TAD C600 line preamplifier Page 2

All we ask is a usefully low output impedance, to drive potentially long cables connected to a (hopefully) high-input-impedance power amplifier sensitive enough to be driven to full output by a few volts, so that the preamplifier primarily acts as an attenuator—though of course we also want the preamplifier to be able to produce gain, particularly those of us who listen to vinyl; many combinations of cartridge and phono stage don't produce enough voltage to drive an amplifier to full output.

In the real world, though, while most preamplifiers get right the impedance/attenuation/gain/distortion/noise side, most fail, to varying degrees, at not adding to or subtracting from the original signal, notwithstanding claims to the contrary. As we all know, everything affects the final sound—so injecting the signal into anything, be it a complex device such as the C600 or a passive attenuator, will affect the sound.

Sometimes the resulting sound is better than the source, sometimes it's worse. And all of the time, what finally emerges from the loudspeakers depends on the synergy, or lack thereof, among preamp, amplifier, and speakers—which makes reviewing that much more difficult.

Superb-sounding Preamplifiers
I've had three superb-sounding preamplifiers in my system over the past six months, including the TAD C600—the other two were my reference, the darTZeel NHB-18NS ($33,500), and Ypsilon's PST-100 Mk.II ($37,000, which could just as easily be my reference)— and even though all three were ultraquiet, low-distortion, the sound coming from my speakers was different with each.

Compared to the Ypsilon or the darTZeel, the TAD C600 produced the most extended, most muscular, most tightly defined bass—and here's where it gets subjective and system dependent. The C600 had these qualities almost to the point of distraction—it was almost too well damped, controlled, and punchy to produce the kind of supple, graceful textural and tonal gradations that reproduce convincing-sounding instruments, as opposed to just bass.


When I relistened to the darTZeel preamp, the first notes I took about its bass performance when I played the same tracks via the Meridian Digital Music Server were: "relatively soft and less than muscular by comparison" and "where's the punch?" The Ypsilon split the difference. The darTZeel and Ypsilon seemed to better integrate the bass with the rest of the audioband because, along with its tight, punchy, fully extended bass, the C600 was somewhat shy in the midbass and lean in the midrange. I couldn't describe the sound as rich, but I could certainly describe it as airy and fully extended on top.

Two of the C600's strong suits were its natural mid-to-high-frequency attack and effortless transparency. So while its mid-to-high-frequency response was not warm, soft, and tube-like, its attacks were sweet and natural, and not at all "wiry" or artificial sounding—and in that regard it almost did sound like a tube amp. I couldn't call the C600 aggressive or thin on top, though some might think the overall sound somewhat lean and clinical.

What did all this mean in terms of the reproduction of actual music? It was mesmerizing with guitarist Antonio Forcione and singer Sabina Sciubba's version of Stevie Wonder's "Visions," from their album Meet Me in London, downloaded at 24-bit/96kHz resolution from Naim Music. Forcione's attacks on his acoustic guitar were appropriately tight, fast, and clean. Had they been overhyped, his nylon strings might have sounded like steel, but they sounded like nylon.

The guitar was carved nicely into three-dimensional space. Sciubba's voice was also rendered cleanly, if a bit lacking in chesty warmth. The same track through the darTZeel produced a warmer, almost buttery sound with a more convincingly natural and fleshy voice and somewhat less-well-articulated guitar attacks, though with more background fill, which helped produce a more complete overall picture. The Ypsilon again split the difference.

The bass extension and thrust of the Small Faces' psychedelic, flange-saturated "Itchycoo Park," from There Are But Four Small Faces (Immediate Records), engineered by the great Glyn Johns, was depth-charge deep, while the transparency and extension on top was superfast and spatially revealing—but the combination sounded discontinuous, as if two different recordings had been patched together: one containing the bass, one containing everything else. Through the darTZeel the sound was more of a piece, but it made me want to put the C600 back in the system because, immediately after the swapping out, it sounded too soft.

On the other hand, Part 3 of Duke Ellington's Black, Brown and Beige, from the CD edition of the old Columbia "360 Sound" stereo recording produced at the 30th Street Studios, sounded lush, romantic, and acoustic through the darTZeel, while through the C600 the brass was a bit too biting and the clarinets lacked body. Again, the Ypsilon split the difference, sounding overall more "neutral" than either of the other two.

I could listen happily to János Starker, Antal Doráti, and the London Symphony's recording of Dvorák's Cello Concerto (CD, Mercury Living Presence 432 001) through all three of these preamps, but if I had to choose one, it would be the darTZeel. (I'd listen more happily to the vinyl edition, Mercury Living Presence SR90303, despite the less-than-ideal pressing I once heard [I don't own a copy].) The darTZeel's reproduction of the tone and texture of the cello, and particularly of the horns, were just right through my system. The C600's rendering of the acoustic of Wembley Town Hall, where the recording was made, was more revealing and holographic, but the cello lacked some of its rich, woody tone.


