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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
sirspeedy70680e509
1,064 posts
 
Mike,thanks for not getting too hot headed towards my comments.I will tone down my act.I have a friend in NY,who is unmarried,and very wealthy.He goes through megabuck equipment like golfers go through putters.I hope you do not fall into this category.He also,never gets the performance from his stuff that the equipment is capable of,since he really gets off on "The Latest Stuff" and is quick to turn around his purchases.Yes,it is NONE of my business,but,when you post pics of such a fine custom room,it is human nature to analyze what may or may not be best served.

Since I do feel that the Exquisite REF is,not only a fabulous speaker,but a work of art as well,I simply cannot believe anyone dumping them for anythimg else.I suspect you like to have equipment come and go,and it is your own decisions,but you do pass yourself off as an "experienced and capable hobbyist/reviewer"so you become subject to scrutiny.To me your decision to go towards the Von S seems to try to move closer to your Rock Music tastes,and I understand that.I am surprised you didn't want to try adding the subs.

When you posted a review of your "WONDERFUL" room process on Positive Feedback,both I and my friends felt you could never live with the Kharma's,based upon the comments made about you losing bass.We also were surprised,since you seemed to love the Ex Ref,that you didn't build a slightly smaller room to allow those speakers to pressurize it better.

When all is said and done,since I too went through my own set of decisions when driving my own custom room,it is only your business what you do.I appologize,in advance if I seem to question your process and decisions.However if you put it out there,this is what good critical audio discourse can be about.Anyway I wish you the BEST and hope you,and all other "Thinking" hobbyists enjoy your music!!
sirspeedy70680e509
1,064 posts
 
Twilo,in response to your amp comparison question,I think you will find your answer at--High End Audio.com
cinematic_systems
282 posts
 
"We also were surprised,since you seemed to love the Ex Ref,that you didn't build a slightly smaller room to allow those speakers to pressurize it better."

Just so it is clear JTinn's description of how Mike's room interacts with the Kharma Speakers and the bass has nothing to do with the Kharma's ability to produce bass, nor is it remotely correct. Infact if 25hz cannot pressurize the room how can smaller wavelengths pressurize the room? You would think someone with 45 years experience would understand basic room acoustics.

His bass problem currently has to do with his amplification choices and the fact that to make a room the size of Mike's room flat in the bass something has to be done with the lowest frequencies. After seeing the specs on the Dartzeel it is not a good match for the Kharma's for making bass. And the perceived dynamics likely has something to do with the overshoot that creeps up in the square wave as the amplifier is pressed, which explains why JA only measured the square wave at 55 watts. To drive those small Etons effectively more power is needed.
sirspeedy70680e509
1,064 posts
 
CS,sorry,but I was referring to Mike's own comments,in the past,no one elses.Also,mine is soley an opinion,and entitled to be wrong,as in my opinion, is yours, in this matter.Unless the 200 page set-up guide that came with my speakers is totally wrong(I doubt it)the room absolutely affects bass,as does an amp.Ever hear of room loading?I don't care what the actual low frequency cuts off at,and am not worried about the actual lowest frequency limit.I have heard some set ups that cut off about 45hz that have "better perceived" bass than the low bass systems that you may enjoy measuring.I'd rather just listen,and get a sense of a full range sound,in itself.What I do is listen to a very wide variety of "Classical and Popular" recordings,that I know to have "convincing" low frequencies.If I get a good sense of balance,then it is "Right".Few systems really are,regardless of the measured lowest frequencies.Try putting away your fancy test equipment and use your ears a bit more,you may be able to save some potential customers some money?

If you feel the need to measure is that important,as opposed to critical listening,usually with a group of other experienced hobbyists,then knock yourself out.But,please don't condescend as to how much listening years I've had.I don't know where you got the number "45 years" from.Did you read THE DA VINCI CODE?
howie
230 posts
 
Cinematic Systems, you forget that Mike also has the Tenor 300 hybrids and I think Mike has had guests bring over amps to audition as well. It's hard to believe that a different amp can help add that much extra bass. Nothing I've read/heard tells me that the Tenors and Dartzeels are chumps in the bass department.

Sirspeedy, I believe the dimensions are arrived at by Rives, perhaps you should take it up with him. Honestly, I too think it makes more sense to buy speakers that fit the room rather than the other way around. Mike had a chance to build the ideal room, making sacrifices to the room just so the rest of his equipment will work better seems rather silly considering the cost of the project. From the little I know about room acoustics, I believe that a smaller dimension would at least be in some ways a compromise. It's a lot easier to change your gear than to change your room.

Like many people here and on AA, I've followed Mike's journey for a little while now. He owned his old speakers and amps for more than 2 years I believe, and other stuff a lot longer. Is that considered a fast turnaround? You're right that considering the size of his investment, I really don't think he's the type to live long with compromises. If the VR9s doesn't do it for him, I don't think he'll stick with it for long. It's not like he needs industry accomodations or whatever, so I really do believe Mike is after better reproduction of his music.
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