"With the Model 9600, Mr. Yamada shows that he can design and manufacture an amplifier that's just as remarkable as his digital gear."

January 2009

Zanden Audio Model 9600 Mono Amplifiers

by Marc Mickelson

Inch for inch, pound for pound, there is no more enduring symbol of high-end audio than the vacuum tube. Most of the groundwork for this device was laid in the nineteenth century, with the first amplifying vacuum tube appearing in 1906. More than a century later, with the invention of the transistor to replace it in between, the vacuum tube still goes strong, almost completely because of its use in audio electronics. Owning a preamp or power amp with tubes is a rite of passage for an audiophile -- one that some of us repeat and others learn their lesson from the first time, retreating to the no-maintenance comfort of solid state.

Come on in, guys. The water's fine! Modern tube products are as reliable as their solid-state counterparts, and while I'm willing to say that the sound of the two is a matter of preference, I prefer that my music have the touch of tubes -- for the beauty, grace and humanity they impart. I believe in measurements but don't listen to test tones, so I'll take better sound with music over better measured performance any day of the week.

I'm confident that Kazutoshi Yamada would agree with me. Mr. Yamada, as I call him, is responsible for the products that bear the Zanden Audio name, all of which but two -- the Model 2000P CD transport and DSC-1 digital signal conditioner -- use tubes, and often lots of them. Mr. Yamada's amplifiers have been low-power single-ended-triode (SET) designs almost exclusively, a trend broken by the push-pull Model 9600, whose healthy power output is said to be delivered with the finesse that many SET amps achieve.

Inside the Model 9600, concise version

The most distinctive feature of the Model 9600 ($51,975 USD per pair) is one that has nothing to do with its sound. It's the pair of portholes on the front and rear of the amp that allow you to peer inside and see the tubes and transformer within. The amp delivers 60 watts of class-A power from a pair of 845 output tubes in a push-pull circuit. This is specified as "nominal power," and it's more than likely the power output at a certain reasonable amount of distortion -- say, below 5%. "Maximum power" is 90 watts, probably at something approaching 10% distortion. This is not where you want the amp to be running. It's the equivalent of revving a car into the red.

The Model 9600 is proudly a no-negative-feedback, fully balanced design, and it has only an XLR input jack. Speaker outputs are available for 2-, 4- and 8-ohm loads, and I recommend trying them all with your speakers, as you will likely find one that simply sounds better than the others. In addition to the 845 output tubes, there are pairs of 5R4WGBs and 5687s, and a single 5AR4 and 5687. The amp has a fixed bias, so in terms of maintenance you won't have to do anything more than insert the tubes. The 845s are as big as cocktail glasses, and inserting them requires a twist at the end -- just like a gin-and-tonic, come to think of it. The amps are cube-shaped -- 17 3/8"H x 12 1/2"W x 17 3/4"D -- and weigh 94 pounds each. The ample light the 845s cast through the portholes and pierced covers makes the Model 9600s look especially dramatic with the lights off.

Use

I used the Model 9600s in my system two different times over the course of the last year. The amps were used with a Zanden Model 3000 preamp and the still-gorgeous-sounding Model 2000P/Model 5000S transport/DAC combo. Even the interconnects, speaker cables and power cords were from Zanden, comprising a full system, except for the phono stage (which Mr. Yamada also makes), turntable and speakers. To answer the question that may be on your mind: Yes, there was a sonic fellowship among all of the Zanden products -- a way that musical detail was revealed: with consummate ease and naturalness. I will write about this later in the year, when I cover the Model 3000 preamp, but suffice it to say that there is a sonic signature that all of the Zanden products have and that doesn't end up going overboard when you are completely Zandened.

Speakers early on were Wilson Audio MAXX 2s, with a pair of MAXX 3s in use as 2008 turned to 2009. Other preamps used with the Zanden amps were an Aurum Acoustics CDP preamp/CD player with internal phono stage and an Audio Research Reference Three. Other amps used in place of the Model 9600s were Lamm ML3 Signature and M1.2 Reference monoblocks, and an Audio Research Reference 110 stereo amp. In addition to the Zanden digital separates and Aurum CDP, I used an Ayre C-5xe for digital playback. LP playback came via a TW-Acustic Raven AC turntable with Graham Phantom B-44 and Tri-Planar Mk VII UII tonearms, on which were mounted Dynavector XV-1S stereo and mono cartridges. Phono stages were an Audio Research PH7, a Lamm LP2 Deluxe and the Aurum CDP's highly flexible internal unit. Phono cables were an AudioQuest LeoPard and the one that is integral to the Tri-Planar tonearm.

