Esoteric C-02Reviewers' ChoiceWhen audiophiles gather, they inevitably salivate over Esoteric’s cutting-edge digital components -- its transports, digital-to-analog converters, and word clocks. Analog? Not so much. Mention Esoteric’s preamplifiers and power amplifiers and you’ll likely hear this common generalization: Despite their technical competence, the sounds of Japanese analog products lack body, passion, and soul.

That generalization is not true of Esoteric’s analog gear, which is fast and detailed, yet also rich, full-bodied, and romantic. I’d go a step further -- I believe that one of the key ingredients in the secret sauce Esoteric uses to make their digital gear is the outstanding design of their analog circuitry.

Much of the problem may relate to the fact that, as far as I can tell, Esoteric hasn’t adequately publicized its analog competence. For example, while it’s not uncommon for other manufacturers to use Esoteric’s digital components at audio shows, if you want to hear the company’s analog offerings, you generally have to visit their own room. But Esoteric’s show rooms have been the last places you’d want to audition audio gear. Typically, the company presented a silent display of almost every one of its many current models, along with a few from sister company TEAC. The components actually plugged in and playing were usually little more than afterthoughts squeezed into whatever space remained, and hooked up to cables and speakers that don’t do them justice. The sound in Esoteric’s show rooms was never very impressive.

Time and again, I shared these concerns with Tim Crable, Esoteric’s former director of sales. He always agreed with me, but things never changed -- until last year’s T.H.E. Show Newport Beach, held in late spring. Complete with Cabasse speakers, Wireworld cables, and a full array of Esoteric reference components that had had been set up with care, Esoteric’s room boasted what has been described as “best of show” type sound quality. If this is Esoteric’s game plan for future shows, I suspect that word of their products’ analog capabilities will quickly spread.

Sometime before T.H.E. Show 2013, I heard that Esoteric had released a reference line-stage preamplifier, the Master Sound Works C-02 ($24,750 USD, or $26,500 with optional phono stage). According to the C-02’s brochure, it reaches “the ultimate height in analog audio technologies.” Suspecting that this statement might have behind it something more than mere marketing hype, I asked my editor to obtain a review sample. Esoteric has also released the less expensive C-03X preamp ($13,990), to replace the outgoing C-03. But in light of its Bugatti-like price, I was more interested to hear what’s offered by the C-02.


The C-02 is the latest member of Esoteric’s Master Sound Works line. As I explained in my review of the Master Sound Works A-02 power amplifier for SoundStage! Hi-Fi, this means that the C-02 benefits from what Esoteric has learned from its relationships with recording studios, sound laboratories, and other professional customers.

The C-02’s preeminent feature is undoubtedly its dual-mono design. In some dual-mono preamps, the left and right channels are routed through the opposite sides of a single circuit board, while others employ mirror-imaged boards. In both cases, the mono signals proceed through paths that typically differ in length, direction, and/or location within the case. The C-02 is atypical in having two identical boards, to give the two channels identical signal paths.

As is standard in dual-mono designs, each of the C-02’s channels has its own separate power supply. However, the C-02 is atypical in that each channel’s circuitry contains two transformers. In fact, a total of five transformers is used: one each for the input and output of each channel, and a fifth for the control section. Among other benefits, this is claimed to significantly reduce interchannel crosstalk and noise.

Esoteric C-02

Another important feature of the C-02 is Esoteric’s Quad Volume Control System (QVCS). Changing the volume alters the gain in each of the C-02’s four circuits: a positive and negative for each of the two stereo channels. Many volume controls alter the gain in only two circuits, which, Esoteric says, may cause a gain imbalance between channels of up to 5%. Although such imbalances are rarely severe enough to be audible, the work that has gone into the QVCS illustrates the lengths to which Esoteric will go to create as perfect a product as possible.

The user can select from five volume curves. By selecting the appropriate curve, the C-02 can be optimized to complement the efficiencies of the power amplifier and speakers used, or to simply accommodate personal preference.

In order to prevent noise generated by the QVCS from infecting the signal path, the control system communicates with the C-02’s audio circuitry only via a photo coupler -- there is no electronic or physical coupling between the QVCS and the signal path. Adjusting the volume control activates an onboard microcomputer; a photo receiver senses light from an emitter, and an adjustment in the volume is made. At that time, the microcomputer tells the photo coupler to disengage from the audio circuitry and turns off the QVCS.

