The Pass Labs XA 60.8 Monoblock Amplifier Review Part 1. VS the INT-250
By Steve Huff
This is Part 1, Part 2 coming soon (will be linked here when completed)
It’s a funny thing. Since I moved from Arizona to my new home 2300 miles away, in the middle of nowhere, I have spent months building my newest (and hopefully last) audio system. I have been taking my time (with patience) as I have learned in life that patience can bring great rewards. In years past I would walk into an audio shop and drool over something new and just want it immediately. These days I am happy to take my time. In fact, my new “reference” system in my dedicated room has been worked on since November 2020.
I also have to take my time to spread out the costs as we all know how expensive this hobby (I call it a passion) can be!
For many years one of my goals was to own (or at least audition) a Pass Labs product. For me they have always had this certain attraction. It could be that they always get rave reviews, or it could be the simplistic yet handsome design. It could also be that Nelson Pass is considered a genius in the audio world…a magic man who really knows his stuff. All of these things are true without question and it has taken me a lifetime to finally be able to try out a Pass Labs product. I have now (this year) been able to listen to the INT-25, the INT-250 and now the XA 60.8 Monoblocks. Soon I hope to be able to try out the XP17 Phono Pre and a dedicated Pre Amp from Pass. I spent 35 years in a pass labs drought and now that drought has lifted!
Since I was assembling a new system this year I decided to buy the INT-25, the entry level integrated from Pass Labs. I LOVED IT (and still do) and was wowed by the power it seemingly fed my speakers with. Even with such a low 25 WPC rating it brought the goods. You can read my full review of that piece HERE.
Getting that taste of what a Pass Labs amp can bring I immediately knew I had to give the head honcho integrated, the INT-250 a try. While it only puts out 15 WPC in Class A (and 250 in class A/B) it had the power as well as the delicacy to drive my Dynaudio Heritage Specials with authority and finesse. I have that INT-250 in my system now and truly feel it is a special piece. You can read that review HERE.Some have called it the greatest integrated amp ever made.
Even with the INT-250 running the show I was still having thoughts of the small INT-25 in my system. It had more of that Class A flavor than the 250 and yes, I have found there is a difference between Class A, Class A/B and Class D amps when it comes to sound (also heat and energy costs!)
They all have a sound signature, and while none of them are bad by any stretch of the imagination I have discovered I have an affinity for the sound of a great Class A design. Call me old school or old fashioned but I find the sound of pure Class A has a sound that speaks to your soul. It’s rich, it has depth, it has oomph, and sounds like butter melting on a slice of bread at times. (Smooth, silky, slightly sweet).
For me, an amplifier running in Class A sounds pure, slightly warm with some weight and a juicy kind of vibe that fills my space with magic..depth..texture and a pure tone. While Class D amps may make more sense today (much more efficient and the good ones sound fantastic) there is something special about an amplifier running in all Class A. I had a taste of it with the INT-25 and that amp will always be within my memory as one of my favorites of all time. For what it is, if you have efficient speakers one needs to look no further as that 25 is a special piece and it is the lowest price integrated that Pass offers. It’s an amazing match to Klipsch Heritage BTW ; )
There are limits to that INT-25 though, as it is really meant for speakers that are not a hard drive. While the INT-250 gives me that power to drive my Heritage Specials with ease, there is still a bit of that Class A magic missing as at its heart, the 250 is a Class A/B amplifier. Even so, with the 250 I get more transparency, air, detail and expansion of the stage but I lose some depth, texture and a little of that Class A fullness.
After hearing what a good lower power Class A amp can do in the INT-25 I then wondered what something like a set of Pass Labs XA60.8’s would bring to the table as they pump out up to 120 WPC in Class A (into 4 ohms, which my speakers are). A huge step up from the 15 of the 250 and the 25 of the 25.
