Auris Audio Adagio 300B

Some time ago we were contacted by the Auris Audio company, after we saw their products at this year's High End show in Munich. These unknown tube amplifiers from Serbia accompanied by small Boenicke Audio showed such an addictive sound, that we were very enthusiastic about having a chance to listen to these devices more closely. It was unusual situation and the surprise is all the greater, because this fresh company presented several other products - preamplifiers, integrated amplifiers, power amplifiers and even a couple of DACs and headphone amplifiers. We could have expected that at least dozens of distributors will be willing to promote this brand in their countries. Indeed Auris Audio aroused so much interest that we had to wait a few months for the first amplifier for the review.

The brand was established by Milomir Trosic who is a CEO and Co-Founder of the HCP telecommunication company. So we are not dealing with a situation where one idea has been evolving for fifteen years to finally come out in a form of a plastic box with wires sticking out of it. Milomir Trosic is an audiophile, but also a successful businessman who knows how to run a company. He hired a team of experts, organized a well-equipped factory, released beautifully illustrated catalogues and launched a modern website. Finally a new company has been entirely successful at the Munich exhibition. Distributors and journalists sent emails and received all the necessary information, but only one thing was missing - the boxes with the equipment. Serbs got down to work very quickly, and after refining the last details, here it is - the Adagio 300B - one of the best amps in Auris Audio's catalogue.

Auris Audio Adagio 300B
Who would have thought that you can design and make an amplifier like that without at least 20 years of experience.

Design and functionality

It's hard to believe that such a sophisticated and refined product left the warehouse of the company, which a year ago almost no one had heard of. Yes, perhaps it is possible to design a nice amplifier in such a short time, but still you need to cope with the design, packaging, ensuring a steady supply of components, refining the process of production, securing repeatability and checking the quality of final products. And I didn't mention the marketing, legal actions, building a dealer network or organizing a photo shoot. Maybe I'm exaggerating, but many companies need several years to organize all of this. Baring in mind the scale of the project undertook by Serbian engineers, I cut the company tape on the package and looked inside cautiously. After removing the protective foam with cut-outs for transformers' housings and boxes with tubes, the main content showed up... Let me be brief - it looks like a work of one of the greatest legends of the high-end tube world. Adagio 300B is a very heavy amplifier which captivates by stunning design and craftsmanship. You could look at the details like knobs, wood panelling, leather covering or sockets under the microscope, and even then it would be difficult to find any flaws. I know this because I watched the photo processing and I couldn't notice the smallest defects even on a very high magnification. All the pieces fit together perfectly, sockets meet all the criteria of functionality, and you just want to touch and feel the beautifully finished knobs. I guess that Milomir Trosic had many hi-end amps in his life and he knows how all the details should look and work. Not only is the external appearance and design perfect, but the product as a whole picture. With the entire framework, documentation and wooden remote control it makes an excellent impression.

Some audiophiles assume that anyone can make a nice tube amp. The schemes are available, different types of circuits have been rehearsed so many times and all the innovation ends on improving the available technology. But even if we assume that all knowledge about the development of tube amps has been explored, there is still the issue of putting it into practice. In the case of Adagio 300B I have no doubt - this is an example of a very solid work comparable with the best devices of this type in the world. Serbian amplifier is also very pleasant to use. We receive only a beautiful device with metal, wood and leather, the tubes and the remote control. There are no gauges or manuals thicker than an Ikea catalogue. No one forces us to study the charts illustrating the tubes biasing. The front wall is decorated with only three knobs - an on/off switch, volume knob and source selector. On the back we have four RCA inputs, speaker terminals for 4 and 8 ohms and a power socket. The red LED flashing towards the ground informs us about the amp's activity, besides the hot tubes of course.

When I tried to get to the inside of the amplifier, I noticed some nice details as the company logo placed on the inner parts of the meters. These are not just some items purchased from an electronic warehouse. Even the remote control in the form of wooden bar with metal panels gives some clue about the level of overall refinement. At the top there are only three buttons for volume control and muting, while at the bottom the engineers placed the inscriptions and four small legs resembling those added to small DACs. Here they are glued, because... They also mask the screws holding the metal plate to the wooden body. That's why the remote control won't slip on the surface of the table.

