darTZeel NHB-18NS preamplifier and NHB‑108 Model Two power amplifier
Regardless of how much high-end audio you have heard, when you experience something exceptional, the music lets you know all about it. It might all start with a small spark of revelation. But it will grow, and I’ve read many people say that it is like hearing a piece of music for the first time. I get that entirely and have been lucky enough to experience that same feeling several times (but not many more) over a long period of listening and writing about audio equipment. When it happens, it typically leaves a hunger for more and more of whatever a particular system is dishing up. This awakening and re-alignment of musical perspectives are truly wonderfully addictive.
Hervé Delétraz is the man, and he designs and manufactures the small darTZeel range high in the Swiss Alps. He runs a CNC facility, making custom metalwork for specialised applications and companies who need components of the very highest quality and precision. Music is his passion and darTZeel is his expression of that love. Listening to his amplifiers, I think he hears music in the same way that I do. As a name in the audio world, the company has always seemed somewhat elusive to me. It’s one of those products that I have heard much about but have only managed to hear for a very brief listen over the years. So, you can imagine how quickly I jumped at the chance to review this darTZeel pre/power in its latest form; I didn’t need asking twice. Two months down the line and I am still genuinely staggered at how good it is.
Hervé’s expensive machinery comes in handy here. The construction of both the pre and power amplifiers is exacting and distinctive, right down to the red casing with gold front and rear panels. Internally, things are just as impressive and beautiful. On the subject of the darTZeel aesthetic I have to say that some visitors found the pair somewhat ‘bling’, but I think that is because they are unusual and undoubtedly bold. I love the look, not least because it is backed up by such a memorable performance.
The front panel of the NHB-18NS preamplifier is simplicity itself. A pair of lightly-weighted knobs fitted with rubber O-rings control both the inputs and the volume level settings. The latter is referred to as a Pleasure Control while the input choice becomes the Enjoyment Source and on the darTZeel one does not select an input but rather ‘enables’ it. NS stands for ‘No Switch’, as the preamp doesn’t use switches or relays. There are over 1,200 electronic parts in the preamplifier, and the signal path has come in for exceptional attention. There are merely seven transistors from input to output to keep the signal pure. The optional phono stage – not supplied in the test unit – has just six transistors: this is purist circuit design par excellence.
The volume dial is a continually-rotating design, and though details of its operation are scant, it seems clear that it works through the cunning and contactless use of light. It exudes a quality feel, supported by the wonderfully uncomplicated remote. Finished in matching red, it feels hewn from a solid billet of aluminium and can turn the volume up and down or mute it, and that’s about it. It is however very slippery, and I couldn’t find any rubbery ‘blobs’ in the box to prevent the remote from disappearing down the edge of the sofa. I would add discrete micro feet to keep it in place.
Power up the pre and the word ‘Foreplay’ appears in the window on the top right of the fascia and when you switch it off, ‘Climaxed’ appears. Yes, it is a bit cheesy at first, but you don’t notice it after a couple of times, and it’s just a touch of light-heartedness from Hervé. Somehow it sits rather well with the colour and other design details of the amplifiers. It didn’t bother me in the slightest when listening to the darTZeel duo, and it adds much-needed character in an increasingly corporate audio landscape.
Most importantly, the NHB-18NS is battery-powered. The separate box through which that battery connects to the mains is a recharging unit that maintains power to the preamplifier and sets it into recharge mode when the batteries are running low. A fully charged NHB-18NS will run for eight hours before the cells need recharging and then it will run direct from the mains while this takes place. Twin modes are available. ‘Auto’ is battery mode, and this is how the unit should be powered when listening. ‘BTM’ is Battery Through Mode which kicks in when the charge gets too low and before full battery mode restores. Detailed monitoring of battery condition ensures that you will always get the best available sound quality, dependent on battery condition. When the pre is running from the mains, there is a slight drop in class, but the low impedance nature of the full battery condition is always preferable. The state of the battery is verifiable through the LEDs on the front panel. If this sounds in any way complicated, it isn’t. In use, you plug it in and go as everything is completely automatic and silent. The batteries themselves are Lithium Ion Phosphate and underwent a full three years of testing before Hervé was happy to include them in his preamplifier. I have used battery-powered preamplifiers before over the years, and my memory is that they were a bit of a pain for debatable gain. Not here though, as their implementation is superb, though they do need some running-in to achieve their full duration and lowest output impedance. In its manual, darTZeel suggests fifty to one hundred cycles.
Preamplifier inputs are fascinating due to the unique inclusion of BNC alongside the conventional RCA types. Each has a small toggle switch beneath it to select various gain levels. These are named as Zeel inputs while line outputs are mirrored by BNC’s and named DarT. There are a single pair of balanced XLR sockets as inputs and a single pair of XLR inputs. I am struggling to think of components with BNC outputs that might suit the darTZeel but, in the fullness of time, there will be products from the company that use this connection. However, there are a set of BNC cables included which can be used to connect both units.
The NHB-108 stereo power amplifier – in its latest Model Two guise – has an output of 150 watts per channel into 8 ohms. It is built to the same incredibly high standards as the NHB-18NS preamplifier. It’s dual-mono and offers the expected RCA or XLR inputs plus of course a Zeel 50 ohm BNC option. The circuitry is I am informed somewhat unique and is the subject of several patents. The mineral glass top plate of the power amplifier reinforces the fact that this is indeed something different. The sculpted gold bus-bars that link each channel’s six large capacitors are beautiful.
