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Harmonics
DarTZeel hits a home run for fine textures and richness of strings. Neville Marriner, Mozart: Eine kleine Nachtmusik [Angel] shows off the harmonic lushness of the amp. No touch of violin hardness or steeliness, just the correct amount of weight and richness that is ethereally beautiful. Timbres with the 108 are natural with just a touch of sweetness. In food terms, smooth, creamy and sumptuous. The Reiner/Chicago Strauss Waltzes [Classic Records] invite one to be drawn into the rhythmic sweetness and be swept through and along with the music. If the midrange ain't right, nothing else matters. The d'Art nails the midrange, approaching if not exceeding my beloved Tenors - rich, pure and truthful.


Upper midrange/lower treble
For brass, I revert to Rob McConnell and the Boss Brass, Big Band Jazz [Umbrella direct-to-disc]. This record is toe-tapping, kick-in-the-butt fun. "Porgy & Bess" is hard to reproduce properly or a least to my taste. Unless VTA, VTF and associated gear are right, you either have a soft, boring, unappealing mess or hardness like an ice pick through your ears. The 108 present brass with that indefinable but real bite yet lacks stridency or hardness of any kind.


Bass
The bass is killer - powerful, fast and precise. Bass decay floats in the room mixing realistically with each successive note analogous to real music in real space. It's almost a tad heavy but I love it as it offers a solid foundation and solidarity that in my room was heretofore missing. I don't care what type of bass freak you are, the dartz won't leave you wanting. The Oscar Peterson Trio's West Side Story [DCC] demonstrates the purity and delineation of the bass endowed with lifelike harmonics. Each note is distinct with a 'live' weight. You can picture the fingers rolling off each string. The three instruments are sitting in bold relief from each other yet remain wonderfully linked to each other. The drums aren't just heard but you feel the pressure waves.


The opening drum notes of "Bird on a Wire" [Jennifer Warners' Famous Blue Rain Coat] show the depth and power of the bottom. The 108 totally changed my perception of this record. Something that I heard a hundred times over now comes across with new power, force and emotions. The claimed frequency response for the 108 indicates a wideband flat response without a hint of an emphasized low end yet the darTZeel presents music with a realistic foundation previously unheard in my room.


Listener Fatigue? Not.
Fatigue is non-existent. Three, four or five hours later, you are still looking for more. The sign of a great piece is that urge to rediscover favorites, running around like a kid saying "let's listen to this one, then this one and that..." The Walker Proscenium and the X-2s did it for me. So does the darTZeel now.


Dynamics
Whatever I threw at it, the 108 kept its cool. From Big Band to Zeppelin, the dartz took it all in stride, including my torture test of the Utah Symphony with Berlioz' Symphony Fantastique [Reference Recordings]. The dynamic impact of the recording was as forceful and alive as I've ever heard. From the delicate inner detail to the prodigious crescendo, all was presented in the proper space and detail. I tried to make the eyes blink to indicate clipping after 100dB worth of Led Zeppelin II [Classic Records]. The 108 failed to bat an eyelash.


Soundstaging
Soundstaging is often a one size fits all, either bigger than life, constrained between the speakers or somewhere in-between. Amps and other audio equipment generally have their own unique character that will impose its definition on the stage. When it goes wrong, you get a ten-foot tall singing head and other such anomalies. The 108 allows the music to fill its own natural space. Big band jazz should be reproduced - well, big. And it is, filling the room. Likewise small jazz and voices should not be wider or more massive than in person and with the darTZeel they are not. It's not the end of the world to hear a somewhat inflated soundstage -- some might even prefer it -- but to hear an amp reproduce the appropriately sized acoustic space differently for each recording is really cool. None of these characteristics overwhelm the sonic presentation with the possible exception of the deep bass and warmth. Even then these transgressions are extremely minor.