The Adagio 300B is using one of the most iconic power tubes. The 300B triode is a true sanctity for many audiophiles. The owner of the 300B Single-Ended amplifier is a member of the elite club. Other fans of valve amps will perhaps bow down to them. And not without a good reason. Firstly, these amplifiers are inherently expensive. Secondly, the quality of the output signal will almost certainly be high, but the quantity - low. In comparison with solid state amplifiers, this is a completely different level of sensitivity. To show the whole grandness of this construction we need appropriate speakers, with the sensitivity exceeding 90 dB's. This is not a big problem, because even some conventional sets by Focal or Triangle offer such values. If we look for really high-efficiency speakers, like for example WLM or Living Sound, we can even get 95-98 dB's. The choice of the right company for such an amplifier is absolutely crucial, including not only the speakers, but also the source, cables or power supply. However many audiophiles confirm, that a well-configured 300B SE amplifier can repay the listener for every little thing and every penny spent on seemingly unimportant accessories.

Auris Audio Adagio 300B
Nothing unusual on the back, but it's all there.

Sound performance

Every audiophile knows what to expect from such amplifier. Results may be different with budget tubes like EL34 or KT88 of unknown origin, but when you have a wonderful, well-made 300B amp, there is only one possible scenario... I expected the performance to be warm, pleasant, delicate and charged not only with sounds, but emotions. In my head I had an idea for a description of the sound, but when the speakers began to move, I realised that starting this paragraph with stereotypes would be unfair. The Adagio 300B presented very natural and superbly balanced tone. Neither balmy mid-range nor delicate tremble, but the overall consistency and tangibility of presentation were brought to the forefront. One minute after the first run, the amp had the right to a bid clamour and harsh, but from the first moments it showed correct, and even more - a pleasant, full and elegantly decorated sound. Despite these positive observations, I decided to give it some time for a decent warm-up and after this I totally got involved in music. The bass gained agility and energy, without losing the mild filling. Mids cleared up and took a little step forward on the soundstage. High frequencies were more open and saturated with the smallest details. This is exactly what so many people love in triode amps. However these changes didn't result in the loss of the homogeneity of signal nor upset the balance between the different parts of the bandwidth.

If you didn't have contact with hi-end tube amp, I strongly urge you to try such an adventure at least once in your life. It may turn out that in the pursuit of the perfect bass and dynamics, you forgot about other aspects of music reproduction. A good tube amp is able to show subtle differences in terms of timbre and vocals and can treat resolution as something natural, not desperately scavenged from recordings. While many transistor devices focus on speed, power and selectivity of sound, tube amps show the world made of a million shades of violin, guitar sounds containing the aura of soundboard and vocals sounding in a completely natural and organic way. After a while we begin to see the center of the tones, rather than focus on the beginning and end of each note. Therefore, the music is more complete and our ears have enough time to catch what is really important. All of this is mounted in a space which is not only a collection of sharply outlined shapes, separated by meters of air. The soundstage is indeed wide and deep, but the instruments come together in all kinds of interactions. Each sound is presented as the sound engineers and musicians wished. So we can get the drums recorded in heavily damped studio and some more open vocals in front of it. We can notice a lot of such stories and they don't even require our special attention. The Adagio 300B presents even the most complex textures with great equanimity, which is also reflected in our comfort of listening. The gibberish or chaos didn't show even in the electronic recordings. And if you play some heavy music, you will understand why guitarists love their tube amps so much. At once you hear the slightest differences between the instruments. Once you enter this world, everything else can seem a bit black and white.

For me the Adagio 300B accumulates all the advantages of audiophile tubes. A great amplifier with delightful, rich and incredibly addictive performance. Disadvantages? Well, the only one is a result of the purist design of this device and the tubes. If we use the common speakers with the effectiveness of 86-90 dB, it is impossible to listen really loudly. If you like to listen to music at high volumes, they should look for sets with very high efficiency. But there is a plenty of possibilities, so my only gripe about Adagio 300B can be negligible.

