Auris Audio Fortissimo

Watching the development of companies representing the audio industry can be very interesting. With time, you can make predictions of certain trends, and after many years check whether they turned out to be true. Today's review is not just another description of an interesting product, but also the continuation of my adventure with Auris Audio, which four years ago provided us with one of the first amplifiers in their history - the Adagio 300B. We didn't expect it to be perfect, but in many ways it was. Considering that the company was founded just a year earlier, it was hard to believe. This elegant and very refined amplifier using famous directly heated triodes wasn't made by accident. In the following years, the Serbian company proved it wants to continue making hi-end gear for true audiophiles, or even go a bit further. The latest Fortissimo integrated amplifier is a good case in point.

If you asked me four years ago how I see the future of this company, I would imagine two scenarios. Either it's going to be a spectacular success, or it will turn out that its founders have marketed the brand too quickly with a whole range of models and will quickly go on to defensive. None of these options worked. After a fairly spectacular start, the Serbs began to operate quite normally. They introduced new models, expanded the distribution network and presented their products at the largest exhibitions, such as High End in Munich, AXPONA in Chicago, Audio Video Show in Warsaw, and even the CanJam in Singapore or New York. The catalog has evolved nicely during these four years. A whole series of compact devices in metal jackets has been discontinued. More expensive models decorated with wood and leather turned out to be more popular. Loudspeakers are also maintained in a similar style, and there are already six models to choose from. But it's quite clear that Auris Audio specializes in making tube amplifiers, and recently they introduced even bigger ones with slightly different housing design - Forte 150 monoblocks and Fortissimo integrated offering 100 W (RMS) per channel, which is quite some power for a tube amplifier.

Auris Audio Fortissimo
A massive front panel with only two knobs is very appealing.

Design and functionality

Fortissimo is currently one of the most exclusive amplifiers on the planet. According to my information, the one delivered to our office was the second one in existence. Obtaining and transporting it will be the most difficult stage of the entire operation for every audiophile. It is not a device you can get in any store. The amplifier is packed in a wooden crate which was dragged out of the truck with a forklift and barely made it through the door. To open the lid you have to remove six sealed screws. After lifting the heavy piece of wood, we see a large piece of grey foam and a user manual on top of it. Remove this element and finally, you will see a part of the amplifier - round transformer covers and tubes packed in small cardboard boxes. There's also a remote control which is a beautiful piece of metal with three buttons and a company logo.

When we remove another two precisely cut pieces of foam, we can finally grab the amplifier and put it in place. At this point, it's best to ask another person for help. The device stands on spikes, and because it weighs thirty kilograms, when I was removing it from a wooden chest I did not think to look underneath. Placing an amplifier on the top shelf of my rack was a mistake. Why didn't Auris put a small warning label next to the manual? Well, I guess I just learned another lesson. Obviously, I decided to share my doubts with the manufacturer, so I hope none of the Fortissimo owners will scratch their rack as I did. Serbs, however, made sure the tubes were properly marked. Each of them has its own place, and the only thing we have to do is to match the tube's number to the slot. You just can't make a mistake here, but that said, adding one white glove to the box would be a nice motion. Especially considering the price of the amplifier.

Fortissimo looks like a marriage between a classic tube amplifier and a crazy artistic project. The amp is equipped with an input selector, volume control, remote and a basic system of setting the output tubes' bias. At the back, there are three unbalanced input and one XLR input, loudspeaker outputs with 4 and 8 Ω terminals and a three-bay power socket with the main switch. Fortissimo is fairly simple, although the presence of a remote control and an XLR input is still beyond the standards of many manufacturers of tube audio equipment. On the other hand, the device is totally hi-end. The Serbs created a great, difficult and in some respects a bit impractical piece of machinery. It's clear that its designers didn't have to worry about any restrictions. The huge casing is made entirely of metal, adorned with wooden side panels with the company logo. The great "Auris" name was also placed on the front panel, precisely between the knobs. The big piece of aluminum meets the housing only in four places. If it matched the shape of the amplifier, it would have to be rectangular, but the designer had other ideas and came up with a more complicated, rounded form protruding beyond the outline of the amplifier itself. It's the same story with the rear panel, so when looking at Fortissimo from the front, we also see the edges of its back wall. If these elements were longer, they could be used as handles, but I guess it's just an aesthetic thing without any apparent function.

Fortissimo fully deserves its name. It's really big, heavy and very tall. Transformer covers are particularly interesting. They probably didn't have to be so big, but they were fitted to match the height of the glass panel on the front. This is the only element that "covers" the tubes. The manufacturer didn't include any additional frame that would actually prevent the hot tubes from being touched. The glass pane installed between the metal posts is purely decorative. But, convenient access to the upper section of the amplifier has its justification. In addition to the tubes, on the top of the amplifier, we can find an elegant meter with a big knob and four tiny potentiometers associated with each of the power tube sockets. It's, of course, the bias regulation system. The knobs operate smoothly and allow the indicator to be "zeroed" with high precision. You just need to find a nice, flat screwdriver and try not to touch the tubes which are really close to the action. However, once the bias is set, it can't be impaired by accident.

