Pass Laboratories XA200.8 monoblock power amplifier Page 2

Just as many inspired musicians invest their sound with a soulful glow that can grow in brilliance, the XA200.8s seemed to illuminate music from within in a way that complemented that artistic brilliance. In contrast with some tube amplification of my experience, the inner glow I heard with the XA200.8s sounded like something that arose organically from within the music. At the beginning of Mahler's Symphony 2, in the recording by Iván Fischer and the Budapest Festival Orchestra (SACD/CD, Channel Classics CCS SA 23506), the impact of the ominous march of cellos and double basses, the cries of the brass, and the merciless roll of drums were in no way sweetened, softened, or prettified by the Passes, but the beauty of the sound allowed the emotional truth behind the notes to come through in spades.

The XA200.8 didn't deliver the fattened midrange I've heard from some components —its midrange was unique in radiating color and beauty. Midrange-rich voices—eg, those of Lorraine Hunt Lieberson, Anne Sofie von Otter, Ella Fitzgerald, the mature Sarah Vaughan, Matthias Goerne, Gerald Finley, Billy Eckstein, Kurt Elling—or an instrument with a full midrange core, such as the cello, didn't sound unnaturally beefed up or altered.

Music was also reproduced with grace. In her irreplaceable recording of Sondheim's "Send in the Clowns" with Count Basie and his Orchestra, from A Little Light Music (CD, Pablo/JVC-XRCD VICJ-60246), Sarah Vaughan sings with a refinement and spirit that differentiate her from some of the great belters—eg, Bessie Smith, Ethel Merman, or the early Barbra Streisand. When soprano Elly Ameling delivers an exquisite turn of phrase topped with radiant highs, or one of soprano Elisabeth Schumann's golden highs seems to pop out of nowhere, their heart, soul, and intelligence are palpable. The XA200.8 opened a window on such points of creation and, without editorializing on them, let me hear great art in all its subtlety and splendor.


Listening how music sounded through the XA200.8s, I thought of Glinda (Billie Burke) introducing herself to Dorothy (Judy Garland) in The Wizard of Oz: "I am a witch. I'm Glinda, the Good Witch of the North."1 The bubbling smile in Burke's voice complements her sparkling, star-tipped magic wand and jeweled crown with a special glow that defines her as a magical being of light. Similarly, the XA200.8s invested music with a special glow that let me feel its inspired essence.

This glowing sound in no way diminished the impact of music that is about things very different from goodness and happiness. The low, multilayered rumble and churning at the beginning of Alban Berg's often brutal Three Pieces for Orchestra, in the superb recording by Michael Tilson Thomas and the San Francisco Symphony (24/192 WAV, SFS Media/HDtracks), or the terror in Maria Callas's voice in the bloodcurdling Sleepwalking Scene of Verdi's Macbeth, in the 1958 stereo recording with Nicola Rescigno conducting the Philharmonia Orchestra (24/96 WAV, Warner Classics 634015/HDtracks), were enhanced by the special illumination that the XA200.8 brought to them. It was as if I were listening from a prime seat in the orchestra section where maximal color evoked maximal emotional response.

By now you may be wondering if I'm about to claim that the Pass Labs XA200.8 is the sun, moon, and stars, and better than Peter Pan or Beyoncé. Hardly. It had limitations, and one of those was in the bass. As much as the $42,000/pair XA200.8 delivered copious deep bass, it lacked the speed and slam of the Dan D'Agostino Master Audio Systems Progression Mono ($38,000/pair) and some of the other monoblocks I've reviewed—eg, the Audionet Max ($30,500/pair).

