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Equipment Review

November 2002

Opera Audio Consonance Reference 9.9A Mono Amplifiers

by John Potis

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Review Summary
Sound "You will be surprised by the treble performance…neither sweet nor edgy, polite nor intolerant"; "the most open and transparent midrange that [John has] heard in quite some time -- maybe ever," but "forget about tube warmth or any added bloom"; "didn’t push the envelope of power, but the lows were very focused and well behaved."
Features "Uses a Shuguang 845 direct-heated triode output tube in a single-ended class-A circuit…to produce 28 watts of rated power with no global negative feedback"; 4- and 8-ohm speaker connections.
Use "Those who   may not be served by this amplifier are those with inefficient and non-SET-friendly speakers and those who suffer an intrinsically lean-sounding room/speaker combination"; required some break-in, but not hundreds of hours worth.
Value "The most open, most uncolored, and most transparent midrange I've heard and enough power to play music at the levels I enjoy."

At the point I discovered I would have power amplifiers from Opera coming my way for review, I had never heard of the company. But soon thereafter, SoundStage! published Marc Mickelson’s very positive review of Opera’s inexpensive Consonance M800 monoblocks, and my interest was piqued. I then looked at the company’s broad range of offerings and lapsed into confusion. This eight-year-old company located in Bejjing, China has an extensive product line, sometimes with subtle differentiations between models. Everything Opera builds seems to get the name Consonance, and the review samples came with the Reference 9.9 designation on them as well. But there is an entire series of Reference 9.9 amplifiers utilizing various output tubes for different levels of power and sonic signatures. This series includes the 845-based 9.9A, the 211-based 9.9B, the 300B-based 9.9C, and the 2A3 based 9.9D. Prices vary, with the 9.9A amps coming in at $5500 USD per pair.

Getting to it

According to Opera, each 9.9A amplifier uses a Shuguang 845 direct-heated triode output tube in a single-ended class-A circuit. The input signal goes through NOS Siemens 60S/E88CC and a US-made NOS 5687 (driver-stage) tubes to produce 28 watts of rated power with no global negative feedback. Kimber high-purity wire is reportedly utilized in the point-to-point-wired circuit, and resistors are Chinese military-grade metal-film types. Signal coupling capacitors are Rel-Cap/PPMFs.

Above the power switch is the Magic Eye 6E2-tube power indicator. This vacuum tube shows two vertically oriented luminescent bars that extend from the top and bottom toward each other as power output increases. When the power output of the 9.9A is at maximum, the two green segments meet in the center to form a solid line. I’m told that the 6E2 tube, with its claimed 10,000-hour life, is Russian military surplus and still in production. Opera says it has loads of the tubes in inventory should you need a replacement.

Around back is more evidence of solid build: a gold-plated and solid RCA jack for input, two pairs of Charming Music Conductor gold-plated binding posts -- separate pairs for both 8- and 4-ohm outputs -- and an IEC power receptacle to allow experimentation with power cords. Though placed in the rear of the amp where one would suppose it would be protected, the large 845 is nevertheless surrounded by eight vertical chrome-plated rods and two horizontally oriented "donut" spacers that look great, structurally bolster the cage for added protection, and can be oriented to reflect back toward the amplifier some of the 845’s emitted light in case one judges the glare a distraction (are they serious?). Each amplifier weighs in at 66 pounds and stands 10 1/2" tall (at the tube in the rear), 15" deep, and 18 1/2" wide.

The Reference 9.9A is a beautiful amplifier. The richly grained and superbly finished -- to the eye and the touch -- cherry tops are quite the complement to the half-inch-thick brushed-aluminum faceplate. In the lower center is the large push-button power switch that slides in and out with a uniquely smooth and tactile sensation. Somebody at Opera wanted the Reference 9.9A’s owner to be reminded of its build quality every time the amp is switched on.

System

The Opera amps were mated with Silverline Sonata II, Zu Cable Druid, and Merlin VSM-Millennium loudspeakers. Preamplification duties were handled by the Herron Audio VTSP-1A. CDs were by way of the Pioneer DV-525 DVD player used as a transport to feed a Bel Canto DAC1.1, while SACD sound was via a Sony SCD-CE775 player. Interconnects and speaker cables were JPS Labs Ultra Conductor, and the digital cable was the DH Labs D-75. Power cords used were the Virtual Dynamics Power 3 on the power amps and the Power 2 on the preamp. All non-digital equipment were plugged into an Audio Magic Stealth purifier, and Vibrapods were used extensively.

