Review of Dartzeel NHB-108 Amplifier


Dartzeel is a relatively new entry to the high-end game. Despite being reviewed by John Marks in a recent issue of Stereophile, the company's only current product offering, the NHB-108 stereo amplifier, hasn't gotten a lot of press on these shores. Hopefully this "review" will do its part in rectifying that.
As many of you probably already know, Switzerland-based Dartzeel is the brainchild of one Herve Deletraz. Herve is a wonderful guy who's dedicated to the very best customer service. As essentially a one-man operation, I'm sure his time is limited, but he's always responded to my e-mails in an extremely courteous, timely manner.

On to the amp. I'm not one for technical details, so I'll leave them to those of you who want to visit Dartzeel's website. Basically, the 108 is a "purist" stereo amp rated at a relatively modest 100 wpc. Its smallish dimensions belie its weight, which measures around 65-70 pounds.

Internally, the amp is incredibly well laid out (if tightly packed), with an attention to detail that one should expect--but doesn't always receive--from components in this price range.

Outside, it's purely love-hate. (Refer to the website for pictures). Either you get it or you don't. Personally, I've grown used to its appearance over time, but it's taken a while to become acclimated. If WAF factor is any sort of issue, practice up on your compliments. Then again, I may be overstating the case. While it's not Liv Tyler, it's not Janet Reno, either. Time reveals its inner beauty.

Performance-wise it's a much more straightforward issue. In my experience the 108 is the most balanced, natural-sounding amp I've ever heard. It has a way with timbre that's downright spooky--up there with the very best tube units one cares to mention. The sound is just "right"--every note is reproduced with a tonal correctness and warmth that is as close to the real thing as I've heard in an amp. Because of it's sheer naturalness, it can take a while to overcome the initial impression that it is somehow soft or rolled off. That is most emphatically not the case! Dynamics are crisp and fast, and the frequency extremes are right where they need to be--not overstated or highlighted at all, just perfectly natural and realistic.

The only potential weakness of the 108 is its power rating. It flows a nice amount of juice for 100 watts, but one could theoretically run into problems with particuarly current-hungry or inefficient speakers. Part of the amp's midrange purity, I believe, is attributable to the use of the bare minimum of bipolars in the output stage. That, of course, comes at the price of power, but in this case the tradeoff is more than worth it. Just take some care in speaker matching--as you should, anyway--and you'll be rewarded with a sound that balances the very best of solid state with a midrange that will make some question whether they even need to fuss with tubes.

Despite its novel physical appearance, the need for careful speaker matching, and the fact that the US dollar has been taking a Tyson-like beating lately, the Dartzeel is a serious contender in the super-amp category. Yes, there are amps out there that do this or that "better" than the 108, but I've yet to hear one that strikes a better balance between the various areas of performance. It's a stunning piece of engineering and a landmark amplifier.

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Product Weakness: Appearance is strictly take-it-or-leave-it. Power rating requires some attention to speaker load. Cost.
Product Strengths: Naturalness, midrange magic of the highest order, speed, dynamics

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Associated Equipment for this Review:
Amplifier: Dartzeel NHB-108
Preamplifier (or None if Integrated): EMM Labs DCC2
Sources (CDP/Turntable): EMM Labs CDSD
Speakers: Von Schweikert VR-4 Jr.
Cables/Interconnects: Jena Labs Pathfinder
Music Used (Genre/Selections): Rock, blues, country, some classical
Room Size (LxWxH): 24 x 20 x 7
Room Comments/Treatments: Echo Buster, ASC
Time Period/Length of Audition: 3 months
Other (Power Conditioner etc.): Shunyata Hydra-8
Type of Audition/Review: Product Owner
hooper
Sean writes:
Jtinn: Jenna's cables are based on a woven pattern. While the cables may present a consistent nominal impedance when measured at one end, the design geometry consists of multitudes of impedance bumps along the entire path of the cabling.
That doesn't make much sense to me. How do you know these "impedance bumps" are there? How can you measure them?

Regards,
Cinematic Systems, do not twist everyone's statements out of context and use it to make broad sweeping statements about one's meaning. I can do the same and declare that your statement that seems to imply that jazz musicans don't know what they're doing, shows your lack of knowledge and ignorance. You used the label/term musicians broadly, while I almost clearly defined them. Explain to me, how a musician, who has no interest in putting out a record, NEEDs people like you? If you think I'm arrogant for saying that to musicians who simply enjoy playing music, people like you are irrelevant, than so be it.

In historiography, the "official scholar" and recorder of dynastic history is important because he has the power to "twist" history, not because he is "needed". Written history has made it easier for historians, but history has been passed along fine without being written down. Are recording engineers and such important? Yes to the recording process. Music has been played for many centuries without being "recorded". It's arrogant to think that people need you to record them in order to play music and be a musician.

There's a common belief that the best musician in the world, if there is one, is probably sitting at home practicing. It's certainly a lot merrier playing music with others, but again, you don't NEED anyone to play music.

If planet Earth is near extinction, you'll find people playing music and you'll find people who thinks music is important and inspiring. Good luck finding people who think your job is relevant.
Mike: Speaker design is a science more-so than it is an "art". While many in the design / manufacturing / distribution / sales / reviewing industries of "high end" audio would have you believe otherwise i.e. "the talented and very secretive audio guru's working their black magic", etc..., without the science, formula's and consistencies noted amongst specific design parameters, speaker design would be more "guesswork" than "art". As such, applying the science, formula's and commonalities amongst operating parameters is what makes up about 90% of the speaker design. The other 10% is finessing the variables into place to achieve the specific voicing / electrical characteristics that are desired.