When it came to the speed and impact of the slamming bass of "Electrified II," from Yello's Toy (24/48 WAV, Polydor 4782160/HDtracks), or the stereo remix of "Lucy in the Sky with Diamonds" from the Beatles' Sgt. Pepper's Lonely Heart Club Band (24/96 WAV, Apple/Parlophone B0026524-02/HDtracks), the XA200.8s sounded a bit soft and unfocused next to the D'Agostino Progression Monos. I played through the Progressions a recording of works by J.S. Bach arranged for mandolin, cello, and double bass and performed by Chris Thile, Yo-Yo Ma, and Edgar Meyer (24/96 WAV, Nonesuch 558933/HDtracks), and couldn't help noticing how much tighter and more defined Meyer's bass sounded through the D'Agostino amps.

The Progression Mono may lack the XA200.8's special glow, but it scores major points in bass, detail, and honesty. If I wanted to hear the differences among the sounds of major orchestras, or compare the tones of Daniel Hope's and David Oistrakh's violins, I think I'd turn first to the Progression. Its sound is more straight-ahead and naked in its honesty.

The XA200.8s' reproduction of air around individual instruments was fine, but through Wilson Audio's Alexia and Alexia 2 speakers the Progression Monos topped it in the presentation of the entire acoustic spaces of recording venues. The D'Agostino also excelled in dynamic contrast—hardly a surprise, given the Progression Mono's greater power into these 4 ohm Wilson speakers: 1000W vs the XA200.8's 400W.


Which led to another observation: The Pass Labs amp was really challenged by the original Alexia's impedance dip in the bass, which rendered its low bass flabbier than I have heard from any other XA.8-series amps of my experience. The Progression's bass, on the other hand, sounded impressively tight through the original Alexias. Through the Alexia Series 2 speakers, although both amps delivered more bass—and bass that was better integrated with the midrange and treble—the Progression Monos retained their supremacy as the tighter, faster, and more powerful bass conduit. (See my Follow-Up on the Alexia 2.)

But I can easily overlook the XA200.8's shortcomings because I would never want to be without the drop-dead gorgeousness of its sound. I'm not sure I'd be equally enthused were my daily fare jazz, rock, souped-up pop, etc. But it isn't. For the music I love, from grand opera to chamber music, listening through the Pass Laboratories XA200.8s compounded joy and beauty with more joy and beauty.

Few power amplifiers I've heard have sounded as beautiful as Pass Laboratories' XA200.8 monoblock. Having to stick to Stereophile's policy of not commenting at length on a product's sound quality until that product has been reviewed in our pages, when all I wanted to do was wax ecstatic about the sound of these amps, has been frustrating indeed.

Now I can say it: I love the sound of the Pass Labs XA200.8 monoblock. It is the most beautiful-sounding, color-rich amplifier ever to grace my system, and its ability to illuminate music from within with subtlety and finesse puts it in a class all its own. It's a big beast, heavy and expensive and room-heating, and it's not the last word in bass slam, bass speed, and other things. But it sounds so gorgeous that all music lovers, regardless of financial means, owe themselves the gift of hearing it in a system that will show it to its best advantage. The XA200.8 is a masterpiece of amplifier design, and proof of Nelson Pass's genius and unfailing commitment to musical excellence.

Pass Laboratories
13395 New Airport Road, Suite G
Auburn, CA 95602
(530) 878-5350

Bogolu Haranath's picture

"The Heat Is On" ........... Glenn Frey :-) ............

Axiom05's picture

How do we use the measurements to determine the dynamic range in bits for an amplifier?

John Atkinson's picture
Axiom05 wrote:
How do we use the measurements to determine the dynamic range in bits for an amplifier?

1 bit is equivalent to a dynamic range of 6.02dB. So you could say that an amplifier that has a S/N ratio ref. full power of 96dB has an effective resolution of 16 bits.

John Atkinson
Editor, Stereophile

Axiom05's picture

So with a S/N of 88.2 dB for the audible bandwidth, this amp has less than 15 bits of dynamic range ref. to 1W into 8 ohms. I'm not trying to be contentious, just trying to get this straight in my head. We don't know what the S/N is for full output power, correct?