I have always been an integrated kind of guy. Keep it simple right? Many have told me to give a set of monoblock amps a try with a nice preamp. I was told “you will be impressed” vs an integrated. Seeing that I have owned nice integrated amps for so many years I decided it may be time to see for myself if there truly is a difference, and just how big of a difference there would be.
Like it was meant to be. The Xa 60.8’s arrive.
A short while ago by some streak of fate I was able to take delivery of a pair of Pass Labs XA60.8 Monoblock amplifiers. YES! Now I was going to be able to hear what the differences were between the INT-25/INT-250 and the XA60.8’s driving my speakers. In all honesty, I felt there was still more performance to wring from these lovely two way bookshelf speakers, and I wondered if these beautiful mono block amps could do it.
My Dynaudio Heritage Special Speakers are fantastic. You can read about them on various forums and most who own them echo my words about them. They are indeed special, and while there are so many amazing speakers out there that I would love to audition and hear I do not feel I would ever need to sell these little wooden boxes. They look classic, and sound so good with their solid foundation and beefy midrange. They are transparent yet meaty. They are small yet sound close to full range in the right sized room. They are made with high quality parts and sound like it. They are also limited to 2500 pairs and will hold their value well. You can read my full review of the speakers HERE I you missed it.
While I have interest in a set of Serblin Accordo’s and Focal Dioablos these Dynaudio Heritage speakers are beautiful and for me, have no real negatives besides not being as open and crips as a Focal speaker and not being as rich and romantic as a Sonus Faber or Serblin design. I love all three sounds but the Heritage offers a nice balance of all of these sounds.
They also have been sounding very nice with any Pass Labs product I have thrown at them (even the INT-25) and was excited to see how they would handle the XA60.8 Monoblocks.
My Beloved INT-250 Glowing Blue
Pass Labs has another integrated in their lineup that sits between the 25 and 250 and it is called the INT-60. The 60 delivers 30 WPC of Class A and after that it heads into Class A/B territory. The XA 60.8 Monoblocks deliver a full 60 WPC of Class A into 8 ohms and a whopping 120 WPC into 4 ohms (my speakers are 4 ohms). So these mono blocks are like the INT-60 on steroids. Separate power supplies, no crosstalk and each speaker would have an 88lb amp driving it to its peak performance. No compromises.
Be warned though. These monoblock amps are electricity eaters and heat monsters as well. Running them for the first 6 hours had my room heat up a few degrees and at 800 Watts of usage for the pair, it’s like having eight 100 watt light bulbs going on at the same time when running the amps. With the amps and the INT-250 running I am sure my electricity meter was spinning nice and fast.
Even so I was excited to try them in a couple of ways. First, using my INT-250 as the pre-amp which is what this (part 1) review will be based on. The INT-250 has pre amp outs and can be used to drive external amplifiers. While this is not as ideal as something like an XP-12 or XP-22 dedicated pre-amp from Pass, this would allow me to hear the differences between the INT-250 on its own with it’s own powerful 250 WPC amplifiers inside vs the pure Class A monoblocks, which have less rated wattage power for my power hungry speakers.
A few weeks after listening with the INT-250 as the pre amp I will attach a Pass Labs pre-amp to see if that takes it even further. As for cables, I am running everything balanced with Nordost Blue Heaven cables and one Audioquest Columbia XLR from Pre to Amps.
Delivery and Burning In
Pass Labs sent me the XA60.8’s to check out. To review. To evaluate. To see what I thought of them in my system. Just to note, I make not a cent from these audio reviews. No affiliate sales, no kickbacks, none of that. I love writing reviews as audio has been a lifelong passion of mine and I happily do it without the need for a paycheck. So my words here are from the heart, not hype or for affiliate sales.
When the UPS guy came and dropped off both boxes he said “What is inside of these boxes”?!?!?. I told him it was a pair of monoblock amplifiers and he just gave me a look like “What”?!?! Lol. These boxes were heavy at around 100lbs per box. The amp weight is 88lbs a piece or almost 190lbs for the set. Phew, and I thought the INT-250 was a beast.
