[trekker]

Very nice review of the Ref 9's  http://www.positive-feedback.com/Issue22/nuforce9.htm

[rustydoglim]

Bob Wood has an interesting review here:
http://www.greathometheater.com/studio.html
In the review, he asked: Is illusion better than reality?
We'll wait for his conclusion as he is still learning about the amp.

As many reviewers and audiophiles have realized, NuForce amp is ultra pure. And there are some people who don't like it.  I disagree with Ed's review on Postive Feedback on the part where he said the amp filtered out warmth, sweetness.  We just don't add MSG to your music. If you want to have the warmth of a tube amp, match NuForce with a tube preamp. Perhaps this is just an emotionally reaction. Music evoke emotion and sometimes if you're in the wrong mood (perhaps that's what happened to Ed initially), anything new sounded bad.

BTW, the turn on pop on Ref 9 happened to a some units on version 9.0 but there is absolutely no pop on version 9.02 (there is no 9.01) that we have been shipping since Novemember. PFO and TAS received 9.0 version.

[timothyharnett]

So, in summary, what's the difference between 9.0 and 9.02?

[NealH]

That is a very nice review.  And, it is what I would expect of a very neutral and transparent amplifier.   The descriptions and comments in the review also fit my Bel Canto evo amplifier to a "T".  

In regards to adding bloom or texture, some tube preamps can soften the sound a bit which may give the impression of adding fullness or texture but, many tube preamps today are very neutral and will not add coloration or artifacts.  So one needs to be careful in thinking they can achieve a "fuller" or "more developed" sound character merely by adding a tube preamp.  It's not always true.  

Remember a typical tube amplifier has slightly different distortion spectrum and, dynamic output impedance than typical solid state amplifiers, switching amps included.  The distortion spectra usually includes more even order content than a SS amp which can provide a bit of that perceived "textural" sound.  In addition, the higher dynamic output impedance of the tube amplifier will interact with the speaker impedance (especially the complex crossover impedance) and this generally has the effect of providing "bloom" to the midrange.  It can be a a pleasing sound character indeed.  OTL amplifiers are the extreme example here.  

Of course there are tradeoffs on this "bloomy" sound character and, it usually is in the bass area.  Woofer cones are generally the speaker elements that need the most damping and, a higher output impedance amplifier is not going to provide the damping that a low output impedance amplifier is.  So the result a "looser" bass and less well defined bass character.  

My point in this is that a tube preamp may provide some of the desired fullness but, it does not necessarily duplicate the same type sound character that a tube amplifier will provide.

[rustydoglim]

9.02 has the overheat protection circuit. Since our warranty covered any problem and over heating occurs to a small percentage of customers, we don't recommend existing customer to upgrade.  We recommend that you wait until next generation circuit (don't have any schedule and no gurarrantee that it will be sounding better than current circuit) to decide if it is worth the upgrade.

[Carlman]

In the PR review, he mentions a lot about getting the right cable... and that stock wasn't bad but he tried a bunch of other ones..
I'm guessing he didn't care for the sound until he found the right power cord... or he wouldn't have looked, right?

So, if they're so sensitive to PC's, why don't they come with a cord that sounds great from the start?  I think the supplied cords are the typical 3-prong black plastic cables that cost a few cents.  I mean, if the retail price was 2550 vs. 2400 would anyone really care?  Especially if they came with super-nice cords from the start.  Why not at least supply Volex 14/3 cables?  They're only a few bucks.

The only reason I ask this is because I had a chance to review these amps but I didn't feel like going through my (and my dealer's) bag of power cords finding the right one...  As a result, the amp didn't fair well in my comparison because I wasn't willing to go through a separate day of power-cord comparing.  

So, any chance you'll find (what you consider) the best sounding cord to mate with these amps?

-C

[zybar]

...So, if they're so sensitive to PC's, why don't they come with a cord that sounds great from the start? I think the supplied cords are the typical 3-prong black plastic cables that cost a few cents. I mean, if the retail price was 2550 vs. 2400 would anyone really care? Especially if they came with super-nice cords from the start. Why not at least supply Volex 14/3 cables? They're only a few bucks.

The only reason I ask this is because I had a chance to review these amps but I didn't feel like going through my (and my dealer's) bag of power cords finding the right one... As a result, the amp didn't fair well in my comparison because I wasn't willing to go through a separate day of power-cord comparing.

Carl,

In all fairness, couldn't the same be said for pretty much any other amp or gear?  Very few products come with anything but a cheap cord (please let's not turn this into a discussion on whether cords matter or not).

I thought about what cords might make the Ref 9's sound better when I tried them, but ultimately didn't put a lot of effort into it since I felt that my amp with a stock cord or upgraded cord was preferable.

George

[KJ]

So, if they're so sensitive to PC's, why don't they come with a cord that sounds great from the start? I think the supplied cords are the typical 3-prong black plastic cables that cost a few cents. I mean, if the retail price was 2550 vs. 2400 would anyone really care? Especially if they came with super-nice cords from the start. Why not at least supply Volex 14/3 cables? They're only a few bucks.

