Pass Labs • XP-25 Phono Stage

by Paul Bolin | January 26, 2012

© www.theaudiobeat.com

The world of audio is diversifying with ferocious and disorienting speed. Ten years ago the idea that an audiophile would be enjoying his or her favorite music by scrolling through a playlist on a laptop computer and funneling material downloaded from the Internet into a DAC the size of an eyeglass case would have sounded rather bizarre, to say the least. That very process is now a commonplace sight at audio shows, as are, of all things, analog tape recorders, once thought to be as dead and buried as the original Volkswagen Beetle.

However, for many of us who love music in all its forms, it remains the analog LP that is first in our hearts. Whether that music lover has a simple Rega plug'n'play package or something like Michael Fremer’s Continuum Caliburn playback system, the Universal Brotherhood of LP Lovers encompasses us all. We get it -- the rightness and completeness of music that comes from the analog LP and from no other format that is meaningfully available.

Histories and mysteries

While turntables and tonearms remain a fascinating universe in and of themselves, for me there is something about phono stages that remains alluring in a deep and special way. They have a profound effect on an audio system and have intrigued me for years. Over the past 15 years, my tendency has been to find a phono stage and stick with it for a long while. In that time, my long-term references have been, in chronological order, the Audio Research PH3 and PH3 SE, the Manley Steelhead, and for the last five-plus years, the Aesthetix Io Signature. I have hugely enjoyed every last bit of their wide performance envelopes and sheer musicality.

Two other phono stages I had for shorter periods of time left me in a state of, if you will pardon the unfortunate Rumsfeldian phraseology, shock and awe. Back in 1999, when I was writing for The Abso!ute Sound, I found myself in possession of an FM Acoustics 222 phono stage for three months. That little Swiss jewel retailed for the then-brain-zonking price of $22,000. The review of the 222 (and companion FM Acoustics line stage and power amplifier) was eventually aborted for reasons having to do with the then-importer of the components. I had never heard anything like the 222 in terms of resolution, space, tonal density and correctness. In retrospect, I was glad I didn’t have to write about it, because at the time I didn't have the context or descriptive vocabulary to describe what it did.

In 2003, I managed for a few weeks (through various connections in the audiophile world) to get my hands on the then-$32,000 Boulder 2008 phono stage that Michael Fremer had reviewed for Stereophile. It was as unashamedly astonishing as the FM Acoustics had been. In addition to the things the FM Acoustics 222 did, the Boulder added the very odd sensation of, to borrow Mike’s take on it, a ceaseless, continuous series of images that constantly renewed themselves and hung in the room with such palpability as to make me goggle, questioning my own ears and sanity. "Holography" starts to convey the sensation, but in a rather limited way. Seriously, it bordered on a low-level kind of psychedelic experience. Listening to the Boulder and the FM Acoustics phono stages, I felt like I imagine Einstein must have felt when his Theory of General Relativity began to coalesce in his mind: the implications of the reality were staggering.

On to the present. I had wanted to audition a Pass Labs component for a number of years, but for some reason the occasion never arose. After hearing the marvelous-sounding Pass Labs room at CES 2011, I decided that the time had come and that a phono stage was the component. Fortuitously, Pass Labs was happy to provide me with the subject of this review.

Material realities

The XP-25 is a joint effort by Pass Labs founder (and genuine audio legend) Nelson Pass and his co-designer Wayne Colburn. Their stated intention was that "music must flow effortlessly from LP surface to the listener’s ear." The XP-25 builds on the foundation established by the XP-15. There’s no confusing the two, however. The XP-25 is a dual-chassis unit, with power supply and audio circuitry each contained in its own minimal, elegant, and superbly made aluminum chassis. The DIN-25 cable connecting the two chassis carries only power.

Contrasting with its smaller brother, the control unit allows for the connection and selection of two 'tables (or 'arm/cartridge combinations mounted on a single 'table) and provides, big as life on the front panel, precision-machined and engraved knobs for adjustment of gain, capacitive loading and cartridge loading. Pass Labs also thoughtfully provides, in addition to the input selector switch, a mute switch and a high-pass filter, useful if rumble is a problem.

