Review: Pass Labs XA-100 monoblocks Amplifier

Category: Amplifiers

I first would like to share a very brief history of what amps I have used before, in a bi-amped configuration, that came before the Pass Labs XA-100 monoblocks, to bring a perspective of why I believe these monoblocks are the best amps I have ever had in my system.

I have always bi-amped my MG-20's, which have been in my system for over 14 years. I still use a pair of Threshold SA-1's to power the bass panels. I used a pair of Pass Labs Aleph 1's for close to 9 years to power the midrange and ribbon tweeters of the 20's. I loved the warmth/musicality/richness of the Aleph's in my system, but became curious about some of new SS designs that were being highly regarded. At the same time Pass Labs had come out with their new X series amps, which I found to be much more dynamic/detailed/transparent then my Alephs, but were somewhat "cool" for my sonic taste and not as musical as the Aleph 1's. Finally, I auditioned an Edge NL-10, that was a terrific amp in that it had all the virtues of SS design, dynamics/details/extension, and still offered a very "musical/silky" sonic signature. So, I made the change and was very satisfied for over two years.

Then Mr. Nelson Pass and his team At Pass Labs came out with his XA series and X-.5 series. When I auditioned the 350.5 it knocked my "sonic socks" off because it had all the virtues of the Edge NL-10, dynamics/transparency/extension to a somewhat better degree, but added more realistic timbres, more air around players in a larger soundstage and finally what I just like to refer to as "musicality/liquidity" that just sounds more like real music to me. The 350.5 offered a few watts of single-ended class A before going into the next 50 watts of class A before finally going A/B biasing. So what would the XA amp's offer sonically, that only offer and stay in single-ended class A mode?

All the Pass Labs amps are beautifully built and are real gems visually, including the XA-100 monoblocks. I never in any of my reviews spend time on design or mechanics because its easy to go the website to get those details, I rather just share the sonics of the piece I have auditioned or have decided to put in my system. I believe informed audiophiles know that Nelson Pass is a genuis and his products have the highest build quality and engineering in high end audio.

I could give you paragraphs of audiophile cliches regarding the beauty of XA-100's, but I'll spare you and be succient regarding the details of their sonics. Everything that the 350.5, which still is a wonderful amp, had to offer was improved in what I call the "analytical" categories that audiophiles use to dissect the sound of amps. Yes, the Xa-100's were great in those areas, such as details, total and complete transparency, the most realistic and natural timbres I have ever heard, a top end that is airy and natural, midrange bloom but without losing mico-dynamics and decays, rock solid imaging on a realistic sized sound stage with most air and a three-dimensionality to the players that I have ever heard in my system. Good stuff.

But, what really amazed and delighted me was the "pure", I know this a very subjective, "musicality/effortlessness" of these monoblocks. Not "layed back" or a "fat tube sound", but just a true beauty that allows you just to relax and enjoy the music and not be aware of any specific aspect of the overall listening experience. Now, don't get me wrong, the dynamics,prat,drive of the music is there, but is offered in an overall perspective which just seems more natural compared to any other amp I have ever auditioned in my home system. Peter, one of the good guys at Pass Labs, had a great way to describe this quality," the XA amps just invite you into the music, more then other amps", its a great way to put the experience into words.

Please, I'm not saying these are the GREATEST amps in the world, their is no GREATEST, but the XA-100's I believe rank right up their with the other world class reference amps available today. If what I wrote has conveyed to any great degree what the XA-100's have to offer, I hope you might now be curious to hear them yourself and come to your own conclusions regarding their sonic virtues. These monoblocks are going to stay put in my home rig and I feel lucky that I could muster up the cash to keep them.

A final note. Through the years I have found the people at Pass Labs, including Nelson Pass, to be generous with their time on the phone, always willing to answer any qusetions, and I believe to be very honest regarding their products. Both Peter and Kent are fine gentleman, this time I spent more time harassing Peter regarding all kinds of matters regarding the XA amps, and he always answered my questions in a very informative and friendly way. Thanks Peter.

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