In addition to the Zanden cables, I used AudioQuest William E. Low Signature interconnects and speaker cables along with Shunyata Research's new Aurora-IC interconnects and Aurora-SP speaker cables. A Shunyata Research Hydra V-Ray and a number of Shunyata Anaconda and Python power cords -- both Alpha and Vx versions -- handled power duties, trading time with an Essential Sound Products Essence Reference power distributor and a number of Essence Reference power cords. Again, I also used Zanden's own power cords with the company's electronics.

Preamps, phono stages, the turntable and Ayre C-5xe all rested on a Silent Running Audio Craz 4 Reference equipment rack. The Lamm amps had dedicated pairs of Silent Running Audio products underneath -- Virginia-Class platforms for the Lamm ML3s and Ohio Class XL Plus² platforms for the M1.2s.

The Model 9600s, and perhaps other Zanden amps that use the same layout, are the only tube amps I know of that you can set on carpet without worrying if doing so will restrict airflow to the tubes and create a fire hazard. The amps use ambient cooling through the chassis top and sides to keep the tubes from overheating, so there are no fans to deal with.

What you will have to deal with at some point is moving the amps. They are a bulky mass to pick up and carry around -- too tall to stand over and grab underneath easily, too big around to carry like a sack of grain. Some well-placed furniture sliders under the feet will solve this problem.

Sound

My mental database of tube amplifiers I've heard grows with each year. I've heard dozens of tube amps in my system, some that were noteworthy in one way or another, and others that were extraordinary in just about every way. Yet I can't think of an amp I've heard that sounds quite like the Zanden Model 9600. It certainly has a sound of its own, one that is defined by its finely drawn treble and rich midrange, and especially the way it portrays space. It also has enough power to drive most speakers to very high levels and confidently portray large-scale dynamics. It is for connoisseurs, those listeners who are open to being seduced, not married to the notion that having a sonic personality is detrimental for a power amplifier.

I've been beating the drum of mono LP playback over the last few months, and much of this has occurred because I've been listening to the Model 9600s. It's not just that these amps sound spacious -- which they do -- but the way in which harmonics are reproduced within that space: with a delicate complexity that imparts musical information in a relaxed yet easily apparent way. This has brought great mono recordings like Dizzy Reece's Soundin' Off (Blue Note/Classic Records 4033) to life. Here the sonic story isn't Reece's trumpet but Walter Bishop, Jr.'s piano, which isn't relegated to background fill, as happens with many Rudy Van Gelder recordings from the 1950s. Instead, the piano is in the foreground, and the Zanden amps convey its complexity of tones and overtones with consummate realism amidst vast acoustic space.

The ultimate effect of this is to spread the mono image -- it's anything but a pinpoint between the speakers. And with spacious stereo recordings, the Zanden amps will have you thinking your listening room has grown in size. The Avishai Cohen Trio's Gently Disturbed (RazDaz Recordz SSC4607) is a recording of a seriously talented contemporary piano trio, and it sounds big, not just in terms of soundstage width but also height. The Wilson Alexandria X-2s are champs at conveying height information on recordings, but the new MAXX Series 3s are not far behind. With these speakers, the Model 9600s were able to convey a piano whose overtones seemed to climb up to the ceiling -- of the recording space if not my listening room. As much as I love vintage jazz, discs like Gently Disturbed show how far recording techniques have come, and the Zanden amps only aid in this sort of discovery.

The Model 9600s' spaciousness is matched in quality by their meaty midrange. This isn't lushness to the point of sounding portly and dark but instead a solidity that gives singers a corporeality that doesn't go to extremes. There is copious detail too, putting this midrange squarely in the "special" category. One of the cuts from the CD-R sampler I brought to CES made this plain. You may think Hope Waits is somehow related to Tom Waits because she covers one of his songs, "Get Behind the Mule," on her eponymous debut CD (Radarproof RPR 1019), but she's not. The choice of this song for her -- she sounds a great deal like Norah Jones -- is odd, but she makes it work, delivering an intense, even sensual rendition that the Zanden amps make the most of, turning Waits' voice into the focal point, so to speak, of the cut, with its sparse instrumentation. The same thing happens with the booming sax of Tina Brooks on the 45rpm version of the classic True Blue (Blue Note/Music Matters MMBST-84041). Some of what makes analog so special is the handling of the midrange, which, again, has great harmonic complexity. The Zanden amps convey this along with a roundness that plants the performers in the room. The Music Matters True Blue is in stereo, not mono, but I won't hold this against it, so acute is the profuse immediacy of the musicians. You want presence? These amps have it, but not at the expense of delicate texture and detail.