Note that unless you deactivate the C-02’s automatic power-saving feature, included to comply with European regulations, you won’t have any volume. Depending on the option chosen, the C-02 turns itself off after 30, 60, or 120 minutes of non-use.

The C-02 includes very high-quality components, such as large capacitors and silicon-carbide (SIC) barrier diodes made by Schottky. The latter, more expensive than standard Schottky diodes, are extremely fast and quiet. But the components used in the C-02 are not necessarily the costliest or even have the best reputation. Rather, as with all Esoteric components, they’re selected based on listening tests.

As part of the C-02’s dual-mono design, Esoteric developed a five-compartment, “3D-optimized” case that makes possible extremely short circuit paths. It also permits the digital, power, and control mechanisms to be placed forward, far from the sensitive analog circuitry at the rear. Included in the latter is the critical output-buffer amplifier circuit, which both serves as a line driver and prevents noise and electronic surges from entering the C-02 from the power amplifier.


I’d asked Esoteric to break in the review sample while I cleared my review queue. They told me that they’d run the unit for a few weeks so that it would be “nice and toasty.”

But clearing my review queue took longer than expected, and it was now many months since I’d spoken to Esoteric; I was pretty sure that Tim Crable had forgotten about the review. When I called to ask if it was still on, he replied, “Oh, yes -- the C-02 is here and is still being burned in for you.” At that point, I feared that the review sample might be not so much nice and toasty as burnt to a crisp.

For a preamplifier, the Esoteric C-02 is big and heavy. It measures 17.4”W x 6.3”H x 17.8”D and weighs a power-amp-like 71 pounds. And when the review sample finally arrived, I found it physically imposing in a way that even those impressive measurements hadn’t suggested. Indeed, it made my C-03 preamp seem downright puny. Still, one thing the C-02 and C-03 do share is their museum-worthy, ultra-modern design and impeccable build quality. Thick aluminum is used for the C-02’s front, top, and side panels, and the steel bottom plate -- the actual chassis -- is 5mm thick. The large volume knob and input selector are machined from aluminum blocks -- I could feel the build quality as I turned them.

Speaking of those two knobs, their tops are backlit in blue when their functions are engaged. Though this defeatable feature is vaguely reminiscent of the garish and utterly useless lights that MartinLogan affixes to the undercarriage of its fantastic Summit X speaker, the C-02’s glowing dials are well within the borders of good taste. Also, when a function is activated via the C-02’s remote control, the dials alert you that the C-02 has received the infrared signal. Other than these knobs, the only other control on the C-02’s front panel is a small power button. The front panel also contains a dimmable LED display and a remote-control signal receiver.

Esoteric C-02

Around back, the C-02 sports two pairs of fully differential balanced XLR and three pairs of single-ended RCA analog input connectors, a signal ground connector, and an AC power inlet. The third single-ended connection can be used as a home-theater pass-through. RCA and XLR outputs are standard as well.

The impressive remote control is standard Esoteric issue and worked well. Its aluminum body is finished in leather on the bottom and sides. Via the remote, the output level for each input and left/right balance can be adjusted, phase can be inverted, and the brightness of the display dimmed or turned off.

Esoteric offers a two-year limited warranty on all components, including the C-02, extendable to three years with mailing of warranty card. While there are less generous industry warranties, it would be nice to see something lengthier, perhaps five years, particularly in light of the C-02’s cost.


I positioned the massive Esoteric C-02 on a Synergistic Research Tranquility base, itself sitting on a 1.5”-thick piece of Plexiglas. Under that was a DIY amp stand. The C-02 is supported by four proprietary Esoteric feet permanently affixed to the bottom plate. However, as had been my past practice with Esoteric components, I didn’t use the feet. I got better results with Synergistic’s MIG feet, which I placed between each of the supporting levels.


I expected that, as a new reference component, the Esoteric C-02 would make continued progress with respect to a variety of audio benchmarks. Even more, I hoped it would retain what has been the crowning achievement of Esoteric’s analog gear: the ability to sound romantic, full, and rich without sacrificing speed, detail, and transparency.

As far as the benchmarks are concerned, the C-02 retains Esoteric’s signature large, airy sound. For example, the electronic panning effects in “Welcome to the Machine,” from Pink Floyd’s Wish You Were Here (16-bit/44.1kHz FLAC, Capitol), were supersized. Soundstage depth was expansive, with very tight and extremely focused images that layered to the rear in a manner that unequivocally denoted a cutting-edge product.

