Alieno Amplifier 250 LTD

ALIENO 250 LTD

The first tube amplifier utilizing two 300Bs generating 250 Watts per channel.

ALIENO is an OTL-OCL (Output Transformer Less & Output Capacitor Less), Single Ended, pure Class A amplifier.
ALIENO is NOT a hybrid tube/transistor amplifier.
This innovative LTD “Loudspeaker Tube Direct” technology allows the use of tubes exclusively for amplification circuitry, with transistors used exclusively for power supply and protection circuits.

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) − Certified room of Varese

 

Our exclusive LTD technology in ALIENO was inspired by two primary factors in our study of tube amplifiers.
The first is the historical benefit of utilizing an OTL configuration over other traditional approaches.
Eliminating the output transformer from the signal path is extremely important.
It is in fact the most important component in the signal path where sound transparency is concerned.
In its absence, the true sound of tubes can be expressed in all their fullness.
In addition, some of the flaws generally attributed to tubes, such as slowness, lack of impact, poor low frequency control, to a large extent are not caused by the tubes themselves, but the output transformer.
Going through any output transformer, the signal undergoes two important transformations: from an electrical signal it is converted into a magnetic field and subsequently re-converted into an electrical signal.
After this double conversion, a degradation of the purity and immediacy of the sound is inevitable.

The Second: Single Ended triode circuitry is renowned for its magical musicality, and notorious for its lack of power. The ideal amplifier for purity and clarity should combine the positive qualities of single-ended outputs with the elimination of an output transformer.
It should also have sufficient output power to drive any reasonable load.
These desires were our motivation for inventing the innovative circuitry of the LTD design.
Output power comes from the power tube, while supplies to the load, both voltage and current, where the current is supported by our unique semiconductor power supply process.
With 250 Watts per channel and generous amounts of current, ALIENO ensures authoritative control of speakers in any dynamic range, precisely tracking complex impedance load demands even of the most difficult to drive loudspeakers, allowing the full freedom to choose their typology.

Our LTD technology differs profoundly from traditional circuits defined as ‘hybrid´, which in addition to the output tubes, also include the use of transistors.
In a hybrid system, after voltage amplification by the tubes stages, the signal is then delivered to the solid-state section for current amplification.
Two points must be underscored:

  1. In hybrid designs, the tube is tasked with increasing the signal voltage only, but not its current;
    this generates a partial, but important, loss of the tube signature on the sound.
    This precious purity and tonal structure are the desirable aspects of single-ended sound which must not be lost.
    The “magic” of tube sound is thus only partially expressed in hybrid designs, since only the voltage modulation supplied to the loudspeaker has those tubes qualities, while the current supply adds the signature typical of transistors.
  2. Moreover if we consider, that although quantitatively inadequate to the direct driving of a speaker, the current supplied from a tube (not modified by the transformer´s interposition) is at its core excellent for speed, impact and modulation, we put all our energy into preserving 100% of these virtues and delivering them unchanged to the speaker connectors.

In addition to its sonic excellence, ALIENO pays attention to technical performance too, both for interfacing with the most difficult speakers, and in relation to its intrinsic stability and practicality of use.
With a damping factor that exceeds one hundred, and a managed output current of approximately 200 Amperes, we have created an output power structure enviable even for a transistor amplifier, let alone a single ended tube output stage.
All this with NO negative feedback.
Stability and user practicality of ALIENO are assured through no required manual Bias regulation, thanks to electronic circuit management of the KT150 tubes.
All parameters are constantly optimized over the entire operating life of the tubes.
In addition to the security and consistency of a system which is always perfectly fine-tuned regardless of electrical grid conditions and power tube aging, the control circuits allow “Tube Rolling” without worrying about Bias regulation.
Another significant advantage is found in the extended longevity of 300B power tubes, which being little stressed, will last well beyond their typically rated five thousand hours.
In ALIENO 300B dissipation is about 20W, half of the maximum expected by tube manufacturers.
Balances between various sections of the circuit are intrinsically managed and ensured through active circuitry and precise passive components selected for their sonic purity.
No trimmers to adjust and no negative feedback, which is totally absent, just the purity of the original tube sound.

Alieno 250 LTD specifications

  • Typology: Vacuum Tube Stereo Power Amplifier, Pure Class A, Single Ended OTL-OCL (Output Transformer Less & Output Capacitor Less), with proprietary LTD technology.
    The acronym means: “Loudspeaker Tube Direct”.
    Tubes are used exclusively for amplification circuitry and solid state exclusively for the power supply section.
    No hybridization of tube and solid state technology. Transistors are utilized for power regulation, stabilization, and safety circuitry ONLY.

No hybrid tube/transistor sound!

  • Power Output: @ 3 Ohms – 250 Wrms continuous per channel.
  • Distortion: typically 0,1%, max 0,5% from 20 to 20.000 Hz.
  • Frequency Response: ± 0,5dB from 5 to 100.000 Hz.
  • Internal bandwidth: > 1 MHz
  • Gain: 22dB.
  • Input sensitivity: 2,5 Vrms.
  • Input impedance: 100 K ohms (irrelevant capacity).
  • Input connectors: Rca and XLR.
  • Optimal Load Impedance: 2 − 8 Ohm.
  • Signal to Noise Ratio: > 100 dB.
  • Damping Factor: > 100.
  • Overall Negative Feedback: totally absent Negative Feedback.
  • Slew Rate: > 300 Volts/microseconds.
  • Output Current: > 100 Amps peak per channel.
  • Tubes required per channel: one ECC82, pre-ampli and driver tube.
    • one KT150, stabilizer tube.
    • one 300B, output power tube.

 

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  • Tubes management: Constant optimization of all tube operating parameters, including bias, over-voltage and over-current protection, along with real-time output impedance management.
    Auto adjustment of balance differences between each tube in the circuit.
    Imprecisely matched tubes or individual tube lifecycle issues are wholly compensated by regulation circuits.
  • Protection features: Thermal threshold independent for each channel.
    One AC main fuse and five fuses on each power supply sector.
    Protection for wrong connection between power supply unit and amplifier unit.
    Double timer for a gradual loading of the charge on AC power grid.
    Each protection has its independent warning led, including the fuses.
    On/Off “thump” eliminated by delay relay transient protection.
    Infallible loudspeaker protection circuitry.
  • Dimensions (including cables plugs on rear panels):
    Amplifier unit, cm. 45 x 50 x 28; inches 17,7″ x 19,7″ x 11″ (W x D x H).
    Power supply unit, cm. 45 x 60 x 27; inches 17,7″ x 23,6″ x 10,6″ (W x D x H).
  • Weight: 100 Kg net − 220,4 lb.

ALIENO is distributed by Acustica Applicata − Italy