Sound

The Reference 9.9As required some break-in. With the amps out of the box and warmed up, I can’t say that I was as impressed with their sound as much as their construction. But within a maximum of ten hours of use, they came into their own. The 845 tube has the reputation of being a very midrangey tube, and at first that’s pretty much all I heard. But before long, both ends of the spectrum filled in nicely.

Listening to the Reference 9.9C

Along with the 9.9A, Opera also sent along a pair of their 9.9C amplifiers, which sell for $5900. The decision was made to measure and review the 9.9A, but the 9.9C was more than deserving of passing mention. In many ways the 9.9C is similar to the 9.9A -- from the front the two look identical. On the rear are three binding posts instead of four-- a negative and two positives -- one each for 4- and 8-ohm speakers. The biggest difference (structurally) between the two amps is the tube complement. The 9.9C uses a single Chinese 300B tube in each amp for a claimed 10-watt output.

Of course, two different tubes make for two very different-sounding amplifiers. If the 9.9A using the 845 output tube is vanilla, then the 9.9C with its richer-sounding 300B would have to be French vanilla. The two amplifiers share much in common sonically, like the pure and grain-free treble and the uncommonly transparent and unfailingly musical midrange. What separates the two amplifiers is the 9.9C’s warmer overall character, its deeper bass, and its even higher degree of focus.

The 9.9C’s bass is a completely different animal as compared to that of the 9.9A. Where the latter is clean and tight, if a little truncated in extension, the 9.9C's bass goes deeper with more subjective power. While the bass is more powerful, it is also a bit more ripe. It gives up some of its sibling’s precision in exchange for a bit more embellishment. On some pop music, such as James Taylor’s Hourglass, the bass could be a little overdone, a little uncontrolled, and a little bit obscuring of harmonic detail. On well-recorded classical discs, such as Sony’s Rostropvich Return to Russia [Sony SK 45836], the added adornment sounded magnificent.

I could imagine that the 9.9A’s complete honesty through the upper bass and lower midrange could leave some intrinsically stark speakers sounding lean and threadbare. If this is the case, the 9.9C offers a gentle warming that even with my speakers was not what anybody could term disagreeable. OK, it was rich and endearing, and it never seemed to get in the way of musical integrity.

The other difference between the two amplifiers was a subtle one but one hard to turn away from once I heard it. One day a friend of mine brought over a CD of Japanese drum music. With its more prolonged periods of deep silence between notes I noticed that the 300B variant was a little quieter than its 845-based sibling. I’m not talking about hum or any other artifact, but a very subtle electronic mist that overlaid the 845 amp’s presentation. This happened very early in the review period, and I was never again made aware of its presence. But I suppose it is due to its absence that the 9.9C had a higher degree of focus than the 9.9A. While the 9.9A did an excellent job with soundstaging, the 9.9C did a spectacular job -- the best I’ve ever experienced. Voices were highly focused and seemed to emanate from a very highly defined point in space. Instrumental outlines were incredibly delineated.

The 9.9C is a wonderful amplifier that varies from its very capable 845-based cousin in some sonically meaningful ways. But with roughly one-third the power, it does have its down side. On one hand it would seem that I’ve failed to discover the proverbial free lunch, but on the other, what I have discovered is some exceedingly delicious fare at a very fair price -- no matter which Opera amp you choose.

...John Potis
johnp@soundstage.com

If you believe everything you read about the 845 tube, you will be surprised by the treble performance of the 9.9A. It was neither sweet nor edgy, polite nor intolerant. It was just there and reflected exactly the music playing, honestly and accurately. I didn't realize just how honest, extended and revealing the 9.9A's treble was until I listened to Harry Belafonte’s Belafonte At Carnegie Hall [RCA LSOCD 6006] . First, the recording is overlaid with a slight haze of whitish noise -- probably the result of a slightly noisy microphone preamp used on the original recording -- that I had never noticed before. Second, several times throughout the disc when Belafonte really belts it out, he overloads the same microphone preamp, and the resulting distortion is, shall we say, less than pleasantly reproduced by the Opera amplifiers. I won’t blame the Operas for that, though. Not only did the amps do a grand job of illuminating the rear corners of the stage, they also did an exemplary job of highlighting the front corners too. Acoustic guitars from "Sylvie," "John Henry," and "Mama Look A Boo Boo" were all placed front stage left -- with varying degrees of prominence. Completing the aural reconstruction of the stage on "Mamma Look A Boo Boo" was the brass section as well as backing vocals at front stage right. That brass section, by the way, sounded wonderfully authentic for its just-right balance of agreeable brassiness that managed to sound properly aggressive while avoiding any undo edginess. Of course, Belafonte was served up with excellent clarity, exhibiting absolutely no recognizable coloration.

