ATC-3 + ATM-1S

Translation: Krzysztof Kalinkowski

Devices from the Japanese Air Tight, a brand owned by A&M Limited, are just plain beautiful. Oh God, for how long I waited to test something coming from that company! I saw them and listened to them during shows, mostly on the High End in Frankfurt and then in Munich (coverage of the High End 2008 HERE), but it was kind of licking an ice cream in wrapping. When the devices reached me everything was confirmed, what I thought about their esthetics and building quality. They are small, but their every element shows delicately (because this is not a scream) that it comes from Japan.

And the history of the company Air Tight (or actually A&M Limited, the owner of the brand – bit I will use the name Air Tight for simplicity) is as interesting as its sound. You could become acquainted to it to some extent during the test of another amplifier – the integrated L-505f Luxman. Why Luxman and Air Tight? Well, nothing in the world happens from itself and also does not exist in a void. So the three companies I value highly are closely related: Luxman, Leben and Air Tight. The parent company was Luxman. This is the company the engineers Atasushi Miura (AT) i Taku Hyodo (L) come from. In case of the first one two facts related to Luxman were most important:

  • 1956: Atsushi Miura joins Luxman.
  • 1961: Atsushi Miura marries the oldest daughter of K. Yoshikawa (owner of the company). Becoming a family member, in 1968 he becomes the head of the sales and main manager in the Tokyo office. In the years 1977-1980 he works in the New York office of Luxman, leading the American division named Lux Audio of America. In 1985 he retires and (in the Air Tight catalog the date mentioned is 1986), together with Masami Ishiguro, he founds A&M Limited starting with the ATM-1 amplifier.

    Now also with the test of the CS300 Leben I mentioned the biggest personalities from the world of tube audio, that I need to recall now:

    Air Tight - Mr Miura
    Ex-Pro - Mr Kondo
    Leben - Mr Hyodo
    Luxman - Mr Ueda
    Mactone - Mr Matsumoto
    Reimyo - Mr Kiuchi
    SD Sound - Mr Ishigami
    Yoshiba Onkyo - Mr Yoshiba

    It can be clearly seen, that Miura-san is in the narrow group of people, who have a real influence on the history of Japanese audio. From the above data it is clear, that the company A&M Limited got its name from the first letters of the given names of its creators. The history also shows that the company was founded after Miura-san moved to USA. Still it was founded in Japan and all devices are manufactured there, including lots of components used in those, like output and power transformers. In 2006 a new factory was opened in Takatsuki (half way between Osaka and Tokyo).

    The tested units are in some way archetypical for this company and show, especially the amplifier, that if something is good, then it is good now and will be good in the future. And that it does not have to be changed in a way of revolution but just has to be improved. Like I said, this is mostly valid for the power amplifier ATM-1S. I mean the integrated amplifier ATM-1S. I mean… Yes, this is the case I like, because it allows to think about our linguistic habits, and recalls, that nothing in life has only one meaning. On the other hand, at this occasion, we can try to organize the world around us a bit. Because the model ATM-1S is described in the company materials as a power amplifier. Regardless of how we can call it, it is an amplifier with two pairs of EL34 tubes in the power stage and a tube preamplifier based on the 12AU7 and 12AX7. Very nice, big, solid and expensive Hashimoto output transformers were applied, as well as a proprietary, also beautiful, power transformer. The amplifier is handcrafted in a magnificent way, and also looks magnificent. And now we approach the clou: the device is equipped in two line inputs - one on the back and one on the front – and volume control in the form of two independent potentiometers. To be able to know what we deal with, we have to ask what a preamplifier is. In short – an element of the sound path regulating the volume. That’s it. It does not have to amplify anything, as there are passive preamplifiers, also in integrated amplifiers (eg. Creek), or even to have an input selector. So only the regulation of the input level is sufficient. There is one exception to the rule: some devices have variable inputs or outputs, but with small regulators, located often on the back plate. That was the case with the DAC1 USB from Benchmark (test this month). Technically speaking, this is a DAC with a preamplifier (I am not talking about the version DAC1 PRE, but about DAC1 and DAC1 USB). But from the user standpoint this is a DAC with a regulated output level. I think that the key here is the intention of the controls: if it is easily accessible (like in the case of the fantastic amplifier Art Audio Quintet) we can talk about an integrated amplifier. But if it is only a regulation that allows adjusting the setting to a specific system, like in the DAC1, then we have to talk about a power amplifier or variable output DAC. If we follow this way of thinking – and this is how I think – then the ATM-1S is a classic integrated amplifier. On this background, from the methodological point of view, the preamplifier ATC-3 is almost boring. This is just a stereo preamplifier. Only beautifully made. But, but – we just agreed the ATC-1S is an integrated amplifier… Yes, that is true. But the manufacturer, and the distributor, show, that attaching it to a preamplifier improves the sound significantly. And this can be understood easily – a big part of integrated amplifiers with a passive preamplifier (and we deal with this case here) sounds with a deeper, fuller sound, when the signal is prepared earlier. In a preamplifier.


