Anyone auditioned Pass Labs XP-30 preamp?


Has anyone heard the XP-30 that was released a couple of weeks ago?

I have the XP-10 and just wondering how much better the XP-30 is at $16.5K? How does it stack up against the Ayre KXR preamp?
sfstereo
Interesting read Rower30, thanks for sharing.
I found myself agreeing throughout because I have the XP-20 & you mention characteristics synonymous with the XP-20.

I hope I get to hear the XP-30 in my system!
There are not many preamp out there which can beat my humble aragon 28k.
Throughout my comparison, it stood well against ml326s, accuphasec2420, ayre5xemp, mbl5010, jeffrowland capri,

It completely trounced moon740p, musical fidelity , rogue audio.

Other makes not yet tried.

Pity it does not have balanced output, cannot fully bring out my amp's potential
The expensive lesson here is, never read too much into a manufacturer's technological breakthrough bulls and fancy marketing crap.

Second, never fully believe what the reviewer says.

3rd,in audio, an equipment which measures well does not necessarily sound good. In fact, it could be a sign that something else is compromised which is why it measured so well.
The moon740p measured impeccably and touted some technological advancement M-eVol2 volume control, mLovo crap. 120db sn ratio....
Won a reviewers choice who need to have his ears checked.
no, its not system matching or break in time, i took care of that.
It sounded refined, smooth and smooth means veiled. Lack of airiness, clarity and crispness.
Everything seems polished and filtered and bloated, that is probably why it measured so well.

My aged aragon trounced it in every aspect.
XP-30 Impressions

I've been developing the Belden ICONOCLAST TM series of audio cables, and have used a Pass Labs XP-10 almost through the process for it's stunningly good resolution and transparency compared to about anything I threw at it. I was told to aim for the XP-30 as nothing has the tonal balance of the Pass Labs, which I so admired. Sure, everyone should have one of those except the cost!

That line of reasoning didn't work too long and as things go, I kept saving for the XP-30 up grade (I'm told it IS and upgrade!). So after two years of stuffing money aside, I took the plunge and ordered a unit from Pass Labs. It comes in ONE rather big HEAVY, for a pre-amplifier, box.

I won't go into detail on the unit as it's been out awhile, except that it is a three chassis unit that DOES take several days to reach stable operating temps. LOTS of metal. Unlike any pre-amplifier I've ever owned, the two channel gain stages DO get warm. Initial plug in sound was warm and hazy, and my cold MOON W-8 amplifier and not recently played Martin Logan CLX with stereo balance force 212 subs were just telling me to go away. I turned on the radio to about 75 dB SPL and left for two days. When I stuck my head in the basement, the RADIO was simply amazing sounding, not like I've heard it before. I sat there and listened, I swear to it, the RADIO for several songs. Times a wasting...on to records and the VPI classic 3.0 signature with a SUMIKO Blackbird cartridge.

The XP-30 is super easy to get used to, and is essentially like my XP-10. I did set the internal gain to +16 dB from 0 dB stock, with a +23 dB still unused. I am using an Austin Audio Works head amplifier that is a lower gain output, so I need a little OOMPH from the preamplifier. The switches are on the inside, and I wish they were located on the bottom of the unit so the circuit length could be near the same, but improve the user experience. But, it is generally a one time thing and it done.

More on the XP-10. This unit has excellent resolution and openness. The bottom end is VERY tonally good but softer sounding than typical. It has tight resolution, but is dynamically just shy of ideal. It is great sounding, but lacks some PUNCH at times. The mids are the XP-10's strong suit, and it leverages them to great advantage. Treble is either great, or can be on the hard side depending on the source material. And, they are slightly out of character with the rest of the XP-10's “sound”. The treble tends to say, “listen to me” at times. It very good, but can be a touch pushy for attention through the CLX.