Three different levels of gain are available: 53, 66, and 76dB (3dB less gain is available from the unbalanced outputs), as are nine loading options -- from 30 ohms to 47k. Lastly, capacitive-loading options range from 100 to 750pF; this will be of more immediate interest to moving-magnet and moving-iron users, though Pass Labs recommends that even moving-coil users experiment with different settings, which I did to little detectable effect. Around back live the electrical connections: two sets of RCA inputs along with RCA and XLR outputs.

The XP-25’s manual deserves more than a cursory description. It is well written in "normal," not technical, prose and provides a through overview of the Pass Labs methodology and design philosophy. It also provides a truly excellent overview of how to determine the best combination of gain and loading for moving-coil cartridges. Desmond Harrington, the president of Pass Labs, with whom I corresponded while the XP-25 was in transit, also owns a Dynavector XV-1s cartridge, which has been my reference for years. I began with -- and wound up permanently returning to -- his suggested values of 66dB and 100 or 160 ohms, with the latter providing just a dash more sparkle in the top octaves.

Installation was a snap: place on rack, connect cables, set gain/loading and voila! I must admit that I cheated slightly in one respect: the two chassis did not sit on separate shelves as my analog rack is a bit full. I did place three Nordost Titanium Sort Kones between power supply and audio boxes. As the eternally on XP-25 never gets more than slightly warm to the touch, ventilation isn’t really an issue. A Nordost Odin power cord was used for all listening, as is the norm for my reviews.

Most solid-state components I've auditioned over the years have required a fairly substantial break-in period before revealing their best. Not the XP-25. If it changed at all -- I think it might have -- it did so only very slightly and in the first 20-40 hours.

Substance exists only in nothingness

The first thing I noticed about the XP-25, even before turning to critical listening -- something it would be impossible not to notice -- was its preternatural, utter silence, like that of the Boulder and the FM Acoustics phono stages. In fact, it brought a new and enlightening meaning to the concept of intertransient silence. The reissue of Kraftwerk’s Trans-Europe Express [Kling Klang STUMM 3055], through the XP-25, contained images that popped into the room, full blown, out of jet-black backgrounds. There are no acoustic instruments on this record, and the XP-25 tracked the often explosive transients of the synthesizers at what seemed to be the speed of light. Steven Morris’s drums on Joy Division’s "Heart and Soul," from Closer [Factory FACT XXV], had a sound so sudden that they sounded almost like gunfire.

Bass was always clean and controlled and as deep and powerful as the source material required. As Marc Mickelson pointed out in his recent review of the Tidal Sunray, deep bass has to be more than merely present to convey a convincing sense of the size and shape of a space. It has to bloom naturally. This the Pass Labs did magnificently. The Meistersinger prelude from Klemperer Conducts Wagner [Angel 3610 B] was grounded by a profound, naturally powerful bass; I could feel the double basses and cellos moving massive amounts of air and defining the space in which the recording was made. Switching musical gears, Jack Casady’s monumental bass guitar on Jefferson Airplane’s live Bless Its Pointed Little Head [RCA LSP-4133] packed his legendary thunder in all its resplendence and made me appreciate once again his superb playing.

The XP-25’s midrange was sufficiently lifelike such that commentary is difficult. The strings on the Meistersinger had a marvelous sheen with no wiriness or edginess to be heard -- posh and plush while retaining top-shelf definition. Likewise, the strings on the classic Arthur Fiedler/Boston Pops traversal of Offenbach’s Gaîté Parisienne [RCA LSC-2267] had a whipped-cream lusciousness and a dancing, rhythmic vitality. Nor was brass shortchanged. The Stan Kenton Band’s Rendezvous with Kenton (rainbow label [Capitol ST 932]) was recorded live (back in 1957!), albeit with no audience, in the Rendezvous Ballroom in Balboa, California. The hall acoustic is powerfully present, and the rich moo of the massed trombones, the dense tones of chorusing saxophones, which always had just the right balance of reed and metal, and the trumpets’ crispness and definition with no artificial sharpness were a wonder to behear. Timbrally the XP-25 was unimpeachable, and everything about the 18-piece band was harmonically present and flawlessly accounted for. Similarly, "Sorta Blue" and "Dreamsville" from Henry Mancini’s Music From Peter Gunn (RCA black dog [RCA LSP-1956]) were creamy and delectable. Pete Townshend’s acoustic guitars on "Behind Blue Eyes" from Who’s Next [Track/Classic Records DL 79182] sparkled, as did Tim Renwick’s classic Fender Stratocaster sound on Al Stewart’s "Apple Cider Reconstitution" and "The Dark and the Rolling Sea" from Modern Times [Janus JSX 7012].