    Directly after switching from my system to the Air Tight one (and that was how I started the listening session) the sound seems more delicate and lighter. It can be heard clearly, that the sound is shaped in a way, that its main energy falls on the sustain of the tones, to have the musical “value” not in the attack phase but just a tad later. If such a procedure is done a bit deeper, it gives a somewhat sweet sound, incredibly characteristic for some Japanese devices. Here we have something between the sound of TRI and Lebenem, Accuphase and Luxmanem. It was fantastically audible with the disc Spiritchaser Dead Can Dance (4AD/Warner Bros Japan, WPCB-10078, SACD/CD), in the piece Song of the Dispossessed, opened by a simple riff on a classic nylon string guitars. It was clear, that this is such kind of guitar, such strings, without a trace of doubt, because without any hardening or brightening of the sound, that sometimes makes us wonder, if those strings aren't metal. Unfortunately I did not see the color of the strings (those can be black, white or transparent), but this is not the right price range. OK, I'm joking :-) The tone was very nice, because the guitar sounded in certain “soft” way without softening the moment the flat pick touches the string (or the nail – I cannot distinguish that, but I would bet on the pick). The sound of the whole disc was vivid and one could listen really very nicely to what the magicians from Mobile Fidelity, the company creating the DSD re-masters of the whole discography of this group, did to the source material. It “entered” smoothly, one could feel the same thing as with other Japanese devices: the mentioned “softness”, showing the sound in a natural way, that does not need cutting out of the context to be described, in contrary, it needs the smooth cooperation of the whole frequency range. It is also about going in depth, without bouncing everything of the maybe resolving, but hard, and thus a bit pinching, recording surface. From the beginning it was also heard, that it is not about cutting the frequency range extremes (this is a way that simulates vividness easily). In contrary – the upper midrange was strong and expressive. This is what made the voice of Lisa Gerrard a bit glassy and bright at high volume levels. But this is just a hint to the loudspeakers to be used with Air Tight. In my opinion the ideal combination would be with the Art Loudspeakers (test of the model Stiletto 6 HERE) - high efficiency, splendid timbre. And it is not even that the amplifier cannot handle more difficult loudspeakers. My Dobermann do not have high efficiency and need lots of kick in the midrange. The Japanese amplifier handled them without problems, but in the volume level range normally used for listening. Higher u the volume – and it will be just like I described or we change the speakers.

    But this is not a one-dimensional – vivid and pleasing system. Regardless how this one dimension would look attractive it has nothing to do with high fidelity (and please do not forget that high fidelity and “High Fidelity” are at stake here). Air Tight devices, while keeping the overall character I described, react immediately to disc changes. Changing to the newest re-master of the material from the disc Just Walkin’ - Wes Montgomery (Verve/Universal Music Japan, VCCU-9355, CD) the sound hardened and the resolution almost disappeared. At least in a part of the recordings (the disc is composed from recordings from various periods, not published earlier). It was also a bit closer than in my reference system. There was also no trace of washing out or warming of the sound. I think that this is characteristic for good devices – the capability of differentiation.

