I was on iFi Audio's website checking out their new iTube (which seems similar to Decware's ZBox with a few extra doo-dads) and part of the copy add stated the following ...

Many audiophiles wax lyrical about the ‘magic of tubes.’ Why? Because the scientific fact is that adding tubes to a HiFi system increases our intrinsic enjoyment of music. The harmonic characteristic of tubes eases tension and gives us a greater sense of well-being.

The Frankfurt University of Music and Performing Arts conducted an extensive scientific study(1) where participants reported a ~60% decrease of tension, nervousness and a 120% increased sense of well-being with a HiFi system including tubes, when compared to a solid-state system.

(1) Jürgen Ackermann - PhD Thesis at the Frankfurt Hochschule für Musik und Darstellende Kunst (Music and Performing Arts University)

A lot of us already know whether on a conscious or even a subconscious level that there is something special is going on when we listen to Decware and/or other high quality tube based designer audio gear, but now I have some scientific studies to reference.

After reading that copy add from iFi, I googled "Jürgen Ackermann" and found a really great article from Stereophile called "God is in the Nuances" in which the author Markus Sauer references the studies of Ackermann in pretty good depth.  In the same article Sauer talks about his attraction to tubes and high efficiency speakers and how they go against the grain as far as the engineering numbers go, but defy logic on how they draw us into a deeper emotional level over solid state gear.

What else I found interesting on Ackermann's study is that the setups he used in his experiment were not all analog, but even the combination of a CD transport and Tubes made big differences in the way people enjoyed and perceived the music.

Although the test group was not aware of what equipment they were listening to, the study was not some double blind deal where they were a/b'ing setups either, but more of a behavioral study that goes beyond the subjective/objective argument so many get dragged into and instead focuses on how the groups were reacting to tubes vs solid state at any given time.

Anyways if you have a few minutes it's an interesting article that backs up what we Decware guys already know!