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Positive Feedback ISSUE 49
may/june 2010



720 Preamplifier

as reviewed by Marshall Nack






Kharma Exquisite-Midi.

mbl 6010D preamplifier and Soulution 710 stereo amp. ASR Basis Exclusive phono preamp.

VYGER Baltic M turntable, Shelter Harmony cartridge, mbl 1521A transport, mbl 1511F DAC.

Interconnects are Tara Labs The 0.8, Kubala-Sosna Emotion, Audio Note Japan, and Kharma Enigma. Digital cables are Tara Labs The 0.8, Kubala-Sosna Emotion and Audio Note Japan. Speaker wires are TARA Labs The 0.8, Kubala-Sosna Emotion, and Kharma Enigma. AC power cords are Tara Labs The One and Kubala-Sosna Emotion.

TAOC Rack and TITE-35S component footers, Harmonix RFA-78i and Marigo VTS Room Tuning Discs, CORE Designs amp stands, Acoustic System Resonators, Argent Room Lenses, Echo Buster and Sonex acoustic panels, TARA Labs PM/2 and IDAT power conditioners, and Ensemble Mega PowerPoint outlet strips.


A Teleportation Device


"Teleportation—noun. A hypothetical method of transportation in which matter or information is dematerialized, usually instantaneously, at one point and recreated at another."

For us audiophiles, it ain't hypothetical. Many have experienced occasions when the system takes you away from your physical location, to a place that only exists in your mind. If your rig is really good at this, it can teleport—or transport—you with regularity. Call it audio magic. That's part of the allure of this pursuit.

The Soulution 720 Preamp paired with the Soulution 710 Stereo Amp, as I have had it configured for the last month, is making this magic nightly in my living room. It takes me on a magic carpet ride, but not to the usual place we associate with audio teleportation. Most of the time, we're referring to the warm and fuzzy, fictional environment engendered by low powered Single Ended Triode tube amps. The Soulution gear takes me to actual concert halls I've recently been in.

SOTA Resolution

Let's begin with a discussion of resolution.

When audiophiles talk about resolution they mean quantity and specificity of information. It's a given that upping resolution is always a good thing… or is it? Because, sadly, most of the tools we use to increase resolution come bundled with artifacts like shrunken and hard-edged images. These actually heighten the unreality of the reproduction.

There are some components that boost resolution and avoid these side effects. The 720 is one of them. The stage it throws is packed with at least as much info as you've ever experienced from an audio system. However, you'll notice something unprecedented about the shapes of the images upon it. While some shrink, others actually gain in girth. Not only are the images variously sized, but this is not random—they mimic what occurs naturally. A French horn throws a huge, recessed image; a flute is a point source.

And then there's the shocker. I've commented before about how some components project a stage with no extraneous or unaccounted for sounds—everything on it seems purposeful. The 720 takes this to the nth degree. Not only is everything purposeful, but every inch of it is controlled. Images that have expanded girth don't get loose and sloppy. Think of a weight lifter who works at increasing mass. He does it in such a way that it's all toned and chiseled. Like that gym rat, the 720s mass has resolution. You can "see" stuff going on everywhere within the image.

When the first violins are playing, the 720 allots them a large expanse of real estate, enough to proportionately hold the entire section. Where they begin and end is not in doubt; the demarcation is obvious but not etched. And within the mass you hear variation and textures. You can even pinpoint which chair is having an intonation issue. There are no more doubts like, "Are the bassoons doubling up on that passage?" Or, "Is that the French horns alone or with the trombones?" There is no ambiguity—control is pervasive.

The upshot of these refinements comes close to how these instruments image in real life, closer than I've ever heard before. Interestingly, I'm even getting some of this from digital source. Imagine that! CDs actually have realistic image encoding, although not as much as what you get with analog. This implies that the well-known issues with digital soundstaging may have more to do with our playback components than with the medium itself. There may be hope for digital after all!

Compared to the mbl 6010D Linestage

It is worth noting that switching between my reference mbl 6010D and the Soulution 720 did not entail major re-tuning of the system. The only thing I had to do was change the power cords. The 720 liked Kubala-Sosna Emotion. As with the 710 Stereo amp, I surrounded the 720 with K-S or Kharma signal wires. The 6010D liked TARA Labs The One. In other words, these two preamps are roughly aligned in terms of tonal balance, weight and body.

However, that does not mean they sound alike. The 6010D is known to be warmish, mid-rangy and weighty; the 720 is nearly as weighty and full-bodied, but it has none of the tubey colorations of the 6010D. It hews closer to neutral, although it is not as neutral as the 710 Stereo amp. Putting in the 720 preamp did not produce the same magnitude of shock as when I put in the 710 amp. All right, maybe the 720 is a bit more full bodied than strictly speaking it should be. But I sure ain't complaining—I like zaftig bodies.

I was a little worried that the 720 might be voiced light or thin or analytical. No sir, the 720 is not timid, not in the slightest. Its dynamic range surpasses the pacesetting mbl 6010D. And it can play BIGGER than it, too. The 720 has no trouble with the most massive orchestral forces. In combination with the 710 amp, its re-creation of large symphonic works is the most convincing I've heard.

Timbral Portraiture

As I found with the 710 stereo amp, timbre is entirely appropriate to the source.