RaimondAudio's picture

We do not know the noise at the full power but we know the THD at full power. In fact, if we have 1% THD, we have 7 bits. But we must to be rational to see the truth: at this power(258w in 8ohm), how many bits will you hear ? Which will be the "THD level" of the room ? In fact, each criterion taken separately does not tell us how nice music will sound. Listening the tested device at home is a must.

Anton's picture

When you measure an amplifier's performance, do you do it "straight out of the wall," or in the context of the power conditioners that are used to feed it?

I don't recall if it's ever been done, but do you ever compare an amp's performance in context of it being plugged into an after market conditioner vs. 'straight up?'

That would be exciting to see!

Long-time listener's picture

Mr. Atkinson, I wrote a question for you under another review which I think escaped your attention, and might be of interest to some other readers--I'd greatly appreciate it if you could reply now:

I'm interested in using either the M32 or the M22--driven directly from an NAD M51--to drive a pair of Dynaudio Special 40s. Could you possibly comment on any difference in sound quality? I understand that the power output would be different, and that one is an integrated and one is a power amp. What I'm interested in, mostly, is the difference in sound between the Hypex N-core of the M22 and the different system used in the M32.

Thank you so much. LTL

John Atkinson's picture
Long-time listener wrote:
I'm interested in using either the M32 or the M22--driven directly from an NAD M51--to drive a pair of Dynaudio Special 40s.

I know from experience that the M32 does a good job driving the Dynaudio speakers. (I review the Special 40s in our September issue.) But as the M32 has a DAC and you already have the M51, the M22 might better suit your needs.

John Atkinson
Editor, Stereophile

Long-time listener's picture

Mr. Atkinson, I think my question was very clear: "the difference in sound between the Hypex N-core of the M22 and the different system used in the M32." I think this would be a question of interest to many readers, and I hope maybe you'll discuss it in the future. Thanks, LTL

lesanderson's picture

Do you understand you are trying to compare an analog power amplifier with a pwm direct digital integrated? It is like comparing an engine to a car as the preamplifier and dac the m22 requires will influence the sound to a great degree.

My opinion is that the architecture utilized in the m32 is the better move for most users.

Long-time listener's picture

Thanks for your reply. My understanding was that the M22 is based on the Hypex N-core, which is a PWM module, and that the M32 is also PWM, as you note, so I'm not sure I understand why you call only one of them "analog." Of course I understand that the pre-amp and DAC will influence the sound.

Could you please expand on why you think the M32 architecture is better?

I'm also considering the PS Audio Stellar M700. Like the NAD m22, I would connect the PS Audio monoblocks directly to the NAD DAC, which has variable output.

Thank you

tonykaz's picture

that scamp Steve Guttenberg is advertising for Under 40 year old Salesmen and Writers + Music review.

I hope you can give him a Stern Staring Down on behalf of all us Old Geezers who's Grandchildren haven't yet sent our "Vintage" Audio Gear to Dave Wasserman so as to Cash in their inheritance.

Pretty soon he'll be wearing a Phonak Hearing Aid Shirt instead of a Rocker's Harvey Shirt.


Tony in Michigan

ok's picture

..that almost all class-a amps I’m aware of are somewhat “soft” in the bass dept. Truth be told – I’m a control freak when it comes to the base; but sometimes I wonder if this whole “tight” thing, as well as the “stage” equivalent etc, does not actually consist another convenient artifact, while my considerable "live experience" does not serve me particularly well.

Jason Victor Serinus's picture

" while my considerable "live experience" does not serve me particularly well."

Since I respect your opinion, could you please rephrase this so I can understand what you're trying to say? What I do know is that, in my listening experience, bass in decent symphony halls and over good club amplification systems is anything but loose, flabby, or of uncertain pitch.

ok's picture

..this is not always the case.

