Pass Laboratories INT-60 integrated amplifier Page 2

Over and over for two days, I played The History of Rock Instrumentals, Volume 2 (LP, Rhino RNLP 70138), and all I had was fun as I tried to decide which track on this extravaganza of Guild, Gibson, and Fender guitars was the most grungy and proto-punk. Link Wray & His Ray Men's "Rumble" used hard twang and long reverb to serve up raw, Eisenhower-era ominousness. Duane Eddy's "Rebel-'Rouser" and Bill Justis & His Orchestra's "Raunchy" both feature grungy, deep-textured sax. But it was the sounds of the piano and plucked double bass in the Wailers' (no, not those Wailers) "Tall Cool One" that upstaged all that greased-hair guitar posturing. The attitude in "Tall Cool One" is sly and cocksure.

Through the Pass Labs–Magnepan combo, guitars sounded extra-rich and tactile. The piano sound was of genuine wooden keys and hammers. But along with all that early-rock swagger was a subtle feeling of rounded lower-level details that sabotaged some of the jukebox impact I was hoping for. The Magnepan .7s never actually sound soft, but through them, instrumental textures—especially of cymbals and snare and kick drums—can feel a little rounded and rubbery. I was expecting the INT-60 to tighten things up a bit more than it actually did. Despite my dashed expectations, the INT-60 was still the best amp I've used with the Magnepan .7s.

Listening with the KEF LS50s
The best thing about the Compact Disc has always been the lovingly remastered sets and series of historical, esoteric, and regional music. London Is the Place for Me: Trinidadian Calypso in London, 1950–1956 (CD, Honest Jon's Records HJR CD2) is a modest but well-chosen compilation that includes high-quality images of each song's original record label. Young Tiger, The Lion, The Mighty Terror, and others are included. It's a CD to be treasured, and I've played it countless times, sometimes for days on end. The music just keeps getting better. However, through most of my systems it sounds as if it's coming out of a table radio. Not with the Pass Labs INT-60 and the KEF LS50s. Finally, this music sounded as free, richly toned, and swinging as I've always wished for. Every song grabbed me, and made me smile and wonder what life was like for Caribbean immigrants in a London still recovering from WWII.

My favorites are The Mighty Terror and Rupert Nurse's Calypso Band doing "No Carnival in Britain," and The Lion doing "Some Girl Something"—both are pure dance-around head shakers. In "No Carnival," the trumpets, clarinets, and (especially) the saxophone all sounded brassy, sweaty, and full-on blatty. Congas had volume, wood, and skin. For the first time ever, voices sounded rich and full. I could sense the microphone in The Terror's hand. The Pass Labs INT-60 and KEF LS50 speakers showed me Kodachrome glimpses of a real 1950s London.

The INT-60 may be made in California, but the way it reproduced songwriter and visual artist Terry Allen's Human Remains (CD, Sugar Hill SHCD-1050) took me right to Lubbock, Texas. I called all my friends: "You won't believe how perfectly perfect the tones of Allen's and Lucinda Williams's voices are in 'Back to Black'!" This was the first time that, from song to song and from instrument to instrument, the reverb throughout this album seemed properly scaled. It was also the first time I heard so much wood and metal. In "After the Fall," the bass was stronger and reached lower than ever. "Hey remember all those psychedelic nights / When your head came loose and floated into the lights / And all them girls without any tops at all / Down in the dirt uhhh huhh after the fall."

Listening with the DeVore Fidelity Orangutan O/93s
Imagine: The ultra-informative Roksan Radius 7 turntable with the dynamic Dynavector 20X2L moving-coil cartridge loaded by Dynavector's super-fine SUP-200 step-up transformer pulsing Parasound's pure-toned Halo JC 3+ phono preamplifier feeding the Pass Labs INT-60 connected via Auditorium 23 speaker cables to John DeVore's vividly lucid Orangutan O/93 speakers, all together playing "Wreck of the Old '97," from a mono first pressing of one of Sun Records' earliest offerings, Johnny Cash's All Aboard the Blue Train (LP, Sun LP 1270): "He was goin' down grade makin' 90 miles an hour / when his whistle broke into a scream." I could feel Cash's guitar strums in the hairs on my arms. Guitar tones were sharp and thick. Need I tell you how thrillingly this killer rig reproduced this masterpiece from Cash and producer Sam Phillips? Okay then—I will.