The 720 doesn't euphonically beef up the bottom or foreshorten the top. It doesn't strip off or add bloom. It's sound is as satisfying as that from a refined tube amp.

But the two preamps differ considerably in timbre. Julia Fischer sounds fabulous on Russian Violin Concertos, (Pentatone Classics PTC 5186 059). You couldn't ask for more, inner life is extraordinary…

…except she sounds even more fabulous through the 6010D. This is because SOTA resolution reveals all: the good, the bad, and the ugly. Where her tone can be a bit edgy through the 720, the mbl is forgiving. Where the 720s stage is clean as a whistle, highly transparent and holographic, the 6010D gives her soft focus romanticism: there's none of the 720s crispness.

Phono Playback

The 720's built-in phono module is VERY good, indeed. Objectively speaking, this is the finest phono stage I've encountered. (Note: the preamp, without phono, is available as the Soulution 721 Preamp, MSRP $35,000.) I could go through the audiophile report card and check off every category, but I don't think that's necessary—it will uniformly get the highest scoring. And yet…

720 phono module

The 720 phono is distortion free and totally silent. It begins with the foundation laid down by the linestage and builds upon it, yielding unprecedented control over the loudest crescendos. It is such an advance in clarity and resolution as to make these seem unlimited. If dynamic range is one of the areas where digital beats out analog, that advantage has been neutralized with the 720 phono.

The 720 phono is highly dimensional, putting a lot of space between instruments. You feel you can walk into its soundstage, just like you can with the line stage. The word that applies is transparency.

On HI-FI Fiedler, with Arthur Fiedler and the Boston Pops (LSC-2100, Shaded Dog), it's as if a 10X jeweler's loupe has been inserted between you and the stage.

Compared to the ASR Basis Exclusive

My reference ASR Basis Exclusive, which I know intimately, having compared it to many other stages, has the reputation of being quite neutral. Its matter-of-fact voice is a tad warm and a little dark. It is also a pacesetter for low noise, great dynamics and its timbral portrayal is second to none for solid-state.


Well, guess what—the 720 phono manages to make the ASR seem noisy, even possibly distorted on signal peaks. Egads! This is almost like the comparison of the 720s linestage to the mbl 6010D.

When I run the ASR into the 720, the stage becomes schmeered compared to the 720s own phono. It doesn't have that level of transparency or image specificity. The 720 phono is so neutral it makes the ASR seem colored. The ASR colored? I don't know quite what to make of that. This will take some getting used to.

But oddly enough, it has more flow, just like the 6010D line stage does. HI-FI Fiedler through the 720 phono doesn't sound like Shaded Dogs usually sound. These fifty-year old LPs are antiques, reflective of a time when tubes ruled and before engineering ran amuck and took over the show. We old-timers prize their ambience and air, their warmth and lushness. This stuff doesn't come through the 720 phono. Is it suppressing it, or is it a reflection of the 720's neutrality?

Technical Discussion

I noted in the 710 Stereo Amp review how this large box is crammed to the gills with circuitry. There's much more stuff inside the 710 than any amp I've had the pleasure of poking into.

710 exposed

720 exposed 

The interior of the 720 Preamp is just as dense. The old paradigm of "the fewer the parts, the greater the purity" does not apply. There is a huge assortment of innovative circuitry inside; most of its purpose is beyond my understanding. (Go to the Soulution website if you want more info.)

Just to give you a taste, a large menu of pre-set features includes some unusual ones that you set from the remote control and the front-panel display. For example: you can program the Start-Volume, which defines the volume level after powering on; Start-Input, determines which Input is active after turn-on; Dim-Volume, sets the volume level the preamp goes down to after you push the Dim button; Balance, for left-right adjustment.


More esoterically, how about: Bandwidth IN, the bandwidth of each input can be set individually; Gain IN, each inputs' volume can be set. This is also where you set the Phono-Gain.


Well, they went and did it again. Once again, my assumptions and expectations were tossed to the wind. I tell ya, this could get annoying—if the results weren't so darn exhilarating.

The Soulution 720 solid-state Preamplifier is the worthy companion to the Soulution 710 solid-state stereo amp I enthused over a few months ago (and subsequently purchased). SOTA performance levels were achieved in the whole swath of evaluation criteria. The 720 gives you weight, body and slam combined with resolution and refinement—veritably, a Panglossian audio world. IMHO, there is no doubt this is the finest preamp to grace my portal. You may have a preference for one of the handful of other top units, like the mbl 6010D, but at this level, it's a matter of taste.

The combo 710 Stereo Amp and 720 Preamp is the closest I've come to reproducing live acoustic instruments. I'll tell you one thing for sure: for rendering large-scale symphonic forces, this combo has no equal.

The built-in Phono Stage is outstanding. It handily beat out my ASR Basis Exclusive, one of the best solid-state units available. For the extra $5,000, you get a world-class phono stage.

As with the Soulution 710 amp, the only thing I would like to reiterate is the need to choose ancillaries carefully. Avoid analytical sounding wires and gear. Marshal Nack

Soulution 720 Preamplifier (with Phono Module)
Retail: $40,000

Soulution 721 Preamplifier (with out Phono Module)
Retail: $35,000

web address:

Importer information

Axiss Audio, Inc.
Gardena, CA 90248
TEL: 310-329-0187
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