Audio Tekne TEA-2000 Phonostage

It happened only once before that High Fidelity tested the same product twice. It was the Nagra's PL-P preamplifier, that was firstly reviewed in our issue No. 19 (November 2005), and later in issue No 50 (November 2008). If memory serves it has never happened again within the whole 12 years history of High Fidelity. The simple reason being that there are so many interesting devices to review that often they have to wait in line for a few month before we can actually perform a test. Why? Because there is only so many reviews we are able to perform monthly (only 24 hours a day for us too, you know) and reviewing the same product more than once would take a spot from some other, interesting product.

If memory serves I re-reviewed this product out of curiosity—I wanted to find out how this great product would work in my new system and what would be my own perception of it after a few years that surely changed my experience, knowledge and expectations. There is no other reason, than curiosity, also this time that could justify my choice. The Audio Tekne TEA-2000 phonostage was already reviewed for “High Fidelity” almost a year ago by Marek Dyba (see HERE). Since then Marek had a chance to assess also more expensive products designed by Mr Kiyoaki Imai, and I was getting anxious to listen to at least one Audio Tekne product myself. Knowing that I would get the TechDAS Air Force Three turntable for a review, I asked Hari Strukejl of Natural Sound, Audio Tekne's distributor for several countries in Europe, if he could deliver a 'proper' phonostage that could accompany this deck. He offered TEA-2000.

Manufacturer calls this product: Phono Equalizer Amplifier and actually it is a small amplifier. It features a vintage look, like something that could be made in 1960ties with its shape, painting, tubes and old-fashioned switches (AT's English webpage looks like it was created also back then AT). It's a tube phonostage with semiconductor based power supply that works with MC (Moving Coil) cartridges only. This is not only a disguise, but an the expression of Imai-san's work ethic.

The unit is supplied with such a thorough and detailed documentation, that I have probably not seen ever before. I remember that in the 1970s and 1980s many amplifiers, including Polish ones, were supplied to the customer with electric wiring diagram. Today, such a scheme, at least its simplified version, customer receives from Accuphase and Luxman. With the Audio Tekne however, we get a detailed diagram, along with specific voltage measurements marked manually on it. We also received a montage scheme, where one can see exactly where in the spatial arrangement of point-to-point montage each particular element is placed, we also get photos in unit's interior and exterior, and even a sheet with RIAA measurements on dozens of points! Nobody here is afraid of copying or stealing manufacturer's ideas. There is only one Mr. Imai after all.

I guess, he doesn't have to worry about those who might try to steal his ideas as the secret of his devices' performance lays in special transformers. TEA-2000 features a unique design—it works in push-pull configuration, that is used almost exclusively for the output stages of power amplifiers. Its correct operation is possible with the next idea—the use of transformers, and not capacitors, coupling following stages of the device. This is historically the oldest solution, but it was dropped by the industry a long time ago, mainly because of the cost. The secret to the construction of high quality transformer falls within the field of art and there are very few who mastered it. Mr. Imai uses the transformers of his own design featuring extra large Permaloy cores.

This is one of the reasons why the device is so expensive. It's not the only factor, but probably a decisive one. Because TEA-2000 is a quite small, but very solidly and competently built, and yet it's hard to recognize what one pays that much money for as the reasons behind the steep price are hidden inside metal chassis. Its functionality is also limited. There is no load or gain adjustment, unless as such we consider two inputs—for cartridges below and above 10 Ω and two outputs—with higher and lower gain. But, to 'make up for it', the company offers a number of accessories which, although not cheap, can improve buyer's mood, as well as the performance of the device. For example, special carbon spacers insulating tubes from vibrations, as well as Litz type interconnects. Because I wanted to hear Audio Tekne system, I used them in the test too.

