Aesthetics and functionality
The SM-6L6 is a push pull vacuum tube integrated amplifier built by AAAVT, an Italian young but quite famous company. The amp has a black protection grid to cover the “hot” tubes in compliance with the Italian rules on safety. The only tubes that remain exposed are the two front VU-meters realized with the “magic eye” tube. In many old tube radio receivers the “magic eyes” were used to show the accuracy of the tuning and, in the tape recorders, as pointers of the recording level.
If you do not like this kind of tubes, you can easily remove them without compromise the sound quality. Be careful and do it only when the amp is switched off and cold.
Despite being budget for the category of tube amps, the SM-6L6 is elegant and shows a certain care in the details. The two control knobs are made of good plastic – it looks like metal – whit the one on the right dedicated to the volume, with precise and smooth clicks, and the one on the left dedicated to the selection of the line inputs.
On the left there is also a 6,3 mm headphones jack output. The RCA connectors, dedicated to the four inputs of the rear line, are too close and in the middle there are the screw connectors for the 4 and 8 ohms outputs, which are suitable for banana pins. Between the output connectors, there is a lever to exclude the loudspeakers and to allow the use of the sole headphones, which are always active even when the loudspeakers are connected.
On the top are placed ten tubes: the two magic eyes, which give an idea of the power expresses for the two stereo channels, two JJ Tesla ECC83S preamp tubes, two JJ Tesla ECC89 drivers, 4 6L6Y RCA NOS NIB power tubes with great sound qualities and made of black varnished metal, instead of glass.
The AAAVT amplifier is available in a number of versions, with 6N1 - 6N2 - 12AT7 - E88CC preamp tubes and 12AU7 – E99CC – E88CC – 6N1 drivers. According to the manufacturer, if the tubes and the counter reaction rate change, the performances change as well, mostly in the low range.
The SRPP input stages and drivers are reconfigured in Italy and vary depending on the tubes chosen by the customer. Finally, the power and output transformers are putting together under the same lid surmounted by a thick aluminium panel on which are printed the AAAVT logo and the type of model.
An amp without any frills, although the magic eyes are, but complete with everything and more, like a headphones output that it is not so usual to find in such devices and that is welcomed for the positive sound outcomes about which I will tell you later.
The overall aesthetics is very pleasant, with some reservations about the grid, easily dismountable nonetheless, if you do not fear being burned when the amp is on.
Altogether the quality is good, with no particular highlights, but with a sensation of reassuring toughness together with a significant weight. There is no remote control.
The technical specs talk about a power of 23 W per channel, a signal-to-noise ratio superior to 78 dB(A), a frequency response of 6hz-70 khz (-2db), a 5% distortion (according to the measurement technique used to define the vacuum tubes clipping power), a size of 340x360x160 mm and a weight of 13,4 kg.
Use and listening impressions
I find this amplifier very interesting from a listening point of view. It has shown a great synergy with the other components of my home system without requiring any change in the set-up.
Easy to insert and this is a great quality, indeed. Another quality is the quickness in being operational: about fifteen seconds to have a quite good performance, thirty minutes to have the best one.
It acted great with the ProAC Studio 125 speakers, which are very easygoing in terms of powers and impedances, and I did not miss my reference vacuum tube preamp and my 120 W solid state power amp even if the sound setting was quite different. A brief test with the Mission M32i (“garage” system), a pair of cheap bookshelf loudspeakers. The match is possible but somehow penalizing because unable to pick out all the uncommon skills of the SM-6L6.
The sound of this integrated amp, with its declared 23 W per channel, is worthy of more powerful amplifications. It performs homogenously in all the ranges, low included, showing a presence and a richness in substance also with the volume up. The timbric is the strength point of this amp that can express itself in all the harmonic content and with good balance. Better results in expressivity and presence inside the medium and high range. The low range is deep and well articulated, although less controlled and less reactive in comparison with my reference device. The high instruments and the women’s voices, always gratifying in their intelligibility, are never scratching even if they do not seem limited in extension.
Hence, there is some kind of softening in the high frequencies, in a way that privileges the expressivity rather than the absolute and faithful respect of what is contained in the original audio track. This feature can be found in several vacuum tubes amplifiers and represents something that divides the taste of the enthusiasts. Here the result is absolutely enjoyable. Yet, at a deeper analysis and mostly in comparison with solid state amplifications, there is some smoothing in the asperities of certain recordings and sometimes a slight tone emphasis in the medium range which can, however, generate a tempting addiction and determine the famous charming of the tube sound.
The sense of the rhythm is good, the low range has no so quick reflexes, but they are acceptable and maybe many people like them this way. There’s also some dynamics that contributes to the total impression of an incisive, exciting sound with striking and vivid colours. The image is good, with the soundstage well delineated in width, height and depth. In conclusion, a sound of high level, which gives great emotions without spending lots of money: the promotional price is now 595.00 EUR.
One thing about the headphones output. I tested it with the Sennheiser HD600 with custom cable. Well, also here the SM-6L6 is delicious and you can enjoy its good performances by night without disturbing your neighbourhood. Furthermore, the sound has three-dimensional peculiarities.
The AAAVT SM-6L6 has an automatic bias adjustment that offers always the best possible performance.
Regarding the fine-tuning, I have found the ideal effects by using the Analogue Research Silver Raincoat power cord, whose characteristics go along with the amp, and Stat Audio power and signal cables, very neutral and correct.
I suggest placing the amp with its feet on a hard surface, like marble, stone or directly on the floor.
Music selection
Patrizia Laquidara, Indirizzo portoghese, CD Virgin
The Dave Brubeck Quartet, Time Out, CD Columbia
J.S. Bach, Concerti BWV 972, 973, 974, 975, 976, 978 e 981 per organo, CD Fonè
Romantic Harp Concertos, 2 CD Brilliant
Corelli, Vivaldi e Telemann, Concerti, CD Avvenimenti
The Jazz Tribe, CD Red Records
Sax Today, LP Red Records
Associated equipment: to Fabio "Puzzled" Barbato's system
