The Alieno is a two chassis stereo amplifier with a power supply, which looks like a full-size conventional Class A solid-state stereo amplifier, on the bottom, and a pair of small input tubes, a pair of KT-150 driver tubes and a pair of 300B output tubes recessed in an acrylic box on the top. The power supply on the bottom is connected by three umbilical cords to the tube circuits on the top: there is what looks like a left channel cable, a right channel cable and a power supply cable.
Jeroen showed me the manual for the Alieno and the description exclaims at least twice that whatever you think of this circuit design it is not a hybrid and there is no solid-state amplification going on. There is no output transformer and no output capacitors to couple the amplifier to the loudspeakers. Alieno terms this OTL/OCL.
So how is a single KT-150 driving a single 300B producing 250 watts per channel? Maybe the tubes are amplifying voltage, and devices in the power supply are amplifying current? But the manual expressly disclaims that this is what is going on. So what
is going on?
I don't know what's going on, but I know I like it. The Alieno drove the 91dB M3s to SPL of 100dB or more without breaking any sweat at all. (It was convenient that Jeroen and I like the same fairly loud listening level.)
As much as I love the crystalline transparency of Atma-Sphere amplifiers and of the Einstein OTL I hear a lean-ness in those amplifiers to which I am not accustomed from various transformer-coupled tube amplifiers. The warmth and body to which I am accustomed from output transformer-coupled amps may, in fact, be a colouration artifact of transformer output stages. And I'm quite sure the transformer adds a slight layer of haze, the absence of which gives the OTL amplifiers this crystalline clarity and transparency that I love.
Somehow this Alieno manifests most or all of the crystalline transparency and little or none of the transformer haze -- without sounding lean. We have to understand the circuit design of this Alieno amplifier. I have researched it on the Internet and I find very little about Alieno Ltd. -- and nothing in English.
I enjoyed very much the sound of Jeroen's system! I heard crystalline transparency and enormous jump factor and lifelike dynamics. All of the time Jeroen has spent on acoustic treatment results in great width and depth of soundstage. With Magico speakers and solid-state preamplification I was not surprised to hear incredible detail. I heard the best and most detailed rendition of Dreams I have ever heard!
Thanks very much to Jeroen for a great day and evening and a wonderful listening session, and for introducing me to a new top amplifier contender!
