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Pass Labs INT-250 Integrated Amplifier - "It's Good To Be The King!"

08-13-2018 | By Robert S. Youman | Issue 98

Pass Labs INT-250 Integrated Amplifier

"It's good to be the King!" While sitting back and listening to the Pass Labs INT-250 integrated amplifier, I couldn't help but giggle and think about this infamous line from Mel Brook's underground 1981 classic film, History of the World, Part I. What I was hearing had me glued to my seat and skimming through my little black book of notes from past reviews. I rarely look back, but I wanted to verify my thoughts. Do we now have a new "King of the Hill" or is my head spinning for some other reason?

For the past few years, I have been on one heck of a blazing trail listening to and reviewing most of the top integrated amplifiers in the industry. This includes the latest and greatest from D'Agostino, Devialet, Vitus, T&A, Esoteric, BMC, Simaudio, and many more including three models from Pass Labs. As always, system synergy is critical, but I must say that the INT-250 ($12,500) sits close to or at the top of that list for performance, if not value. This includes comparisons to models two to three times the list price.

Review System

  • Sonus Faber Stradivari Speakers
  • Magico Q3 Speakers
  • REL No. 25 Reference Subwoofers
  • Devialet 1000 Pro Integrated Amplifier
  • Pass Labs INT250 Integrated Amplifier
  • Pass Labs XP-15 Phono Preamplifier
  • VPI Avenger Plus Turntable
  • VPI JMW 12-3DR Tonearm with Nordost Reference Wire
  • van den Hul Crimson XGW Stradivarius Moving Coil Cartridge
  • Esoteric K-01X SACD/CD Player
  • Aurender N10 Music Server
  • Synergistic Research Element CTS Cable throughout
  • Synergistic Research PowerCell 12 UEF SE Power Conditioner
  • Rix Rax Hoodoo Component Rack
  • Magico QPod Footers

Caveat Emptor

System synergy and personal taste are critical when evaluating high-end audio products. This review is based on my subjective requirements, my subjective ears, my specific system, and my specific listening room. This combination is only one data point of many that exist out there for these components. Please consider my comments and analysis accordingly.

Pass Labs INT-250 Integrated Amplifier


The Pass Labs INT-250 brings a sparkle to the eye of virtually every visitor to my listening room. Though I have some stimulating eye candy already in the room like the Devialet 1000 Pro integrated amp, the Esoteric K-01X CD/SACD/DAC, and the Sonus Faber Stradivari speakers, lately it's the INT-250 that draws the immediate attention and the sighs.

Gotta love the newer Pass Labs .8 series profile which the INT-250 follows very closely. I give the entire effort an A+ for it's dazzling industrial design. This includes the machined silver aluminum front panel, the blue LED current meter, and the trenchant black heat sinks. From the rear we have the massive industrial handles along side the over sized Furutech torque limited binding posts. Build quality is superb and would pass any mil spec like requirements. Congrats to the Pass Labs team on another stunning beauty to add to the tradition and legacy.

The INT-250 weighs in at a hefty 105 lbs. and has a fairly large footprint at 19" wide x 25" deep x 9.1 high". Primarily a MOSFET transistor based amplifier, power is rated at 250 wpm into 8 ohms and 500 wpm into 4 ohms. The INT-250 is a fully balanced Class A/B design and is highly biased into Class A up to 15 watts. There are four inputs with optional single ended and balanced terminals for each and two outputs with single-ended and balanced terminals for each. All your basic controls are available on the front panel and on a simple but elegant metal case remote.


Bottom line. The Pass Labs INT-250 can do it all. Sound quality and performance can be competitive with the very best whether we are comparing integrated or separate components. From my past experience and review of the flagship XS 300 monoblock amplifiers ($85,000), the INT-250 has a definite branch in the family tree. Trickle down technology is alive and well at Pass Labs.

Working from the bottom up, the INT-250 can provide tremendous drive and slam in the bottom octaves. Some might argue that bass performance in past designs for the Pass Labs Aleph, XA, and XA.5 series were a bit soft and overly ripe in some systems. The new .8 series and specifically the INT-250 are the antithesis of these criticisms. Tight, tight, and more tight. Detail, detail, and more detail. If you want bottom end grunt and dynamic punch, you can get it with the INT-250, even with some of the most difficult loads.

As always with Nelson Pass designs, mids are absolutely glorious. There is a timbral purity that will immediately saturate all your senses. Female and male vocals have the proper harmonics and tone of the real thing. Saxaphones are round and woody. Piano is properly fleshed out and as physically palpable as I have heard with any other amplifier. There is a rich sonic texture that just cannot be ignored.