But does it rock?
Everyone has those special 'go to' albums, those lifelong favorites we know intimately. These recordings send you back to a special time and place or allow you to zone out. For me it's the toe-tapping PRaT of a Pop group or Classic Rock. If the equipment in question brings that ineffable smile to my face and I involuntarily move to the music, I know that we have a winning piece of equipment on our hands. I won't insult you with discussions on depth, soundstaging and other audiophile buzzwords. Hey, it's only rock and roll. But for me, it better be fun. Does the 108 deliver Rock & Roll? Let me tell you, Zeppelin, Elvis, Santana and Talking Heads through the darTZeel/X2 combo is a hell of a lot of fun. With its prodigious low end, the driving bass lines charge like a muscle car. The opening moment of Stop Making Sense [Talking Heads, Simply Vinyl, "Burning Down the House"] will blow you away with tremendous power and authority. The clarity and lack of hardness just begs for the volume to be turned up. Perfect rock amp? Well, Rock can be hard, raw and bright. If you like those characteristics emphasized, look elsewhere. Hard, raw and bright are not in the 108's vocabulary.


Who wouldn't like this amp?
Is this the perfect amp? Nothing's perfect. Does the darTZeel have the last words in iron-fisted control of the speakers? Nope. It's better than most tube amps but not as good as the best solid state. With my previous Levinson 33hs, there was no doubt who was in charge. The amps were boss especially in the lower octaves. The darTZeel lacks the last word in bass tautness but do not mistake this for flabbiness (distinctly not the case).


Secondly, this is a medium-power amp. However and as with tubes, there's a lot of perceived power for 160 watts. Truly cruel speakers might have a problem. But since the X-2s are very efficient for traditional speakers, it's pure speculation on my part. Still, it's fair to point out that power freaks desirous of ear-bleeding levels into brutish speakers may need to keep looking. Because this is a sweetly melodic amp, an overly warm system might not be the ideal fit. That's talking extremes. For the big meaty part of the bell curve, the 108 should be a superb if expensive fit for most any system I can think of.

Summary
Hervé started this journey with the premise of designing not just another amp but one that was truly better. Did he succeed? Spectacularly so. The 108 is a dazzling tube-sounding amp cavorting around in the guise of transistors. It has the best traits of tubes and solid state - magic midrange with spectacular soundstaging. It is harmonically rich and satisfying. The sound touched my soul. It infused air around the instruments and made music come alive with a deep and powerful low end. It is truly involving, with a gorgeous liquidity that conveys the emotion of the music. Having graduated to tubes, I thought I'd never look back. The darTZeel has made me rethink that premise. It's a stunning piece of equipment that has raised my system to a new level of performance. Highly recommended.
trimmer for DC offset compensation
darTZeel comments:
We at darTZeel are extremely pleased having received such a rave review on the NHB-108 model one. I personally believe that this review comprehensively summarizes all previous ones and adds even more to the understanding of our company's philosophy.

I was particularly glad in reading that Mike found the bass no less than fully present and delineated. It's the first time a reviewer reported that the bass could be a little bit on the heavy side. Other reviewers described it as being a little shy. My guess is that it will mostly depend on the speakers used. The Alexandrias are very big speakers so it's not surprising that they should excel in the bass. The NHB-108 was designed for extreme transparency. Most users report back to us that their speakers usually sound better than ever before when powered from our amp, to the point that occasionally speakers would have to be repositioned to cope with a room's low frequency modes. Thanks to its lack of phase shift even at extremely low frequencies, the NHB-108 can reproduce very deep bass not previously heard, especially when using flagship speakers like the Alexandrias.

Thank you, Mike, for spending enough time with the NHB-108 to fully capture and share what this machine really is about and what we tried to achieve. The rather long break-in period is unfortunately difficult to cut down at the factory, both because our customers usually want their machine as soon as possible and also because the moment we put the amps into their shipping cartons, the capacitors drain and lose their charge, requiring days or weeks to achieve full reformation again. Once plugged in and broken in, the sound keeps shining even after powering the NHB-108 off for days, provided you don't unplug the power cord.

While the break-in process make strike non-audiophiles as unusual, nobody would argue that a brand new car doesn't also need some time before it drives best. While working well at first ignition, I always noticed that my cars were much more pleasant to drive after, say around 40,000 miles or so. Is it the car which really performs better or the driver who gets fully accustomed to the machine? Certainly both. The same is true for audio gear, I think.

Thank you again for this beautiful and revealing review.

Hervé Delétraz
Manufacturer's website
US distributor's website