How did tis thread turn into a discussion of power cords?
IMO, if a power cord makes any difference to your system, then your power supplies are not very good. All too common, alas.
There is a special place in Hell reserved for the guy who invented the IEC power cord.
What an idea, removable power cords! Anyone who has worked in the pro audio/video world will know what I mean. How many power cords have you lost and had to scramble for on a gig? If they were attached, they wouldn't get lost - duh. Any power cord sounds much better than none at all. Phooey....
<rant off>
IMO, if a power cord makes any difference to your system, then your power supplies are not very good. All too common, alas.
There is a special place in Hell reserved for the guy who invented the IEC power cord.
What an idea, removable power cords! Anyone who has worked in the pro audio/video world will know what I mean. How many power cords have you lost and had to scramble for on a gig? If they were attached, they wouldn't get lost - duh. Any power cord sounds much better than none at all. Phooey....<rant off>
Member
Joined 2003
I like removable power cords, but then again I always have a spare and don't tend to loose things. Removable power cord makes for easier device transportation since you don't have this dangling cord hanging off your equipment, with a metal end to scratch everything it drags across.
Fancy power cords don't make a difference and anyone who knows basic electricity should know this. It's all in your head. Case closed.
Back to discussing how much the Nuforce amp sucks 😉
Fancy power cords don't make a difference and anyone who knows basic electricity should know this. It's all in your head. Case closed.
Back to discussing how much the Nuforce amp sucks 😉
The Absolute Sound has reviewed D-200 in the April/May issue. Readers can compare this review versus the NuForce Ref 9 review in January.
Do you see Nuforce going around posting all over the internet hyping our amps? No. This thread wasn't even started by us. All we have done is offer review amps to professional audio reviewers when asked. Keep in mine that 2005/2006 is the coming out year of Class D amps where they showed that the technology can really compete and even out performed SS or tube amps in sonic quality (ie listening test). So it is no surprise that reviewers are all interested in Nuforce amps. We do not offer amps to anyone who asked (we are a for-profit company!). Sander want us to mail two Ref 9 all the way to The Netherland on our own expense just because he asked? We told him that his website doens't qualify.
If you check audioasylm, audiogon etc forums, the postings are all started by customers. We only response to questions or clarify misleading information. Yes, we do remind people of professional reviews.
If you think reviewers can be manipulated by $$$, then why is Nuforce the only amp that has so many positive reviews in such a short period of them? I am sure a lot of other companies are in better position to assert the influence than a tiny and young company like us. Bel Canto, PS Audio, CI, Jeff Rowland, etc all have switching amps on the market. They have been around much longer than us. Being skeptical is good but that doesn't mean you shouldn't keep an open mind.
Jason
Well maybe Economics works different in Belgium but...
You have a dealership network with locations in Denmark, France and Germany - surely it's possible for you to let Sander contact one of those three dealers and let them send him 2 monoblocks? Sander might even pick them up, and it won't cost you a dime. But of course there's this comment:
Keep an open mind but check reviewers for qualification.
In that case, even if you suspect that Sander has a grudge against Nuforce and *will* review biased negatively, I'd still let him have a go at your amps. If they are really that good, they will change his mind. If not, he'll be forcing himself to find the tiniest flaw in your amps.
Negative feedback is feedback as well, it will help you to build the improved Nuforce Reference 10 someday. Unless of course, if the nuforce 9 lives up to the hype and is by all means perfect...
You wonder why we're all so sceptical about your amps? Because there hasn't been anything really negative about them yet, and the negative review of an older product gets squashed for lack of qualification of the reviewer.
PS. I checked too fast, there's even a dealer in the Netherlands......
Hi Jason,
Just wanted to let you know, although I already posted the same comment in a different thread in a different forum, we've got two Ref 9s on the way. These are from an end user and have recently (last week) been modified to the latest revision. These we'll use to redo all the measurements and listening tests. Once those are completed I'll revisit the article we've written and update it, or write a follow-up article which details our experience with them.
It goes without saying that we make every effort to do a proper evaluation of these amplifiers. What does make me different than most other reviewers is that I've designed and built quite a few amplifiers over the past 15-years, some of the recent ones being class-D. Therefore I have a far better grasp of what makes a good amplifier work and what doesn't.
I think my postings here in the Class-D section of the forum are a testimony of that.
Best regards,
Sander Sassen
http://www.hardwareanalysis.com
Just wanted to let you know, although I already posted the same comment in a different thread in a different forum, we've got two Ref 9s on the way. These are from an end user and have recently (last week) been modified to the latest revision. These we'll use to redo all the measurements and listening tests. Once those are completed I'll revisit the article we've written and update it, or write a follow-up article which details our experience with them.
