Pass Labs XA30.5 Class-A Stereo Amp Reviewed

Published On: February 20, 2012
Last Updated on: October 31, 2020
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Pass Labs XA30.5 Class-A Stereo Amp Reviewed

The handcrafted amp XA30.5 Class-A amp from Pass Labs is definitely a pretty face. But according to Jerry Del Colliano's evaluation, there is more than enough performance to back up the XA30.5's looks.

Pass Labs XA30.5 Class-A Stereo Amp Reviewed

By Author: Jerry Del Colliano

Pass-Labs_XA30-5-Review-Front.jpgAhh, the thought of audio jewelry - it's a warm, happy place to go to, isn't it? Internet-direct high value gear is all the rage these days, but for those of us with a Jones for something really exotic, it's hard to scratch that urge with an amp packing a Bang & Olufsen Ice-amp in it. We long for something more over-the-top. We long for something a little more handmade. We long for something with extraordinary performance. We long to empty our checking accounts and to hell with the consequences. 

Additional Resources
• Read more stereo amp reviews written by's staff.
• Find a pair of Bookshelf Speakers or Floorstanding Speakers for the XA30.5 to drive.
• Explore sources in our Source Component Review section.

The Pass Labs XA30.5 at $5,500 for a 30-Watt power amp is the living, breathing definition of audio jewelry. Designed by legendary engineer, Nelson Pass (Adcom, Threshold, First Watt, Pass Labs), this amp is designed for those with a taste for the best. It's the smallest but most tasty white truffle in the case for those who know what pure, clean sound is and are willing to pay for it. Note: the Pass Labs XA30.5 isn't for everyone. It's really a solid state alternative to the single-ended triode tube amp but doesn't come with the tubes, heat and miniscule power output. With that said, you are paying 300 plus Watt per channel money for 30 Watts per channel of audio-goodness. How can this make sense?

Lower power Class-A amps are a cult audiophile component that requires you to use speakers that are willing to play along. Forget Revels and many Bowers & Wilkins. You really need higher efficiency loudspeakers to get the most out of a Class-A amp packing only 30 Watts - at least if you plan on any spirited listening. You don't drive electrostats or harder-to-drive speakers like a THIEL with a 30-Watt Class-A amp. Wilson Audio, Focal, some Bowers & Wilkins and a whole host of other options from brands like Tekton Audio, Avantgarde and beyond will fit the bill nicely though. 

When I worked for Mark Levinson at Cello Music and Film Los Angeles, we sold very high-end Tom Colangelo designed Class-A amps that sounded just like tubes but without the tube headaches and service. Mark explained Class-A operation as the most wasteful design for an amp in terms of power in versus power out but the resulting power out was the sweetest of nectar. He went on to compare a Class-A power amp to a faucet that could only run all the way on. Class-AB amps (think Pass Labs X250, Krell 402e, Mark Levinson 532h, Classé CT-M600s are able to draw from the wall differently. Most music doesn't need all of the power an amp can provide all the time but when the musical soundtrack (or movie for that matter) swells up, the power needs go through the roof and a Class-AB amp draws from the wall as needed. Class-A amps run balls-out all the time. They provide the power they can offer more evenly and with a controlled, stable sound that Class-AB amps can't compete with. 

Pass-Labs_XA30-5-Review-connections.jpgThe Hookup
Setting up this 75 pound amp is not really much different than setting up any power amp that you might encounter. Unbox. Drool at the gorgeous metal work and blue meter that makes McIntosh look cheap. Quickly, plug in XLR cables (many would use RCAs depending on the setup) and let the sucker break-in. Now break-in is a worthy topic for a Class-A amp. If you are going to bring one home for an audition, then you should make certain that the amp has had no less than 100 hours of time on it. I could make the argument that the amp doesn't really come to life until about 250 hours of break-in. If you think that is silly, then you are either a) normal or b) a Class-AB client. Class-A amps need major break-in time to come to life. They also sound best when left on, which your power bill might not like but your ears will love.

