If we are being truly honest with ourselves, buying a valve amplifier in 2018 is a bit of an anachronism. And we should bask in that! Yes, there are good sonic reasons for buying a valve amplifier (they did in the 1970s and onwards what LP does today – people choose them because they sound better), but if you are going to go a bit retro with your equipment, make it look good! Which is why the Auris Audio Fortino 6550 is the perfect modern valve amp.
Auris Audio is one of a number of brands coming out of Eastern Europe. This Serbian-based company first hit our particular radar screen thanks to its excellent headphone amplifiers, but we quickly realised this is just a toe in the Auris waters. The company makes an extraordinarily comprehensive range of audio components, from DACs and preamps, through power amplifiers, headphone amplifiers, and even loudspeakers. Most of its audio electronics are centred around valve technology (although it also makes a couple of Class D designs) and we thought a good 50W integrated valve amplifier would be a great place to start. A 50W valve integrated amplifier is also like ordering pasta al pomodoro in an Italian restaurant. It’s an easy way of spotting whether or not the person making the thing knows what they are doing!
I don’t know about his culinary skills, but Milomir Trosic of Auris Audio really does know his way around an amplifier circuit! As the name suggests, the four input Fortino 6550 is powered by a quartet of 6550 power tubes, driven by four ECC82 double triodes. This delivers 50W per channel in push-pull or ultralinear operation. 6550s are a little unfashionable at the moment (the fashonistas are going to KT150s this season) but I can’t for the life of me work out why this should be, aside from novelty. 6550s are widely available, affordable, powerful and sound good. They represent a fine balance point between the cheap-but-lower powered EL34s that dominate the guitar amp world and the more esoteric Kinkless Triode designs. The more I think it through, it must be snob factor and novelty that drives brands to KT150s. Regardless, Auris’ use of 6550s makes the amplifier more affordable both to buy and in long-term care and feeding.
A simple yet surprisingly accurate way of determining the abilities of a valve amplifier before it is even powered up is the ‘lift test’. Unless it is an output-transformerless design, a valve amplifier’s performance is in no small part governed by the amount of iron in the output transformers. I’d say you can never put too much iron into a transformer, but physics (and physiology) disagree. However, if you find yourself easily lifting an amplifier like this, don’t expect good bass depth from it. Auris builds well, and builds heavy. Reassuringly heavy. It’s just about a one-man lift if that one man is wearing a weight belt and knows how to lift, but realistically, this is an uneven, two man lift with much of the weight toward the rear of the amplifier – exactly as it should be. Be warned, however, the underside of the Fortino 6550 comes with four quite spikey cones that could shred hands and damage furniture. Fortunately, in the latter case, the amp comes with four little protector pucks.
What makes the Fortino 6550 all the more fun to use is its fully autobiassing. The less than good thing about 6550s is their affordablilty means finding well matched pairs is often difficult. Autobias means you don’t need to devote regular sessions to fiddling round with a screwdriver and a multimeter to ensure those cheaper valves aren’t drifting. Autobias can also prolong the life of valves as it compensates before the valves begins to run hot. The Fortino runs its 6550s relatively cool anyway (possibly thanks to having them exposed to the elements meaning there is a lot of dissipation going on) so I wouldn’t expect to chew through power valves.
Whether in walnut and matt black or our preferred choice of matt creamy white textured finish and contrasting walnut, the Auris Audio Fortino 6550 looks truly lovely. The three transformer towers contrast with the three control dials (power on, volume, and source selection), and while the fence in front of the tubes is perhaps the loosest definition of the term ‘valve cage’ I’ve come across, there’s little denying it makes the amplifier look extremely good, and you’ll want to put it on show. Most of the time, when we say ‘it looks better in real life’ or ‘pictures cannot do it justice’, it’s polite code for ‘this thing is ugly’, but the Fortino is one of those rare devices in audio that really do look even better in real life. Even the illuminated underside on power up is more ‘elegant’ and less ‘neon lights highlight the rust underneath Barry’s 1986 Vauxhall Nova.’ in short, nice!
There are valve amplifiers that seem to want to pretend they aren’t valve amplifiers, both in looks and sound. Audio Research is a prime example of this in some products: they might bristle with ‘toobs’ but sound like solid-state. And some amplifiers go in the opposite direction, delivering a sound that is so lush and soft you feel like you are being drowned in sofa cushions. Auris toes a middle path with the Fortino 6550. The amplifier makes a smooth and satisfying performance at all times, just staying the right side of ‘rose-tinted’ by making that same sound extremely detailed and focused. That ‘lift test’ described earlier pays off by making an amplifier with extremely good bass, albeit possibly defined more for medium-sized loudspeakers in medium-sized rooms than full-range behemoths in auditoria. Partner this with a pair of good, relatively efficient stand-mounts or fine floorstanders (alongside Auris’ own interestingly-named Poison range, I’m thinking of products like those from DeVore Audio would be absolutely perfect in this context) and the resultant sound is captivating and the kind of thing you will never even think about upgrading.
The soundstage is outstanding too, although it’s possibly more about soundstage depth than width. This sounds truly superb with small, classic jazz sets – Wes Montgomery’s ‘Four On Six’ [The Incredible Jazz Guitar of Wes Montgomery, Riverside] illustrates this perfectly, by producing a tight quartet very much between the speakers but stretching back into the room well. This isn’t rigidly applied, as the sound of a full orchestra is not constrained, but is still tighter to the loudspeakers than it is expansive and ‘CinemaScope’ in outlook. This deeper than wide soundstage is more aligned toward solo instruments like piano, or string quartets than it is to blaring out Mahler’s Eighth, but the beauty of the Auris Forino 6550 is that it doesn’t seem to hold back in terms of dynamic range, or even soundstage foreshortening when things get complex, it simply trades soundstage width for depth, and that’s a trade-off I feel comfortable with.
The really good thing about the Auris Fortino 6550 is it is surprisingly rhythmic, with a really good sense of pace for a valve amplifier. OK, so it’s not something that will make Naim Audio enthusiasts start to reach for the thermionics, but by comparison to many of the more leisurely-paced valve amplifiers at this price, it’s extremely good at keeping a beat.
In fact, there’s not much wrong with the Auris Audio Fortino 6550. Yes, by comparison to the really large valve amplifiers from the usual suspects, it lacks some dynamic contrasts and cavernous bass, and compared to a good conrad-johnson integrated at a similar price, there is a foreshortening of contrast and ‘microdynamics’, but this might be gilding the lily. The flexibility of the Fortino (even if the remote control is at best perfunctory here) makes it win out over an amplifier that is essentually a passive pot with a power amp attached.
That is the beauty of the Auris Audio Fortino 6550. It offers just that little bit more for the money. It’s extremely well-built, looks fantastic, has just enough additional functionality to make it attractive to audio enthusiasts, and sounds better than many of the rivals at the price. On balance, this is a gem of an amplifier!
- Type: Integrated tube amplifier
- Input: 4 ×RCA
- Class operation: Class A/AB
- Configuration: Push-Pull
- Vacuum tubes: 4 ×ECC82, 4×6550
- Load impedance: 4 Ω and 8 Ω
- Frequency response:
17 Hz–30 kHz (± 1,5 dB)
- Output power: 50 W
- Input Impedance: 100 kΩ
- Dimensions (W×D×H):
mm 450 ×400 ×270
- Weight (kg): 19.5
- Price: £4,795
Manufacturer: Auris Audio
UK Distributor: Elite Audio Distribution
Tel: +44 (0)1334 570666