Jason Victor Serinus's picture

which is why I wrote, "decent symphony halls and over good club amplification systems"

ok's picture

..but in fact is somewhat tautological a thought in the sense of imposing certain preconceptions of “good sound” to reality and consequently using the ensuing real/ideal fusion as a reference point for what "good sound" sould be actually like; I am inclined to call this inevitably circular interaction “the hi-end audio uncertainty principle” :-}

Jason Victor Serinus's picture

But wait, that could mean you're bad. If good = bad, and bad = good, then where are we? Oh dear, back to the drawing board. Now, if I could figure out what a good drawing board is....

ok's picture

..but reality stil holds on its own ;-)

Jason Victor Serinus's picture

what is real when the news is fake?

ok's picture

said reality is that which persists though you have stopped believing – or something close; his love for music was also as strong as his hate for reality..

Bogolu Haranath's picture

There are also, Philip K Dick awards .......... Wonder who gets the award(s) this year? :-) ............

jeffhenning's picture

So a pair of these amps:

  • Weighs over 300lbs which is as much my fridge, washer and dryer combined
  • Uses 10 cents of electricity per hour and generates as much heat as a couple small space heaters so, if it's not below 70° outside, you're running your AC, too
  • Offer really good noise specs, but the rest of its performance is mediocre
  • Are low level distortion generators
  • Cost $42k

Given that a pair Benchmarks AHB-2's is $6k, Devialet's most powerful amp is $19k and both of these are drastically superior in every way compared to these behemoths, why would anybody buy them?

These amps are absurd. A waste of money that keeps wasting money every minute they are powered on.

Bogolu Haranath's picture

Also, PS audio Stellar amps, Stereophile class A recommended ........ Costs thousands less ......... The Sim audio amps, reviewed in recent Stereophile, weigh 300 pounds each! :-) ............

Bogolu Haranath's picture

I Googled it .......... The weight of Muhammad Ali when he was the heavy weight champion was 236 pounds .... He was 6 foot 3 inches tall :-) ............. His famous quote "Float like a butterfly, sting like a bee" :-) ..........

Zarathustra's picture

"..., why would anybody buy them?"
Ask NP at Maybe he can enlighten you ;-)

Anton's picture

This would an interesting situation for comparison with speakers with different impedance 'propensities' than Wilsons. Their size mitigates against easy comparisons!

Also, perhaps all that power conditioning took its toll. Especially with regard to the adjectives about the bass, where that stuff can really turn an amp into an anchor. Did they get a chance to just play plugged right into the wall?

Power 'conditioners' aren't exactly a one size serves all kind of proposition.

It could be cumbersome to get a handle on these monsters in conjunction with the effects of Audience aR2p-TSSOX, Tweek Geek Dark Matter Stealth (with High Fidelity & Furutech options) power conditioners; Nordost QB8, 2 QX4, QK1 & QV2 AC power accessories.

That's more conditioners than at my hair stylist's!

Allen Fant's picture

An excellent article -JVS
which Pass Labs, 160.5, 200.5 or 200.8, did you enjoy the best?
As always, Thank You JA, for the measurements.

Jason Victor Serinus's picture

Of course, it's also mated with better components than I had some years back.

Mikke's picture

I have owned both the 100.5; the 160.5; the 200.5 and now the 200.8 (A serious case of Audiophile insecurity, perhaps?).
However, I fully concur that the 200.8 is the better amplifier. It surpasses the others in the XA range by far.

gizmo101's picture

It can function as an amplifier, heater and BBQ grill!

Bogolu Haranath's picture

"All About That Bass" ......... Meghan Trainor :-) ........

Bogolu Haranath's picture

"Hot Stuff" .......... Donna Summer :-) .............

Ortofan's picture

... If he were to lower the distortion of his amps to levels similar to that of the Benchmark amp, would he be able to maintain the same subjectively appealing sound quality?

