The ancient poetry of El Din's singing is driven and supported by playing of the oud, and the first thing I noticed was how full and authentically wooden his instrument sounded. The second thing I noticed was how the XA25 revealed the vibrations in the spaces between the oud's string courses, sound holes, and soundboard. I could sense the XA25 reproducing a boiling, stream-like continuum of acoustic energy.
This is what high-quality audio is supposed to do: make the energy coming out of the speakers resemble the energy that went into the microphones, so that wooden instruments sound exactly like the vibrating wood they are. The Pass Labs XA25 made the DeVore O/93s seem less like rattling boxes, more like projectors of aural holograms.
As I played more music through the Pass-DeVore combination, I began to realize that the XA25 is the most transparent amplifier I've ever heard. I also began to wonder if the reason it took so long to break in wasn't just a break-in thing—it was the unusualness of its transparency that was breaking me in.
Late one rainy night, listening to some Slovenian tango—the Mascara Quartet's Barco Negro (LP, Sazas Biem VVE LP 001)—I was reminded of the first thing I'd noticed about the XA25's sound: the intense presence of the midrange. The song "Barco Negro" (Black Boat) was first recorded in 1954, by the queen of fado, Am†lia Rodrigues. The Mascara's version, with singer Polona Udovic, is no match for the original, but it showed me how uniquely solid the XA25's midrange was. Udovic's voice felt strong and forward; male voices felt chestier, drums more corporeal. This midrange solidity wasn't subtle—the more I listened, the more I suspected it was having a psychoacoustic side effect of making the octave just below it (125–250Hz), as Irish Brother said, "thinner than normal."
The Mascara Quartet hails from Slovenia, but the dark melancholy and eccentric pacing of their music is pure Latin milonga, with overtones of downtown New York avant-garde. The excellent Pass-DeVore partnership displayed all the subtly striding rhythms and eccentric fluctuations of Mascara's milonga vanguarda.
Listening with the Stirling Broadcast LS3/5a V2
I'm currently so enamored of Stirling Broadcast's LS3/5a V2 speaker because, more than all other audio traits, I value accurate tone, vivid rendering of space, and realistic texture. The more instruments, singers, and rooms sound like themselves, the more the recording process reveals itself, and the more easily I can dream along with the music.
Dear Reader: If you can live with a pair of small, pipe-and-slippers British loudspeakers, the combo of Stirling LS3/5a V2s and Pass Labs XA25 was an enticing combination with all types of music, playing really big and dance-hall lively. Both Barco Negro and Lily of the Nile sounded more complete, full, whole, and natural than through the Magnepan .7s, KEF LS50s, Zu Audio Soul Supremes, or DeVore Orangutan O/93s.
Compared with the First Watt J2
The Pass Labs XA25 ($4900) puts out 25Wpc into 8 ohms. So does the First Watt J2 ($4000). (Both were designed by Nelson Pass.) Besides a heavier, more attractive case, the additional $900 buys you: an amp capable of putting as much as 50Wpc class-A (or 100Wpc class-AB) into a 2 ohm load like the Magnepan .7s (the First Watt J2 struggled with loads below 6 ohms);
an amp that makes music with less richness of tone and less saturation of color than the First Watt J2, which shows me the different hue of each star in the night sky—the XA25 shows me the pulsating energies that fuel them; and
what might be the most transparent amplifier available at any price.
Compared to the Line Magnetic LM-518 IA
The Pass Labs XA25 ($4900) and the Line Magnetic LM-518 IA integrated amplifier ($4450), the latter used only as a power amp via its pre-in jacks, made for a very interesting comparison—not only because I'm deeply fond of the LM-518's scintillating midrange and near-perfect high frequencies, but because this pair of 25-watters might be two of the most different-sounding amps I know. When I removed the Pass Labs from the system and began listening to the Line Magnetic, all I could hear were the luminous note decays of Peiju Lien's pipa in "Le Luneux," from Transcending Continents & Memories: Medieval Europe Meets Traditional Chinese Meets Avante-Gard [sic] (LP, MA Recordings M091A-V). This mix of French medieval, post-postmodern, organetto, hardingfele (Norwegian fiddle), percussion, and traditional Chinese pipa (a lute-like instrument) is surely one of producer, engineer, and MA owner Todd Garfinkle's finest releases on levels both musical and sonic.
It had been a while. I'd forgotten just how grainless, present, and refined the LM-518's 845-tube highs could be, but I instantly recognized them as better than the XA25's. In fact, through the Stirling LS3/5a V2s, the top six octaves of the LM-518 pretty much define the type of sound I admire. (MOSFETs vs 845 bright-emitter tubes?)
After listening so long to the push-pull, solid-state XA25, abruptly switching to a single-ended tube amplifier like the LM-518 was disorienting—and intoxicating. My friend Sphere and I always pay attention to what we call the Sequence Effect: Our perceptions of the character of the component just switched to are dramatically affected by the sound of the component that immediately preceded it. With the LM-518 in the system, I listened to several complete albums before I could stop noticing the exquisiteness of the sounds emanating from the Stirling LS3/5a V2s. The LM-518 made music sound and feel less weighty and sinewy than the XA25. But in exchange, the LM-518 delivered infinite multitudes of refined, subtle contrasts.
