About five years ago, I'd just gotten an HRT Streamer HD DAC with balanced outputs, and had also just upgraded my system amps to a pair of Emotiva XPA-1Ls. The Emotivas were (and still are!!) capable of fully-differential, balanced Class A operation, and I was itching for a balanced preamplifier to help me enter what I was hoping would be a significantly enhanced era of system performance. Enter the Luminous Audio Axiom II, which was about as close to an elegant, single-source input solution for my particular situation as $299 would procure. I couldn't find anything approaching a traditional, full-function balanced preamp for less than a grand, which was an impossibility for me at the time. And besides, I was pretty deep into the whole emerging computer based audio thing; spinning discs and LPs were essentially dead to me because of my lackluster CD and LP system capabilities. So a single balanced input would work just swimmingly with my then current situation. And it did, performing admirably until this past summer, when my audio-related needs at my new listening room changed dramatically.
The PS Audio Gain Cell Preamp/DAC is now the centerpiece of my home system, and as a multiple-input, line-level preamp with a magnificent built-in DAC, it offers true perfectionist audiophile performance with the ability to easily control multiple balanced, single-ended, and digital sources. The sound quality, flexibility, and performance of my current rig places me at a level of audio perfection I previously would never have believed possible, making the old HRT unit seem like not much more than a toy (albeit, a good-sounding toy!). But that's not in any way a knock on the Axiom II Passive Pre. It provided the kind of clarity and authority to my system's sound that I wouldn't have thought possible at the price point—especially in such a relatively simplified setup. You know, sometimes less really is more!
While I was constantly impressed and pleased with the Axiom's sound quality (I even upgraded from the baseline model to the Caddock resistor), I really missed the ability to remotely adjust the volume. One thing about dealing with digital files of varying provenance (.wav, .flac, .dsf, or .dff) is that there are often wildly varying volume levels between the files you select for playback. Making getting up out of the listening chair often (much too often!) to make volume adjustments a bit more of a chore than one would expect.
So just prior to the recent holiday season, I was offered the opportunity to play about with the latest iteration of the Axiom II line; it's Luminous Audio's top-of-the-line passive preamp that includes their signature Walker Mod and also features remote volume control. The Walker Mod is the result of Luminous Audio's Thom Walker, who took the baseline Axiom and added a greatly improved, cost-no-object attenuator; six-nines ONO cast copper internal wiring; greatly improved chassis damping and custom Sorbothane feet; and top-of-the-line Vampire RCA jacks and external connectors. The remote version adds a high-quality external power supply to provide juice to the volume control and display functions. Tim Stinson, the head honcho at Luminous Audio, feels the upgrades are so remarkably good that the Walker Mod Axiom II—in systems that are fundamentally conducive to working well with a passive pre—will go toe-to-toe with any preamp in the world, regardless of cost. There are systems out there in which the stars just don't quite properly align to allow the effective use of a passive pre, but nonetheless, that's a pretty impressive claim!
The Axiom II is custom-built to your specifications; you provide information for your loudspeaker's efficiency rating, power amp input impedance and input sensitivity, and—if needed—your CD player's output voltage. This allows the folks at Luminous to build the Axiom to provide a range of volume adjustment that should be perfect for your particular situation. At the point you're placing your order, you're also offered a menu with a plethora of choices. Choose from either baseline/upgraded Axiom/Walker Mod unit; choices for RCA or balanced inputs and outs; the option to control multiple sources with additional inputs/outputs; and remote control options. There's also an option to have your unit factory burned-in; believe me, burn-in does make a difference with these units. All said, you can spend upwards of $1200 USD on one of these babies; my review unit came equipped with RCAs, a single input, and remote volume control with an MSRP of $849. Although I run my system fully balanced, I chose the RCA version for review so that I could easily see how the Axiom II would handle LP playback with a phono pre input.
Upon opening the box, most people will immediately be impressed with the heft and appearance of the Axiom line—this thing just exudes quality, and no corners have been cut in the construction process. Fit, finish, and detail are superb, to say the least. The Axiom II is compact, but the metal case and thick aluminum faceplate add significantly to the unit's weight, so even if you've got a tangle of heavy cables coming in and out of the back, the Axiom will easily stay put in your equipment rack. And with the remote controlled version, there's a small window that displays the volume level; it's dimmable through multiple steps to completely off, if you so desire. The small but substantial metal remote wand only includes buttons to control volume, mute, and the brightness of the display. No remote control of input/output selection is available.
