"... However, in my system, the darTZeel "sound" is ideal for all musical genres: good grip on bottom, natural transient performance, plenty of air on top if it's in the recording, and never even a hint of etch, grain, or edge. These are expensive, powerful amplifiers, handcrafted in Switzerland." — Michael Fremer (Stereophile)

"... As I had hoped, PrimaLuna's new EVO 400 was more concise-sounding than the ProLogue Premium preamp. It generated clearer, more muscular presentations, with sharper focus, and more distinctly punctuated momentums." — Herb Reichert (Stereophile)

“… The Progression Preamplifier by D'Agostino is simply an excellent stereo preamp. While I was expecting a pretty strong performance, the Progression went above and beyond my sonic expectations. Expect the warmth of tubes without the headaches associated with tubes.” — Brian Kahn (Home Theater Review)