The revealing nature of the XA25 helped me recognize the wildly different but equally revealing nature of the LM-518, as well as the transcending, hypnotizing time warps of Transcending Continents & Memories. The Pass XA25 and Stirling speakers let this exceptional recording sound achingly pure and refined. The LM-518 did less of that.
The LM-518 IA and XA25 threw equally enormous soundstages, but the quality of those soundstages was enormously different. The Pass's sound spaces were absolutely quiet and profoundly empty. With the Line Magnetic, spaces seemed less vacant, more grainy and hazy through the presence region. The LM-518's best trait was how its midrange seemed fantastically charged with the energy of players playing, and with lingering, vibrating sounds. The XA25 emphasized rhythm and vitality.
Conclusions
The Pass Labs XA25 is not subtle about what it does well. Partway through my listening for this review, I began to imagine how this amplifier could be audio's Salvator Mundi. Its divine transparency blesses and illuminates every aspect of the music it touches, enhancing the subtlest aspects of tone, texture, microdynamics, space, and atmosphere. Its midrange force makes rhythms stronger, and exposes the flesh and blood of players and singers. Those are rare and important qualities, but still, the XA25 made me nervous—it took me a long time to grasp the essential character of its unique sound. Now, finally, I'm awed by how lucidly it renders music. Pass Laboratories' XA25 is reasonably priced, strong beyond its power rating, and positively revelatory. Classe A se você, por favor.
The Mascara Quartet hails from Slovenia, but the dark melancholy and eccentric pacing of their music is pure Latin milonga, with overtones of downtown New York avant-garde. The excellent Pass-DeVore partnership displayed all the subtly striding rhythms and eccentric fluctuations of Mascara's milonga vanguarda.
Listening with the Stirling Broadcast LS3/5a V2I'm currently so enamored of Stirling Broadcast's LS3/5a V2 speaker because, more than all other audio traits, I value accurate tone, vivid rendering of space, and realistic texture. The more instruments, singers, and rooms sound like themselves, the more the recording process reveals itself, and the more easily I can dream along with the music.
The Pass Labs XA25 ($4900) puts out 25Wpc into 8 ohms. So does the First Watt J2 ($4000). (Both were designed by Nelson Pass.) Besides a heavier, more attractive case, the additional $900 buys you: an amp capable of putting as much as 50Wpc class-A (or 100Wpc class-AB) into a 2 ohm load like the Magnepan .7s (the First Watt J2 struggled with loads below 6 ohms);
The Pass Labs XA25 ($4900) and the Line Magnetic LM-518 IA integrated amplifier ($4450), the latter used only as a power amp via its pre-in jacks, made for a very interesting comparison—not only because I'm deeply fond of the LM-518's scintillating midrange and near-perfect high frequencies, but because this pair of 25-watters might be two of the most different-sounding amps I know. When I removed the Pass Labs from the system and began listening to the Line Magnetic, all I could hear were the luminous note decays of Peiju Lien's pipa in "Le Luneux," from Transcending Continents & Memories: Medieval Europe Meets Traditional Chinese Meets Avante-Gard [sic] (LP, MA Recordings M091A-V). This mix of French medieval, post-postmodern, organetto, hardingfele (Norwegian fiddle), percussion, and traditional Chinese pipa (a lute-like instrument) is surely one of producer, engineer, and MA owner Todd Garfinkle's finest releases on levels both musical and sonic.
After listening so long to the push-pull, solid-state XA25, abruptly switching to a single-ended tube amplifier like the LM-518 was disorienting—and intoxicating. My friend Sphere and I always pay attention to what we call the Sequence Effect: Our perceptions of the character of the component just switched to are dramatically affected by the sound of the component that immediately preceded it. With the LM-518 in the system, I listened to several complete albums before I could stop noticing the exquisiteness of the sounds emanating from the Stirling LS3/5a V2s. The LM-518 made music sound and feel less weighty and sinewy than the XA25. But in exchange, the LM-518 delivered infinite multitudes of refined, subtle contrasts.
The revealing nature of the XA25 helped me recognize the wildly different but equally revealing nature of the LM-518, as well as the transcending, hypnotizing time warps of Transcending Continents & Memories. The Pass XA25 and Stirling speakers let this exceptional recording sound achingly pure and refined. The LM-518 did less of that.
The Pass Labs XA25 is not subtle about what it does well. Partway through my listening for this review, I began to imagine how this amplifier could be audio's Salvator Mundi. Its divine transparency blesses and illuminates every aspect of the music it touches, enhancing the subtlest aspects of tone, texture, microdynamics, space, and atmosphere. Its midrange force makes rhythms stronger, and exposes the flesh and blood of players and singers. Those are rare and important qualities, but still, the XA25 made me nervous—it took me a long time to grasp the essential character of its unique sound. Now, finally, I'm awed by how lucidly it renders music. Pass Laboratories' XA25 is reasonably priced, strong beyond its power rating, and positively revelatory. Classe A se você, por favor.