Never before the Pass-and-DeVore combo had Cash's voice had as many subtle, super-rich shadings of tone and texture. Never had it sounded stronger, denser, more real. Never had I noticed as many low-level contrasts. Never. "He was found in the wreck with his hand on the throttle / scalded to death by the steam."

So imagine this same system playing the stereo and mono versions of Gunther Schuller's "Conversation," recorded in 1960 by the Modern Jazz Quartet with the Beaux Arts String Quartet, conducted by the composer and released on Third Stream Music (LPs, Atlantic 1345 mono and SD 1345 stereo). This is early multitrack recording at its best, preternaturally clear and tastefully mixed (multitrack wizard Tom Dowd joined engineers Earle Brown and Frank Abbey to create the Full Spectrum Stereo version). It's a sophisticated and nearly magical musical experience, but when I switched to the mono version, the first thing I noticed was how the bass felt more full and powerful than in stereo. Percy Heath's double bass appeared almost life-size in my room. Then violist Carl Eberi, pianist John Lewis, and vibraphonist Milt Jackson entered, and all that extra corporeality began to pulse and morph in the most tantalizing and mesmerizing ways. The supercreative minds behind this music entered my consciousness.

I have compared the mono and stereo versions of Third Stream Music on numerous systems—some costing well over $100,000. Each time, I hear some new difference(s) between them, but I've never enjoyed the individual molecules of the MJQ's vibraphone-charged air as I did with the Pass INT-60 driving the DeVore Orangutan O/93s.

Listening with the Falcon Acoustics LS3/5a's
I hadn't planned to include Falcon Acoustics' LS3/5a speakers in this review, but late one night I put away the DeVore Orangutans and set up the Falcons on stands 12" from the front wall. Then I turned out the lights and played that Johnny Cash album again. I thought that the Pass Labs INT-60 would do good job of driving my favorite almost-invisible speaker—but I never imagined that Cash's shivering voice would sound as perfectly toned and as tangibly present as it did in "I Heard that Lonesome Whistle." I knew the Falcons could boogie and roll, but I was still surprised by the pulse-quickening, wheel-driving momentum I experienced with "Rock Island Line." Every vocal and instrumental tone began and ended in a fresh, firm, complete manner. Every bass pluck and guitar strum—every change in the timbre of Cash's voice—registered positively on my awareness spectrum.

As the cowcatcher of that Rock Island Line locomotive plowed my speaker cables, its engineer gloated, "Well I fooled you, I fooled you / I got pig iron / I got all pig iron." Playing this "hot stamper" Sun LP through the Pass INT-60 and Falcon Acoustics LS3/5a's made Cash's voice and guitar sound extraordinarily solid and real.

Stashed in my bunker are 10 pairs of speakers. The Pass Labs INT-60 integrated amplifier drove all of them with winsome ease, natural authority, and the most realistic timbres imaginable.

Every night, the INT-60 delivered what British beer brewers call sessionability—which New York Times writer Alex Halberstadt defines as "the degree to which a substance incites you to consume more of it." (footnote 1) The INT-60's dominant trait was to suck me in and glue me to my seat as it continued to reproduce music with so much low-key flavor, natural color, and more-ishness that I could never play just one record and go to bed early.

Like a sessionable beer, the INT-60 was not too anything: never too bright, dark, bland, or spicy, never too wet or dry. It always sounded relaxed and balanced. It could play softly and quietly, and rhythms would still sparkle and jump. It could crash a train and not break a sweat. It kept a steady hand on the amp/speaker interface. It felt infinite and invisible. It got out of the way. It did everything right—or, at least, what I imagine "right" to be. It transcended all notions of tubes vs solid-state. It was everything I expected from the House of Taoist Masters, aka Pass Laboratories, Inc., and much more.

Footnote 1: Alex Halberstadt, "Letter of Recommendation: Cheddar and Sour Cream Ruffles." New York Times, August 17, 2016.
Pass Laboratories Inc.
13395 New Airport Road, Suite G
Auburn, CA 95602
(530) 878-5350

Allen Fant's picture

Great as always review- HR.
The Pass Labs & First Watt integrated amps are on my short list to demo. Several choices in each brand- which one shall I start auditioning?

findcount's picture

bet they could sell this amp 30-40% cheaper if they didn't used an over-the-top chassis

Anon2's picture

There's a whiff of a self-serving argument in the 6th paragraph of this article. I am sure that this integrated is a fine piece of equipment. But to dismiss "measurements" is one many postures of the audio community that needs to be challenged.