When it came time to put pen to paper, I played James Taylor’s Hourglass [Columbia CK67912]. The first thing that greeted me was the most open and transparent midrange that I’ve heard in quite some time -- maybe ever. Taylor’s voice was clean, clear, completely distinct and independent from the instruments. A lot of amplifiers have a tendency to allow some smearing of his voice with a layer of grunge, which makes it sound both murky and dark. Not so with the Opera. Taylor's voice was clean and unfettered. Bass on "Line 'Em Up" sounded nicely rounded with the appropriate amount of bloom, though it seemed to lack a little of the powerful extension of select other amps. Acoustic guitar had an authentic flow and a 3-D presence that could only be improved upon if I played the instrument myself.

The opening of "Gaia," also from Hourglass, had me focusing attention on the vocals and to a lesser extent than usual on Taylor’s acoustic guitar. The guitar was reproduced with aplomb, but the authenticity of Taylor’s voice was disarming. The traveling bass drum was reproduced with more authority than I would have thought a 28-watt tube amp capable. The Opera amps presented the soundstage of "Ananas" with a leading edge somewhat behind the speakers, which is also a little further back than I’m used to hearing it, and I found this interesting. Relaxed soundstaging is often associated with amplifiers with a laid-back tonal balance, which the Reference 9.9A does not have. While not bright, it is lively and vivid. A bouncy electric bass propels this song’s energetic rhythm, which is prominent in the recording and very powerful. Once again, the Opera amps didn’t push the envelope of power, but the lows were very focused and well behaved. Ditto the bass drums.

If I may borrow from Marc Mickelson’s review of the Opera M800 Mono Amplifiers where he attributed to them, "Not the kind of seductive, illuminated-from-within SETness.…" Well, the Reference 9.9As do have that, and they have it in spades. For me, the phrase brings to mind the soft luminescence from within an internally lit orb -- uniform, soothing to the senses yet revealing of its contents -- as opposed to the same globe illuminated by an external source, resulting in enough harsh glare over portions that will either partially or completely obscure inspection of its contents. The 9.9A’s soft glow reveals the intricate details of the music in a musically natural way. I observed the intricacies and inner workings of the music with neither undue prominence nor barrier. As compared to the way other amplifiers do it, the effect is similar to what you can imagine if you were sitting in your favorite concert hall and the ceiling and roof were suddenly removed to allow in the fresh air and sunshine while simultaneously removing a very major source of coloration-inducing reflections and standing waves.

This is not to say that the 9.9A is the most detailed of amplifiers. It is not. While it is very good overall, hyper detail is not the 9.9A’s thing, and these amps will not get you close enough to smell the rosin on the violinist’s bow. The musically involving 9.9A is a big-picture amplifier, and while minute details escape the 9.9A’s scrutiny, no musically important ones do. Depending on your priorities, this may be one of the amplifier’s biggest strengths or its biggest weakness -- or you may notice the missing minutia but not care. I didn’t care. The Opera 9.9A has the ability to offer up enough musically significant detail to get you to the live performance without exaggerated resolution to constantly remind you that you are listening to an artificial re-creation.

But it is also important to note one more thing about the 9.9A, which worked in my favor but may not in some systems. Where it comes to the harmonic body of instrumental tones, particularly those having fundamentals lying between the midbass and lower midrange, the Opera amps will do nothing to flesh them out if your system is on the thin side. Forget about tube warmth or any added bloom -- that’s not what these tube amplifiers are about.

I also couldn’t help but marvel at the drive of the Opera amps seemingly few 28 watts. The bass-rich downbeat on "Alive" from Pearl Jam’s TEN [Epic/Associated ZK 47857] energized the entire room and floor. But it took the same bass lines in conjunction with the bass drum, guitar and vocals on "Why Go" to finally get the 9.9As power indicator to start dancing -- though all indications were that I wasn’t in danger of running out of juice. At this point I started to wonder if it was possible to clip the Opera amps into my Silverline speakers. But it was idle curiosity -- I had no intention of subjecting my ears to those volume levels. Suffice it to say that the Sonata IIs seemed to have all the power that they needed.