    The bass was strong and full, although it was not warmed like with some other EL34 based amplifiers. It was closer to the TP305 VR from Edgar than the Manley Snappers, it would rather be the AI-45 MkII Linear Audio Research than Edgar TP 101 MkII, or Synthesis Flame. When in the Song of the Stars from the mentioned Dead Can Dance disc a low hum comes in the beginning the AT shows it in that way – saturated and a bit soft. There is no talk about going as low as the Luxman M-800A, but this is different power and different money. This is also how the contrabass sounded, that opens the fantastic disc Happy Coat Shota Osabe Piano Trio from the recently received pack from Winston Ma with new re-masters (Sho Studio of Music/First Impression Music, LIM, K2HD031, K2 HD, CD). The sound of this instrument was strong, full, and with that “thorough”. The whole had a smaller volume and was shown closer to the middle of the stage than in the reference system and the instruments were in general placed a bit further away. There is no strike with details but they are also not especially masked. Sometimes the upper midrange is being heard very strong, you have to watch out for that choosing your speakers. Such way of sounding allowed to show much information on the technique of playing, murmurs of the players, etc, that were softer earlier. The upper treble is rather delicate, but nobody places it under the carpet. This was nicely heard with Sonny Rollins saxophone on the disc Way Out West (Contemporary Records/JVC, VICJ-60088, XRCD). This is when I heard that the AT is going in the direction of thorough playing rather than sweetening the sound, but without reaching the end, as for the money the sound can be reproduced more resolved (look here – CEC AMP6300).

    Interesting results were achieved connecting the ATM-1S directly to the variable output of the Lektor Prime (the volume regulators on the amplifier were put on maximum). The sound became much more resolved and more “present”. And contoured of course. At the same time the upper midrange sounded a bit too much “at your face”, without the breath given by the preamplifier. Maybe connecting the amp to loudspeakers with a softer sound than the Harpia will be the solution to the problem, but I did not test that. Anyway, without the preamp the fluency was lacking a bit. Another interesting connection was made with the tested in this issue converter DAC1 USB from the company Benchmark, using the amplifiers controls to set the volume. The DAC1 USB is a very vivid, a bit dark device, that was for the good in this connection. There was no resolution or depth like with the Prime, but the tonal balance was better. The upper midrange was toned down and not as extruding as earlier. Earlier, with the ATC-3 in the sound path, there was no problem with the sharpness of that frequency range, but there were occasionally more accented elements present. Also the bass improved; in connection with the Prime it was too light. Now it was stronger and better articulated.

    Let’s summarize our findings: in direct connection to the ATM-1S amplifier both the DAC1 USB and the Lektor Prime sounded with better resolution. But the fluency of the sound disappeared and (especially with the Lektor) slight importunity of the upper midrange appeared. This can be probably explained away with the high output impedance of the player and a much lower one of the DAC. The preamplifier, at least in my opinion, unambiguously improved the sound of the ATM-1S amplifier. Not in all aspects (resolution was unfortunately lower), but summa summarum - it was better. And in general, the AT system sounded with an extremely balanced sound, attentive sound, situated someway between sweetness and precision. The drawing of the instruments is maybe not as precise as with some other devices from the same price range, but you cannot have everything. The craftsmanship of the devices is perfect, better than the Leben, something like Luxman or Accuphase in the split systems. They are not big, and this attracts me even more. Really a valuable proposition, just needing toned down high efficiency loudspeakers (like Art Loudspeakers) and it will be super.


    Just like I wrote, the craftsmanship of both units is just beautiful. The same care of detail like with Accuphase. Its front panels are made from thick, perfectly processed aluminum plate, anodized to a characteristic, steel-blue color (something like navy-blue). Near to the top cover there is a deep milling that optically lightens this element. The enclosure is varnished in a dark graphite color. The titanium colored knobs are rolled out and knurled. Fully professional. To the side, near to the right side there is a tablet with the company logo, finished in ‘old gold’ color.

    ATC-3 is a tube type line preamplifier. Its front panel bears two big knobs – one for the input selector and one for the volume – and three smaller ones – one for the tape monitor, the second chooses the mono or stereo mode (nice for mono LPs!) and the third one is for balance. To the right we have a mechanical power switch with a amber LED above it. There is no remote control – probably Miura-san thinks like Hyodo-san – in my preamp RS-28CX also does not have a remote. Unfortunately. On the back we find splendid RCA sockets from the American company CMC. There are two variable outputs from the preamplifier and one fixed for the recorder. We have five inputs, one of them being for the tape loop, and selected by the ‘source’ knob on the front panel. There is also a IEC power socket and – this is usual for Japanese units – a separate ground terminal (gold plated), which can be used to connect all devices in a system.