I unpacked the amps where the UPS guy dropped them off, right on my front porch. I carried them into the house using the heavy duty handles on the back, and it wasn’t so bad. In my listening room, which is all the way in the back of our house I placed them near each speaker that they would be powering.
The amps have one XLR balanced input and one RCA input on each amp with two sets of speaker being posts as you can use either one as a left or right amplifier. You can not use one as a stereo amp even though with both sets of biding posts it may appear this way. Once set up, hooked up and ready to rock and roll I turned them on and let them settle in for a few days.
One day I was running them in quietly for 12 hours and decided to check in on the sound. When I walked into my closed door room it was sweltering hot. My 12X18 room has one window AC unit as it is separate from the house central AC and I did not have that window unit on and it was a balmy 91 degrees outside. The listening room was steaming as between the INT-250, the 60.8’s and the outside temps it was HOT. I turned on the AC unit and within 20 minutes it was comfy again ; )
But these amps run hot. Much hotter than the INT-250 which I feel never gets that hot. The 250 is basically a Class A/B design though and only offers the first 15 watts in Class A. The XA 60.8 monoblocks are biased deep into Class A and with the 120 WPC going into my speakers, all Class A, they were running pretty warm. So yes, all you have heard about these amps getting hot is true! Even so, once the room was cooled off it was not an issue. One of my other favorite amps of all time which also ran in class A (and used Tubes) ran super hot but man did it sound amazing (Line Magnetic 219ia). It seems heat = glorious sound.
After a few days of running in (these were not brand new but refurbished so I was told a full burn in was not fully needed) they started to sound settled in and I decided to sit down and listen, and then compare to my INT-250 alone.
The Listening “Experience”
OK, the amps were run in, they were all hooked up with decent cables and I had my digital front end and now vinyl front end ready to go. I was all set to listen to tracks I know backwards and forwards to see how a set of $15k monoblocks compared to a $13k integrated amp alone.
Anytime I get a new audio piece in I am excited but also keep my expectations low and I understand that once you get to this price range we are dealing with “different” rather than “better”. I knew the 60.8’s would offer me a different sound, but not necessarily better. I knew the sound of the 250 very well, as I listen daily in this room to it as I write, think, daydream or drink coffee. It is my escape, and how I am able to live life without stress. It’s an Experience.
Music does and can speak to our soul and it’s amazing what beats, rhythms and words can do to our metal state. Music for me, is a healing process which is why I have always had a system in my life. Ever since I was 15 I have had a 2 channel music system and while it is very “Niche” today to have a high dollar audio system, it is more satisfying to me than buying a new camera. a new car, a new house or well, new anything. For me, it’s the ultimate cleansing tool, to rid my mind of negativity, stress, or worry.
Music has a way of calming our soul when we actually sit down, and listen to a system that has been designed to “take you away”. My system is designed to do just that and while it is not perfect or even 100% where I really want it to be, it truly does heal my mind, body and soul.
When I listen for an hour or even a few hours I always leave my listening space happy, calm and with an inner peace. This is why I love music and enjoy having a nice two channel system. It’s why I write these reviews…from my passion for music and because I know there are many out there like me who understand and want to read as much as they can about it. So I hope you enjoy these reviews as they always come from the heart. If this review helps one person, then I am happy : )
The First Sounds Emerge (Vinyl)
As I sit on my couch which has been set up for a “sweet spot” right in the middle I first put on a record from Dead Can Dance called Anastasis. I have had this album since 2016 on clear vinyl and the sound/recording quality is astonishing on my pressing. It’s probably my best sounding album. The sound is so full, the bass so rich and present (I can feel it in my seat), and the vocals can be haunting. It’s a two record set but really nice to listen to when I want to zone out a bit.
I put on “All In Good Time” and while I knew what this track sounded like on all other systems I have had over the last few years this time it was extremely touching.