Cons? The first is, of course, the price. Auris Audio is certainly a less recognizable brand than Audio Research, Manley, Air Tight, McIntosh, BAT, Audio Note or VTL, but in terms of build quality, it has nothing to be ashamed of. Seeing Fortissimo in real life, you won't wonder why it costs so much. It's just obvious. As for its practical stuff, I have a few small reservations. I don't understand why the main power switch has been placed on the back. Usually, this suggests to keep the device running all the time and turn it off only when we leave home for a long period of time. However, in the case of a tube amplifier, it's difficult to accept such an explanation. Reaching to the rear is not a problem since such a big amplifier won't be placed in a small cabinet, but anyway I think that a power/standby switch on the front is a better idea than a gargantuous logo. I liked the start-up procedure, during which the tubes are heated in a stable and safe way. The finale is indicated by a loud click. Another warning concerns very high output power. During the listening sessions, I quickly realized that this is one of these amplifiers you don't mess with. Just be careful with the volume control... Depending on the speakers, the so-called realistic volume level can be reached as early as 9 or 10 o'clock. Adjusting the volume with the remote control is just absurd. A short push of the button causes a significant increase in power. It seems to me that the potentiometer should be calibrated differently. But overall, Fortissimo is a perfect example of a hi-end tube amplifier made in a truly uncompromising manner. Is it enough to win the hearts of audiophiles?

Auris Audio Fortissimo
Just the basic stuff on the back, but the balanced input is worth noticing.

Sound performance

Looking at this huge amplifier I was still wondering if its external form is actually a manifestation of an uncompromising internal design or a bit of an unnecessary show-off. Despite the huge enclosure, Fortissimo doesn't have four or even eight power tubes per each channel. Its circuit must be very similar to the competition, such as Octave V 110 SE, Jadis DA50S, Leben CS-1000P, Audio Research VSi60, Trafomatic Audio EOS or Ayon Spirit III. I simply wasn't expecting this much power. The first listening test literally punched me into the floor. The loudspeakers exploded with dynamics and huge soundstage. The listening room was just flooded with convincing and three-dimensional sound in the blink of an eye. The sound was based on solid, deep and meaty bass. But there was more to it than that. The amplifier showed very sophisticated midrange with clean and natural vocals. The sense of clarity extended all the way up to the treble. Nevertheless, the way Fortissimo shifts and builds a realistic musical event in the room is, without a doubt, the most impressive thing about it. The amplifier was clearly in charge of the whole performance as if it wanted me to know it's doing almost all the work in the system. The speakers reacted to every impulse as if they were afraid that I would turn the volume up and stretch their membranes to the limits of their endurance. In fact, it could have happened because I was enjoying this spectacle more and more with every record. Hearing such a good sound, we only want it to last as long as possible. Fortissimo needed thirty minutes to convince me it's one of the best amplifiers I ever reviewed. That's just the fact. And although there was still much more to discover, I already knew it's one of those devices I'm going to remember for a long time.

The Serbian amplifier takes no prisoners. It shows us everything it has to give during every listening session. Unlike tube amplifiers which seduce us with an endless foreplay and make us listen to subtle nuances, Auris shows brave, mature and smashing sound without any hesitation. There's a very masculine character in its performance. But once we get used to the huge soundstage and mighty bass, we can discover other elements that translate into naturalness, realism, and tangibility of the sound. The key to all this is the midrange, which is important in every device, but in the case of a tube amplifier - absolutely essential. I'm sure every audiophile will have high expectations in this matter. After all, we buy tube amplifiers to experience this extraordinary delicacy, warmth, and color. In combination with fantastic microdynamics, various reverbs and true timbre of every musical note, we can immerse ourselves in music completely. And that's just how Fortissimo sounds.

What is extremely important, the sound is not overheated, although it should be placed on the warmer side of the temperature scale. The vocals are phenomenal. They don't sound like they are in an indefinite abyss. They are here, just in front of us. Auris certainly has a bit of a typical tube romanticism, but this part of its nature is always balanced by power, bass, and dynamics. The warmth is slightly neutralized by the background that stretches behind the vocals, giving the impression of incredible depth. After some time, when we get used to this 3D soundstage, we start to notice that on some recordings there's more to discover even within this second or third layer of music. Serbian amplifier doesn't get lost in this mixture of sounds. In this respect, Fortissimo reminds me of hi-end amplifiers by Naim. In general terms it is, of course, a completely different style, but if we are talking about the soundstage? Yes, to me it's something very similar. At first, it seems we won't be able to comprehend with this vastness, this ocean of sound, but it takes five minutes to get accustomed to and afterward we perceive this giant spectacle as something very natural and physiological.