    It turns out that the enclosure is made from thick steel plates. Inside a view like from most respected Japanese companies. The whole montage is made in a combined technique with PCBs and point-to-point. To the right we have the power supply. It is based on a big, classic EI transformer. It is placed in a way, that the least emitting edge is facing the circuit, something usually not noticed. Big capacitors are employed, with Air Tight logo on them, but manufactured by Mundorf, as widely known. It looks like the anode voltage is stabilized and the filament voltage is rectified and filtered. In both circuits Nichicon capacitors were used. The audio circuit is mounted on a separate PCB, next to a thick shield, where the tube sockets were attached to. The latter are being seated from the other side, horizontally. On the PCB we find very nice resistors and splendid capacitors - ASC Capacitors (American ShiZuki Corporation – a company with 50 years tenure) from MFD series, polypropylene and metallized.

    The audio circuit starts on the input sockets, from which the signal (from all of them) runs with separate cables, quite long, to the large, open, source selector on the front panel. The cables to, and from the selector, run separately. From the selector two unshielded cables lead the signal to the ‘stereo’ selector, and then to the balance regulation and volume. The last two are hermetic potentiometers from Alps from the ‘Blue Velvet’ series. From the latter with two unshielded cables the signal gets to the PCB I mentioned. In the amplifier section three tubes are employed – two miniature double triodes 12AU7 and one 12AX7, all made by Electro-Harmonix, with Air Tight logo. The company performs a selection of all tubes and uses only those that pass selection with ‘platinum selection’ markings. From the PCB we go back to the back plate with the same wires as we got there first, to the RCA – both outputs are paralleled, and the signal goes to output 2 and gets elongated to output 1.

    The integrated ATM-1A is a fully tubed device, with the power section in classic Williamson setting, with a pair of EL34 in push-pull setting per channel. The phase splitter, in a setting developed by the company Mullard, is based on 12AU7A tubes, that work also as the output tube drivers. On the input there is a single 12AX7 tube. All tubes come from Electro-Harmonix and were thoroughly selected (‘platinum selection’). Behind the tubes we see big transformer boxes – those are superb Hashimoto products. The power transformer is also big, and Air Tight manufactures it by itself. In front of it, in the original ATM-1 model there were rectifying tubes and driver capacitors. In the 1S version there is the window of a meter allowing us to set the power tubes bias. In the front we have three knobs – two for volume control and one allowing choosing between the front and the back input. On the back there is a single pair of RCA sockets coming from CMC and two pairs of speaker terminals from the same company. There is no marking for which impedance they were prepared.

    Inside we find point-to-point connections. From the input on the back plate with two long cables we run to the input selector at the front panel. Next to the selector we have the front inputs, much worse than the back ones, but only about 2cm of cable is between them and the selector. So it is worth to try which input is better. The volume is controlled in two separate Alps ‘Blue Velvet’ potentiometers. The low power tubes are mounted in sockets screwed to a big, thick copper plated plate, working as a shield. In the circuit splendid passive elements are visible, like the precise, low-noise resistors with gold plated pins and ASC polypropylene capacitors. In the power supply a choke is used (for the anode) and three big capacitors, just like in the preamplifier. It is worth to mention, that the potentiometers to set the bias are not ‘run of the mill’ cheap things, but big, high power, nice potentiometers from the Japanese company Cosmos. The whole looks incredibly solid.

    Technical data (according to manufacturer):
    ATC 3
    Input impedance 110mV (with 1V output)
    Input impedance 100kΩ
    Output voltage (nominal) 2V
    Output voltage (maximum) 15V
    Output impedance 200Ω
    THD <0.01%
    S/N 90dB (weighted)
    Dimensions (W x H x D) 430 x 90 x 325mm
    Weight 8kg
    ATM 1S
    Input sensitivity 1V
    Input impedance 100kΩ
    Output power 2 x 36W/8Ω
    Dimensions (W x H x D) 368 x 293 x 231mm
    Weight 22kg

    ATC-3 + ATM-1S

    Price: ATM-1S – 17 500 zł; ATC-3 – 12 000 zł

    Distribution: SoundClub


    SoundClub Sp. z o.o.
    ul. Świętokrzyska 36/45
    00-116 Warszawa

    Tel. 022 586 3270
    Fax. 022 586 3271





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