Highs are clearly delineated and exquisitely revealed. Not overly sweet, you get plenty of inner detail and attack. Strings can be lush and expansive when called for, yet there is still an immediacy and agility that will wow you even on the most nondescript recordings. High hat cymbals are especially impressive with a delicate balance of both shimmer and harmonic brilliance—very rare these days especially on digital recordings.

Imaging and sound stage depth and width are very good to excellent. I would say that other designs might have slightly more air and definition, but very few with these strengths can provide the sonic beauty and liquidity that I describe above. This is a very subtle observation. With a nicely balanced system, you will be extremely pleased regardless.


As always, system synergy and subjective priorities can drive comparisons, but based on my specific biases and my specific listening room, my three favorite integrated amplifiers over the last three years or so would have to be the D'Agostino Momentum ($45,000), the Devialet 1000 Pro ($34,990), and the Pass Labs INT-250 ($12,500). Let's ignore the price differences for now and just talk about sound.

Compared to the Devialet 1000 Pro, the Pass Labs INT-250 has a richness of tone and an organic purity that for me was quite compelling. This is probably no surprise for those familiar with the house sound of these brands, but with the latest upgrades for both hardware and software, do not discount the Devialet 1000 Pro. I still find it to be extremely musical with plenty of harmonic density and color. It's just that the INT-250 can be so charming and so seductive.

What really surprised me was how well the INT-250 compared with the Devialet for bass performance. Those Devialet hybrid Class A/D 1000 watts RMS are still my bench mark, but the INT-250 is definitely in the team picture. Both can deliver a depth charge like bottom end with layers and layers of information. Yep, I used the term "layers" when describing bass performance for these two amplifiers. When have you seen that term used for that frequency range? Both are that good!

The D'Agostino Momentum is an interesting comparison. It too has a rich tapestry and sonic beauty that can be quite alluring, yet not quite as saturated and with slightly less bloom and roundness in the mids and highs. Again, to each his own.

The Momentum provided a three dimensional sound stage and imaging that was in some ways competitive to the very best flagship mono blocks that I have had in my listening room. Air. Ambiance. Spaciousness. The Momentum was slightly superior in these areas.

On the other hand, the Momentum had excellent bass performance but not in the same class as the INT-250. When the Momentum rattled the walls, the INT-250 shook the very foundation of my house. In fact, every visitor to my listening room commented on this before all other variables. 

Also, please note that in addition to my Sonus Faber Stradivari speakers, I also had a friend bring over his pair of Magico Q3 speakers for a few days of listening. The Strads are known for their warmer balance and musical presentation. The Magico Q series is known for extreme speed and detail along with some of the best "truth to the source" performance available. This provided an interesting range of challenges for the INT-250.

The results were intriguing and somewhat surprising. The INT-250 showed it's flexibility and was an excellent match for both speakers. I was concerned that the INT-250 and Strad combination would be just "too much chocolate in the pudding" and that it would tire the senses over time. This was not the case at all as I quickly settled in on this duo for many many extended listening sessions of pure joy. Though there was excellent synergy at all frequencies, it was the bass performance that got my attention. The Strads can really deliver the thunder with the right amplifier. The INT-250 proved to be up to the challenge.

The Magico Q3 speakers clearly found a Ginger Rodgers to its Fred Astaire. Combing the strengths of both designs was a match made in heaven. My friend commented that he found the overall sound to be much more musical and relaxed with a nary a loss of any information or speed. He was particularity pleased with the playback of Rock and Electronic music which was not a particular strength of the Q3 speakers in the past.


Al Di Meola, John McLaughlin, & Paco de Lucia, Friday Night In San Francisco (LP)

One of my all time favorite albums, Friday Night in San Francisco was released in 1981 on the Phillips label. I have multiple vinyl, CD, SACD and high resolution digital copies on several labels including Phillips, Columbia, Classic Records, and Impex. FNISF is an exhilarating live acoustic guitar performance from three of the finest guitarists ever. The amazing interplay and improvisation will have your hair standing on end. The new Limited Edition 180 gram re-issue from Impex is the one to have. I will have a complete review in the next month or so. An absolute must have for both sound and performance.