Whether or not one agrees with the specific figures ( 90% / 10% ) i used, i don't think that anyone familiar with the nuts & bolts of speaker design will question the comments that i made to any great extent. That's because they've studied the science enough to know what to expect out of a product based on how repeatable design parameters are implimented, sometimes even before they hear the product itself.

The only real "catch" here is the "10%" that is art / magic, which can take a poor design and make it listenable, a mediocre design and make it more enjoyable than expected i.e. "a world beater that is greater than the sum of the parts", a good design and make it into something truly enjoyable, etc...

On the other hand, one can have all the "right parts" and a great circuit with a very poor implimentation. As such, that last 10% could kill what should have been at least a decent product.

The point that i'm getting at is that 90% of the equation starts with the design i.e. the consistent and repeatable performance characteristics that are predictable based on science and math. The finesse factor / how it is implimented is what makes the difference once all of the science / math have been implimented. In this case, most of the "science" is pretty straight-forward, hence the ability to describe specific sonic attributes and electrical characteristics onto it as a product. As i mentioned, what instrument radiates 100% of the sound that it produces away from the listener?

With that in mind, i'm not saying that you or someone else can't or won't like this speaker. What i am saying is that based on the money involved and the other design approaches that could have been taken, the end product seems to be questionable in both value and performance. Then again, most every "high end" speaker falls into that category to one degree or another with some being far more questionable than others.

As a side note, this is a 94 dB speaker according to Von Schweikert's website. The rating of 96 dB's only applies if the bass and treble boost circuitry are engaged. In effect, it looks like the active equalization circuitry ( fancy tone controls ) not only increases the average sensitivity, but also delivers the "big & dynamic" ( bright and thumpy ) sound that so many "audiophiles" seem to like. The fact that Legacy voices their products in much the same fashion shows that personal preference may be a better selling tool than accuracy and linearity are. At least with Legacy products though, you do get a lot of driver surface area for the money. In that respect, they are a "bargain" amongst "high end" speakers, even if they aren't anything close to what "high end" audio USED to be about.

Metralla: How do i know that this cable has impedance bumps? That's easy. I have eyes and know how to interpret what i see : )

Honestly though, much of the "science" discussed above that makes speaker design repeatable also applies to the conductivity and electric parameters of cable design too.

I'll try to keep this simple. A conductor in free space presents a specific impedance / velocity of propogation. Placing other conductive objects in proximity close enough to disturb or "couple" to the field produced by the conductor passing signal will change both the impedance and velocity of the signal.

Given that the cable design being discussed consists of a woven pattern, you'll have a conductor that is "somewhat" in free space and then that conductor is placed above / below / next to another conductor. It then hits an open gap in the weave and then is placed in close proximity to another conductor above / below / next to it. This produces a random yet repeated change in impedance until the end of the pattern.

Think of the electrons in the cable as a car and the woven pattern as traffic on an expressway. In some spots, the car can pick up speed as there is no impediment to flow i.e. open space all around it. Once it hits a pack of cars ( enters an "intersection" in the weave ), the speed of travel ( velocity of propagation ) has to be altered. Once the car ( electron ) makes it through the congested intersection ( areas where conductor cross section comes in contact or closer proximity with each other ), it can now procede ahead at full speed as there is a open area i.e. another "gap" in the traffic before it has to weave in and out of the traffic, slowing down progress once again.

When looking at the progress that the car ( electron ) made travelling from point A to point B, we can ascertain the "average speed" ( nominal impedance ) that it took. Only problem is, that average speed is a combo of both "open road" speeds and "heavily congested traffic" speeds, which equate to the different impedances, "electrical bumps" and velocities that the electrons encountered.

As to my vantage point, i'm in a helicopter flying overhead going directly from point A to point B. Not only can i see all of the changes in traffic flow ( impedance alterations ), but i've got a much shorter path since i don't have to weave around other obstacles, which requires me to alter my speed. Once again, this is why the shortest and straightest path is typically the fastest and most consistent route. I also new what to expect in terms of traffic flow ( impedance and speed of conduction ) as i had observed these characteristics many times before with both my naked eyes ( visible traits ) and by studying traffic logging data ( test results ). Knowing what to expect on any adventure and how best to deal with the variables involved can be rewarding in both time and monetary expenses. This is why educating yourself on the subjects that you'll be dealing with is both wise and enjoyable i.e. it pays for itself.

Hope this helps and made the explanation easy enough to follow. Sean
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PS... That explanation is pretty rudimentary, but it gets the point across.
Joperfi: Duke doesn't have this problem for very specific reasons. Duke plays his cards above the table for all to see in a most up-front and helpful manner.

Mike: I never said or meant to infer that you were a "stirrer of the pot". How you got that impression, i don't know. If you can point out how & what you interpreted in one of my posts as saying that, i'd love to see it so i can both correct it and learn where i made such a mistake.

To be quite honest, i meant what i said in your system thread. I also appreciate the amount of time and effort that you've invested in responding to questions about your room construction, system selection, listening comparisons, etc... I didn't know if you had seen my initial questions pertaining to room modeling, hence my bringing it up again. Then again, i also didnt' know if i was being blown off because i was publicly "lambasting" your dealer.

Jtinn: Since you called me to task on my lack of audio industry affiliations and design / product familiarity, i am looking forward to your expert and professional reply to the comments / explanations that i've offered above. I see that you've taken the time to respond to and applaud Howie's criticism of Cinematic Systems, yet you've failed to offer any further insight or technical commentaries as to other comments / criticisms being made in this thread.

If you wonder why others have commented on why you find yourself in the situations that you do, now might be a good time to reflect on the situation. Sean
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