Solid State Power Amp Reviews

Pass Laboratories XA200.8 monoblock power amplifier Associated Equipment

Sidebar 2: Associated Equipment

Digital Sources: dCS Paganini SACD/CD transport, Scarlatti clock, Rossini & Vivaldi DACs, Network Bridge; Intel NUC7i7BNH computer with 8GB RAM, 128GB SSD, running Roon; Linksys router with two TP-Link gigabit Ethernet media converters & multimode duplex fiber-optic cable; external hard drives, USB sticks, Apple iPad Pro.
Power Amplifiers: Dan D'Agostino Master Audio Systems Progression Mono monoblocks.
Loudspeakers: Wilson Audio Specialties Alexia and Alexia 2.
Cables: Digital: AudioQuest Diamond (Ethernet), Nordost Odin 1 & Odin 2 & Valhalla 2 (USB), Wireworld Platinum Starlight (Ethernet). Interconnect, Speaker, AC: Nordost Odin 2.
Accessories: Audience aR2p-TSSOX, Tweek Geek Dark Matter Stealth (with High Fidelity & Furutech options) power conditioners; Nordost QB8, 2 QX4, QK1 & QV2 AC power accessories; Greenwave EMI filter; AudioQuest NRG Edison outlets; Grand Prix Monaco rack & amp stands, 1.5"-thick Formula platform; Nordost Sort Lifts (speaker cables); Marigo Clear Transformation mat; Stein Music Super Naturals, Signature Harmonizers, Blue Suns/Diamonds, Quantum Organizer; Bybee Room Neutralizers; Absolare Stabilians; Resolution Acoustics room treatment; Stillpoints Aperture panels.
Listening Room: 20' L by 16' W by 9' H.—Jason Victor Serinus

COMPANY INFO
Pass Laboratories
13395 New Airport Road, Suite G
Auburn, CA 95602
(530) 878-5350
www.passlabs.com
ARTICLE CONTENTS

COMMENTS
Bogolu Haranath's picture
Submitted by Bogolu Haranath on July 24, 2018 - 10:08am

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

Axiom05's picture
Submitted by Axiom05 on July 24, 2018 - 2:21pm

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

John Atkinson's picture
Submitted by John Atkinson on July 24, 2018 - 3:15pm
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
Submitted by Axiom05 on July 24, 2018 - 4:18pm

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
Submitted by RaimondAudio on July 25, 2018 - 1:40am

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
Submitted by Anton on July 24, 2018 - 5:38pm

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
Submitted by Long-time listener on July 25, 2018 - 5:23am

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
Submitted by John Atkinson on July 25, 2018 - 11:54am
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
Submitted by Long-time listener on July 25, 2018 - 8:10pm

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
Submitted by lesanderson on August 3, 2018 - 7:08pm

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
Submitted by Long-time listener on August 3, 2018 - 9:41pm

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
Submitted by tonykaz on July 25, 2018 - 1:24pm

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.

Thanks

Tony in Michigan

ok's picture
Submitted by ok on July 24, 2018 - 2:48pm

..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
Submitted by Jason Victor Serinus on July 24, 2018 - 3:54pm

" 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
Submitted by ok on July 24, 2018 - 4:57pm

..this is not always the case.

Jason Victor Serinus's picture
Submitted by Jason Victor Serinus on July 24, 2018 - 5:04pm

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

ok's picture
Submitted by ok on July 25, 2018 - 1:19pm

..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
Submitted by Jason Victor Serinus on July 25, 2018 - 3:53pm

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
Submitted by ok on July 25, 2018 - 8:15pm

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

Jason Victor Serinus's picture
Submitted by Jason Victor Serinus on July 26, 2018 - 9:10am

what is real when the news is fake?

ok's picture
Submitted by ok on July 30, 2018 - 2:31pm

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
Submitted by Bogolu Haranath on July 26, 2018 - 12:36pm

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

jeffhenning's picture
Submitted by jeffhenning on July 24, 2018 - 3:38pm

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
Submitted by Bogolu Haranath on July 24, 2018 - 4:43pm

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
Submitted by Bogolu Haranath on July 24, 2018 - 5:16pm

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
Submitted by Zarathustra on September 13, 2022 - 7:13am

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

Anton's picture
Submitted by Anton on July 24, 2018 - 5:39pm

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
Submitted by Allen Fant on July 24, 2018 - 5:55pm

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
Submitted by Jason Victor Serinus on July 24, 2018 - 9:02pm

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

Mikke's picture
Submitted by Mikke on August 9, 2018 - 4:05am

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
Submitted by gizmo101 on July 24, 2018 - 9:43pm

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

Bogolu Haranath's picture
Submitted by Bogolu Haranath on July 24, 2018 - 6:57pm

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

Bogolu Haranath's picture
Submitted by Bogolu Haranath on July 24, 2018 - 7:18pm

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

Ortofan's picture
Submitted by Ortofan on July 24, 2018 - 8:41pm

... 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
Submitted by tonykaz on July 24, 2018 - 8:58pm

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
Submitted by Bogolu Haranath on July 25, 2018 - 7:23am

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

volvic's picture
Submitted by volvic on July 25, 2018 - 5:08pm

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
Submitted by Ortofan on July 26, 2018 - 2:29am

... 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.

https://www.stereophile.com/content/pass-laboratories-xa25-power-amplifier

Bogolu Haranath's picture
Submitted by Bogolu Haranath on July 26, 2018 - 6:47am

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

Anton's picture
Submitted by Anton on July 26, 2018 - 9:59am

It is lovely.

DetroitVinylRob's picture
Submitted by DetroitVinylRob on July 26, 2018 - 7:04am

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
Submitted by Bogolu Haranath on July 26, 2018 - 7:20am

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

dumbo's picture
Submitted by dumbo on July 28, 2018 - 7:15pm

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
Submitted by Zarathustra on September 13, 2022 - 7:10am

"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.

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