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Pass Laboratories INT-250 integrated solid-state amplifier Review

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Pass Laboratories INT-250

Pass Laboratories has a core of talents I dub the Pass Labs Four: Founder Nelson Pass, not a boastful character but witty, adventurous and quiet, that is until you get him up on a stage and he opens up. And he attracts talents and major nerds who are like him. Then there is Kent English, North American Sales and Worldwide Support, and a scientist by training. The Pass Labs Rushmore and other speakers bear his mark. Wayne Coburn, Nelson’s Co-Designer and Lead Digital Designer, whose brain children the phono stages, linestages and integrated amplifications are. Last not least, Desmond Harrington, president of the company, Lead Industrial Designer and Graphic Artist.

Dagogo readers know that I consider the source to be the most important component in the audio system. Analog is a most engaging medium and I have five turntables to boot, but the digital medium remains the only widely available one allowing for a single-sitting through a Richard Strauss tone poem non-stop. Digital sources like the Bricasti M1 dual-mono DAC is my preferred, sub-$10k product that elevates the performance statue of a majority of transports paired with it. You get what your source trickles down.

For our readers who have done due diligence in acoustic treatment and have secured the best source component as per their budget, the cable system should be the next priority with the caveat that it is auditioned before purchase. A system will only sound as good as what the cables allow through; always complement the competency of your system with complimentary cable system. Then, choose the kind of loudspeakers you have always fancied and you will have come to the crux of system building: choosing the right amplifier.

While the source is the first piece in the system building block, the amplifier anchors the potentials of the system for the long run. Pick an underpowered amplifier and you will find constantly unfulfilled predicaments in your audio experience. Pick a competent one and you will have acquired license to choose a wide range of speakers, secure in the knowledge that you have the force and finesse at home to drive them. Without a strong amplification system, any and all loudspeakers that strike our fancy will just be mere possibilities at best plus haunting prospects of under-performance. Think of the possibilities when there is a strong and pristine sounding amplifier in your system already, waiting to flex its muscles.

With a highly hobbyist stance, Pass Labs produces not just powerful behemoths that can drive the most demanding speaker system in the world, as evidenced in its $85k Xs 300 quad-chassis monoblocks and the $42k XA200.8 pure class A monoblocks. The company also produces the XA25, a $4,900 pure class A stereo amplifier outputting 25 wpc into 8 ohms and 50 wpc into 4 ohms.  Between the Xs300 and the XA25, there are some eleven models in between.

The company also offers three integrated models.



The $7,250 Pass Labs INT-25 at 25 wpc into 8 ohms, 50 wpc into 4 ohms and “stable into any conceivable load,” is the integrated version of the XA25 stereo amplifier. Next model up is the $9,000, 93 lb class AB and high bias INT-60, which takes us into a slightly different world of finesse and force while still delivering pure class A performance up to around 30 wpc, then switching to class AB to deliver 60 wpc into 8 ohms and 120 wpc into 4 ohms.

The flagship integrated INT-250, the subject of this review, costs $12,000 and is equipped with the company’s industry-leading Class A/AB amplification in a 250 watts-per-channel configuration. At 19 inches wide, 21 inches deep, 9 inches tall, and weighing 105 lbs, the INT-250 shares the immensity of the company’s monoblock physique. On paper, it produces pure Class A output for the first 15 watts; in actual listening, I found this device while running mostly in Class AB, to be of the same bloodline and lineage of the XA200.8 that manifests an industry-exclusive finesse and strength akin to that pure Class A sound.

INT-250 Rear Panel

Extended auditioning of the INT-250 in my system driving the $95,000, 105dB efficient Destination Audio Vista Horn confirmed the integrated amplifier’s SET-like finesse. Those first 15 Pass Labs watts albeit in solid-state execution made it the quintessential alternate amplification system for the horns after Destination Audio’s own $39,000 preamplifier and the 1.8 watts-per-channel monoblock amplifiers package.

And recently, the same first 15 pure Class A wattage also tied the colossal, $25,000, 90dB/8 Ohms Sound Laboratory Majestic 645 electrostatic panels exceptionally well over, going a long way towards driving the massive panels no doubt, before the remaining 235 Pass Labs watts kicked in for good measure, a further confirmation of the integrated amplifier’s superiority in finesse and strength.

In portraying piano solo or massive orchestral presence, the INT-250 carried a differentiating ability parallel to my experience of its preamplifier siblings. Now married internally to a Pass Labs preamplification stage, the need for exotic interconnects is mitigated tenderly and fidelity is assured masterfully.

Featuring four pairs of RCA inputs among which two pairs are also XLR double sourced and thus switchable, the INT-250’s provision of one pair of XLR and RCA outputs cemented its universal appeal as the most flexible amplifier at the highest performance level possible ever to grace my system, lest our readers want to spend considerably more for fancier looking models of other brands. The large speaker binding posts are the same as the bigger power amplifiers with the torque limiting ratchet design. It is a delight to tighten spade plugs with it.

Desmond Harrington and company once described the now-discontinued, $7,500 INT-30A as the “jewel in the crown.” Granting that a pure class A amplifier producing 60Wpc into 4 ohms, resplendent with full JFET input complement and comes complete with a preamplification stage is a thing of desire, I will not hesitate to choose the INT-250 over the INT-30A . For even in class AB, the INT-250 sounded so similar to the XA200.8 monoblocks, and was capable of such driving force and accorded such operational flexibility with the exceedingly fine preamplification stage that it was the most hardcore and hence ultimate embodiment in the integrated amplifier category. The Pass Labs Class AB integrated flagship was of such exceeding performance I lost sight of the performance of the Xs Preamp with the XA200.8 monoblocks.

Good amplifiers litter the marketplace on an unprecedented scale these days. It is only when one begins to build an ambitious system that the current, massive crop of amplification designs show its limitations. Creators of the “super” amplifiers have no choice but batten down now. With the Pass Labs integrated amplifiers, particularly the INT-250, we can own a piece of history and share in the experience of the extraordinary together.

Now, if you need to have the best or got to spend that $100k first before your wife does, then by all means procure the Xs Preamp and the Xs monoblocks. Otherwise, the INT-250 is the gargantuan all music loving souls like us will ever need, and what a gem the giant is.


Copy editor: Dan Rubin



Acoustic Sciences Corp TubeTraps
Audio Reference Technology Analyst EVO, Analyst SE, XLR, RCA interconnects, power cables, Super SE power cables
Harmonix Reimyo by Combak digital coaxial cable
PS Audio DirectStream Power Plant 20 AC regenerator

Clearaudio Master Innovation turntable system with Smart Power 24V battery power supply
Koetsu Jade Platinum cartridge
AMG 12J2 tonearm
Stealth Audio Cables Helios phono cable

Esoteric K-03 SACD player/CD transport & G-01 rubidium clock
Bricasti Design M21 USB DAC
Bricasti Design M1 DAC

Destination Audio 417A tube phono stage
Destination Audio 76 tube preamplifier
Destination Audio 45 tube monoblocks
Destination Audio Vista Horns

Pass Laboratories Xs Phono
Pass Laboratories Xs Preamplifier
Pass Laboratories XA200.8 pure class A solid-state monoblocks
Bricasti Design M28 solid-state monoblocks
Sound Lab Majestic 645 electrostatic panels


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