With the 60.8’s running the show, the sound was quite bigger, deeper, fuller, and more human than I remember with other systems. It was less technical and flowed in a way I have never heard this track flow. Fluid and slightly thick, like oil running through an engine. The Bass could be felt in my chair, and I do not use subwoofers. The midrange was sublime and tangible (though part of this is the Koetsu Black Cart) and the entire production just sounded so right. No extreme precise surgical imaging here, just sweet music with just the right amount of 3D, depth and life. Vocals were locked dead center with a richness that I have heard only a few times in my life.
Bottom line? These amps made everything sound bigger and more real than anything I have had in the past. Such a sweet balanced sound.
I swapped back to using the INT-250 for amp duties and removed the XA60.8’s as I wanted to hear the difference immediately.
I will say up front that the INT-250 is an end game integrated and it also sounded fabulous but it was very different. The INT-250 did not sound any more powerful, in fact, it sounded less powerful as I had to go up with the volume dial a few notches to get the same volume as when it was driving the monoblocks.
What I heard with the INT-250 was less a powerful and impactful bass, a lighter footed sound and yet a more expansive sound with more precise imaging. But I don’t know…gone was that oh so right tonal richness, the thickness and the beefy mids of the mono amps and that feeling of all out POWER…the sound I could feel in my gut. In its place was more air, more precise imaging, and a wider soundstage. Now, some may prefer this to the fuller, meatier sound of the Class A XA 60.8’s as it is more “Audiophile” and while the INT-250 does have some warmth and meat of its own, compared to the XA60.8’s it sounds thinner, less powerful and less focused/refined.
How could this be? The INT-250 has 250 WPC into 8 ohms and a whopping 500 WPC into my 4 ohm speakers. The XA60.8’s are putting out 120 WPC into my speakers yet they sound bigger, have more authority and are truly pushing these speakers to their maximum potential.
It’s Class A my friends and why some audiophiles will only buy and run Class A amps.
A look at my Analog setup with sound demos. Running the XA60.8’s
Class D amps are fantastic and much more energy efficient but when you have that certain Class A sound in your head, that sound you know you love and the sound that touches your soul then there is nothing else that can get close.
While I loved the sound of both the INT-250 and the Mono’s, I did prefer the sound of the XA60.8’s with that Dead Can Dance album. It just had more authority and it connected with me better with the all Class A power. With the 250 the sound was “looser” and not as composed or together sounding. That sounds CRAZY to say as the INT-250 is world class and anyone could be happy for life with just that piece! The XA60’s do bring more oomph, drive and it even seems to bring more power/juice to the speakers.
Even when listening to thin sounding albums that I never listen to because of a thin sound (Depeche Mode 101 is a good example) it became tolerable with the XA60.8’s as there was now serious weight behind the music and the midrange magic was back.
More Sounds Emerge (Digital)
Next up I fired up my digital setup and listened to tracks I know and love with both the INT-250 on its own and with the XA60.8’s connected.
My digital setup consists of a Lumin U1 Mini and I have been swapping DAC’s here lately between a Chord Qutest and the new iFi Neo iDSD unit, which I have to say I slightly prefer to the Chord (and it’s half the cost and includes a headphone amp). You can see my review of the iFi HERE. It’s an AMAZING DAC for the money, and I highly recommend it.
My analog front end is now more costly than my digital front end but I have found over the years you must spend more on Analog to get it to sound as good as a modest digital system, and EVERYTHING makes a difference. The table, the arm, the cartridge, the phono preamp are all ingredients to achieving analog success. I found when you skimp on just one of these areas, the entire sound can fall flat. So Analog takes an investment if you want it to match Digital, with a good digital front end of course.
These days, digital can sound spectacular with a lower cost outlay than a good vinyl system. My vinyl system retails for $6700 (soon to be much more after I add a better phono preamp) and my digital about $2700 and the sound is better on the digital setup, depending on the quality of the recording or course. Even so, there is a different vibe with vinyl. It is more ritualistic. More nostalgic. It’s more fun and makes me listen to an entire side of an album rather than skip skip skip as I find myself doing with digital sometimes.
