Country of Origin
Reviewer: Srajan Ebaen
Financial interests: click here
Main system: Sources: Retina 5K 27" iMac (4GHz quad-core with Turbo boost, 32GB RAM, 3TB FusionDrive, OSX Yosemite. iTunes 14.4), PureMusic 3.02, Audirvana 3, Qobuz Hifi, Tidal Hifi, Denafrips Terminator, Soundaware D300Ref SD transport & USB bridge; Preamplifier: Vinnie Rossi L2 Signature with WE VT52/300B or Elrog 50/300B; Power amplifiers: Kinki Studio EX-B7 monos; Headphone amp: Kinki Studio; Headphones: Final D8000; Loudspeakers: Audio Physic Codex; Cube Audio Nenuphar; Aurai Audio M1 [on loan]; Cables: Complete loom of Allnic Audio ZL3000; Power delivery: Vibex Granada/Alhambra on all source components, Vibex One 11R on amps, LessLoss C-MARC Entropic cords between wall and conditioners; Equipment rack: Artesanía Audio Exoteryc double-wide 3-tier with optional glass shelves, Exoteryc Krion and glass amp stands; Sundry accessories: Acoustic System resonators; Room: 4 x 6m with high gabled beam ceiling opening into 4 x 8m kitchen and 5 x 8m living room, hence no wall behind the listening chairs
Second system: Source: Soundaware D100Pro SD transport; DAC/pre: COS Engineering D1; Amplifier: Bakoon AMP-13R; Loudspeakers: Acelec Model One w. Franck Tchang magnesium 360° super tweeters, Zu Submission subwoofer, LessLoss Firewall for Loudspeakers; Power delivery: Puritan Audio Lab PSM-156; Equipment rack: Hifistay Mythology Transform X-Frame [on extended loan]; Room: ~4x6m
Desktop system: Source: HP Z230 work station Win7/64; USB bridge: Audiobyte Hydra X+; Headphone amp: COS Engineering H1; Headphones: Audeze LCD-XC; Powered speakers: Fram Audio Midi 150
Upstairs headfi system: Source: Soundaware A280 SD transport; DAC: Auralic Vega; Integrated amplifier: Schiit Jotunheim R; Headphones: Raal-Requisite SR1a
2-channel video system: Source: Oppo BDP-105; DAC: Kinki Studio; Preamp: Wyred4Sound STP-SE II; Power amp: LinnenberG Audio Liszt monos, Pass Labs XA-30.8; Loudspeakers: German Physiks HRS-120; Room: ~6x4m
Review component retail: $7'250
Fish'n'chips. Unlike leaving the EU, the English would say that these two things get on very well.
So do a preamp and power amp. Together, in one chassis. Snug. Served.
Where's the greasy newspaper wrapper?
Like fish'n'chips, an integrated amplifier needn't be poncy. Pass Labs never are. What they are very much about is serious hardware with big transformers, mujo heat sinks, heavy chassis, heavy class A bias, high temps. "Big iron" as Nelson Pass likes to say.
With the INT-25, their smallest class A stereo amp called XA25 hops into the same bed as a simplified front end of the existing INT-60 machine. That makes it an X-rated and perfectly pervy proposition. For Pass, it's also very compact.
So let's get onto its case and into it, first of the pater familias below. It's the standalone amplifier with 2 x 700-watt push/pull power devices per channel. It's what I'd prefer by a few sonic whiskers to the heavier bigger more expensive XA-30.8 we already own.
The basic stats for its integrated version are 26dB of voltage gain, the same 25/50/100wpc into 8/4/2Ω power, DC-100kHz bandwidth at -2dB, less than 150μV of noise, a slew rate of 100V/μs and 10A of peak current. That corresponds to 200 watts peak power into 2Ω. All of that fits into 17×17.9×6" WxDxH and weighs 51lbs.
As a pure single-ended design, the three inputs are exclusively on RCA. The remote switches power, inputs, volume and mute. Volume by precision resistor array traverses 63 x 1dB steps.
As we did for our XP-12 review, this is a two-in-one job—today's theme is integration after all—between regular Warsaw correspondent Dawid Gryzb and yours truly.
The power-amp version without preamp stage or volume control.
To establish a proper place setting, refamiliarize yourself with the XA25 in our archives, also the reviews of Terry London for HomeTheaterReview, Herb Reichert for Stereophile and Steve Guttenberg for The Audiophiliac Hifi reviewers don't always agree. In this instance, we all thought this amp was very special. Getting it packaged with a tailor-made linestage to simplify ownership without dumbing down results should be of special appeal for many.
By January 18th, an email arrived from Bryan Stanton, head of Pass Labs' PR agency. "I'm delighted you got your hands on the new Pass Labs INT-25." Which I hadn't. In fact, Desmond Harrington with whom these plans had been cooked at Munich HighEnd 2019 had a few days prior explained that review samples still were very sparse on the ground. But our names were on the card and the card was in the black hat. Bryan's note suggested that, shaken or stirred, our card had just fallen out? I wrote him that he knew more than us. "Aha! I was fooled by what I thought was an interior photo of it on your rug — never saw that one before. And, you're unfortunately correct. They're severely back-ordered. Company policy is 'paying customers first'. That sorta cramps my style. The one in February's Stereophile was the only one I could pry out of them. And I still can't believe they allowed me to have it."
Fish'n'chips. Still on order in Ireland. Already served in the colonies, in limited quantities. But by July 22nd, Desmond had a sample on hand. To shake things up, he'd send it to Dawid first. I'd man the 2nd opinion so I could knowingly disagree with his 1st. Boss man privilege. Of course if it went like last time, we'd agree perfectly. And Dawid takes better photos. It was only right that he'd handle those as well. So let's give the keyboard and camera to our man in Warsaw now. Action!