October 2002

Audio Aero Capitole TransTRAC Stereo Amplifier

by Jason Thorpe

People have a tendency to form tribes. The tube tribe revels in the lush midrange, the lack of harshness, and the spacious imaging of their tube totems. The transistor clan, on the other hand, raves about vise-like bass control and neutral tonal balance.

There are dog people and there are cat people.

Of course, there are ways around this light/dark, good/evil dichotomy. Over the years several companies, most notably Counterpoint, have produced amplifiers with a tube input stage and transistors at the outputs. In theory, you get the tube mellowness on the input and the silicon artillery to control the speakers. This approach, however, still relies most heavily on one technology or the other, each responsible for different tasks. The tribes are still at war.

Enter Audio Aero, which seeks to unite these seemingly irreconcilable groups with the Capitole TransTRAC amplifier.

You can’t get there from here

Located in Toulouse, France, Audio Aero is a division of the Mazères Aviation Group, which is made up of five high-tech companies whose main businesses are aeronautics and racing. The company’s aerospace roots, according to Audio Aero, help to ensure the quality and reliability of their audio products. Some of the other offerings in the audio field, such as the Capitole power amplifier and CD player, have at one time or another received praise here at SoundStage!.

At first glance, the Audio Aero TransTRAC (which stands for Transistor Tube Relay Amplification Concept) seems to be a well finished but conventional stereo tube amp. After all, you gotcher two E34Ls per channel, two output transformers, and one power transformer. Although the TransTRAC is beautifully chromed, there seems to be nothing tricky about this French amp.

Look closer, however, and you’ll see that there are heatsinks that run down the length of each side of the amp (perhaps for decoration only, as they never got even remotely warm). There are also only two speaker terminals for each channel, rather than the multiples for varying impedances that you’d expect to find. This isn’t your father’s Dynaco Stereo 70.

With the 40Wpc TransTRAC, Audio Aero has found a way to make tubes and transistors work together. Not, as you might expect, with each technology handling one stage. Instead, the designers of the TransTRAC have found a way to run the tubes and the transistors in parallel, both sharing the task of driving the output stage. This, according to Audio Aero, provides the best of both worlds. The E34L tubes are run in triode, which gains sweetness and immediacy, while the DMOS-FET transistors aid in delivery of current. As near as I can ascertain from the rather sketchy accompanying literature, it’s not a case of running the triodes up to their power limit (around 24 watts) and having the transistors kick in above that mark. Rather, the transistors are constantly in the circuit and share the load equally. When overdriven, however, the tubes give out before the transistors, which supposedly helps to keep the sound clean even when the amplifier is pushed to its limit.

The TRAC concept is used in other Audio Aero products, such as the Capitole and Prestige amplifiers, which use triode and pentode tubes, also in parallel. According to Audio Aero, this technology was pioneered in the early '50s, but until now it has never been used with any great success. Audio Aero is reportedly the first company that’s been able to take advantage of the benefits of this idea while managing to avoid the substantial penalties involved with its implementation.

At $6000 USD, the TransTRAC isn’t cheap, but Audio Aero certainly gives full value in the build-quality department. This amp screams luxury! The chrome is flawless, and the input and output connectors are high-quality items. The TransTRAC accepts both balanced and single-ended inputs, the choice of which is selected by a small toggle switch. The transformers are large and capped with chrome covers, and the front panel is satin-black anodized aluminum punctuated by the central power button. Just so you can’t say that Audio Aero skimped, the three footers are Black Diamond Racing cones.

The TransTRAC is a dense piece of gear. At 46 pounds, it’s quite heavy for its 16"W x 12"D x 8 1/2"H size. Besides the E34Ls, which are Tesla branded, the TransTRAC uses Sovtek 6SN7GT input tubes. There’s no provision for biasing the power tubes, and this procedure is not mentioned in the owner’s manual, so I just ran the amp as I received it. The TransTRAC is also available in an integrated version for an extra $600, should you choose to forgo a preamplifier.

Help from my friends

I used my Sonic Frontiers SFL-2 preamp in order to take advantage of the balanced inputs, which I found to be the best-sounding way to drive the TransTRAC due to noticeable gains in depth and transparency. I did, however, receive good results with the FT Audio LW1 passive preamp. Speakers alternated between Hales Transcendence Fives and Tannoy TD10s. The sources were a Rotel RCD975 CD player that fed an Audio Aero Prima DAC and my Roksan Xerxes/Tabriz/Artemiz combo via a Sonic Frontiers SFP-1 Signature phono stage. I used my EAR 509 monoblocks as comparison amplifiers.