So let’s listen…
I sat back and put on some Lana Del Rey, Karen Dalton and Melody Gardot.
Listening to “Bad News” from Melody Gardot’s “Live in Europe” album was another experience and sounded fabulous through the INT-250, which is how I started. I love this swaying bluesytrack on this live album. much more so than the studio version. It has a true live vibe, and that Saxophone is so awesome to hear, especially near the end when it hits you in the chest with that big deep bassy growl.
With the INT-250 I heard what I was familiar with. A nice sense of space, a true live feel. Natural but semi precise imaging with a deep and wide soundstage. I felt as if I was in the audience, somewhere in the middle of the theater and I was able to hear all sounds, nuances and finger plucks with ease. Melody’s voice was dead center and seductive but not full on “throaty full”. There was a nice balance that offered me all of the qualities I love in my music listening. I said “Steve, this is all you will ever need right here” and I was right. It was an amazing listen.
I then hooked up the XA60.8’s to the INT-250’s pre-amp outs and listened again.
There it was, the difference of an all Class A amplifier. The sound became bigger, had more authority, had a meatier and deeper midrange, sounded smoother and while the soundstage became a tad smaller, the intimacy was greater. The sound was more cohesive and less “loose” with more boom to the drums and more meat to the instruments. It was “Juicy” and I was digging it. A lot.
Now I felt as if I was in the first 3 rows, and it was almost as I could see the sweat on Melody’s face as she sang with such passion. The guitar was more present and had more life and was more noticed, and that is huge as that instrument is a huge part of this song and helps to drive the beat. When the Sax came in it was bigger, sounded more real and had more life.
As good and as special as the song sounded with the INT-250 alone, the XA60.8’s brought a more intimate and more tangible performance to my room. As if the artists were performing just for me in my space rather than for 10,000 others.
I listened back and forth a few times, with other tracks and it was always the same result. To be honest I loved both presentations but I leaned way more to the Monoblocks, as the class A sound is something I love. It’s lacks nothing. It’s pure music and it just oozes and flows right to the heart.
I also know it will get even better.
I have yet to hear these amps with a proper pre-amp! While the INT-250 has this pre-amp out capability there are trade offs to using an integrated amp as a pre amp. I was told the performance would go up with the 60’s when I added a proper pre-amp. If this is the case, I may be in trouble : ) I WOULD LOVE to hear what an XP32 would sound like with these beautiful amps (and that would prob push me over the edge to upgrade) but I may start with an XP12.
The Specs of the XA60.8 Amplifiers
From the Pass Labs Website:
“Offering all the sonic benefits of the .8 amplifier line, a pair of XA60.8’s also grace the listener with mono-block performance: dedicated power supplies for each channel, dedicated circuitry for each channel and dedicated chassis’ for each channel offer a cleaner, better defined image and soundstage. Beautiful to the ears and eyes, this model achieves levels of focus and intimacy normally associated with the finest tube amplifiers. The XA60.8’s do all of this while providing greater control and power.”
VS the All Class A INT-25?
These amps sound different from the all class A INT-25 I owned. While these amps provide the grunt, all out power and human touch the smaller one box INT-25 was like a blend of the INT-250 and XA60.8 combined into one smaller and lower powered integrated. That INT-25 is a special piece as well but better suited to more efficient speakers.
So far the sound of the XA60.8’s have impressed me and Pass Labs is 100% correct in what they say above.
“Beautiful to the ears and eyes, this model achieves levels of focus and intimacy normally associated with the finest tube amplifiers. The XA60.8’s do all of this while providing greater control and power.”
While I do not feel they sound exactly like a tube amp, they do have some of the qualities of a tube amp and do not sound quite like a solid state amp. All of the Solid State amps I have had in the past all sounded like Solid State and some were well…thin, grating and not so hot.