Such a great sound couldn't be achieved by accident. To make every element of the presentation so refined, the designer must have taken care of every single element of the amplifier. There is no other way to make it work. Building audio equipment by trial and error, or stopping at the stage of one of these errors and putting the device on sale anyway, one can only get a sound that works under given conditions. With loudspeakers offering a characteristic sound, with one music genre, or in one particular system and listening room. Here we have a device which serves us with a whole lot of ear-catching things, and at the same time cares about the overall naturalness and proper balance between all aspects of the presentation. We can, therefore, make very bold experiments regarding the accompanying equipment. We don't have to stick to the rules, using only high-efficiency loudspeakers and silver cables. I admit that in our listening test the loudspeakers with dynamic and clear sound worked best. However, if you like the sound of PMC, Graham Audio, Dynaudio, Spendor or Harbeth speakers - why not?

One thing is certain for me. Fortissimo presents such a high level that regardless of the speakers, we should simply enjoy every listening session. The flagship integrated amplifier by Auris Audio simply blew my mind. With such a machine we always have a high probability of spectacular success. Fortissimo is so effective and determined in its actions that it does not care about any obstacles. Instead of a situation in which after many months of listening tests we get the sound we wanted, here we achieve our goal right after removing the amplifier from the wooden box, connecting the cables and a short warm-up. For many audiophiles, it's a dream come true. If you decide to face a few difficulties to bring this amplifier home, you will be able to enjoy the level of sound quality that is unreachable for most amplifiers on the market, regardless of the price.

Auris Audio Fortissimo
Side panels made of solid wood are supposed to reduce unwanted vibrations but you have to admit they look great as well.

Build quality and technical parameters

Auris Audio Fortissimo is a stereo integrated amplifier using a quartet of Tung-Sol KT120 tubes working in a push-pull configuration in the A/AB class along with four ECC99 double triodes provided by JJ Electronic. The manufacturer decided to implement KT120 in a pentode configuration, thanks to which they managed to obtain 100 W (RMS) per channel. In the back, there are outputs for 4 or 8 Ω speakers, three RCA inputs, and one XLR input. We know little about the internal design of the amplifier. Auris publishes only a handful of information and basic technical data on their website. Due to the high risk of damage to the 30 kg amplifier and the fact that we received it directly from the manufacturer, we didn't open its chassis. The high mass, however, indicates there's a lot going on there. The aluminum casing with wooden sides is probably just a small part of the story. Round covers on the back of the amplifier suggest that Auris chose toroidal output transformers, but that's just guesses. As for the parameters, Fortissimo certainly has nothing to be ashamed of. Its frequency response extends from 15 Hz to 50 kHz and the signal to noise ratio is over 85 dB. As in the tube amps, distortion is quite high. The manufacturer states that at 1 W it's kept under 1%, but at full power, it can reach up to 5%. In real life, however, I doubt anyone would approach this level of power. If you don't want to see woofers shooting out of the speakers and your tweeters on fire, be gentle with the volume knob. Seriously.

Auris Audio Fortissimo
This picture shows how big the Fortissimo really is.

System configuration

Equilibrium Ether Ceramique, Pylon Audio Sapphire 31 StereoLife Edition, Sound Project Nina, Marantz HD-DAC1, Audiobyte Black Dragon, Astell&Kern AK70, Cardas Clear Reflection, Equilibrium Tune 33 Light, Enerr Tablette 6S.


Fortissimo is a powerful, original and uncompromising device designed with a lot of courage and no visible restrictions. It is also an electronic work of art, where each element is refined and beautiful. Above all, however, it is one of the best amplifiers I have ever heard. It combines brutal power with sweet midrange, exceptional delicacy, and everything one could expect from a truly hi-end equipment. It is really wonderful. Naturally, each audiophile will consider at least a few options before purchasing such a costly toy. Many devices at this price point have much to offer. But only a few have this amazing ability to combine various advantages in their sound in such a spectacular way. A real elite in the world of tube amplifiers.

Simple but big. Really big.
1 / 15

Technical data

Output power: 2 x 100 W
Inputs: 3 x RCA, 1 x XLR
Remote control: +
THD: < 1%
Tubes: 4 x KT120, 4 x ECC99
Frequency response: 15 Hz - 50 kHz
S/N ratio: > 85 dB
Dimensions (H/W/D): 33,5/49/44,7 cm
Weight: 30 kg
Price: €10925
Manufacturer: Auris Audio

Sound performance



Editor's rating


StereoLife High End