It goes without saying that we make every effort to do a proper evaluation of these amplifiers. What does make me different than most other reviewers is that I've designed and built quite a few amplifiers over the past 15-years, some of the recent ones being class-D. Therefore I have a far better grasp of what makes a good amplifier work and what doesn't.
I think my postings here in the Class-D section of the forum are a testimony of that.
Best regards,
Sander Sassen
http://www.hardwareanalysis.com
I can confirm that Sander has an open mind and that he is a class-d fan. I am also convinced that he can enjoy ANY good sounding class-d amp.
I'd recommend a follow-up.
Regards
Charles
Nphysics said:
Yes. Want some examples of that? I'll even include incognito attempts to do the same on this forum. Let me know.
Were those real customers or.. oh nevermind.
http://www.diyaudio.com/forums/showthread.php?postid=863715#post863715
How do you respond to this review? Was there some misleading information about it you'd like to clarify?
Why did you decide not to participate? What exactly is the selection criteria for your reviewers?
No one is saying you offered them money, just saying there's more than one way to skin a cat, and you know a few of them.
EDIT: I think a follow up is the way to go too.
panomaniac said:How did tis thread turn into a discussion of power cords?
IMO, if a power cord makes any difference to your system, then your power supplies are not very good. All too common, alas.
There is a special place in Hell reserved for the guy who invented the IEC power cord.
<rant off>
I've no idea either 🙂
I fully agree and am glad to hear of your findings on power cords, that must mean I have a very good PSU (I should!!) and agrees nicely with my own findings in this case.
On the other hand, when I start selling high end power cords, I think I'd prefer to have Robert F review them, you're not going to qualify
I ran many simulations with different forced dissymetries to try to increase 2nd harmonic distortion.
-110dB for 2nd harmonic distorsion vs -80 dB third harmonic, for 50% modulation index M. Similar result for M=90%
-110dB for 2nd harmonic distorsion vs -80 dB third harmonic, for 50% modulation index M. Similar result for M=90%
Koolkid,
I can tell you there's a world of difference between simulations and real world results, you should realize that by now.
Best regards,
Sander Sassen
http://www.hardwareanalysis.com
I can tell you there's a world of difference between simulations and real world results, you should realize that by now.
Best regards,
Sander Sassen
http://www.hardwareanalysis.com
SSassen said:
I agree with that statement. The art is in matching simulation with reality. However if simulation is no good, forget about real world to be any better.
The theory behind higher 3rd harmonic is quite simple: in UcD type of modulation, self-oscillating frequency deceases with amplitude AND its rate of change. Therefore more distortion as amplitude goes up, therefore for a sinewave, high odd harmonic distortions.
Also remember that scoping an SMPS or a class-D amp requires a lot of skill and preparation. The skilled in the art knows a scope probe jack is needed, otherwise switching spikes mask the reak waveform. Even an inch of ground lead will capture mostly spikes in SMPS probing.
Let's see if a DIY can simulate a class-D amp with better than -80 dB for the first few harmonic distortions. Let's see how good the "expert critique" is too.
Koolkid,
I've simulated and built several that easily accomplish this, here's an example, a 2nd order UcD with one active pole. Obviously I'm not sharing the actual schematic as I do not want anybody using this for commercial purposes. This prototype scored an impressive 0,004% on the testbench, a factor two higher than the simulation, quite a good result I must say.
Best regards,
Sander Sassen
http://www.hardwareanalysis.com
I've simulated and built several that easily accomplish this, here's an example, a 2nd order UcD with one active pole. Obviously I'm not sharing the actual schematic as I do not want anybody using this for commercial purposes. This prototype scored an impressive 0,004% on the testbench, a factor two higher than the simulation, quite a good result I must say.
Best regards,
Sander Sassen
http://www.hardwareanalysis.com
One key difference: the -112dB 2nd HD is for 20kHz input in my example, vs 1kHz in Sassen's example.
Nevertheless, 0.0017% THD @1kHz is darn good, (ca. -95dB), even in simulation only. Now why not manufacture them and send them to professional reviewers? and possibly make more money than doing hardware analysis and make money via ads. Or go broke should there be a bad review.
Nevertheless, 0.0017% THD @1kHz is darn good, (ca. -95dB), even in simulation only. Now why not manufacture them and send them to professional reviewers? and possibly make more money than doing hardware analysis and make money via ads. Or go broke should there be a bad review.