Incidentally, still waiting for reviews of more recent power amps from Rotel. The $1600 (and under 40lbs. for a 2-channel unit) RB-1582 MkII can generate about 250W into 8Ω and 435W into 4Ω, according to the HiFi News test. Peak power into 2Ω is over 1kW.
If you need even more power, the RB-1590 has about double the output at about double the price and weight.

tonykaz's picture

I hope you keep those Amps and use them as your Reference, .10 Cents per Kilowatt hour is pretty much a National Standard, leaving them on will probably cost about $5.00 per day. ( about $1,800 per year ). Port Townsend Air Conditioning is a nonsense thought, you need that Clean Heat from those Amps.!!

Besides, you're not wasting $100,000 Plus +++ on one of those old fashioned 33.3 rigs and all the sundry paraphernalia needed to support the very pricy Vinyl coming to you on a regular basis from Sir. Chad & friends.

Stereophile readership needs you to be a Reference Level person of Integrity, you need those Amps to properly do your job : Being Our Reference Level Audiophile, reporting on all things important ( all things "Stereophile" to me and our man in Oh'Canada ) !

Tony in Michigan

Bogolu Haranath's picture

ML 536 mono-blocks, Stereophile class A cost $30k ........... ML stereo 534 cost $20k .............

volvic's picture

I can only imagine how my recordings of Fischer and Schnabel would sound through a Pass amp like this one. In my cramped Manhattan apt my Klout will have to suffice. Paired with my SME 10, LP12, and modded 1200, I bet it would be magic, notwithstanding the irrelevant comments from some “expert” on analogue’s shortcomings from Michigan, as seen above. Thanks for letting me dream JVS and thanks for an entertaining review.

Ortofan's picture

... and determine if the sound quality is also "magic".

Your Linn Klout has a rated output of 80W into 8Ω and 160W into 4Ω. According to the Stereophile test, the output of the Pass XA25 reached the clipping point (~1% THD) at 80W into 8Ω and 130W into 4Ω - not much difference. Plus, one two-channel XA25 costs only about one-tenth that of a pair of mono XA200.8 amps and weighs a much more manageable 45lbs.

Bogolu Haranath's picture

XA25 may be the "best bang for the buck" in the Pass line-up ...... Stereophile class A :-) ............

Anton's picture

It is lovely.

DetroitVinylRob's picture

So a reality check...

Does one care more about absolute bass slam than beautiful sound?
And, in a real, live, acoustic setting, does bass slam, or is it a bit soft and unfocused compared to amplified reproduction? I believe it is the latter.

So I for one, could not care less about absolute bass slam or playing music at deafening pressure levels.These are unrealistic ideals imho.

My ears find even Nelson's most modest (power related) efforts (ie: SIT 2, J2) very musically faithful and rewarding in their own way.

Perhaps we have excepted far too poor driver efficiency and poorly engineered impedance curved loudspeakers that demand these enormous power consumers/producers. Should we perhaps look back, and reevaluate our implementation? I think so.

But there will always be those who oppose unnecessary resistance with more power...

I too care more about gorgeous music

Bogolu Haranath's picture

"Bang Bang" .......... Jesse J, Ariana Grande & Nicki Minaj :-) ..........

dumbo's picture

These two items should not be used together if one is seeking audiophile approved levels of SQ, especially during a review.

I've yet to find a power conditioner that did not negatively impact music transients, midrange snap, bass slam, bass depth...etc

I've owned some of the audiophile favorites in terms of power conditioners and no matter how bold the claims are from the PC manufacturer that their product doesn't limit current or in some cases believe their product has more power then the wall plug....its all BS.

Even my little Pass XA60.8's are negatively impacted using the well reviewed Shunyata Denali. Same story for the big Torus RM20.

These monster XA200.8's should never be plugged into anything but the wall directly and reviewing them any other way is doing a dis-service to your readers and potential buyers.

JVS...dont let that bad a$$ system of yours go to waste...its time to start De-Tweaking it and let the music flow as intended :)

Zarathustra's picture

"Although Pass Labs specifies the XA200.8 operating in class-A, I suspect that even with its massive heatsinking, the amplifier doesn't have sufficient bias current to allow class-A operation up to its specified maximum power."

If you make such a claim you should follow up on that.