Voices were beyond reproach -- lively, textured and well variegated. Virginia Astley’s fragile, almost little-girlish voice on "Some Small Hope" [WEA YZ107(T)] is surrounded by a crystalline ice forest courtesy of Ryuichi Sakamoto’s synthesizers. It sounded delicate and sweet; when David Sylvian’s mellow baritone enters, the contrast of the two voices was absolutely lovely. On a recording like Acoustic Sounds’ spectacular 45rpm reissue of Dusty Springfield’s Dusty In Memphis [Mercury/Acoustic Sounds APP 8214-45], the XP-25 revealed incidental details like Dusty’s breathing and the incredible force of her voice when she really let loose on "The Windmills of Your Mind." The XP-25 had a completely natural quality: no strain, no stress, just fully fleshed-out music. The incomparable Sandy Denny was a nearly touchable presence on "Autopsy" from Fairport Convention’s Unhalfbricking [Island ILPS 9102].

The XP-25’s treble was as extended as that of any phono stage I have ever heard and totally grainless. Massed strings had perhaps the most lifelike sound I have heard from a phono stage. The Prelude to Act III and Liebestöd from Wagner’s Tristan und Isolde (Skrowaczewski/Minnesota Orchestra [Vox Turnabout QTVS 34642]) has string sound that is utterly true to the character of Orchestra Hall -- hardly surprising given that it was recorded by the legendary engineer Marc Aubort. It was absolutely ravishing. The shimmer of a live string section is in part a reflection of the fact that even the finest players cannot play in totally perfect unison at all times, which results in overtones that create that "shimmer." Many components add a glamour of their own with a slight tilt in the upper mids and lower treble. Not the XP-25. It offered as much in the way of pure neutrality as the much more expensive Boulder and FM Acoustics components, and that is a lot.

Given that background silence it should be no surprise that the XP-25’s dynamics are exceptional. Keith Moon’s drums on "Won’t Get Fooled Again," also from Who's Next, exploded out of my Wilson Sashas with hurricane force, as did Roger Daltrey’s immortal scream. Big orchestral recordings had a majestic, force-of-nature quality. Equally impressive was the Pass Labs’ remarkable subtlety with the English horn solo in the Prelude to Act III of Tristan. A single double-reed instrument was perfectly scaled and the slightest variations in level were tracked superbly.

Hearing a ridiculously complex studio recording like "The Adventures of Greggery Peccary" from Frank Zappa’s Studio Tan [Warner Bros. DSK 2291] proved that while transparency is often sacrificed on the altar of timbral richness (and vice versa), this was not the case with the XP-25. Zappa crammed nearly every conceivable space with instruments, voices, and sound effects, all of which the Pass Labs phono stage revealed with effortless clarity. Pick one thing and focus on it or kick back and let Zappa’s bottomless well of wit and musical invention wash over me -- the XP-25 let me do either with the greatest of ease. The XP-25’s neutrality combined with its silence and dynamics to produce a transparency that was truly special. The tiniest of nuances were wholly knit into a presentation that was truly a single and unified thing.

Both the Skrowaczewski and Klemperer recordings I mentioned earlier can produce truly immense soundstages in both the lateral and front-to-back dimensions, and the XP-25 was able to create the details of spaces down to the last corner -- or mouse hole -- illuminating them with a clear and even light. The layering of the sections of the orchestra was exquisitely subtle and lifelike. The vast stage on Peter Gunn had so much air around each instrument that it can only be described as utterly luxurious. On a big rock recording like Siouxsie and the Banshees’ "Wheel’s On Fire" (English 12" 45 [Polydor/Wonderland SHEX 11]) the effect was just as spectacular. Whether naturally or artificially created, there was no soundstage too spacious for the XP-25 to render. At the other extreme, the Fairport Convention LP is a very intimate recording, and it was just that with the Pass Labs. Whatever spatial minutiae are engraved in the grooves will pop directly into the room if the rest of your system is up to what the XP-25 can deliver.