"Measurements" don't matter; only some ethereal out-of-body experience does. Well, then why not join the ranks of most audio publications and stop going through the sweat of "measurements" altogether?

Based on my research only Stereophile, Soundstage! (Canada), and (Poland) bother to do comprehensive measurements on a regular basis. Credibility is gained in my book by the efforts made to subject equipment to the objectivity of measurements. Soundstage! proudly enters disclaimers of how their methodology complies with those of the Canadian Bureau of Standards.

And, yes, measurements do matter, particularly for those of us on a budget. Measurements show where there is superior workmanship done on a budget.

I recall reading in a leading car magazine about 18 years ago that my sporty, econobox Japanese sedan had "measurements" that were quite similar to a German import costing over 2 times as much. But perhaps I missed the sublimities of the leather seating and all of the prestige. Forget that the car was not much faster, not much more powerful, and had about the same dBs (bad ones for automotive pursuits) of sound inside the driver's cabin.

I have also found that my favorite brand of timepieces (available for a reasonable price today at a mall near you) has a 5 year warranty. To my surprise, much of the finery of Geneva and Le Chaux de Fonds, costing 10 times as much, or more, often comes with a much shorter warranty.

Instead of asking why "measurements don't matter," I'd ask another question. Why does a product costing $9,000 not have better measurements, in some areas, than a $999.00 Class C integrated amp listed on the current line-up of "Recommended Components" in this publication?

I for one am delighted that I have the "better measurements," and a good audio experience to boot, off of an integrated amp (the predecessor of your Class C item) which I purchased as dealer demo for 8.7% of the price of the item under discussion in this article. I hope this fine piece of gear in this article is 11 times better than what I found on a Saturday afternoon.

Oh, and my car: it lasted 17 years; probably it out-lasted its luxury rival, and spent less time in the shop. My watch is still going strong after 15 years.

This publication, and the audio hobby in general, can't afford to dismiss the value-for-the-money trade-offs that exist in this pursuit, most your readers do it every day; we look at the "measurements," too.

Jason Victor Serinus's picture

Read the paragraph again:

And what about measurements? Can John Atkinson's graphs of impressive sinewaves and squarewaves corroborate relative value? Maybe . . . but, as my friend Steve Guttenberg always says, "Measurements are useless at predicting user preferences."


Long-time listener's picture

"Measurements are useless at predicting user preferences."

??? I find measurements quite useful at predicting MY preferences--and I'm a user, aren't I? I have learned, through correlating measurements with listening, to avoid like the plague any speaker that shows signs of upper-midrange or presence-region forwardness, or that has certain other anomalies that I hate. Likewise there are certain features I look for in amp measurements.

jmsent's picture

which measurements you are referring to that are inferior to the $999 model? From what I see, the measurements of this amp are quite excellent overall. Certainly nothing to disqualify it from sounding absolutely superb. All engineers engage in trade-offs. You can run tons of loop feedback in an amplifier and get lower distortion specs, but often at the expense of sound quality . That's not the way Pass designs their amps.

jim davis's picture

I recently displaced an Ayre AX5Twenty in my main system with the PASS INT-250. If one can afford the step up from the INT-60, I strongly recommend it. The added bonus is not only are the sonics superior, but so is the interaction with the manufacturer. Kent English at PASS couldn't be more invested in ensuring a new customer's delight with a PASS product. Apparently, Charlie H has schooled the Ayre staff to make it clear that customers were clearly misguided to call Boulder and that their concerns would be best directed to their respective dealer.

cgh's picture

My understanding is they are different. Both are "point 8" but the 60 runs a higher bias and is class A up until 30 watts. The 250 leaves class A at 16 watts.

jag's picture

i just purchased the new Rega Brio integrated amp. for $1000 it will give any SS amp i have heard a run for it's money. ethereal highs and profoundly musical. a heavy hitter at only 50 very powerful watts. seperate power supply for the pre-amp which simulate Class A sound. one does not have to spend crazy money for high end sound.