My first selection was the brand new album by the great jazz pianist Ahmad Jamal: Marseille (Jazzbook Records) captures the sound of Jamal's piano with great accuracy as he plays it in a studio venue. I was immediately struck by two attributes of the XA25's performance. First, its overall liquidity was striking in how the music seemed to ooze out of the Ulfberht speakers and just flow/float into my room. I am not just talking about being grainless compared with other great solid-state amplifiers; this one had a special quality that I have only found in the very best tube amplifiers that seem to get you closer to the music in a relaxed way. Secondly, I believe that the XA25 is the quietest amplifier I have ever had in my system. I could hear every micro-detail easily and clearly, with no sense of the music being analytical or exaggerated compared with listening to live music.
The next selection came from the great jazz tenor saxophonist Johnny Griffin. The Kerry Dancers and Other Swinging Folk (Riverside) is an album that I always use as a test recording for timbres/tonality/color. It also helps me get a take on how well a component handles individual imaging, how three-dimensional the players sound, and how much air/space is around each player. I was very fortunate to hear Johnny Griffin play many times in jazz clubs in Chicago, so I use this recording as a gauge to see how close a system can get to producing the illusion that I'm hearing him play live. With the XA25 driving my system, it got very close indeed. The timbres and color saturation equaled what I normally experience only with tube-based SET designs. The sound of his tenor saxophone had a sensational lifelike presence in its tonality and came closer to his real-life sound than I have ever heard in my system before. The XA25 also rendered one of the highest levels of what I call image density or palpability for each player. The size of each individual player was accurate, along with that person's placement in the soundstage. If I didn't know better, I would swear that the XA25 was a world-class tube amplifier, due to the overall liquidity and voluptuous timbres/tonality of the instruments and three-dimensional imaging. Yet it also delivered unbelievable transparency and extension/control of the bass frequencies.
One of my favorite pop vocalists of all times is Steve Winwood. His new album Greatest Hits Live (Thirty Tigers) contains extended lengthy jazz/blues versions of his greatest songs throughout his career. The sound of this live recording is one of the finest I've heard in the last 10 years. The XA25 created a wall-to-wall representation of where Winwood and his band were performing, with tremendous depth and height, and made the 21-driver, seven-foot-tall Ulfberht speakers totally and completely disappear into the soundstage. With this recording, the XA25 showed the type of control and macro-dynamics it has on tap. When the band was ripping at the highest volume levels, the XA25 never broke a sweat or showed any strain at all. According to my dB meter, the system was hitting peaks of over 110 dB. I quickly lowered the volume level to protect my hearing and let the foundation of my house settle back to normal.
My final selection was the album Dreams and Daggers (Mack Avenue) by the highly acclaimed jazz singer Cecile McLorin Salvant. The recording features both live and studio performances. To a certain degree, Salvant sounds like a young Billy Holiday and shines in her phrasing. She also has a pristine tonality that clearly conveys her emotions. This recording again showcased the extraordinary way that the XA25 produces a delicacy and sweetness of colors/tonality and, at the same time, reveals every little simmer and nuance of her voice, rendered in a very natural/organic fashion. When her bandmates kicked in, I could easily discern their placement around her on the bandstand.
The XA25 amplifier is not a balanced design, so you can only use single-ended RCA connectors to drive it. The XA25 is so transparent that you'd better have a reference-level preamplifier to drive it; otherwise, you will not get the total magic that this amplifier has to offer. Finally, speakers with very low sensitivity and/or wicked impedance slopes might not be a good match for the XA25.
Comparison and Competition
In the $5,000 price bracket that this amplifier falls into, I have experience listening to two solid-state amplifiers that would be natural competitors. The first amplifier is the Sanders Sound Magtech, which retails for $5,500. The Sanders Sound Magtech has the ability to drive virtually any speaker. However, compared with the XA25, it lacks the overall liquidity and beautiful timbres/tonality, and it sounds somewhat grainy and dry in its presentation. Furthermore, it lacks the XA25's soundstaging ability in regards to image palpability and space between individual players.
The second amplifier, the Aesthetix Atlas, is a little more pricey at $8,000. The Aesthetix Atlas comes much closer to the XA25 in it produces timbres/tonality. It's an overall warmer/sweeter amplifier with a lot less sense of dryness. However, it still does not get the beautiful purity of tone/color that the XA25 nails down in spades. I also do not believe that the Atlas is quite as "cat-like" in its speed or overall macro-dynamics as the XA25.
There is an old platitude often used in high-end audio: the perfect amplifier would have the best of both worlds--the beautiful colors, lack of grain, and space/imaging of a great tube amplifier and the dead quiet nature, rock-bottom/tight bass, and transient speed of a great solid-state amplifier. In my 30 years of listening to great amplifiers from Threshold/Pass Labs, I believe that Nelson Pass and his team have come closest to this utopian ideal with the new XA25 amplifier than ever before in their long and illustrious history.
The XA25's performance in my system is still somewhat shocking to me. I thought I would never hear a solid-state amplifier that could create the gorgeous timbres/tonality/color of the finest tube-based amplifiers, yet that's what you get with the XA25. Another quality that distinguishes the XA25 from other solid-state amplifiers is its amazing liquidity. It's not just that this amp has a lot less grain and dryness. Rather, it's the XA25's total absence of grain and dryness. The XA25 also creates a soundstage with three-dimensional space and air between players, with realistic depth/width/height, and "meat on the bones" image palpability. Then add in the fact that the XA25 has virtually has no noise floor, leading to amazing transparency, and is also fast and dynamic, with a simmering sweet top end and full bass extension with control and grip on the bottom frequencies. The Pass Labs XA25 amplifier will not be leaving my system; it is definitely my new reference solid-state amplifier.
� Visit the Pass Labs website for more product information.
� Check out our Amplifiers category page to read similar reviews.
� Pass Labs HPA-1 Stereo Preamplifier/Headphone Amplifer Reviewed at HomeTheaterReview.com.