Right out of the gate, I thought the Axiom II with Walker Mod was bit cold-sounding. Even though it'd been sitting in the listening room for a couple of months awaiting its place in the review queue. My Emotiva amps idle in Class A 24/7, so that room is undeniably the warmest in the house. The Axiom's casework was even warm to the touch when I made all the initial connections! But the harsh sounds I first heard didn't last very long; I set up a repeat play with a DAC input (the Burson Conductor) and let it go for a few days to try and burn things in a bit more. The Walker-modded unit I received had not been burned-in in advance; the Axiom II's (along with everything else Luminous Audio offers) are hand-built, and they've recently been cranking them out left and right! But within a few days of Thelonious Monk's excellent Straight No Chaser album running 24/7, things started sounding pretty sweet! At this point, I reconnected to a phono input and started spinning LPs; I'm currently using Pro-Ject's The Classic table with a Hana EL moving-coil cartridge playing through a Sutherland KC Vibe phono preamp—the sound coming from the system was very sweet, indeed. A warm, rich and very liquid midrange with deep, authoritative bass—and this was thru the Zu Audio Omens with no sub attached! I played a lot of jazz and other records with good bass content, and was totally, constantly impressed with the weight, clarity, and authority of the bass through just the Omens. Voices, especially female, had a palpability and three-dimensionality that almost defied logic; after about a week of constant play, the Axiom II had reached its stride and sang with just about anything I dished from either digital or analog sources.
When Tim Stinson says he'll pit the Axiom II in a properly synergistic system against even some of the more esoteric and exotic (read expensive) preamps out there—I no longer doubt the sincerity of his claim. In my original experience with my only slightly upgraded Axiom II, my very narrow view at the time was to obtain something that would effectively drive balanced amplifiers at a minimum cost; I hoped for—but didn't necessarily expect—truly phenomenal sound as part of the equation. I can't complain about my $299 upgraded Axiom II; I was pretty much ecstatic with the sound quality it offered. I now see that for less than $900, you not only get the convenience of remote controlled volume that I craved, but you also get world class sound quality with the Walker Mods. Even at triple the price of my original unit, it seems like an amazing bargain.
In my current situation, I absolutely love having the input source flexibility that the PS Audio Gain Cell Pre offers; I love having the option of multiple single-ended analog inputs and yet still have fully balanced inputs and outputs available to my amps. And while I'm very smitten with the quality of the attenuation offered by their proprietary Gain Cell volume modules, I could absolutely see myself being completely, perfectly happy with the Axiom II Walker Mod version. The whole idea behind passive preamps in the first place is to remove the electronic processing and just let the amplifier's output shunt off (and not pass through) the passive pre's internal circuitry. To hopefully hear more of your amp's house sound, unaltered by sometimes excessive electronic pre-processing. More along the line of the "straight wire with gain" thing.
If you research "passive preamps" on the net or on any of the audiophile forums, you'll see an emerging love/hate relationship pattern. People either swear by them—or seem to feel that the resultant sound is somewhat lacking. Of course, you basically have to take anything you read on any of the audiophile forums with a grain of salt—I'm often not completely convinced that some of the naysayers (on Audio Asylum, for example) have even experienced first-hand the particular unit they're so adamantly shredding. Not at all unlike most anything else in audio, superb system synergy is requisite to truly good sound. Passive preamps have the capacity to offer quite spectacular sound on par with the very best active preamps. And there's quite a selection of available models from a diverse group of manufacturers, with some of them priced many thousands of dollars more than a full-featured active preamp. Their appeal is obviously quite real!
My only experience in this arena is with the Luminous Audio Axiom II. Whether with a slightly upgraded entry-level model or with a fully-tricked out ultimate model, the resulting sound quality for me has always been superb and not lacking in any way, though the Walker Mod version decidedly trounced the entry-level model. Of course, when I say "trounced", I have to be objective; it's not really night and day between the two. While both units are built to exacting standards at their respective price points, the Walker modded unit provided perceptible and palpable improvements in every important area of performance and sound quality. I truly felt that while listening to both digital and LP sources that I was hearing some of the best sound my system had ever produced; sound that was engaging, authoritative, and musically very satisfying. I can't see how the Walker Modded version couldn't improve even a cost-no-object system; it's a truly perfectionist piece of kit that approaches the ultimate—and the convenience of remote volume control is the icing. Very highly recommended.
Axiom II Passive Preamp with Walker Mod and Remote Volume Control (Single-ended)
Retail: $849 (USD)
Luminous Audio Technology
All images courtesy of Luminous Audio