SOUND

Recordings used for the test (a selection)

Benny Carter, Jazz Giant, Contemporary Records/Analogue Productions AJAZ 7555, "45 RPM Limited Edition #0404", 2 x 180 g LP (1957/2009)
Bill Evans Trio, Waltz for Debby, Riverside Records/Analogue Productions APJ009, "Top 25 Jazz", Limited Edition #0773, 2 x 180 g, 45 rpm LP (1961/2008)
Bill Evans, Bill Evans Live At Art D'Lugoff's Top Of The Gate, Resonance Records HLP-9012, "Limited Edition - Promo 104", 3 x 180 g, 45 rpm LP (2012)
Cannonball Adderley, Somethin’ Else, Blue Note/Analogue Productions AP-81595, "The Blue Note Reissues, 45 RPM Special Edition #2468”, 45 rpm, 2 x 180 g LP (1958/2008)
Depeche Mode, Fragile Tension/Hole to Feed, Mute Records 12BONG42, 2 x 180 g, maxi-SP LP
Extra Ball, Birthday, Polskie Nagrania "Muza” SX 1414, "Polish Jazz Vol. 48”, LP (1977)
Frank Sinatra, No One Cares, Capitol Records/Mobile Fidelity MFSL-1-408, "Special Limited Edition No. 186”, 180 g LP (1959/2012)
Frank Sinatra, The Voice, Columbia/Classic Records CL 743, Quiex SV-P, "50th Anniversary”, 180 g LP (1955/2005)
Pink Freud, Pink Freud Plays Autechre, MMA Rec MMA03, Limited Edition No 78/250, 2 x 180 g LP (2015)
Semafor Combo, Semafor Combo, OBUH V30, 180 g LP (2012)

Mr Imai prepared some advice for the users of his product. No. 6 on the list says:

A key feature of every audio system should be a proper tonal balance. If you take a component with such a proper tonal balance and connected to the whole system with a distinct 'personality', usually you will get a lot of bad sound. All of its pros and cons will be presented in a very distinct way. And we are particularly sensitive to the poor/wrong part of the performance. Therefore, I strongly urge you to think about the tonal balance of the system as the most important element of the equation.

It is no coincidence that I begin my report on listening assessment with this particular quote—one doesn't need a huge experience nor knowledge on audio to quickly recognize an amazingly accurate tonal balance that TEA-2000 offers. One can't just quickly pinpoint any coloration, no obvious excess or insufficiency in any element. After an extended session in a well known environment one should be able to determine the changes that the device introduces to the sound, but even then they are not irritating and could hardly be called a 'coloration', maybe an intrinsic sonic character at most. I think this slight semantic shift actually best describes the impression that one gets after a longer listening.

It can come as sort of a surprise, because the device is built using two techniques with clear sonic connotations: tubes are used for gain stages, and the coupling is performed by transformers. Each one of them is able to give sound a specific sonic character that can dominate the device's overall performance. But in this particular case I heard nothing of a sort. Accompanied by very well balanced, very expensive components, the Audio Tekne phonostage delivered a much more accurate tonal balance than many other great phono preamps by other brands, even such successful as: Manley Steelhead v2, Phasemation EA-1000, ZYX Premium Artisan or Vitus Audio SP-102.

This fact itself makes the TEA is a very interesting proposition for those who do not have anything in the system to correct, or to 'tune' to their taste. And that's not all—this phonostage, not favoring any kind of music, turned out to be extremely versatile. And I mean a true all-rounder that played equally well such variety of music as Plays Austerche album by Pink Freud, through a lot of records with Polish Jazz, to the test pressing of the Noce Szatana / Ostatni Tabor by Kat and 10" record released by Nuclear War Now label. It was a refreshing listening, because I did not have to focus on some style, and was reaching for a record that just came to mind. This type of freedom of choice is especially important to me.

The basis of this versatility is the already invoked, accurate tonal balance. It's a truly well-balanced performance and I mean it in the best possible way. It has no this 'clinical sterility' of the presentation, no brightness, or dullness. It this level of accuracy that my own selected component from Ancient Audio, Ayon Audio and Soulution had made me used to—each does it in a slightly different way, but the structure is the same. The records are not cruelly dissected on one hand, on the other they are still very well differentiated; differences, advantages and disadvantages are not emphasized by the phonostage and still recordings have their own "tone" and expression.

Another important element of this performance is its smoothness. The presentation is wonderfully smooth. There is no harshness in the sound, all the 'dirt' included in some recordings stays hidden in the background. Throughout the whole band tone might seem a little pastel, but never faded. That is a feature of phonostages with transformers in signal's path made by someone who knows a lot about music, has a sophisticated taste. There are of course the consequences. One of them is a slight smoothing of the dynamics. In the micro scale the preamplifier nicely shows all the changes, shifts, swings, that make performance 'alive'. But on a macro scale one can realize a slight smoothing of the attack.