Track 1 "Frevo Rasgado" performed by John McLaughlin (left channel) and Paco de Lucia (right channel) is remarkable. The combination of the Impex pressing and the Pass Labs INT-250 integrated amp had me wondering if I was listening to a whole new recording. For once, I could really hear the difference in sound between the two guitars. Whether it be the gut or nylon strings, and/or the lighter thinner construction of the flamenco acoustic guitar verses the classical acoustic guitar, you can now clearly hear the unique harmonics of each. The depth and width of the soundstage along with the specific images of both musicians is also more clearly defined than ever. The icing on the cake was the extreme dynamics that now exploded from the speakers when each guitarist ramps up while playing solo or together. Fun fun stuff!

Fred Hersch, Live In Europe (CD)

Fred Hersch continues to evolve his skills and demonstrate his wonderful creativity with every new release. His latest group recording both impresses and delights. Live in Europe on the Palmetto label is one of those magical nights to remember, and I'm grateful that it made its way to tape. Hersch apparently did not realize until much later that it was even recorded. With support from John Hebert on bass and Eric McPherson on drums, we have here one of our most impressive and expressive piano led jazz trios.

I have always heard a strong Bill Evan's influence in all of Hersch's music and that feeling remains true with this effort. Wonderful romantic melodies. Light at times yet also extremely complex during certain passages. You will find yourself totally focused but also very relaxed throughout this recording. From a sound perspective, you gotta love what is happening on piano. The INT-250 again brings out all the proper harmonics and weight that this instrument can provide. The inner detail of both piano and bass is astonishing in the lower registers. Lets not forget about drums and specifically the sound of McPherson's cymbals. You will experience a realistic combination of both splash and bronze that will re-energize your feelings about CD and digital in general. Keep it coming Fred!  

Yes, Steven Wilson Remixes (WAV 96/24)

This is a relatively new download on the Rhino Atlantic label and is available from both HDTracks and Acoustic Sounds. Essentially a 26 track greatest hits compilation that includes Steven Wilson remixes from The Yes Album (1971), Fragile (1971), Close to the Edge (1972), Tales From Topographic Oceans (1973), and Relayer (1974). Please note that there is also a new LP box set available that includes complete pressings of all these albums. Steven Wilson is up to his old tricks again. IMHO, he is an engineering and remix genius. The sound for all of these tracks are a revelation. Check out his Jethro Tull Aqualung remix too. Another epiphany! Come on Steven, please talk to Jimmy Page about one more shot at the Led Zeppelin catalog!

My go to track for Yes is always "And You and I". I cannot tell you how many LP, CD, SACD and high resolution files for this cut that I have thrown at the system over the years without much satisfaction. Somehow I have this unrelenting memory of my original pressing back in 1974 at college that made my Thorens turntable, Shure cartridge, Marantz amplifier, and Advent speakers shake and bake and sing to the heavens. Maybe something else was going on back then. Who knows? Never the less, this Steven Wilson remix along with the Pass Labs INT-250 finally made me feel like I was 18 years old again. When Steve Howe opens the track with his acoustic guitar, there is a natural sheen and electricity to the sound that had me smiling big time. He is virtually standing in the room. When Chris Squire and his electric bass kicks in, it shakes the foundation and I can feel it in my chest. As the rest of the band joins into the fun, the INT-250 manages to sort out all of the musicians without edge and distortion and with clear definition, unlike other releases that I have experienced. This is Yes at its best! Thank you Steven. Thank you INT-250.

Final Thoughts

It goes without saying that many of us are concerned about the future of high end audio. So many variables. So much change. Yet, I continue to see some light at the end of the tunnel while attending various shows like AXPONA, Rocky Mountain, and local audiophile gatherings. The younger generations seem to be taking notice.

Regardless, with these kind of significant investments in hardware and software, two variables that we must now consider more than ever is reliability and support. If there is one company that will still be around for the long term, it's gotta be Pass Labs. Build quality is superb. Reliability is superb. When I think of customer focused management and product support, Pass Labs is right there at the top of the list. If there is one safe place to put your money, Pass Labs gets my highest recommendation.

The good news is that you get all of the above, but also some of the best sound quality and performance available. The INT-250 is just another example from Pass Labs of superb engineering and design that really delivers. I'm sure that readers are tired of hearing about system compatibility and personal taste caveats, but they are important variables in the equation. With all of this in mind, if you are checking out the latest and greatest in integrated amplifiers, the Pass Labs INT-250 is a must audition! 

INT-250 Integrated Amplifier

Retail: $12,500

Pass Laboratories

13395 New Airport Rd. Stuite G

Auburn, CA 95602