Koolkid-
I'd bet your simulations didn't show you these output waveforms ether
http://www.audioholics.com/techtips/audioprinciples/amplifiers/SwitchingAmplifierBasics.php
Image 1: Amplifier A, Differential Mode. 500us/div, 200mV/div.
Image 2: Amplifier A, Common Mode. 500us/div, 1V/div.
Regardless of whatever parameters you chose and simulated in you models, your assumptions for deadtime, effectiveness and necessity of snubbers, and the impact of variances in parasitic charateristics, the reality is quite different, and the results clearly demontrable.
I'd bet your simulations didn't show you these output waveforms ether
http://www.audioholics.com/techtips/audioprinciples/amplifiers/SwitchingAmplifierBasics.php
An externally hosted image should be here but it was not working when we last tested it.
Image 1: Amplifier A, Differential Mode. 500us/div, 200mV/div.
An externally hosted image should be here but it was not working when we last tested it.
Image 2: Amplifier A, Common Mode. 500us/div, 1V/div.
Regardless of whatever parameters you chose and simulated in you models, your assumptions for deadtime, effectiveness and necessity of snubbers, and the impact of variances in parasitic charateristics, the reality is quite different, and the results clearly demontrable.
The issue is scientific truth.
One poster mentioned high 2nd harmonic, I wondered about it as my experience shows low 2nd HD but high 3rd HD. Maybe the answer is "your mileage will vary". End of discussion unless there're rational explanations.
In terms of measurement, as I have alluded too, measurement techniques matter a lot for SMPS and class-D amp. A fuzzy scope pix can be a refletion on the technician or the DUT. Again, YMWV.
This is DYI. People come here to learn a couple of things, to share other things. It's not a political podium or ad medium.
It looks like this thread turns into nasty "my measurements are better than your measurements" or the like. That doesn't interest too many people here.
Hey maybe politics and religions are better subjects for this thread. Here's a good link www.faithfreedom.org
Adios.
One poster mentioned high 2nd harmonic, I wondered about it as my experience shows low 2nd HD but high 3rd HD. Maybe the answer is "your mileage will vary". End of discussion unless there're rational explanations.
In terms of measurement, as I have alluded too, measurement techniques matter a lot for SMPS and class-D amp. A fuzzy scope pix can be a refletion on the technician or the DUT. Again, YMWV.
This is DYI. People come here to learn a couple of things, to share other things. It's not a political podium or ad medium.
It looks like this thread turns into nasty "my measurements are better than your measurements" or the like. That doesn't interest too many people here.
Hey maybe politics and religions are better subjects for this thread. Here's a good link www.faithfreedom.org
Adios.
Hmm, I was just reading through this thread, and I see a lot of people who seem to have made up their minds already on a less than complete set of facts. How about just waiting for the evidence?
As promised I've just posted my evaluation of the latest NuForce 9.02 amplifier, comparing it to the now obsolete Reference 8, and taking it apart for a closer scrutiny of its internals. The full article, including measurements and detailed pictures, can be found at the below url.
NuForce revisited, Reference 9.02, no small miracle?
http://www.hardwareanalysis.com/content/article/1831/
Best regards,
Sander Sassen
http://www.hardwareanalysis.com
NuForce revisited, Reference 9.02, no small miracle?
http://www.hardwareanalysis.com/content/article/1831/
Best regards,
Sander Sassen
http://www.hardwareanalysis.com
Seems like a fair review, no awards but at least it shows promise 🙂
Keep at it Nuforce! This is a good thing.
Keep at it Nuforce! This is a good thing.
Hi Ivan,
I've compared it directly to UcD180, UcD400 and UcD700, 41Hz Amp6 as well as a variety of class-A/B amplifiers. The UcD amplifiers are much, much better performers and the class-A/B amplifiers offer similar or better performance than the Ref 9.02. I did not want to mention this explicitly in the article as that would skew the argument towards UcD vs. NuForce and that was not my objective. I set out to compare the Ref 8 to the Ref 9, as NuForce claims the Ref 9 is soo much better. It indeed is a step up, but only an incremental one.
Best regards,
Sander Sassen
http://www.hardwareanalysis.com
I've compared it directly to UcD180, UcD400 and UcD700, 41Hz Amp6 as well as a variety of class-A/B amplifiers. The UcD amplifiers are much, much better performers and the class-A/B amplifiers offer similar or better performance than the Ref 9.02. I did not want to mention this explicitly in the article as that would skew the argument towards UcD vs. NuForce and that was not my objective. I set out to compare the Ref 8 to the Ref 9, as NuForce claims the Ref 9 is soo much better. It indeed is a step up, but only an incremental one.
Best regards,
Sander Sassen
http://www.hardwareanalysis.com
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