I've never heard an amp where the fundamental sound is completely altered with a uniquely matched PC.  IMO, the Nuforce is no exception.  George's personal review of the Airsine was very favorable, so I believe it would have been appropriate to use Airsines for an apples-to-apples comparison in his shootout.  Although that was not possible, I still believe swapping out stock PCs for "elite" models is best suited for fine tuning to the end user's preferences.  If someone's going to use their high-end PC of choice, why burn an extra $150 unnecessarily?

-KJ

[timothyharnett]

9.02 has the overheat protection circuit. Since our warranty covered any problem and over heating occurs to a small percentage of customers, we don't recommend existing customer to upgrade.  We recommend that you wait until next generation circuit (don't have any schedule and no gurarrantee that it will be sounding better than current circuit) to decide if it is worth the upgrade.

Jason,

Thanks for the response.  That sounds like a good idea.  If your next gen solves the problems that the amp has with RFI (which, as you know,  I've been whining about elsewhere on your board) and it's dislike of speaker plugs falling out (a fault it has in common with many valve amps I've owned), I'm definitely interested in it.

Next year I will be moving to high sensitivity speakers (either Living Voice or some large Tannoy) and losing the noise on turn on would settle my nerves.

Despite these issues I'm still enjoying the amps very much.

[rustydoglim]

I am surprised that Ed recommended us for an award:
http://www.positive-feedback.com/Issue22/awards_2005.htm
"The Nuforce Reference 9s represent the new benchmark by which all digital amps should be measured"  
Thanks!

[Jon L]

I am surprised that Ed recommended us for an award:
http://www.positive-feedback.com/Issue22/awards_2005.htm
"The Nuforce Reference 9s represent the new benchmark by which all digital amps should be measured"  
Thanks!

Congratulations, but why are you surprised? I thought both Bob and Ed gave Nuforce very positive reviews.  Bob gave it "9" in most categories, and his one lowest area was 7-8 in "Textural cues."  Bob's reference is EAR 509 tube amp, which IMO is very, very rich and textured (colored?) amp, so I was actually surprised that he gave NuForce such a great review.

Also, rest assured b/c NuForce is definitely catching on.  At the recent Vacuum Tube Valley show, I counted more NuForce amps than traditional SS amps, for example.  

Keep improving and innovating at reasonable prices, and they will come!

[lbo]

In the PR review, he mentions a lot about getting the right cable......

in my book, that cuts into his credibility right away.

[trekker]

It appears that the newest version 9.02 was just reviewed and compared to the 9.0 ver. http://www.positive-feedback.com/Issue23/nuforce_9.02.htm

Robert H. Levi reviewed both versions and now, " ... the NuForce 9.02 monoblocks are now the most deliciously musical solid-state amplifiers I've heard."

[audiophile39]

Thanks for posting.  Very impressive review.

[Jon L]

I wonder when (what serial Number) the 9.02 revision happened?  Is Ref8 going to receive the same mods?

[timothyharnett]

I wonder when (what serial Number) the 9.02 revision happened?  Is Ref8 going to receive the same mods?

So the 9.02 still has the RFI problem;

"I had one quibble with the 9.02s—they leak RF from all over their cases. No wiring hookup could fix this. No matter where I placed my indoor antenna, even up to fifty feet from the NuForce amps, my tuner was affected. FM will sound distorted unless you use an outdoor antenna. NuForce needs to fix this!"

[NealH]

I would be interested in knowing if the amp carries the "CE" mark and, meets the 55011 (CISPR11) emissions standard.   My  guess is that it doesn't.   There is no excuse in excessive radiation now days as there are many ways to mitigate it in the design.

[timothyharnett]

I would be interested in knowing if the amp carries the "CE" mark and, meets the 55011 (CISPR11) emissions standard.   My  guess is that it doesn't.   There is no excuse in excessive radiation now days as there are many ways to mitigate it in the design.

Can it be sold in Europe without the CE mark?

[NealH]

Can it be sold in Europe without the CE mark?

Not if the spirit of the CE standards/requirements are followed.   In the past it has been possible to bypass the EMC directive and, only mark CE compliance for the low voltage directive.  However, I assume most of this has been cleared up nowdays with addendums to the IEC and EN standards that better specify equipment subject to these requirements.  Equipment like an audio amplifier with a radiating device inside operating above something like 10Khz is required to meet the EMC directive.   This compliance, whether EN 55011 or FCC part 15 is also required for sale in the US - if the spirit of the standards are followed.

[eric the red]

In the PR review, he mentions a lot about getting the right cable......

in my book, that cuts into his credibility right away.

I start losing interest in a review right about the time a reviewer says something like this:

"A word about power cords. You can tell if an aftermarket power cord is right for your amp if it solidly fills in the images of the various instruments. Creating etched images in space is not the goal. The images must have weight and color if they are to sound as close to real as possible. If you are getting ghostly images or vague, etched shapes, try different power cords. I recommend copper cords for most solid-state gear, and (possibly) silver or some other rare metal for tube gear. Listen to the instrumental images on your acoustic recordings and judge the results."

Wow-Power Cords can do all that???