Well its been quite a while since I posted my first comments about the R20's back in March. (#12 in this thread) There's a reason and its a long story. I'll spare most of the details but first I want to give a huge shout out to Jason and Bob for the incredible service and response they have provided. These guys are the BEST and are true professionals in every way!!! It is very comforting to know that these guys are there, passionately standing behind the terrific Nuprime products that they represent.
Next.......and please pay close attention to this; if you are using subs with a Neutrik connector like RELs, do not hook up the sub cables to both terminals. Next, do not only hook up the hot connector and let the ground float. Finally, DO attach the positive connectors to the positive terminal and the negative to the tiny "ground screw" to the left of the negative amp terminal. Otherwise you will blow up the amps like I did; repeatedly.

Then you will have to send them back to Bob like I did; repeatedly.
Currently I'm running the amps with Maggie 3.7is (Mye stands), REL G2's, CAT Legend preamp, Shunyata loom, Triton v2, Typhon, VPI Signature with 3D arm, Koetsu Rosewood Signature, and a Modwright (tube mods) Oppo 105 in a highly treated room. I listen near field about 7' away from the center of the speakers and have spent hundreds of hours tweaking every component. This is a very revealing system that exposes almost everything upstream. Other amps I own and have used for comparison are Carver Black Beauty 305's (KT120's/ 300w each) and a pair of Conrad Johnson Premier 8's with all factory teflon and KT120 upgrades (also 300w each). Both of these all tube mono blocks are outstanding and grab the Maggies with a vice-like grip that won't quit. I've also got a GAT 2 that has temporarily been sidelined while the CAT Legend is commanding center stage. For about the past couple of weeks I have been mixing and matching these electronics to get a good idea about the R20's and as you can see, they are in pretty good company. Plus, I'm a hard core tube, planar, and vinyl guy and in the past have avoided solid state, Class D, and digital like the proverbial plague.
So, what's the verdict on the R20's? Unfrickingbelievable! First, the tonality is unlike anything that resembles classic solid state. Instead, the sound is warm, lucious, and full, with layer upon layer of detail. The attack is sharp and crisp but the decay leaves notes sort of hanging in space with each one wrapped in a bubble of three dimensional reverberant air. All of the textures seem just right too. On cello, violin or stand up bass, you can hear the bow or the plucking of a string, but then the wood of the instrument reverberates in space until that note naturally fades or is overcome by the next. Drum skins are unreal. Horns have a natural, glorious, power to them that captures all of the subtle breathiness of quiet passages, but explodes without a hint of shrillness at a crescendo. And look out for tympani drums; a loud thwack is like getting slugged in the jaw! Dynamics are off the charts. Plus these amps have presence in spades. At times, with the lights turned low, its like the music just showed up on the soundstage and I've been transported to the venue, without the slightest recollection that there are electronic devices actually converting electrons into notes. Its tough to decide what to play next, although I've found myself migrating repeatedly to live recordings because it all sounds so real.
Meanwhile, my tube amps are scattered around the floor like audio jewelry. Beautiful to look at, but..... Anyway, I'm really not one to get carried away and gush about the latest and greatest newcomer to the audio scene. But these amps are something unique, especially at the price. I almost wish they were bigger and heavier and maybe had some KT150's glued to the top of the cases. Or I needed a hand truck to move them around. That way I could sort of rationalize their world class status and come to terms a little easier with how good they sound.
One more quick snippet. Right now I'm listening to "A Case of You" by Dianna Krall. We've all probably heard that cut way too many times. But as the music is playing beautifully, I'm fascinated by her pedal work on the piano. Right beneath her voice and breath, the keys striking the piano wires, the ambient sound of the hall, and the occasional sniffle in the audience, is a strong visual impression of her feet decisively working the pedals. I haven't quite experienced that before. And with almost every album, the R20's are revealing more, much more, than I have ever heard before. These amps get my strongest possible recommendation, and if they work this well with my Maggies, they should have a pretty easy time with just about any other speaker.
Thanks again to Jason and Bob for their great products and for being such terrific folks to work with. You guys are the best!