Alieno Preamplifier
The Alieno preamplifier stands out for some peculiar technical features, most of them are absolutely exclusive.
Alieno´s technology
The same innovative technology used in our 250 LTD power amp is used in Alieno preamp allowing to obtain a powerful yet ultra refined signal. From the inputs to the outputs connectors, a minimal crystal-clear signal path managed by a selected couple of NOS ECC82 tubes, ensures transparency, accuracy and speed of the musical signal, while the exclusive Alieno power supply technology (section of strategic importance where works a selected couple of 6H30), guarantees energy, dynamic and control far beyond any comparison.
It must be pointed out that Alieno´s technology offers a virtually distortion-free signal handling that makes useless the use of feedback which is absolutely not used in none of the preamplifier stages.
On top of a rigidly dual mono implementation, Alieno Pre employs four independent power supply units, beside the ones exclusively dedicated to cathodes and services; this ensures a powerful power supply to all the amplification stages. Moreover each PSU acts in a “virtual battery” mode, thanks to the use of special capacitors whose value an topology has never been used before in preamplifiers construction.
ALIENO 250 LTD is on permanent demonstration by the following HiFi dealers:
Musica & Video – Ravenna (Italy), by the Acustica Applicata certified listening room: www.musicandvideo.it
Certified room of Gallicano (Lucca)
Ground separation not only between the various inputs but also between each stereo channel of the same input: this ensures a superior clearness and intelligibility of even the more subtle nuances and a better soundstage´s representation.
Each inputs allows interface´s optimization with the source of the signal by means of fine tuning of the sensitivity and value of the load. Moreover there´s the option to have a dedicated input for pro sources with floating balanced connection.
The volume´s control is of utmost importance in a preamplifier; typically it´s made by a variable resistor which controls the signal in transit. The most adopted techniques in high end audio are either the potentiometer (i.e. a variable resistor based on a sliding contact), or a series of fixed value resistors. Alieno preamplifier relies on technology which encompasses a step-free behaviour, like the one of potentiometers, coupled with the superior sonic transparency of fixed value resistors. This implementation is absolutely transparent to the final user who perceives the same feeling of a traditional volume control.
Separate and independent groundings
In ALIENO Pre, all the grounds of each input/output are independent and separate, even within the same channel between the left and right signal; this very complex solution from the manufacturing point of view, guarantees the best signal-to-noise ratio, which means a deeper and more silent background of the sound image (noise floor) and the sounds “painted” on this “deep black “are sharper, more detailed and three-dimensional.
This strategy is implemented with precision relays for each channel, which each time an input is switched, also allow auto-muting for about 5 seconds before enabling the new selected input. In the face of this slight delay in switching between one input and another, a further advantage of this technology in addition to the main one described above, is the fact that the preamp circuits “see” only the selected input, because all the others inputs (even if connected with cables to as many sources) are in fact electrically “off”, not having their ground reference. For this reason, none of the unselected inputs can transfer any type of disturb inside ALIENO Pre, which often from the grounds (generally all in common) enters in the circuit in the form of more or less intense hums (the typical ground loops). Last but not least, the fact of electrically “seeing” only the selected input, allows with ALIENO Pre to immediately identify any source that has an unwanted internal disturb.
It is important to specify that in ALIENO Pre, the unselected inputs are NOT short-circuited (as often happened in the past in preamps to obtain 100% of crosstalk), because that condition could be harmful for many of the latest generation digital sources which supply output electrical signals of a certain entity, as they do not tolerate to “encounter” a short circuit when entering in the preamp.
This increasingly mandatory precaution (observing the evolution of digital sources) of NOT short-circuiting unselected inputs in a Preamp, in extreme cases can allow an unavoidable residual passage of the signal by induction. In practice, if the volume of the Pre is quite high and a source is running, switching the Pre to another input a residual music signal at a very low level in the speaker could be heard, coming from the not selected but running source.
Virtual Battery Powered.
This technology allows Alieno Pre to work as if it was battery powered and therefore disconnected from the mains, which frequently carries with it a certain amount of disturbs and irregularities. A series of heavy capacitors takes care of this task, but to get this “virtual power supply” fully operational, they need a few minutes to reach their complete polarization and electrical potential, so it is advisable to heat ALIENO Pre (preferably with a low volume music signal in transit) at least twenty minutes before dedicating yourself to “in-depth” listening, regardless of the temperature of the listening room. Of course you can listen it right away, but after that warm-up period, ALIENO Pre is in its best thermal/electrical condition.
Two levels of attenuation for the inputs
Each input has a selector that allows you to set two attenuation levels for the input signal: – 8 dB and – 16 dB. The components involved for applying these two levels of attenuation are absolutely transparent to the sound, therefore, dynamics, transparency and timbre of the input signal are absolutely preserved and intact as in the zero attenuation position. This solution has been implemented in ALIENO Pre, because now the market offers sources with very diversified electrical output levels, reaching over 5 Volt RMS for the latest generation DACs or digital players; with the option of two attenuation levels, ALIENO Pre allows the user to maintain a more homogeneous volume position, even when the connected sources have important differences between their electrical output levels.
Volume control
The volume control uses a special mixed technique that allows a gradual adjustment of the level totally without jumps, without sacrificing the greater sonic transparency of dividers with fixed resistances. For the user, this implementation is totally “invisible”, in the sense that in use the system is indistinguishable from that of a traditional volume potentiometer.
The 6H30 tube
The last aspect is a bit more Hi-End in the strict sense of the term; this is a specific characteristic of a kind of tube well known in Hi-End world and which is considered important to describe to an ALIENO Pre owner. One of the two pairs of tubes used in ALIENO Pre is 6H30 (the other two are ECC82); this tube among the most famous and appreciated in the audio field, to reach its best performances has the characteristic of needing a long break-in period, reached which, as a “reward”, guarantees a really long performance stability, which in ALIENO Pre extends even more, as it is absolutely not stressed, because it is exploited about 30% less than its electrical limit; at least 5.500 hours of use can be guaranteed for 6h30 in ALIENO Pre. It may take up to 500 hours for 6H30 break-in. For a new owner of ALIENO Pre, the “bad news” ends here, because if the performances are already amazing, hour after hour up to the end of break-in they can only gradually improve further.
For the preference reserved to ALIENO Pre, we find no better thanks than to wish from now on, to reach many times the need to replace 6H30, because fully exploited!