It has been a while since I've seen a heated debate about these amplifiers here, but I know I've participated in quite a few threads that discussed the ins and outs of these amplifiers. Many people that read my posts commented that I had no right to comment as I had not heard and/or measured these amplifiers.
Hence that's exactly what I've been doing in these past few weeks, and the results can be found below, I hate to say 'I told you so' but that's what it boils down to really. If it had been the reverse I'd have been upfront and honest about it as well, as afterall, to err is human.
NuForce Reference 8 amplifier, debunking the myth?
http://www.hardwareanalysis.com/content/article/1828/
Best regards,
Sander Sassen
http://www.hardwareanalysis.com
Hence that's exactly what I've been doing in these past few weeks, and the results can be found below, I hate to say 'I told you so' but that's what it boils down to really. If it had been the reverse I'd have been upfront and honest about it as well, as afterall, to err is human.
NuForce Reference 8 amplifier, debunking the myth?
http://www.hardwareanalysis.com/content/article/1828/
Best regards,
Sander Sassen
http://www.hardwareanalysis.com
The review.
Sander,
This is pretty much the way it looked to me as well but I didn't see the distortion rising as high though. Your test unit doesn't look the same as the one I tested and may really be one of the first ones. You didn't post the serial numbers so I have no way to know. I do understand that the latest ones have addressed a lot of these problems and sound way better. I can't vouch for this as I have not seen the "newest" ones yet.
Roger
Sander,
This is pretty much the way it looked to me as well but I didn't see the distortion rising as high though. Your test unit doesn't look the same as the one I tested and may really be one of the first ones. You didn't post the serial numbers so I have no way to know. I do understand that the latest ones have addressed a lot of these problems and sound way better. I can't vouch for this as I have not seen the "newest" ones yet.
Roger
I have a latest version of the Ref. 9. Sadly, I only have one to drive my center channel. It seems to be better than the one or two channels of my Bryston 9B that I used to use to drive the center channel. However, as I only have one Ref. 9, I can't comment on such things as depth of sound stage and the like. I also do not use an FM or AM or television antenna, although I've had no problems with cable television.
Hey Sander,
Nice review, plenty to sink you teeth into. I, too, wonder how some stuff gets such good reviews. Not having heard the NuForce amps I don't know, but some of the other class-d stuff that gets glowing reviews is a mystery.
From what I know about the NuForce stuff it was quickly thrown together to ride the class-d wave. Your review seems to point this out. It seems odd that a full bridge amp would radiate so much RF. It must be coming out of the case, as the speaker cables shouldn't be radiating much RF (See Bruno's article).
With all that RFI running around, the input wiring should be shielded, but appears not to be. If the RF was getting back into your tube pre, think what was happening inside the NuForce!
Thanks for the revealing review, but I do have to say that the tone of the article sounds a bit like you were "out to get" the NuForce. I don't think you were, but it does sound a bit that way. You might expect some backlash from that.
(And one little gripe - all those pop-up and pop-under ads on your site are awful! They even get thru pop blockers. I like the content on your site - very nice - but all those flashing and popping ads make the site difficult to visit).
Nice review, plenty to sink you teeth into. I, too, wonder how some stuff gets such good reviews. Not having heard the NuForce amps I don't know, but some of the other class-d stuff that gets glowing reviews is a mystery.
From what I know about the NuForce stuff it was quickly thrown together to ride the class-d wave. Your review seems to point this out. It seems odd that a full bridge amp would radiate so much RF. It must be coming out of the case, as the speaker cables shouldn't be radiating much RF (See Bruno's article).
With all that RFI running around, the input wiring should be shielded, but appears not to be. If the RF was getting back into your tube pre, think what was happening inside the NuForce!
Thanks for the revealing review, but I do have to say that the tone of the article sounds a bit like you were "out to get" the NuForce. I don't think you were, but it does sound a bit that way. You might expect some backlash from that.
(And one little gripe - all those pop-up and pop-under ads on your site are awful! They even get thru pop blockers. I like the content on your site - very nice - but all those flashing and popping ads make the site difficult to visit).
Hi Panomaniac,
Alright, I think that's the dissapointment you're reading between the lines, I really expected the Reference 8 to do (a lot) better than this, but maybe I should've worded it more carefully. It is more or less a report of how I went about evaluating these amplifiers and how they fared, so every time I came upon another dissapointment (noise at turnon, lack of good stereo image, etc.) that also got reflected in the article.
Best regards,
Sander Sassen
http://www.hardwareanalysis.com
Alright, I think that's the dissapointment you're reading between the lines, I really expected the Reference 8 to do (a lot) better than this, but maybe I should've worded it more carefully. It is more or less a report of how I went about evaluating these amplifiers and how they fared, so every time I came upon another dissapointment (noise at turnon, lack of good stereo image, etc.) that also got reflected in the article.
Best regards,
Sander Sassen
http://www.hardwareanalysis.com
I believe the RF would be on the outside of the Nuforce (i.e., the speaker wire would be the thing radiating RF energy). I believe there have been many improvements to the Nuforce amps, some of which address the RF issue. I would be more than happy to apply my 100Mhz scope to the output of my Ref. 9. I also have FFT capability. Let me know.
Woops, I guess I'd be able to just reach the lower end of the FM band. Anyway, items under 100 Mhz I could see, but above 100 Mhz, I couldn't see them using my scope/FFT.
