darTZeel NHB-468 mono blocks in my system

Apr 21, 2010
284
8
18
Dallas,Texas
#43
I guess I've missed a lot of posting since moving from California to Texas. Now that I'm settled in, I'm returning to the forums. I've have missed it. The funny thing is I just found a DartZeel dealer near Dallas. Now let me add congratulations Mike. I'm happy for you and hope to read much more about your new amps. I'll live my life through you and all of the other audiophiles on here until I have my new room finished for audio. It's been six months since moving and still no system! :(
 
Likes: Ron Resnick

Mike Lavigne

Member Sponsor & WBF Founding Member
Apr 25, 2010
9,029
2,975
770
#44
as those reading this thread likely know, Michael Fremer wrote a 'rave' darTZeel NHB-468 amplifier review last October, here;

https://www.stereophile.com/content/dartzeel-nhb-468-monoblock-power-amplifier

part of that review is a measurements section written by John Atkinson. John writes some things related to the measured power output of the 468's, which can be interpreted in a number of ways, depending on your level of understanding of the circuits inside the 468's. in the manufacturers comment section Herve Delatraz does briefly address these concerns.

why do i now write this post?

a month or so ago in a thread about the new VAC amps........ in response to comments made in that thread relative to Mr. Atkinson's 468 measurements, i posted this........

https://www.whatsbestforum.com/threads/vac-452-iq-review-in-stereophile.30470/#post-643537

.........quoting part of Herve's manufacturers comments to hopefully add some clarity. well........those who's minds are already made up, and who are unlikely to ever see, let alone hear, a 468, will not change their minds, no matter what. so be it. but some who are actually seriously curious about the 468, deserve to know more. and here is that 'more'.:cool:

as these things sometimes do, word got around to Herve through the regular channels of the world wide web.......and he sent me the message below getting into more detail about this measurement issue. here is Herve's message to me unedited;

Hello Mike !

I hope you are well, and that you keep away from this ugly virus.

Here we are all well and in good health. I really hope it is the same for you.

Well, I am writing you after some reports in whatbestforum.com I got from various distributors / customers, regarding the measured performances of the recently reviewed NHB-468.

I do not participate in any kind of forums, since it usually starts gently but ends less politely than it should.

The other reason is also that people who criticize one brand, generally didn't have a listen to them, and further never committed to buy it and then to live with that specific equipment over the long haul.

I do not want to blame anybody here, it is just usual facts.

Apart from this, forums are a must and very interesting to read; I just try to keep outside and interfering as less as possible.

Back to the NHB-468 review.

John Atkinson was not able to measure the actual output power of the NHB-468, simply because of the new audio circuits I designed, which do not behave the same onto a pure resistive, static charge.

The new circuits, which involve our patent pending CP2C (Constant Power To Current), associated with our software monitoring the entire audio section, prevented the amplifier to deliver its full potential during the measurement procedure.

During a previous event in Bangkok last fall, I went there personally to introduce the NHB-468, and we used the very same speakers Michael Fremer owns, say the renowned Wilson Audio Specialties Alexx.

These speakers are know for exhibiting very complex load and low impedance.

Stereophile review is here:


https://www.stereophile.com/content/wilson-audio-specialties-alexx-loudspeaker-measurements

Impedance is as low as 2 ohm at several points, and barely goes above 3 ohms for the most part of the audio spectrum.

This, related to the NHB-468 measurements, would imply that my amplifiers could not drive such a speaker properly, to say the least, since John Atkinson was able to only put out 101 (!) watts under 2 ohms… Our CP2C allows 222 watts under static conditions, however.

Anyhow, "static conditions" are not the ones you are when playing music for real.

During that exhibition in Bangkok, we were playing quite loud, and for long periods of time (as long as attendees would cope with my eccentricities), and we easily exceeded the 700 watts limit, with ease and a sensation of breathe unexperienced before, even reaching 750 watts, without any sign of distorted or clipped sound.

So, what (nu pun) ?

It is true that during measurements, our embarked software did not behave as intended.

Since then, a fix has been made.

For those who would not believe me, they can feel free to email my distributor in Thailand, and ask him if the room in which we exhibited the NHB-468 with the Wilson Audio, sounded poor and congested.

In the same way, they can also directly ask Michael Fremer. He is honest enough to say the truth.

And, last but not least, it is worth noting that you cannot buy a review in Stereophile magazine. If your equipment is crap, they will write it down. Ask any manufacturer.

Also, I will be happy to personally answer to any question somebody on the forum may have.

You can give them my email, rehve@dartzeel.com

So, Mike, if you can – and especially if you find that it worth it – forward the above onto the forum, in all transparency, it may clarify some questions, especially why there was a so big difference between the measured performance, and we can actually deliver when playing music, feeding real world speakers.

Thank you for reading me.

I wish you all my best. I hope to come soon again in USA.

I miss you all there !

Hervé
 

howiebrou

Well-Known Member
Jun 29, 2012
1,506
1,276
520
#45
Great that Hervé is willing to answer queries. The 468 is a great amp and a friend of mine just bought a pair. I don't normally bother with measurements because a piece of equipment that measures well does not mean it sounds good. Having said that it would still be nice to know what the measurements really are with the 468 if indeed it can be measured in the normal way.
 

Tango

VIP/Donor
Mar 12, 2017
3,999
3,771
495
Bangkok
#46
For those who would not believe me, they can feel free to email my distributor in Thailand, and ask him if the room in which we exhibited the NHB-468 with the Wilson Audio, sounded poor and congested.
Audio Absolute (Mr.Vipol)
Tel: 66(0)2-4898954
audioabsolute8@gmail.com

I do the chorus for you Mike.

Tang ;)
 
Last edited:

Mike Lavigne

Member Sponsor & WBF Founding Member
Apr 25, 2010
9,029
2,975
770
#47

Mike Lavigne

Member Sponsor & WBF Founding Member
Apr 25, 2010
9,029
2,975
770
#48
Great that Hervé is willing to answer queries. The 468 is a great amp and a friend of mine just bought a pair. I don't normally bother with measurements because a piece of equipment that measures well does not mean it sounds good. Having said that it would still be nice to know what the measurements really are with the 468 if indeed it can be measured in the normal way.
as far as the concept of the value of measurements 'in a normal way' i have a few opinions, but i respect the desire to know them. situation ally i use them sometimes myself. it's one part of the picture.

but when my ears tell me one thing, and measurements suggest another, i go with my ears. Herve' is very credible to me after 15 years of owning his electronics. and he does walk down a different path than many electronics designers.

i would suggest you email Herve' with any specific questions as he invites.
 

Kingsrule

Well-Known Member
Feb 3, 2011
984
197
455
#49
Does anyone know how many output devices are in a 468? Also what kind?
I can't seem to find this info anywhere. I do believe the 458 had 4 but not sure
 

Mike Lavigne

Member Sponsor & WBF Founding Member
Apr 25, 2010
9,029
2,975
770
#50
Does anyone know how many output devices are in a 468? Also what kind?
I can't seem to find this info anywhere. I do believe the 458 had 4 but not sure
i know the circuit of the 468 is different than the 458, but i don't think the difference is output devices. if i get a chance to ask the question i will. you are welcome/encouraged to email Herve and ask the question. he is very open typically. his email address is a few posts above on this page.
 
Jun 3, 2018
99
26
23
#51
It will be few. Hervé doesn‘t like the variation of different values in a batch of output devices. I guess it would be six. But not guaranteed...
 

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