What's especially good about all of these things is the way they integrate with the rest of the amps' performance. There is no discontinuity, no sense that the Model 9600s are about only space or midrange presence. As the music starts to plumb the depths, nothing stands out. There's no plumpness to spoil all that treble delicacy, no anemia to counteract the fullness of the midrange, no midbass bloat to ruin everything. The bass region is rather nondescript -- simply there without drama. Bass is tighter than you'll hear from most tube amps and able to convey the unique low-frequency ambience that recordings like Keith Richards' raucous Main Offender (Virgin 86499 2) have. The kick drum here sounds more like the real thing than you'll hear on just about any recording, coming across in short, sharp throbs. This is no problem for the Zanden amps, and for every upper-echelon tube amp I've heard. That's good news -- no bass Achilles heel.

And no Achilles heel, period. Interestingly, the Wilson MAXX 3s are said to be easier to drive in the midrange than the MAXX 2s due to a new midrange driver with double the impedance. Indeed, the Zanden amps took a big step forward in terms of resolving midrange detail with the new MAXXes, elevating the performance of the amp from very good to outstanding -- and unique. The Model 9600s and MAXX 3s prove once again that the amplifier-speaker interface is the most crucial and tricky in an audio system (closely followed by that of the tonearm, phono cartridge and phono stage). I have heard the Zanden amps sound great with Cessaro horn-loaded speakers, but the penultimate Wilson speakers may be even better with them -- able to bring to fruition more of the amps' intrinsic capabilities and not cause me to miss the amps that came before them.

Speaking of which

While Vladimir Lamm decides where the ML3 Signature amps that I reviewed will go next, I've been their happy caretaker. As you probably already know, these two-piece single-ended amps are wildly expensive -- $139,290 per pair, putting them in the price range of CEOs, and a minority of them these days. Still, it's impossible not to admire the sound of these amps. In addition to a top-shelf midrange that's both highly animated and highly refined, these amps can do bass in a way that astute listeners will recognize as keenly rendered -- deep and powerful but not overwhelming -- and well integrated into the full musical spectrum of the amps.

Both the ML3 Signatures and Model 9600s use big, impressive output tubes -- the GM70 for the Lamm amps versus the 845 for the Zanden -- and have more than single-digit power outputs: 32 watts for the Lamm amps versus almost twice that for the Zanden. However, in terms of the amps' sound, there are broad similarities and acute differences. Both amps, for instance, have an attention-grabbing midrange, but it's anything but identical. The Zanden amps sound bigger and more rounded through the mids than the Lamms, which answer with sheer resolution that imparts an energetic character but still renders voices, for instance, with obvious naturalness -- meaning no undue emphasis. Both amps portray space very well, with the Zanden amps doing it in a more obvious fashion, putting slightly greater air between instruments and performers. The Lamm amps have state-of-the-tube-art bass, especially compared to the more self-effacing low end of the Zanden amps. The treble range is noteworthy with both amps, but there is greater solidity with the Lamm amps, more delicate, filigreed highs with the Zanden.

Qualitatively, these are two distinguished mono amplifiers, though their vast difference in price doesn't reflect a vast difference in the worth of their sound. I'm not sure, therefore, that a Lamm ML3 Signature buyer will be deterred by the Zanden Model 9600, or vice versa. At this level, desire for the sound of one amp is more potent than the idea of saving some money. Still, in an all-Zanden system, which would cost less than the Lamm amps alone, it's hard to argue that any amp would be better than the Model 9600.

Further thoughts

Over the course of the last few years, I've heard various iterations of Kazutoshi Yamada's digital equipment, and I've gone on record to say that it's the best I've heard. With the Model 9600, Mr. Yamada shows that he can design and manufacture an amplifier that's just as remarkable as his digital gear. The Model 9600 monoblocks are not without a personality, having quirks that are both musically valid and enthralling. The space that these amps can conjure mixes with their luxurious treble and midrange density to create a musical picture that conveys copious detail and encourages listening sessions that end with CDs and LPs strewn around the room. Even so, their sum is not overshadowed by their considerable parts; nothing stands out to make you think that the Model 9600s trade their musical soul for the ability to be world class in one way or another.

While vacuum tubes will always have their issues, audiophiles will continue to admire them, and an amplifier like the Model 9600 only increases the pull. If your audiophile rite of passage begins with the Model 9600, I predict it will end there as well.

...Marc Mickelson
marc@soundstage.com