Is it ethical to carry ad for a brand of class-D amplifier modules and trash another manufacturer? This is unprofessional and may cause the one who receives the short end to counterattack by one or other means.
Then to believe and state that the feedback is taken only from a single speaker terminal for a H-bridge is not a good way of manifesting one's ignorance about the subject. Hence the credibility of the report is suspicious. But it's good to see the 100kHz frequency response, which directly contradicts the claim of poor soundstage.
Soundstage is in general proportional to the bandwidth of the amplifier, in my experience.
I own Tripath, IcePower, UcD180, SKA, etc..., and have measured them, but for my curiosity only. Typically production units don't measure as good as advertized.
Then to believe and state that the feedback is taken only from a single speaker terminal for a H-bridge is not a good way of manifesting one's ignorance about the subject. Hence the credibility of the report is suspicious. But it's good to see the 100kHz frequency response, which directly contradicts the claim of poor soundstage.
Soundstage is in general proportional to the bandwidth of the amplifier, in my experience.
I own Tripath, IcePower, UcD180, SKA, etc..., and have measured them, but for my curiosity only. Typically production units don't measure as good as advertized.
A real question
Manifesting one's ignorance? Just who's ignorance are you referring to? The H bridge statement was absolutely correct and your response is not!
As far as sound staging goes it has very little to do with bandwidth. It has far more to do with things like noise floor, channel separation and power supply integrity.
Roger
Manifesting one's ignorance? Just who's ignorance are you referring to? The H bridge statement was absolutely correct and your response is not!
As far as sound staging goes it has very little to do with bandwidth. It has far more to do with things like noise floor, channel separation and power supply integrity.
Roger
Anyone can prove me wrong by building an h-bridge amp with feedback from from only one speaker terminal yet getting same low thd as Sassen measured. Until then, I stick to my statement.
Talk is cheap. Show me!
i
Talk is cheap. Show me!
i
The H-bridge comment was correct but I think what Koolkid from Nufroce 😉 is saying is that there actually is differential feedback employed. Which is cool.
Oh, while it may not be a correct review, (seemingly biased) it is nice to see one that attempts to discuss the technical aspects of it which otherwise have gone ignored.
Cheers,
Chris
Oh, while it may not be a correct review, (seemingly biased) it is nice to see one that attempts to discuss the technical aspects of it which otherwise have gone ignored.
Cheers,
Chris
Koolkid,
We have no affiliation with Hypex whatsoever, nor do they run advertisements on our website. We've recently looked at their line of DIY products and constructed a class-D amplifier using their UcD modules and documented the process in an article. What you probably are mistaken for an advertisement is a 'featured article' spotlight of which we always have three on the frontpage, clicking those will forward you to the article in question.
Any more concerns?
Best regards,
Sander Sassen
http://www.hardwareanalysis.com
We have no affiliation with Hypex whatsoever, nor do they run advertisements on our website. We've recently looked at their line of DIY products and constructed a class-D amplifier using their UcD modules and documented the process in an article. What you probably are mistaken for an advertisement is a 'featured article' spotlight of which we always have three on the frontpage, clicking those will forward you to the article in question.
Any more concerns?
Best regards,
Sander Sassen
http://www.hardwareanalysis.com
Koolkid,
It is more complex than that, so allow me to elaborate. For the sake of simplicity that's how I phrased it, but actually both outputs of the H-bridge are summed and then fed into single-ended loop. Or rather there's a PID scheme used, of which only the PI terms are fed differentially but are summed to a single-ended loop, so the D term is single ended. This of course does nothing to cancel out even harmonics as they propagate through the amplifier, hence the high even order distortion that could be cancelled out in a properly implemented H-bridge amplifier.
Best regards,
Sander Sassen
http://www.hardwareanalysis.com
It is more complex than that, so allow me to elaborate. For the sake of simplicity that's how I phrased it, but actually both outputs of the H-bridge are summed and then fed into single-ended loop. Or rather there's a PID scheme used, of which only the PI terms are fed differentially but are summed to a single-ended loop, so the D term is single ended. This of course does nothing to cancel out even harmonics as they propagate through the amplifier, hence the high even order distortion that could be cancelled out in a properly implemented H-bridge amplifier.
Best regards,
Sander Sassen
http://www.hardwareanalysis.com
Very interesting to hear a digital hardware analyst analysing an analog system, Sassen.
I ran thousands of simulations on many different and possible schemes of self-oscillating class-D amps and always got lower even harmonics than odds. Oh maybe my models are incorrect.
I ran thousands of simulations on many different and possible schemes of self-oscillating class-D amps and always got lower even harmonics than odds. Oh maybe my models are incorrect.
Koolkid,
You might want to mention that you are actually NuForce's Chief Technology Officer, that puts your posts in a whole different light.
Best regards,
Sander Sassen
http://www.hardwareanalysis.com
You might want to mention that you are actually NuForce's Chief Technology Officer, that puts your posts in a whole different light.
Best regards,
Sander Sassen
http://www.hardwareanalysis.com
That affiliation has been too obvious for awhile, but yeah, keeping up pretenses at this point just looks silly. Time to put away the incognito "Nufoce is better" stuff and get to the meat and potatoes or it'd be real hard to take Nuforce even half seriously, trusting you can hold your own.
Oh..... that's why this forum is the best ! 😀
Oh..... that's why this forum is the best ! 😀
- Status
- Not open for further replies.