Beautiful as they are to behold, the magic kicks into high gear when you sit down to hear how they behave when confronted with some music. In a word, they are magical and to my ears incredibly special. Where many high-end amps might have their speciality performance areas, the darTZeel is magnificent from top to bottom. They are enormously robust and extended in the bass and almost ethereal through the astonishing midband. At high frequencies, where many amplifiers show limitations, they are as dynamic, textural, subtle, and revealing as I have heard. Very, very seldom have I experienced such an intense, joined-up, and compelling view of the music.
Listening began when I took delivery of the amplifier during an unprecedented and breathless heatwave in London earlier in the summer. I had left the preamplifier charging overnight and found myself up at 5 am due to the sweltering conditions. At that time the body is enormously susceptible to musical influence, and I decided to use the still air for an early venture in darTZeel land. I was feeling in strictly non-reviewer mode, so I scrolled through the new MQA titles on Tidal and stumbled upon Gateways [DG 4836606] and the Shanghai Symphony Orchestra. The opening pieces are musical representations of five elements, and I was instead hoping to be gently introduced to the new day rather than kicked into it. The world was so calm and the sounds so precious that it gave me a whole new level of respect for the way the amplifier controlled the music. The palette of tonal colours and the endless range of textures swirled together, and the system and I shared some precious moments as the musical poetry unravelled. The darTzeel bought me entirely under its spell. Speed is at the heart of much of what it does. Not that great amplifiers ever sound particularly fast from beat to beat. It’s all to do with the way they control every nuance by utilising their power with such musical precision. The five elements, so wondrously formed and excellently recorded, let me ride that musical wave into the day. This amplifier can change character in a heartbeat and from its seemingly bottomless well of possibilities, can shock you or make you cry. Its emotionally engaging capabilities seem endless.
After that, every listening session would become an eagerly anticipated event in itself. I learned quickly that the darTZeel sound is so deep and its overall resolution so intense, that it doesn’t so much ‘play’ the music as ‘grows’ it. Listen to Billy Cobham’s Drum’ N’ Voice Vol 1 + 2 [Sony] if you want to hear what the amplifier can do with a solid rhythm section. It is enormously focussed, extraordinarily potent and utterly relentless in its drive. Cobham plays like a monster! The sound of his snare drum – with its delicate, shuffling little rolls – adds just the right amount of relief to the bass drum that forms the root of so much of the music. The darTZeel shows it to be imposing and metronomic where the tempo is concerned. It drives the speakers with a satisfying weight and a very plain view of the width of the kit, and it adds layer upon layer with unstressed ease that is remarkable.
As a huge devotee of the acoustic guitar and the luthiers who build the very finest on the planet, I was able to obtain some hi-def recordings of various high-end instruments. The art of constructing beautiful objects like these is largely about the control of tensions. With a string pull well above 150 lbs on metal-strung instruments, structural integrity is critical. The top (the bit with the hole) of the guitar does most of the resonance, and the bridge acts as an air pump, not unlike a cone speaker. The top must, therefore, be braced to resist the immense stress of the string tension from tearing the whole thing apart. Mass is the enemy of resonance, and the art is in balancing the two opposing requirements. I’ve gone into detail about guitar-making simply because the darTZeel does the same to the audio signal. As a result, I have never heard the differences in these instruments, drawn in the air, with such incredibly articulate precision and charm. It’s almost cinematic and certainly in full Technicolour. The guitar energises all these different resonances. The resultant tone, note shape, and expression that each musician can extract allow them to create a different kind of tension – this time in the listener. Each instrument drowned the room in dripping colour. The way the daRTzeel shows the differences in reverb speed, dynamics, and the layers of harmonic bloom that swirl around as the art of the luthier joins the circle is fascinating. If you think an acoustic guitar is a simple thing, then I assure you it is endlessly complex in both scale, speed, and tonality. When it comes to the sheer resolving power of the amplifier, then it goes way down to the sub-note level, and it does it effortlessly.
I loved my time with the daRTzeel amps as much as I have with any product over the years. The pair are not in any way ‘cheap’, but they are primarily so involving and musically enlivening that price becomes a secondary concern. They delivered such musical joy and involvement that it has indeed been a rare privilege to have them at home, and I was extremely sorry to see them leave. They are truly exceptional and a huge testament to Hérve Delétraz and his audio art.
- NHB-18NS Preamplifier
- Type: Battery powered line stage
- Inputs: 5 plus optional phono stage
- Outputs: RCA, XLR, BNC
- Analog Input Impedances:
RCA line – 30 ohms
XLR Line – 15 ohms
Zeel BNC – 50 0hms
- Freq. Response: 5 Hz–500 kHZ
- Signal to Noise ratio: > 92dB
- Remote: Yes
- Size: 170 × 440 × 335 mm (H×W×D)
- Weight: 24kg + PS – 3kg
- Price: £39,995
NHB – 108 model two
- Type: Dual mono power amplifier
- Power output: 150 watts RMS @ 8 ohms;
250 watts RMS @ 4 ohms
- Analog Input Impedance:
BNC Zeel – 50 ohms
RCA line – 30 ohms
XLR 30 ohms
- Size: 170 × 440 × 350mm (H×W×D)
- Weight: 30kg
- Finish: Red with gold facia and backplates
- Price: £39,995
Maufacturer: darTZeel Audio,
UK Distributor: Absolute Sounds
Tel: +44(0)208 971 3909