NuForce Reference 9 V2 SE Amplifiers

NuForce Reference 9 V2 SE Amplifiers
A Nu Voice Speaks with Authority


February 2008



Ever since I was smitten by the sound of the NuForce Reference 8 amplifiers back in the summer of 2005, I knew in my heart that the new digital technology would soon assume the leading role in shaping the future of audio amplification. Having evaluated several versions of the Reference 8 and Reference 9 amplifiers and then having moved on to the Reference 9SE and now the Reference 9 V2 SE, I have garnered keen insight into the continuing development of NuForce amplifiers.

Our own Mike Silverton has waxed enthusiastically over the charms and musical merits of the original NuForce 9SE and 9 V2 SE amplifiers in his Random Noise 4 column. He has given his assessment of the comparison between the two. Consider this review as an adjunct to Mike’s report and a longer-term evaluation of the Reference 9 V2 SE amplifier.

My 9 V2 SE amplifiers arrived in late June of 2007 and were upgraded from the original 9SE’s, which took about a week’s time. I had removed the output-terminal filter capacitors from the original 9SE’s, which made them sound considerably sweeter and more natural than the stock amplifiers, so this comparison should be viewed in that context. (The V2 amplifier has a Zobel network on its output that should not be removed or defeated.)

The NuForce Reference 9 V2 SE amplifier is a digital sampling amplifier with analog-like sweetness that also possesses all the best attributes of the finest digital amplifiers, such as high-efficiency, high-power, small size and weight, incredible dynamic contrasts, and extremely low noise. 

The rear panel contains high-quality XLR and WBT NextGen RCA input jacks. Eichmann Speakerpods are standard, as is an IEC AC receptacle. The IEC receptacle allows one to use after-market power cords. The rocker-style Power switch is also located on the rear panel. The beveled aluminum front panel contains a single blue LED in the center indicating power on/off. The LED is just the right intensity for my taste, as opposed to other LED’s that are simply way too bright. The finish on my amplifiers is anodized Rose Copper; Black and Silver finishes are also available.

NuForce is very proud of the new V2 amplifier board, which they consider a breakthrough. The V2 board was issued a patent on May 22, 2007. NuForce has painstakingly refined this board using an ultra-short signal-delivery pathway. Additionally, the board is now mounted to the top cover for much more efficient heat transfer from the output devices. Unique to the Ref 9 V2 SE is a proprietary ESR power capacitor bank to help the amplifier deliver a very steady and stable stream of high power to the speakers. Thus, the rated power has increased from 150 watts to 190 watts rms at 8 ohms and undistorted power peaks of 325 watts and 650 watts can be achieved at 8 ohms and 4 ohms, respectively. 

The bottom line is that the new board has allowed the amplifier to become considerably more efficient and powerful while simultaneously decreasing the already very-low noise floor by another 20 decibels. Incredible! 

The Sound: Take One
When I first received the Ref 9 V2 SE amplifiers from NuForce I played some familiar recordings that I had listened to with the original Ref 9 SE. My impressions were quite favorable. Hearing some familiar tracks from the Jersey Boys (Rhino R2 73271) soundtrack CD, I was struck by the precise focus of the lead vocalists as well as the back-up singers. They seemed more precisely located within the soundstage and more “grounded” on the stage. In comparison, I recall that the original 9 SE portrayed slightly larger, but vaguer singers that at times seemed to float above the stage rather than being grounded on it. So the V2 wins points with me for providing superior image focus.

The other pleasant surprise with the V2 was that the midrange sounded a touch more sweet and natural than the original model even with its output capacitors removed. I was a little worried about that aspect and relieved to find that my concerns were invalid. Sweet sounding recordings, such as any recording from artist Jack Johnson were reproduced as naturally and harmonically pleasing as anyone could want.

NuForce claims that the V2 is 20dB quieter than its predecessor, and that’s a huge figure. I can say that both amps are very quiet but that the V2 is quiet to the extreme. This enables the listener to hear details deep in the background that get lost or obscured by other high-end amplifiers. One can hear the air around the instruments clearly and the lingering decay of piano notes while other instruments introduce themselves to the expansive soundstage. Backing vocalists are more vivid as they spring to life from their specific locations.

