-of-the-art in medium-power tube amplification. It's as good as it gets.