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Positive Feedback ISSUE 32
july/august 2007



Reference 9V2 (Version 2) amplifier upgrade

as reviewed by Robert H. Levi and John Brazier








Avalon Eidolon and REL Stadium III subwoofer.

E.A.R. 324 phono preamplifier, E.A.R. 890 amplifiers (ran as monos), NuForce Reference 9 SE amplifiers, E.A.R. 912 preamplifier, and an E.A.R. 834L Tube Line Stage.

VPI Scout/JMW 9 tonearm, VPI SDS Controller, ZYX R-1000 Airy 3-XSB phono cartridge, E.A.R. Acute CD player, ModWright Sony 9100 Player with tube power supply, ModWright Sony 9100ES with Signature Truth Modifications, Mod/Bybee Filters and Revelation Cryo Silver Umbilical. Alesis Masterlink 24/96 Recorder/Playback Deck, and the Benchmark DAC 1 revised. Grado Statement Phono Cartridge. Pioneer DVL 919 LD/DVD Player, and a Marantz DV8400 DVD/SACD/CD player. Magnum Dynalab MD-108 Reference Tuner, Marantz 10B FM Tuner, Day Sequerra Reference FM1 Tuner, and Scott 350B FM Stereo Tuner, AQ 7500 FM Antenna, Stax 7t Electrostatic headphones, Grado Reference 1 headphones, and a Grado headphone amplifier.

Kubala-Sosna Emotion, Harmonic Technology CyberLight, Harmonic Technology Magic 2, Dual-Connect interconnects, Dynamic Design THB Nebula, Soundstring, Kimber Select balanced, Kimber TAK phono AG, Kimber Hero balanced and single ended interconnects, and Acoustic Zen Silver Reference II balanced interconnects. Kimber D-60 Digital Interconnects. Kimber Select 3038 Silver, Kubala-Sosna Emotion, and Harmonic Technology Magic Reference Silver speaker cables. Kimber Palladian, Tara RSC and Decade, Tice, Soundstring, and Kubala-Sosna Emotion AC power cords.

Monster Reference 350 Mark II v2 Power Conditioner, World Power Power Wing, Tice Clock, and Audio Prism Quiet Line IIs. Cable Cooker 2.5, Winds Stylus Pressure Gage, Bedini Ultra Clarifier, VPI Record Cleaning Machine 16.5. Audio Magic's Quantum Physics Noise Disrupters.


With more power, more definition, more charm, and tons more depth, the newest edition to the NuForce Reference Amplifier line surpasses even my favorite digital amp—the NuForce Ref 9SE! I haven't even heard the Ref 9V2 SE yet, but its little brother is an all around winner. With new patents and a fresh re-thinking, the latest Ref 9V2 powers the Avalon Eidolons as few, very few in fact, solid-state amps have ever done. Still weighing in at only 8 lbs. per unit, the fully balanced V2 now puts out 190-watts into 8 ohms and 300-watts into 4 ohms. It sounds dramatically more sophisticated and images like crazy and, weighting so little, are easy to move around. It is the best digital amp yet for that rightness of tone, and provides almost unmatched depth perspective in solid-state amp land. What a great achievement!

At an MSRP of $3500 per pair, the 9V2 is quite a bargain. I have not heard a digital amp equal it, and it takes at least a Pass X350.5 at $8000 to match it sonically. I used the top rated Kubala-Sosna Emotion balanced interconnects and speaker cables with Kubala-Sosna Power Cords just like I used on my 9SEs and E.A.R. 890 amps—meaning that there were no changes in my reference system except the new NuForce amps sitting side by side on a modified Target amp stand. I disconnected my REL Sub for the audition powering the Avalons all by themselves.

The amps feature single-ended and balanced inputs (via a switch), one pair of speaker binding posts, an on/off switch, and a power light in front. You never need to turn them off. Even so, they are quiet as a mouse on turn on with only a small audible click to let you know you did something. They barely get warm to the touch, but the proof is in the sound—they sound grand!

