Here is my review of the Nuprime Evolution One mono amplifiers after at least 100 hours on them.
Since I loved my Nuforce Reference 20 mono amplifiers, modded by Bob Smith, the first thing I did when I fired up the Nuprime Evolution Ones was to be sure that these new monos did nothing less well than the Reference 20's. I was pleased to still hear amazing bass (controlled, dynamic, fast, detailed and with true timbre). And the excellent highs, mids and PRAT were still there as well. They also were dead quiet which was a question given the new 1 million ohm input impedance and different power supply. They did seem to have more gain than the Reference 20s.
The Evos passed the "do no harm" test. What new did they bring to the table?
First noticed was the freedom from an ever so slight, unnoticeable-till-its-gone digital haze. Wow! Minor and subtle, yet highly important. Next was that the soundstage was much improved in terms of depth, separation of instruments, and air and bloom. Then I was entranced at how much more natural and beautiful high bells sounded - more rounded with more realist timbre, attack, and decay. All voices, especially female vocalists were more natural and captivating. Yet when music was supposed to be edgy it was, they could rock out with the best. When the music is relaxed and sweet, these amps allow you to be emotionally moved by liquidity and languidness ( I think because they sound less digital). This involvement could still be enjoyed at lower volumes than with other amps. They are excellent at naturally presenting the slightest micro-detail with no excessive spotlighting. Solo and massed strings were more realistically presented both in the string sound itself and the body of the instrument.
Where I found the Evos clearly better than any other amp that I have heard in any typology is with highly complex classical music such as symphonies but also complex rock and new age. Everything is more naturally delineated and more realistic sounding even when 100 diverse instruments are playing at once. In fact, I have been listening to much more symphonic music with these amps, where before there was something unsatisfying about the reproduction of such massive and detailed soundscapes. Solo instruments in these works stand out more clearly in character from the mélange of sound around them and dynamic swings are surprisingly instantaneous.
Because these amps are so transparent they act as a very clear window on your other equipment. Therefore I need to mention the rest of my system as well. I am connected with a full loom of Delphi Aerospace Ultra cables distributed by VSA, front end is the Ayon CD 35 which contains transport, DAC and NOS tubed preamp, and speakers are Von Schweikert VR55 Aktives in a 38 by 22 room.
The transparency also means that in my system at least, great recordings sound even better and poor recordings (CDs of 60's rock) are no more listenable than before except that the added slight digital haze most other amplifiers have (unless they are artificially sweet or rolled off) is not compounding the haze present on the recording itself. I like the sound of Pass Labs, Constellation, and VAC amps, yet not even considering the price, size, and heat difference, feel like I like the Evos better. They hit the sweet spot between fluidity and control. There is ample mico-detail for this detail freak and yet they present the music as a whole cloth to be enjoyed as a living presence.