In addition to throwing an extraordinary soundfield, the C-02’s reproduction of music was extremely detailed and transparent. Whether I wanted to fully hear David Gilmour’s sniffle and throat clearing at the beginning of Wish You Were Here’s title track; or guitar-pick sounds in “I Saw Her Standing There,” from Laurence Juber’s LJ Plays the Beatles (CD, Solid Air 2001); or Shirley Horn’s vocal nuances in her Here’s to Life (CD, Verve 314 511 879-2), it was all there.

Looking at another parameter of sound, transient speed, the C-02 could stop and start on a dime. The brass section in Beethoven’s Symphony No.1, with Jan Willem de Vriend conducting the Netherlands Symphony Orchestra (CD, Challenge Classics CC72550), seemed propelled forward to create shock and awe, only to disappear just as quickly. This pointed out how effective the combination of lightning-fast transients and a truly “black” background can be. Yes, a few companies -- Technical Brain and Soulution, to name two -- make analog components that sound even faster, and more transparent and detailed, than the C-02. But to my ears, the products from those companies lack midband warmth and body.

At the same time the C-02 was wowing me with its fast, detailed, transparent sound, it was rendering denizens of the midband -- voices, winds, and strings -- in a way that most preamps can only dream of. For example, in “Too Marvelous for Words,” from Here’s to Life, Shirley Horn’s voice oozed a silken opulence that signaled the presence of a refined statement component. As in only the finest analog components, this ravishing midband was not the byproduct of compression or coloration. Rather, it was the result of the C-02’s incredible ability to convey these frequencies as they naturally appear in live music.

Lower in the audioband, the C-02 rendered each song on Chris Squire’s Fish Out of Water (CD, Atlantic ARC 8065) with incredible pitch definition and articulation. Admittedly, the C-02 didn’t provide a Stone Cold Steve Austin-like beat down over recalcitrant bottom frequencies, as will Boulder Amplifiers’ 2010 preamplifier ($46,000, discontinued). However, I never felt I needed more extension or control. Then again, the Boulder gear I’ve heard, including the 2010, has not matched the C-02’s romantic and emotionally involving nature.

So, yes, the C-02 pushed the audiophile benchmarks while thankfully retaining Esoteric’s full, rich midband. But this machine also did things that I did not anticipate. First, it didn’t sound merely transparent -- instead, it had a next-generation ability to produce realistic-sounding music, as it stunningly demonstrated with several recitatives -- the half-sung, half-spoken passages in opera of the 18th and early 19th centuries. I first fed the C-02 a recitativo secco (i.e., a voice(s) accompanied only by harpsichord) and aria from Act II, scene ii of Carlo Maria Giulini’s recording of Mozart’s Don Giovanni with the Philharmonia Orchestra and Chorus (CD, EMI Classics 56232).

As is common in recitative, this scene requires the singer (here Eberhard Wächter, in the title role) to convey an intensity of breathy energy that is short of outright singing, but forceful enough to be heard in a large hall (in this case, one of EMI’s large Abbey Road studios). This is difficult both for recording equipment to capture and audio gear to reproduce. With lesser preamplifiers, it is typically either underemphasized (and thus sounds whispery) or overemphasized (and thus sounds shouty). Also, the manner in which a recitative is rhythmically paced is critical to its success.

The C-02 rendered the Don as if the playboy himself were holding court in my room. The voicing was so unveiled, the background so quiet, and the timing so right that I have very rarely, if ever, heard anything like it. These qualities combined to create a flesh-and-bones palpability that would be a privilege for any opera fan to hear.

But it wasn’t just voices. Through the C-02, strings, brass, percussion, and woodwinds were rendered more authentically and lucidly than by any other preamplifier I have had in my listening room.

Second, I was unprepared for how the C-02 uncovered the inner details of overtones, and thus how it delineated timbres. Interestingly, what clued me in to this very early on was the unusually lustrous sparkle and sheen of cymbals in “On the Dunes,” from Donald Fagen’s Kamakiriad (16/44.1 FLAC, Reprise). Cymbals have an extremely wide range that can reach all the way into the ultra-high frequencies, from 10 to 20kHz. There’s not much energy or musicality at the top of that range; the delicate, nuanced effects of cymbal shimmer are found from 7.5 to 10kHz. This range is crucial, however, because the overtones of many HF-capable instruments reach into this area, including the trumpet, violin, and many woodwinds.