Cables were Stealth Audio interconnects -- balanced from the preamp to amp and single-ended from the DAC to the preamp. Acoustic Zen Matrix Reference and Silver Reference were used for the analog section and for single-ended duty. Acoustic Zen Satori speaker cable was used exclusively.

Between the ears

This is a big, juicy, lascivious amplifier. From the moment I installed the TransTRAC in my system, I was delighted with how vivid and tactile it sounded.

The first record that I spun up was Michelle Shocked’s Captain Swing [Mercury 838 878-1]. This is my housework LP of choice, as its up-tempo R&B/jump blues seems to give me endless dusting momentum. However, this time I sat right down and listened through the entire album, as the size of the soundstage and the texture of the instruments dusted me. The TransTRAC presented the entire soundstage as a part of an acoustic space that ballooned outward from the speakers. The Audio Aero amplifier didn’t sound recessed in any way; it didn't sound bright or aggressive either.

The TransTRAC reminded me very much of a triode amplifier, as the midrange and lower treble had a burnished, rich glow. But the TransTRAC isn’t a one-trick pony by any means. I’ve sometimes found that triode amps lack dynamic punch and snap, perhaps due to their limited power, which highlights the immediacy of the sound while detracting from its overall realism. The TransTRAC, on the other hand, had the startle factor in spades. The horns on Captain Swing crackled with power, which gave me the impression of sound ringing off the actual bells of the trumpets.

Unlike its low-powered SET cousins, the TransTRAC sounds as if it has much more power than the 40Wpc at which it’s rated. My Hales Transcendence Fives don’t demand gobs of power, but they also don’t cut low-powered amps any slack. Judging by the deep bass, reasonably high volume, and lack of compression via my Hales speakers, I’d guess that the TransTRAC is more powerful than Audio Aero is letting on.

With the TransTRAC in the system I was very comfortable ratcheting up the volume to surprisingly high levels. The usual volume-limiting factors for me are stridency in the upper midrange and lower treble, which result in a nails-on-a-chalkboard sensation that bothers my fillings. This irritation wasn’t a problem with the TransTRAC in the system. While not totally smooth, the TransTRAC's upper octaves refrained from any glare whatsoever. I love the music on Showdown! [Alligator AL 4743] by Collins, Copland, and Cray, but Albert "Master of the Telecaster" Collins’ guitar tone drives me up the wall. The midrange and treble of the TransTRAC made that nastiest of guitars sound a touch more tolerable while retaining the bite that makes the playing so effective.

I said above that the upper range of the TransTRAC wasn’t completely smooth, and this made itself apparent when reproducing hi-hat and other percussion instruments that populate the treble. On "Living It Up" from Ricky Lee Jones’ Pirates [Warner XBS 3432], there’s some incredibly pure cymbal and bell work that gained a touch of immediacy while somehow losing a tiny bit of ultimate clarity. The small amount of texture made the percussion instruments sound very real, but at the expense of the pure tone itself. Via the Tannoy TD10s, this micro-fine texture was barely noticeable, if at all, due to the smooth, rich top end of these speakers. With my Hales Transcendence Fives, however, the slightly analytical metal-dome tweeter allowed me to hear this trait quite clearly. I don’t want to harp about this characteristic, but suffice to say that it was pleasurable, as it enhanced the harmonic body of the treble and added richness to the music.

Throughout the midrange the TransTRAC showed its stuff. Utterly musical, the French amp exuded sex appeal, portraying both male and female voices in a palpable manner. Just about the most blatant example of this was Johnny Hartman’s deep tenor on John Coltrane and Johnny Hartman [Impulse! MCA-5661]. Hartman’s voice on "Lush Life" was dramatically realistic, attaining a presence that was almost creepy. That creamy voice formed a physical body right there in my room.