Auris Audio Adagio 300B
A very pretty amplifier, isn't it? And very well made too.

Build quality and technical parameters

The interior of the Auris Audio amplifier can only be reached from the bottom. Thick steel plate serving as a base of the device is bolted to the wooden panels with fourteen screws, which - as it turned out - do not enter the boards directly, but are joined with metal threads embedded in wood. Although there are no tubes inside a wooden crate, the main compartment is well ventilated with two circular cut-outs sealed with chrome grilles reminiscent of those from the computer PSU fans. Smaller vents have also been cut out around the tube sockets. Lifting the bottom plate is not easy because there are two transformers bolted to it, so the whole thing is quite heavy. I was able to just lift the hood and take a quick look inside. My attention was drawn not only to a high quality of components, but most of all the neatness of the circuit and attention to detail. As the wooden cabinet finished in leather doesn't protect electronics against any interference, the main compartment is lined with relatively thick metal foil. Cables are organised so perfectly as if they were an integral part of the chassis. Some elements are held in place with screws, other with special clips, and, if necessary, glued in place.

When it comes to valves, the amplifier delivered to our editorial was equipped with one 5U4G by Sovtek, two 6SN7's and 300B Gold's (with gold-plated mesh) by Electro-Harmonix. A pair of 300B's which will wear out first should cost about €200. Their lifetime can be estimated at 2000-3000 hours, so if you listen to music for a few hours a day, one set should easily last for a year or two. The most interesting technical parameters worth mentioning are the bandwidth which according to the manufacturer stretches from 17 Hz up to 32 kHz and the THD of 0.7%. Certainly an integrated amplifier built on 300B tubes in Single-Ended configuration will not deliver a massive amount of power. Here we get 8 watts per channel, which narrows the possible choice of speakers, but not dramatically. If you don't believe that a nice little tube like this can perform, I encourage you to listen to one of those big amplifiers with power meters (McIntosh, Accuphase, Luxman) and take a look at the range in which the needles move, even during loud listening. Of course, there's still a question of other parameters such as damping factor for example, but the experience itself is can be very informative.

Auris Audio Adagio 300B
A remote made of wood and metal to match your amplifier.

System configuration

Since an audiophile Single-Ended triode cannot be simply plugged into a random hi-fi system, we've tested the Adagio 300B in two different configurations. In the first one it powered several pairs of speakers including things like Triangle Antal Anniversary, Audel CG Tower and Focal Diva Utopia BE. The signal came from Pathos Digit CD player and all the cables were delivered by Cardas. In the second system the amplifier was working with two completely different speaker sets - Pylon Audio Sapphire 31 and Albedo HL 2.2. In this case, the main source was the Naim CD5 XS, cables were also provided by Cardas, and the power distribution was all done by Enerr. Despite the large variety of speakers used in the test, I didn't feel the lack of dynamics or resolution in any combination. Of course you won't be able to throw a big party with this amplifier if you use some speakers with an efficiency of 86 dB, but if you just stick to 90 dB or higher, it will be more than enough for normal or even pretty loud listening.


At the beginning of this test I already felt that the Adagio 300B can be quite a nice amplifier. What I didn't expect was that it would turn out to be such a refined and complete machine, in terms of the aesthetics and sound quality. Audio Auris enters the world of high-end without false modesty. Not because of the name of the owner or any other connections, but in the simplest possible way - with extremely high quality of its products. If this amplifier was branded with a logo of one of those companies before which audiophiles almost kneel, it would cost twice as much. If the Serbs stick to this path, they can quickly join this elite group.

Company's logo even on the meters.
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Technical data

Output power: 2 x 8 W
Inputs: 4 x RCA
Remote control: +
THD: <0.7%
Tubes: 5U4G, 2 x 6SN7, 2 x 300B
Frequency response: 17 Hz - 32 kHz
S/N ratio: 76 dB
Dimensions (H/W/D): 27/45/32 cm
Weight: 19 kg
Price: €4590
Manufacturer: Auris Audio

Sound performance



Editor's rating


StereoLife High End