While many of the strengths I have described can be reduced to the terms of the audiophile vocabulary, the XP-25 has that special something that can only be described as musical naturalness. While on a Brahms kick, I listened to several versions of the Fourth Symphony, one of them an ancient recording of Hans Schmidt-Isserstedt and the Symphony of the North German Radio Network [Vox STPL512.270]. This is the furthest thing from an audiophile recording I can think of; the acoustic gives something of the impression of a reverberant barn, and the perspective is distant. In spite of this, the XP-25 let me hear exactly what the conductor’s vision of the work was. I then listened to Herbert von Karajan and the Berlin Philharmonic play the same symphony [Deutsche Grammophon 2721 002] and the differences were profound in unexpected ways. The von Karajan version sounded much better in terms of pure quality, and the Berlin Phil’s playing is the best to be had, but the differences in the two conductors’ approaches -- the very way in which they saw the work -- was thrust into incredibly high relief. von Karajan’s was a sculpted and polished-to-perfection version that, while compelling and very beautiful, made me appreciate all the more Schmidt-Isserstedt’s gutsier, more human approach to the same music. The XP-25 has a fundamental clarity that always allowed the music to transcend the recording.

The master’s example

Remember that very Zen quote from Bruce Lee at the top of this review? "The highest technique is to have no technique." To have "no technique" in Lee’s philosophy required mastery of all techniques at a level so total that no thought was required, only the instantaneous and correct reaction to any possible situation. That is where the XP-25 comes in. Ultimately, this sort of completeness of substance, this total isness, is possible only when the contribution of a component is as vanishingly close to zero as the current state of the art allows. This is a phono stage that sonically sums the virtues of all the phono stages I have ever heard at any length. Consequently, this review turned out to be far more an evaluation of the music I heard through the XP-25 than of the component itself.

Are there, in their own ways, phono stages that stand on a similar footing as the XP-25? Will there be better? Yes and yes, for such is the nature of the pursuit of something ever closer to the unattainable goal of perfection. Right here and right now, the XP-25 excels with its uncanny ability to combine a deathly intertransient silence with an equal fidelity to correct timbres. It has dynamics that make records breathe in a fashion ever so close to life, along with a fidelity to the placement of 3D images in a space so real it could be plotted on blueprints. It has exerted as powerful a pull on me as the Wilson Sasha W/P speakers, something I had doubted was possible.

But superlatives are somewhat irrelevant in describing the XP-25. It simply is. It performs the functions for which it was designed in such a complete and characterless way that the only things one hears are the nature of the music itself and the other components through which it must speak. This was splendid and quite amazing, especially to a long-time tube devotee.

Associated Equipment

Analog front-end: SOTA Cosmos Series III turntable, Graham 2.2 tonearm, Dynavector XV-1s phono cartridge, Hovland Music Groove phono cable, Aesthetix Io Signature phono stage.

Preamplifier: Aesthetix Calypso Signature and BAT VK-51 SE line stages.

Power amplifiers: Lamm M1.2 Reference monoblocks.

Loudspeakers: Wilson Audio Specialties Sasha W/P.

Interconnects: Nordost Odin.

Speaker cables: Nordost Odin.

Power conditioners: Quantum QBase 4 and 8, four Quantum QX4s (two for sources, phono stage and line stage, two for power amplifiers.

Power cords: Nordost Odin.

Accessories: Grand Prix Audio Monaco stands and two F1 carbon-fiber shelves, Ultra Resolution Technologies Bedrock stand, Ganymede isolation footers, Nordost Titanium Pulsar Points, Shun Mook Iso-Qubes, Caig Labs Pro Gold, Ayre/Cardas IBE system-enhancement CD, Argent Room Lenses, Disc Doctor and LAST record-care products.

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