This amp has a fantastic sense of rhythm, which manifests itself in the kind of toe-tapping drive that I associate with a really good turntable. The British would describe this as "letting go of the notes," but I kind of like the idea of gripping those same notes. I ascribe the rhythmic agility of the TransTRAC to a combination of its significant sense of power and its delicate handling of the midrange. I bet there are few people outside Canada who have heard of Max Webster, a Toronto-based rock group with guitarist Kim Mitchell as front man. Max Webster’s final album, Universal Juveniles [Anthem ANR-1-1027], was, in my opinion, the band's best; just listen to the loping bass line in "Chalkers" and try to stop your feet from tapping. "And a rocker’s voice screams desire / As a gambler’s heart goes wire to wire." Testify, Kim! The strong drive that the TransTRAC provides made this song seem much more rhythmically three-dimensional and far more entertaining.

While I’m on the subject of bass, I was most happy to discover that the TransTRAC doesn’t sound like a triode amp down in the basement. My Hales Transcendence Fives’ 10" sealed-box woofers demand some current if the bass is to sound deep and tight. Any deficiency here and the low end becomes indistinct and sloppy. The Audio Aero amp, while not a high-powered dynamo, is more than up to the task of driving the Hales speakers. There were times when I thought that I could hear some of the transition between tube and transistor drive, but they were fleeting and few. At these times I felt that the bass and midrange were running at slightly different speeds, somewhat like a subwoofer lagging behind satellite speakers -- as if the transistors yelled giddyup! while the triode tubes grumbled island time. As the review period progressed, however, I noticed this less and less, until it disappeared from perception.

At high volumes, the lowest notes lost just a bit of their grip via the Hales speakers, but that’s to be expected, as they’re large sealed boxes and this is a relatively small amp. The Tannoy TD10s were a better match in the bass for the Audio Aero. Indeed, these higher-sensitivity speakers really sang with the TransTRAC, right from the bass, which was full and authoritative, up through the midrange and treble. In fact, this amp with the TD10s was perhaps one of the best combos that I’ve ever heard when it comes to emotional impact, delicacy of tone, and depth of image.

Although my description of the TransTRAC has so far depicted a self-assured extrovert, its imaging was of an altogether different nature. When the recording demanded it, images took on a sense of delicacy and sophistication. Few amps I’ve heard can match -- let alone improve upon -- the way in which the Audio Aero amp crafts a soundstage. While listening to Giant Sand’s Cover Magazine [Thrill 104] I caught myself looking up in appreciation at the backup singer’s voices on "The Beat Goes On." These images didn’t rely on point-source accuracy; instead, the willowy voices sounded well spaced laterally, which is likely how the girls were arrayed behind the lead singer. The voices and instruments on this track had an aura of harmonic reality about them, which made them that much more believable and realistic.

Like to like?

While they both glow in the dark, the TransTRAC and my EAR 509 amps sound substantially different. Although they’ve got that rich tube midrange, the EARs definitely don’t have the slightly forward character of the TransTRAC. If anything, the EARs sound recessed and somewhat uninvolving in comparison to the French amp.

This doesn’t mean to say that the TransTRAC is aggressive, bright or abrasive. It’s just more engaging. Part of the reason for this reaction to the TransTRAC is the way that it handles the bass and midbass. There’s a sense of sharp delineation to notes in the lower registers that the EARs can’t match. This isn’t so much about bass quantity as it is about dynamic quality. The TransTRAC handles sharp low-end starts/stops with agility, while the EARs blur the distinction of these notes. Admittedly the EAR amps can drive the Hales speakers to higher volumes without losing control, but that’s only due to the additional power and can’t be held against the TransTRAC.

Up higher, too, there’s a sense of homogenization via the EAR amps that’s distinctly missing from the TransTRAC. I think that the term transient snap best describes this midrange quality, and the French amp has it in spades. The EARs have a slightly smoother treble, but, in all honesty, personal preference might decide the winner here. The British amps are slightly more neutral in the highs, but they’re also more polite, with less depth and detail.

You know how to whistle, don’t you?

If vintage tube amps are a kiss from your grandmother, and a good solid-state amp is a calculated peck from a supermodel, the TransTRAC is a luscious smack on the lips from Kim Basinger, complete with a thick layer of ruby-red lipstick. Delicious!

How many times do you get the opportunity to sit and listen to music with Kim Basinger? The TransTRAC is the aural equivalent of that experience. Audio Aero has designed and manufactured an amplifier that evokes emotion, texture and detail in the manner of the best triodes, while avoiding the sloppiness that often accompanies that breed. Add in dynamic agility, spacious imaging, superb build quality and respectable power, and you’ve got an amp that’s ideal for curling up with on a cold winter night.

...Jason Thorpe
jason@soundstage.com

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