Perhaps the most noticeable differences between the two versions are that little bit of extra bass weight, with increased articulation, and the extra sparkle and extension in the high frequencies. If anything, the bass is even tighter and more articulate than the original 9 SE. When I was doing my evaluation of the Benz-Micro MC20E2-L phono cartridge I was amazed by how the electric bass sounded on some pop music releases and by the bombastic crescendos on “Danse Macabre” from Witches Brew (RCA LSC-2225) that climaxed with heart-stopping fury. Much of the power and dynamic bass slam I experienced from those recordings was due to my having one of the world’s leading virtuoso amplifiers as the “maestro.”

At the other end of the frequency spectrum, cymbal crashes had a bit more energy and air, and high-frequency percussive instruments were better defined with greater clarity and incisiveness. On many recordings this served to punctuate the impact of the accompanying bass lines, thus lending a more vivid feel to the compositions. On the other hand, if your system leans toward brightness audition the Ref 9V2 SE with care, as it may increase that tendency.

The Sound: Take Two
As much as I enjoyed the presentation of the Reference 9 V2 SE amplifiers in my system with all solid-state ancillary gear, I felt that something was still missing that I couldn’t quite put my finger on.

But as it happened, one day whilst perusing the for-sale ads at Audiogon, I spied an ad for a custom-built, dual-mono 6SN7 tube preamplifier with transformer-coupled outputs—and it was going cheap! So I jumped all over that bad boy like a bum on a bologna sandwich! The rest is history.

I wasn’t sure of what to expect from the unlikely union between old-school tubes and cutting-edge digital technology, but it all worked out quite nicely. In fact, the results were shocking to me because the NuForce 9 V2 SE’s mimicked the character of the tube preamp so well that the resulting presentation was like hearing the best tube-based system I had ever experienced—only better! All of a sudden, the sound became liquid and silky smooth. Vocals had body and air, and brushed cymbals were simply mesmerizing. From his Continuum CD (Columbia 82876 79019 2) John Mayer’s breathy vocals on “Gravity” swept across the room accompanied by soulful guitar notes that peeked out from the stage and caressed my hungry ears with their genuine blues flavoring. 

But perhaps the most revelatory moment came while listening to Regina Spektor’s CD, Begin to Hope (Sire 44315-2). I remember her sexy, emotive voice calling out to me as she played the piano; and the piano sounded real and vibrant in a way that I’d never heard from my system, until then. The initial key strikes were sharp and clear without any blurring or stridency and the trailing harmonics were pure, natural, and gratuitous. I thought to myself, “This is music reproduction at its finest.”

Summing Up
My view is that NuForce has achieved something very special and uncommon with its introduction of the Reference 9 V2 SE amplifier. They have taken the original highly acclaimed design and refined it to the extreme, creating a considerably better amplifier in the process. This increased performance, while easily measured and documented with test instruments was audible in subtle and not-so-subtle ways during my extended listening evaluation.

While it is easy to regard any amplifier that performs this well as a “benchmark” and a “reviewer’s tool,” what came across most vividly in my home was the beautiful music emanating from my speakers. Therefore, I prefer to think of the NuForce Reference 9 V2 SE as a “Music Machine,” pure and simple.


Nuforce, Inc.
356 South Abbott Ave
Milpitas, CA 95035

Price:$5,000.00 USA

Online Store Email: 
Primary Phone: +1-408-627-7859
Secondary Phone: 1-408-262-6777
Fax: 1-408-262-6877
Skype Id: nuforce-sales

• Configuration: Mono Input: 
RCA and true balanced XLR
• Power output (see Power FAQ)
• Power bandwidth: 100Hz to 20kHz +/- 0.8 db 10Hz -0.5 db 60kHz -3dB 
• THD+N = 0.03%, 1kHz, 10W 
• Input impedance: 45k-ohms 
• Gain: 27dB 
• S/N ratio = 100dB at 100W 
• Eichmann Cable Pod binding posts for spades and banana plugs
• Chassis is made of high-grade anodized brushed aluminum to reduce audio resonance 
• Dimensions: 8.5″W x 14″D x 1.8″H (height does not include feet) 
• Worldwide AC voltage (84VAC to 264VAC). No need for AC regulator if the AC voltage falls within the specified range. 
• Weight: 8 lbs 


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