The Bass

This is the WOW sound of great solid-state amplification. The Avalons just blossom down low when correctly powered and with these amps, blossom they did. Bass fiddle, kettle drum, you name it, had superb solidity and impact. This is the very best characteristic of the 9V2 and is now more integrated into the mids than realized with that of the 9SE. It made the 11-inch woofers in the Avalons sing with glee. I am impressed! Lot's of layering and texturing here along with the power. I have no complaints.

The Mids

Excellent, improved texturing and imaging are obvious. I loved all horns and vocals. There is also very good violin and piano tone though I missed some of the warmth and fleshiness of the over $8k solid-state amps. Imaging is wonderful and very solid without being the least bit etched. The background is stone quiet and the sense of depth is absolutely, positively superb. Excellent micro- and macro-dynamics abound. The soundstaging is very big too. I heard no compression or clipping …ever. Cymbals were silvery, but not crisply so, as experienced in the past. Lots of relaxed sound here with very, very little coolness. The sound was more in the accurate camp and yet always listenable and graciously smooth. They were just a bit thinner overall than top solid state or tube amps. The 9V2's were also consistent with expensive solid state amps displaying an ultra low grain structure to the music.

The Highs

Beautifully integrated into the mids, the highs were the most elegant and delicate from this design. Airy, sophisticated, and extended, the highs sing clearly and musically. I'd put them in the "just right" category for top notch solid-state. They are more elegant and sweet than previous efforts by NuForce and as such, more accurate, too. The ceiling was higher than ever, and the hall sound was very spacious. Maybe a bit less sophisticated and textured than the very best, but very close to great solid-state sound. I detected a touch of hardness and a bit of emphasis on leading edge transients making older classic and jazz recordings sound more modern. Not a big sin mind you, but the Avalons are merciless at revealing everything. No, one is not going to get tube sound here, just very wonderful solid-state performance for sure. And again, I'm very impressed by the black backgrounds and marvelous depth perspective—very, very little graininess was evident.


Yes, just two. About 85% of the interference with FM Tuners is gone. I want 100% and will settle for nothing less. The connectors on the amps are excellent except for the speaker binding posts—I don't like plastic screw down speaker cable connectors and hesitate to use pliers. No other glitches or strange digital noises to report. Nicely done NuForce!

More about the sound

One thing I didn't mention was listening fatigue. There is none. Maybe they aren't perfectly mannered and lush like top tube amps, but the 9V2s are long term enjoyable. I listened for hours on end and enjoyed them immensely. They were even very nice sounding ice cold and brand new! At 24 hours, they opened up and sounded quite fine. At 48 hours, my oh my they sounded great. I loved the way the music bloomed in the room and made the soundstage super transparent. The music very rarely sounded like it came from my speakers as amps in this price range often do. These amps are outstanding at producing an involving musical performance for music lovers. Amplifiers like the 9V2s put the "fun" in this hobby and are a bargain for what they do.

In Conclusion

NuForce's third generation digital amps are lovely indeed. The Reference 9V2s sing accurately and musically and will compete with solid-state amps that sell for twice as much or more! Improved in every way over all previous NuForce offerings, there is obviously new and original thinking incorporated in this revision. I still haven't heard their top 9SE V2 design and can't wait! Meanwhile, if $3500 is your wallet's limit, you will love this amp. I can't name a solid-state amp that gives you soundstaging, imaging, or depth perspective better than these little guys at under $8000! Moreover, at this kind of high power. What a deal! The Reference 9V2s are the best yet from NuForce and receive my highest recommendation. Robert Levi






Vertiy Audio Parisifal Ovations.

NuForce Reference SE monoblocks and Pass Labs X1 preamplifier.

Naim CDX2 and XPSII Power Supply with Sympostium Svelte Shelves and Phat Padz.

Full compliment of Crystal Cables CrystalConnect Reference cables, power cords, interconnects and speaker wire.

Wiremold/Naim Power strip.


These amps have received a lot of press over the last couple of years, so, I really do not feel compelled to get into all the details of this "V2". One needs only to read Bob Levi's or my original reviews, or any one of the many out there to get the gist of NuForce's complete product line. Suffice it to say, the folks at NuForce have "tweaked" their platform again and I use the term "tweaked" very loosely because it is my humbled opinion that this V2 has obtained a new level of performance that is quite impressive. I think the best way to describe my experience with the V2 is by basing my opinion primarily on previous observations of the Ref SE (non V2)—then "update" those thoughts with the V2.