These Pass Labs amps sound different than most solid state amps and offer up some tube flavor with that massive power and bass control. Even so, they do not have the all out bloom of something like a 300B amp nor the “electric drive and energy” of an 845 amp. What they do have is solid USA build, reliability that is off the charts and a way of producing music in your room that is sweet, real and leans to the warm side of neutral with deep and controlled bombastic bass. This is good as it makes music sound more like real life rather than overly processed “HiFi”.
The top end is not crispy or bright or etched, but I would call it “present and fluid”. The treble is not warm but some may miss the bright splash of the cymbals or the dynamic excitement that other solid state amps can bring. The Pass sound is in full effect here. Warm, Fluid, Human, Touching, Deep, Powerful and not Artificial in the least.
While 60 WPC into 8 ohms doesn’t sound like a lot, with a Pass Labs amp you are always getting more than you think when it comes to power. These amps are rated very conservatively and power my hungry speakers with ease. It’s due to the power supplies and CURRENT and is why these get so hot and cost more than your normal Class A/B or Class D amp. It’s also why these sound more powerful than the INT-250 in my system. Each speaker has a full powerful class A amp driving them and each have their massive power supply and feed the speakers separately, rather than in one box. I clearly see and hear the benefits of a set of mono amps, but wether the cost (and heat) is worth it for you, only you can decide.
While the design of these amps (and most of the Pass Labs product line) is more basic, the sound is far from it. These amps do not need flashy gimmicks, or golden knobs. They do what they do and do it better than most I have heard.
This is only Part 1
I will be writing a part two on these amps soon, after I log some time listening with a proper preamp (will be a Pass Labs) and even proper Phono Stage (Pass XP17). Heck, I may upgrade my digital with another new DAC that I am able to audition soon.
This article was just my thoughts on the differences between the XA60’s and my INT-250 using the INT-250 as the pre-amp for the monoblocks. Yes, I like the XA60’8’s better than the standalone INT-250 but I also love the 250 on its own as it provides a different presentation (and doesn’t get as hot). Even so, the XA60.8’s offer up a superior sound to these ears as I prefer deeper, bigger, warmer and meat to the mids. That’s what the 60’s bring in addition to bringing some of that holographic 3 dimensional magic.
The XA60.8’s when driven by the INT-250’s preamp out sounded more human, more real, more tangible, more powerful and had much more weight and oomph compared to the INT-250 on it’s own. It put me into a more intimate lifelike performance yet it still had the magical attributes like depth and a 3 dimensional presentation. The INT-250 was more spacious, a bit thinner sounding, and had a little bit more sparkle and air. Both gave me an amazing experience. Both are end game components and the XA60.8’s sit in that sweet spot within the Pass Labs lineup, offering IMO, a great bang for the buck. While not cheap at $13,500 retail they are a lifetime investment and if the sound of Class A suits you, it could be the set of amps that break the spell of constant upgrades or “What-if-itis” : ) They are special indeed.
As I sit and listen to “The Pure and the Damned” with Iggy Pop through my Lumin U1 Mini, teh XA60.8’s deliver this track with so much depth, bass and a glorious midrange where the voice if Iggy is super realistic. The bass seems to emerge from nowhere, as if I have a sub active. It’s tight though, not flabby. It makes my Heritage Specials sound VERY full range, and that is pretty cool.
Listening to Sarah Brightmans “Miracle” was a mind blowing experience with the 60.8’s. Never heard these speakers sound this big, and I realized that this is how they are meant to sound. This track had magic, depth, and such a sweet sound I was almost hypnotized and brought into the performance.
I look forward to using these with a Pass Labs preamp and when I do, I will write part 2 of this review and let you know how that sounds in comparison to with the INT-250! I am excited to see how much the performance jumps up with a nice Pass Labs pre-amp.
Until then I will be listening to the music as these amps are in a league higher than I am used to and I want to soak it all in while I can : ) More to come from these fabulous Monoblock Class A Beauties.