Bass aside, even Pearl Jam’s early recording benefited from the Opera’s utter clarity and finesse, as Eddie Vedder’s voice was spot-on center and surrounded by a reverb-induced halo. "Black" and the ever-present ride-cymbal on "Garden" were reproduced with shimmer and reach-out-and- touch-it realism. And the same can be said about them on the opening of "Jeremy" -- such crystalline shimmer! And though reduced in the mix, I noticed something I never have before: a flanger used on Stone Gossard’s backing-guitar riffs. Excellent! While you may not think of relatively low-powered tubes for the reproduction of hard-driving rock, the Opera 9.9As were certainly up to the challenge.

Comparisons

The outstanding midrange transparency of the Reference 9.9A compares to the best I’ve ever experienced in my home: that of the Audiopax Model 3, a 7.5-watt SET integrated amp that I reviewed a while back. That the Opera amp offers almost four times the power with the same finesse makes it special. Bass power is probably on par with that of the Conrad-Johnson MV60, which I've also reviewed and isn’t the best in its class, but it’s pretty good. Upper-midrange and treble performance is similar to what I recall from the big Blue Circle BC-8s-- think lively and almost bright but with no harsh or irritable down side. It suffers no artificial sweetening but neither is it ruthlessly revealing enough to chew up lesser recordings and spit them out.

Are they for you?

Those who may not be served by this amplifier are those with inefficient and non-SET-friendly speakers and those who suffer an intrinsically lean-sounding room/speaker combination, as the 9.9A will add no warmth or bloom of its own and won't romanticize in any way. Lean-sounding speakers, such as Zu Cable’s Druid, will require a warmer and more full-bodied amplifier, while the robust Silverlines complemented the 9.9As in every way.

The Reference 9.9A brought to my system a sense of refinement not unlike the fine-tuning of a camera lens. It didn’t change the basic character of the system I’ve assembled; it just made it better by refining it in some areas, cleaning it up in others and bringing it all into a higher level of focus. I wouldn’t refuse just a little more low-end grunt, but I don’t miss it. It’s an easy trade-off for the most open, most uncolored, and most transparent midrange I’ve heard and enough power to play music at the levels I enjoy.

...John Potis
johnp@soundstage.com

Opera Audio Consonance Reference 9.9A Mono Amplifiers
Price:
$5500 USD per pair.
Warranty: One year parts and labor.

Opera Audio Co., Ltd.
C-1501, Building No.9 Kingdom Garden, Xiaoxitian
Haidian District, Beijing, China
Phone: 86 10 62220935
Fax: 86 10 62220935

E-mail: klep@public.bta.net.cn
Website: www.operaudio.com

US distributor:
Quest for Sound
2133 Bristol Pike
Bensalem, PA 19020
Phone: (215) 637-3263

E-mail: questforsound@aol.com
Website: www.audiogon.com/cgi-bin/sh.pl?0&1&adlr&Questforsound&1&


Opera Audio responds:

Thank you for a very thorough and objective review.

Being a relatively new company with about ten years of history, we rapidly reached the status of being one of the best high-end manufacturers in China. Go to our website and you will notice a full array of products -- from amps to speakers. In addition, we are continuously expanding our product line. At the upcoming CES show, we will debut several new products, including the very first tubed SACD player using 6H30 super tubes. Stay tuned.

As with all equipment, we urge readers to make an audition of our reference amps before making a final decision. John Potis makes two important points. You need to give the amps time to break in. The total break-in time is about 150 hours as Opera will run all Reference products for about a week in factory, for quality control purposes, before shipping. Also, system-matching and synergy are mandatory for low-powered SET amps. Both the 9.9A and 9.9C will run great with 89dB/W/m speakers such as the Verity Fidelio as long as the speaker has a SET-friendly impedance and phase angle. SET lovers today fortunately have many more choices than just horns. Excellent speakers such as Von Schweikert DB-99/100 and Silverline Sonata II are great matches for even 300B or 2A3 amps.

In addition, we'd like to add that power cords matter! Virtual Dynamics cords were chosen because of their exceptional price/performance ratio, especially the Power 3. Currently, Opera is making specially designed inexpensive high-performance power cords for our Reference products, which will also be on display at the CES.

See you at San Remo in Las Vegas.

Liu Zhaohui and Ma Wei
Opera Audio

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