In my system, I used a system sourced with an Oppo Digital BDP-93 Blu-ray/DVD-Audio/SACD player and an Apple Mac Pro tower going into a Benchmark DAC1 PRE. The Benchmark is run balanced out (XLR) via Transparent Reference interconnects and run into the Pass Labs XA30.5. The 30.5 was originally connected to Bowers & Wilkins' PM1 bookshelf loudspeaker, but were later swapped out for Focal's Utopia Diablo speakers. Regardless of the loudspeaker choice they were connected via 12-foot runs of Transparent Reference speaker cables. Simply put, the system is a small but very high-end audiophile rig designed to shine at low levels in a less-than-perfect installation in a 25 by 12 foot office. 

Sonically, there is nothing quite like a Class-A amp. While the sound has that "pure" feeling, it isn't as rich, lush and soft as some tubes. The Pass Labs XA30.5 is more of an analytical amp but that can easily be misconstrued to be edgy, harsh or tiny sounding. The Pass Labs XA30.5 is none of those. It's deep, accurate and controlled in ways that you might not believe. Its ability to power speakers is greater than what you might think a 30-Watt amp can do but it must be enjoyed in the right context. 

Read more about the performance of the Pass Labs XA30.5 amp on Page 2.

Pass-Labs_XA30-5-Review-Black-Background.jpgFor example, on "The Sidewinder" from Lee Morgan's classic album of the same name, you can hear a brilliant sheen on the cymbals that is amazingly lively but in no way harsh, bright or abrasive. Think about what a cymbal sounds like if you went out to hear live music. It's bright but not overly harsh. It's lively. It's bold. That's how it sounded on the Pass Labs XA30.5 - like live music. The stand-up bass notes are tight and resolute. Firm sounding and lively would fairly describe the low end on the Focal Diablo Utopia speakers when played on the Pass Labs amp. Overall, the sound draws even the non-audiophile into the music, making them want to pump up the volume to live jazz club levels, which the XA30.5 is more than willing to bring to your living room.

On "See You" from The Foo Fighters' The Colour and The Shape you get to hear the Pass Labs step up and take command of a spacious, hybrid-acoustic track in a way that my larger audiophile rig at home can't do. At the end of the second chorus when the (studio) audience claps you can hear them as if they are in the room with you. The air between Dave Grohl's voice and the walking bass line is audiophile gold. In the more complex verses, the Pass Labs trucks along with a level of control that you never really hear from low powered amps. The snare pops with an accuracy and vibrancy that you don't often hear from any audio system - even expensive ones.

On "Gypsy Eyes" from Jimi Hendrix's Electric Ladyland (UK version), you can hear this level of control again with the opening kick drum. It's more like a heart pumping than it is a drum as it comes out into the musical space and grabs you. Jimi's layered guitars sound warm, round and stunningly accurate. It doesn't take an educated ear to hear all of the layers that Hendrix and Eddie Kramer put into the track. On "Long Hot Summer's Night" you can hear more of the insanely good layering with details so musically juicy that you might fall out of your listening chair. Incredible control allows Jimi's voice to float above the speakers a bit with guitars weaving together a soundstage unlike today's "all levels - all the way up" recordings.

Expanding the depth and complexity of the music I went to Love Ritual: Rare and Previously Unreleased 1968 - 1976 from Al Green and the track "I Think Its For The Feeling (It's Alright)" for a full, soulful ensemble. While the drums didn't sound as master-tape good on this track the big bass sound dispels any idea that the Pass Labs XA30.5 is a sissy little amp. Green's voice leaps outside of the limits of the speakers as if he was in the room. Al Green isn't one known for being reserved and when he his peaks - he soars. It's at those moments that amps can roll over and play dead. It's at those moments when you want to judge an amp like the Pass Labs XA30.5. It never runs out of gas. It never sounds fatiguing. It just rocks the music like it sounds on the recording - nothing more, nothing less.