And although the "accurate tonal balance" was the key phrase of this test, I think we all understand it contextually—as great for the price range and product's type. Because low bass is TEA-2000 somewhat withdrawn. There is no clear shift in the balance up the band, but we do not get a strong bass foundation, and scale of sound is also not the biggest possible. The individual instruments, voices, special effects, if they have been highlighted by the sound engineer, will have a beautiful body, will be large and meaty. This was the case, for example, with the voice of Frank Sinatra on the re-release of his album No One Cares , prepared by Mobile Fidelity. But with a larger number of instruments, when all elements are equally large, the scale of the sound was a bit smaller, and the sound was not so expansive.

On the other hand—literally, because I speak of treble - it is in turn very interesting. The preamplifier shows there full palette of colors, with high dynamics and high energy. Although it features tubes in gain stages, it does not it translate into warm, rounded treble or any problems with resolution in the upper part of the band. Long story short—treble is much, much better than delivered by my RCM Audio Sensor Prelude IC, which, let me remind you, is already a very unique device in this respect. I think that only the most expensive Vitus phonostage is able to deliver a similar level of performance. All others are, in comparison to Audio Tekne, withdrawn and hazy.

Summary

Japanese preamplifier is an oasis of calm. While using it one can listen to music without having to carefully select albums that might sound well, but rather putting on the platter anything one feels like listening to. Clearly, poorly pressed records will play poorly—that's what, for example, the limited, blue edition of Clan of Xymox had to offer—it sounded like mp3—but even in this case it was still a performance I could enjoy. With good pressings everything is the way it should be.

TEA-2000 offers a very smooth, saturated sound, where there is no rounding of the attack, nor warming up. Instead, there is an excellent reproduction of high frequencies, that do not sound in a typical "tube" way, nor in w typical "transistor" one either. Low frequencies are slightly withdrawn, so that the presentation does not have its full momentum. It is obvious, however, that this is a planned 'effect'. Completely under designer's control, because it does not disturb the tonal balance. It's a fantastic phonostage offering such a unique sound that can it can be used to assess all the others. It won't perform better than all of them, but it will always be a great reference, a landmark.

DESIGN

TEA-2000 is a phonostage designed to work with MC cartridges. It is a tube design with a semiconductor power supply section. The first stage is based on coupling transformer but it doesn't add gain but sets loading parameters for the source and performs signal symmetrization. It is one of things that make Mr Imai's designs unique: signal is amplified by a push-pull circuitry. Signal is symmetrized by an input transformer and de-symmetrized in the output one, and between these two gain is applied by double triodes.

The device features an amazingly 'classical' appearance—classical for 1960ties that is. It features a wide front panel and relatively small depth. Just by looking at it one might figure out the path of the signal. On the right side there is an input transformer, than the first tube, an Electro-Harmonix 12AY7 (6072A) double triode. It is coupled with the next triode 5965 (in this particular case the Mullard 188CC was used) using another coupling transformer. Right before the second tube sits the RIAA section with polypropylene capacitors (these look like Philips ones) and precise resistors. A third coupling transformer works between second and third tube, the latter being Phillips E188CC, which is followed by a coupling/output transformer. As you can see there are no capacitors in signal's path, also in RIAA section, where the ones mentioned before work only in a parallel circuit. No negative feedback is applied in this design that features a point-to-point assembly.

At the side there is a power supply section with a large, EI transformer, double LC filter and three rectifiers. It is a "fixed bias” device. On the front there is a large on/off toggle switch accompanied by a large red light. Chassis is made of steel sheets painted with a grey-ish paint. The chassis features four large feet made of cast iron. It features great anti-vibration properties. As far as I know it is used only by few companies including Accuphase, but also Polish manufacturer J. Sikora uses it in its platters. Accuphase paints the feet for its devices, Audio Tekne doesn't so one might get one's hands bit dirty while moving TEA-2000.

There are two RCA inputs—one for cartridges with impedance lower than 10 Ω and the other for all the rest. There are also two outputs, with two different gains. The documentation provided with the unit suggests that the second output delivers 80,5 dB gain.