Sure enough, in Beethoven’s Symphony No.1, the C-02 mastered the high-end overtones, and thus parsed the timbres, of the violins and violas. In other recordings, it identified the unique timbres of instruments such as the piccolo and flute, as well as cello and double bass -- this despite the fact that the pitches of these instruments overlap outside the middle registers, which typically wreaks havoc with a component’s ability to convey timbre. Ace the ends, and the middle -- where the sounds of most instruments exist -- is typically a cakewalk.

Getting the non-fundamental frequencies right is one of the most challenging tasks an audio component faces. That the C-02 did so with such aplomb is enough to place it in the company of the very best reference components.


I won’t spend too much time comparing Esoteric’s new preamplifier to its less expensive and now retired sibling. But if anyone thinks that the C-02 is only slightly better than the C-03, they have another think coming.

The C-02 and C-03 produced soundstages of roughly the same height and width (which is not to say that a larger soundstage would be accurate or desirable). However, the C-02 bettered the C-03 in pretty much every other measure, including vertical spacing, imaging, quietness, transparency, timbral delineation, and realism.

I never realized it until I got the C-02 into my system, but through the C-03, Eberhard Wächter’s recitatives had sounded solid and precisely imaged, but a bit veiled and noisy. The electric panning effects in Pink Floyd’s “Welcome to the Machine” were less distinct, with less of their synthesized details displayed. Shirley Horn’s voice in “Too Marvelous for Words” was more coarsely textured. And the sounds of the violins and violas in Beethoven’s Symphony No.1 were relatively undifferentiated.

Still, owners of the C-03 need not despair -- that model is still one of the great preamplifiers, and offers a good taste of the C-02’s fast, transparent sound while still sounding romantic and full. Despite the arrival of the C-02, that’s something that’s still exceedingly rare.


The Esoteric Master Sound Works C-02 is one of the very few preamplifiers that does it all. It has a fast, unveiled, and ultra-realistic sound; it’s full, refined, and romantic in the midrange; and it’s extremely revealing of timbres, even with respect to the most challenging instruments. These are all things I won’t be soon forgetting.

For now, Esoteric’s analog engineering prowess is still overshadowed by its legendary digital expertise. However, if you have deep enough pockets, you shouldn’t discount Esoteric’s assertion that the C-02 reaches “the ultimate height in analog audio technologies.” Even among the world’s most accomplished analog components, this Japanese preamplifier is transcendent.

. . . Howard Kneller

Associated Equipment

  • Amplifier -- Esoteric A-03
  • Preamplifier -- Esoteric C-03
  • Sources/DAC -- Esoteric K-01 SACD/CD player-DAC, laptop computer running Windows 7 and JRiver Media Center 17
  • Speakers -- YG Acoustics Kipod II Signature
  • Interconnects -- Synergistic Research Element Copper-Tungsten-Silver (components, speakers’ active bass modules)
  • Digital interconnects -- Synergistic Research Tricon USB, Synergistic Active FireWire 800
  • Speaker cables -- Synergistic Research Element Copper-Tungsten-Silver (tweeters), Element Copper-Tungsten (midrange drivers)
  • Power cords -- Synergistic Research Element Copper-Tungsten-Silver Analog (amplifier, preamplifier), Copper-Tungsten-Silver Digital (Esoteric K-01), Tesla Precision AC SE (speakers), Element Copper-Tungsten (Powercell 6SE and Powercell 10SE Mk.II power conditioners), Element Copper-Tungsten-Silver Analog and Digital (Enigma power supply fed by two power cords), Tesla Hologram A (QLS Lines strips with Galileo MPCs)
  • Power conditioners and distribution -- Synergistic Research Powercell 6SE (digital only) daisy-chained to Powercell 10SE Mk.II
  • Isolation devices -- Synergistic Research Tranquility Bases (sources, preamp), Custom Isolation Products amp stand (Enigma power supply), Silent Running Audio VR fp Isobase (amp), Synergistic Research MIGs, Mapleshade Heavy Hats, DIY amp stands
  • Misc. -- Synergistic Research Galileo Universal interconnect and speaker-cable cells, Synergistic Research Acoustic Art System, Acousence Giso LAN isolator

Esoteric Master Sound Works C-02 Preamplifier
Price: $24,750 USD; with optional phono stage, $26,500.
Warranty: Two years parts and labor; three years with mailing of warranty card.

Esoteric Division
TEAC America, Inc.
7733 Telegraph Road
Montebello, CA 90640
Phone: (323) 726-0303
Fax: (323) 727-7650