In my initial review if the stock Reference 9 SE, I wrote…

Listening to Gillian Welch's Revival disc, the simple sounds emanated effortlessly with an decidedly sophisticated touch and level refinement I have not recently heard in my home. It was as if he vocals has been lightly buffed with a soft cloth and polished like an old tea set before a yard sale. She was given new life. Not in an engineered way, though. I have reviewed an amp or two where the sonic signature was clearly engineered to sound "tubey" or "slamming" in a very inorganic way. Distinctly different is the ability of the Reference SEs to reproduce the event as a single presentation and not of discrete performance amalgamated onto one recording.

On the same disc via the V2, all the above can be said again, but there is now a blackness between the notes that gives Welch's performance an extra push towards your own suspension of disbelief that you are in fact listening to an reproduced event. Treble extension has been greatly improved, not that it needed to be, but with the V2 it is clearly superior—I cannot live without it. So much so, that if I did not know any better I would have not been surprised if I were told a ribbon tweeter were installed as part of the V2 upgrade! Welch's voice is not particularly "high" but the smoothness and effortlessness of her vocal range—floating up and down and along the lyric—possesses that "reach out and grab you" realism, and without any abrupt or edginess transitions.

I also wrote in my first review…

Take the latest effort by Dr. John, Mercenary, which is chock full of that full bodied Dr. John music. I found it to be very fulfilling and not once leaving me for want in most areas of the spectrum. The usual gritty vocals were there in just the right balance and credibility. All the while a generously large and well organized sound stage hung behind the good Doctor.

Of particular note, is the "life" the doctor's vocal took on with the V2. I had mentioned that some manufactures of solid-state amplifiers go out of their way to produce products that have a tube "sound". I am not aware if it was the design goal of NuForce to produce a "tube" sound with the V2, but it clearly does have this quality. However, it is not an "engineered tube sound" but a much more legitimate signature that comes off as if it is inherent in the recording—as opposed to being a byproduct of the amplification. Smooth and full is the best way to reference it. However, this smoothness is not at the expense of Dr. John's generally "gritty vocals".

The Reference 9 SE is a great amp and one that I had purchased for my reference. Any issue I may have had with that unit, or that I may have developed over the past year of continual use, have been removed from the equation with the V2. Where I enjoyed the SE, I immediately fell for audible superiority of the new V2. I think its greatest strength is to align its signature sound to that of a more linear design, thereby distancing itself from the "Class D" camp. Before this, one of the most impressive amps I have ever hear, of any design, was the Kharma MP-150—also a switching amplifier. With the V2, it betters my recollection of the Kharma's performance, and not by just a little.

If you were ever on the fence about all these lightweight, tiny and cool running amps making their way to the market, it is time to jump off and join the party. I cannot imagine a truly objective fan of audio and music finding these amps to be objectionable in any way. They may not suit all tastes, but even I can appreciate a good sounding amp of almost any design, while at the same time realizing they may not be for me.

Just like the Reference 9 SEs, the V2s represent an amazing value at an even more amazing performance level. I am overjoyed to send my SE in for the V2 upgrade, as you should be too. John Brazier

Post Script

When our editor posted Robert's and my review it came to my attention for the first time that I did not actually review the Reference 9 SE V2 as I had thought along, but I was reviewing the Reference 9 V2 instead. Reading the two reviews you can see that there was certainly no reason to think I was listening to anything other then a new and improved Reference 9 SE. I was floored. Not only that I allowed myself to make such an error, but that the Reference 9 V2 now out performed the Reference 9 SE! I cannot think of a better testament to the sound than that of my mistake. To think you can outperform the Reference 9 SE with an amplifier $1500 less is astounding. What is more exciting is that I have in a box at home the V2 of the Reference 9 SE!

I know what I am doing tonight!

My sincerest apologies for the confusion, and if it were not for the unbeknownst error and unwitting accolades the error has conferred upon the Reference 9 V2, I may have quietly pulled the review, made some changes, and slipped away with my tail between my legs. But the implications were too great for it to go unheralded. John Brazier

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