NuForce Reference 8 evaluated

[SSassen]

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

[Bgt]

Very good review.

[sx881663]

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

[ctviggen]

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.

[Pano]

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).

[SSassen]

Hi Panomaniac,

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.

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

[ctviggen]

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.

[ctviggen]

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.

[koolkid731]

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.

[sx881663]

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