Using an iPad to access my digital playlists made comparisons easy and convenient, but much of my listening was to vinyl, using the Ypsilon VPS-100 phono preamp. The overall results were the same. Depending on the recording, I sometimes preferred the C600's more surgical precision, and sometimes the darTZeel's more romantic character. For instance, it was through the C600 that I first heard the vinyl edition of the Heartworn Highways soundtrack (HackTone/Diverse Vinyl DIV 016DLP), one of Robert Baird's 2009 "Records to Die For." These original analog recordings were made during the shooting of that 1975 film, which featured such up-and-comers as Guy Clark, Steve Earle, Townes Van Zandt, and John Hiatt, and were transferred by Alan Silverman to high-resolution digital with no compression using a Rupert Neve Legendary Audio System board. The sound opens a spectacularly dynamic and transparent window on a series of live performances we're lucky to have preserved in any format in any quality, never mind a spectacularly natural recording cut to lacquer and pressed by the Pallas Group. The record is still available online if you look—and you should! It was a labor of love for David Gorman, who created HackTone for the express purpose of issuing this recording (but don't miss HackTone's CD compilation of tracks by Arthur Alexander).

This live recording sounded ultraclean and transparent through the C600. The reproductions of the voices and guitars and between-tunes chatter were holographic if a bit chilly, but there was little spatial context. When I reinstalled the darTZeel and listened again, the sense of space, which the TAD only suggested, was there in the flesh; listening was closer to being in the room and experiencing it live, and this despite the C600's ultraquiet backdrops. It wasn't a matter of noise masking the spatial cues; it was more about the tonal balance.

While great recordings sounded great, the C600 was unforgiving of bright recordings. Very familiar oldies, such as Ben E. King's cover of "Spanish Harlem," lost some of their atmospheric ambience through the C600. However, in terms of transparency, macro- and microdynamics, soundstaging, and other areas of audiophile concern, the C600 was a strong contender for inclusion in Class A of Stereophile's "Recommended Components."

Is there such a thing as a preamplifier that's "a straight wire with gain"? Based on the three state-of-the-art models I listened to for this review, I'd have to say, "No way." Each sounded very different from the other two.

TAD's C600 is a meticulously designed and exceptionally well-built high-tech wonder. It's ultraquiet, and sounds every bit as low-distortion and as pure as TAD's specifications suggest. Its heroic chassis damping should produce a serene musical "quiet" presentation, as well as solid image focus—and, indeed, I found both to be among the C600's strongest suits.

The C600's bass performance, particularly its extension and sculpted definition, was stunning, but could at times sound overdamped and disconnected from the rest of the music. But this was dependent on the system and the recording. Above the deepest bass, the overall tonality was on the clinical side, but attacks were just right: not too sharp, and never soft or blunted. And thanks to the C600's ultraquiet backgrounds, sustains were generous, and decays were long and precise with recordings that contained them.


The TAD's subjectively lean midband was an impediment to spatial richness, but again, the final results will be system dependent. No doubt JA's measurements will find the C600 to be ruler-flat within the audioband, as are the other two preamps: the darTZeel, in unbalanced mode, was "perfectly flat within the audioband, with a wide bandwidth," he said; the Ypsilon, in passive mode, was "flat from 10Hz to 200kHz."

So what accounts for the differences I heard among the three amps, easily audible with 24/96 recordings? Everything else about these very different designs, I guess.

The word that sprang most often to mind during my listening to many hours' worth of familiar recordings was unforgiving. The C600 provided no cover for poor recordings, particularly ones that sound bright and/or overprocessed. Nor did the C600 mask anything on good recordings. How you'll react to hearing your favorites through the C600 will depend on your system and your taste. If the darTZeel is a "relaxed fit" pair of Dockers, the C600 was a Spandex leotard. You'll look fabulous in the latter—but only if you're in great shape to begin with.

TAD's demos at CES are always among, if not the, best sounding—and not because Andrew Jones always chooses demo-quality recordings. Clearly, there's exceptional synergy between TAD's electronics and Jones's exceptional loudspeakers. Your dealer should let you hear the C600 in your own system before you plunk down $42,000—but if you already own pairs of TAD Reference Ones and M600 monoblocks, I'd say that if what we hear at CES is any indication, the deal is already sealed..

Technical Audio Devices Laboratories, Inc.
US office: 1925 E. Dominguez Street
Long Beach, CA 90810
(213) 268-2748
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anjeza1987's picture

Nice audio component,but very expensive.

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