With the lights dimmed on a Sunday evening with the sun setting in the distance over the Pacific Ocean, I cued up "Dogs" from Pink Floyd's Animals. I wished I had my SACD of Wish You Were Here that I paid $43 for but it hasn't arrived but is reportedly on the way. On "Dogs" the track develops in gradients from acoustic guitars and subtle organs moving at a pretty fast pace. By the first chorus, the dynamic window is wide open with full rock band dynamics. This a way tougher challenge than the Al Green track, as more is going on meaning more layering, more instruments, more dynamics yet somehow the Pass Labs XA30.5 never faltered even at very high volumes. This is very possibly the most stable amplifier I have ever heard. My 600 watt Classé' CT-M600s offer this level of dynamics (and beyond if you listen to your music that loudly) but even they don't have this kind of control. Not even the $50,000 a pair Mark Levinson N° 53s have this level of space and control.

The Downside
The advantage to the Pass Labs XA30.5 is also its downside which is that this amp while capable of rocking the right pair of speakers like you've maybe never heard - isn't right for all speakers. For example, the Bowers & Wilkins PM1 speakers that I borrowed from Andrew Robinson for this system didn't match up with the Pass Labs XA30.5 the way that I had hoped for. It wasn't that the Pass Labs couldn't power them as it could. It was that the amp/speaker combo didn't create the magic that I got with the Focal Diablo Utopia, which is a 90dB load. The Bowers & Wilkins PM1s were more like 86dB.

You think I was going to say heat, weren't you? Most Class-A amps run like space heaters but the Pass Labs XA30.5 runs cooler than any Class-A amp I have ever auditioned. At most, it's warm to the touch during abusive listening sessions.

For those placing their amp out on display as I did (I bought the most expensive IKEA table I could find for $59 which looks great), the heat sinks are a bit sharp to the touch. You shouldn't have an amp like this out on display in a room where kids are playing and if you are going to move the amp, it would be a good idea to put on some gloves or you might break a nail.

Pass-Labs_XA30-5-Review-faceplate.jpgCompetition and Comparison
This is an odd amp to compare and contrast with. You can talk about all of the usual suspects like the Krell 402e, Mark Levinson No 53, Classé CA-2300 and the like but they don't really sound like this amp. There were elements of the $50,000 Mark Levinson N° 53s that reminded me of the P
ass Labs XA30.5 but that speaks to the value of the amp when you talk about a $5,500 amp in the same sentence as a pair of $50,000 monos.

Sonically, I think Dan D'Agostino's Momentum monoblocks at over $35,000 per pair remind me of the sound that I get from the Pass Labs. Dan's amps have a lot more power and a build quality that is at the A plus level when this amp is solidly an A. And make no mistake - you pay for it.

You could make an argument that products like Decware's single-ended tube amps could compete with the Pass Labs XA30.5 but far too often the Decware SET tube amp rolls over and plays dead on many more types of speakers and with way more popular types of music. Granted the Decware amp is far less costly and it gets you to the same type of special audio experience but it's a far more limiting product to own.

Lastly, if you are looking for a slightly different take, a no-frills one, on a Nelson Pass amp - there is always First Watt. Consider First Watt to be Nelson Pass' side project where he makes some real plain vanilla looking but kick-ass electronics right in his kitchen. These suckers are handmade by the man himself and they have a special appeal and a very limited distribution. Something like the First Watt J2 might be a close comparison to the Pass Labs XA30.5

The Pass Labs XA30.5 is a true niche product in the highly quirky world of ultra-audiophilia. If you need big time power, Nelson Pass has other amps for you either in the Class-A realm or in his X-series amps. If you are looking for the single most pure sounding amp you can invest the better part of $5,500 into - then the Pass Labs XA30.5 is worth seeking out.

This gem from the world of audio jewelry looks the part but sounds even more gorgeous. If the idea of total control, a complete lack of grain, amazing space around the instruments and beaming imaging is your idea of audiophile nirvana, then have I got the amp for you. Pound for pound and Watt for Watt - there may not be a more pure solid-state amp on the market today.

Additional Resources
• Read more stereo amp reviews written by's staff.
• Find a pair of Bookshelf Speakers or Floorstanding Speakers for the XA30.5 to drive.
• Explore sources in our Source Component Review section.

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