Look at it like this, a speaker can have trouble BLENDING all of the drivers to a single whole and so do electronics. It doesn't seem like they should but they do. The XP-10 has a tweeter that is great, but of different character. The softer bass response isn't an issue with me as it is still well blended to the great mid-range. The wonderful 3D sound-stage the XP-10 throws out is also a HUGE bonus in it's price range. This pre amplifier is no slouch.

Until I entered the realm of the XP-30. This unit is a master piece of tonal oneness and natural dynamic impact. The amplitude response seems to be EXACTLY uniform top to bottom, and absolutely seamless in frequency integration. There is but ONE single driver and the frequency or dynamics doesn't change it's spots. It is so uniform you quickly forget all about the pre-amplifier in the chain as your head zeros in on just the music, in one expansive aural view, and I mean ALL of it. Immense in width, height and depth, with seemingly infinite amplitude response. I don't mean in a slam bang kind of way, but even on micro textures, the sound is simply so, so natural in an unbelievable way. They talk about the CLX as ONE driver operating over a wide frequency range, this XP-30 runs away with that idea on the electronics side.

I played the original AMERICA. America album and the acoustic guitar harmonics are so fully fleshed out and right it seems implausible a pre amplifier change could do it, but it does. The richness off the string plucks is simply exquisite. The dynamic response and harmonic structure are way past the best I've heard. Wide band instruments on the XP-10 had an artificial “brightness” to them that was just different enough to take on it's own stage, and you ear taken away from the “whole” at times. Not so with the XP-30. The entire sound stage stays in character, always.

I then went to Peter Paul and Mary - in the wind. This is an old album that is beautiful to listen to. Again, the ability of the XP-30 to throw everything at you in such frequency linear and amplitude linear fashion is unheard of prior to this getting the unit. Female and male vocals are stunning in edge character some refer to as holographic placement. There is no overemphasized leading edge zing to create resolution, but a dead nuts locked on transient response that won't let the music get away. The music is there, and so is the XP-30. When you hear it, you KNOW it is right.

Digital is an achievement too. With my worst stuff the XP-30 has that awful hard edge much more under control (Hootie and the Blow Fish CD). Here is where the XP-10's treble was too eager to please and could spit at times with red book CD's. Not so the XP-30, oh the CD is still HOT, but it lacks the over eager edge that can wear on you. The XP-30 makes sure it isn't any worse than it really is, and I appreciate it immensely!

A incredible run through on Loreena McKennitt - Journey So Far: The Best of Loreena McKennitt CD is just divine. I can't figure out why artist like this aren't WAY out in front of the industry. The XP-30's talents are in kind with Loreena's. Both are a beautiful thing. The XP-30 layers this unique listening experience with the precision to matching her rich and controlled voice.

Bass impact and depth is no longer an issue, you hear the music instead. The electronics vanish. There is virtually no artificial blending of the bass, mids, or treble as there just aren't any seams in their delivery. If you want a pre-amplifier to announce something unto itself, don't get an XP-30. This pre- amplifier is all about the flow of music. The XP-30 doesn't shout anything except the music. The XP-30 is an invisible element in the presentation, not a participant per say. This is how it should be but seldom is.

No tube unit that I've heard comes close to the vast extremes this unit manages with ease. Tubes seem to excel in the mid range, but can't get the exact same wonderful act going down low or up high. I'm not saying tubes can't be darn good, but I can say I want way past darn good, and I want it all the time, and I want it everywhere. SS gives me that in the XP-30.

True, there is the newer Xs line, but the XP-30 gets you squarely in the I can't believe it sounds this good arena at a way lower price. To me, the XP-30 is a deal to be reckoned with. The three boxes take up some space but trust me, you'll be glad to give it up to the XP-30. Change is always full of apprehension, but the buyers remorse on the XP-30 lasted mere minutes. I might be fibbing there as I never heard it try to make me doubt it's character, ever. Yes, it is THAT good.
Hi Mkwglyg,
If you don't mind me asking, what are the brands of both preamps you are refering to? Thanks
-phil
I know it because my 15yr old usd2k preamp 98db sn ratio sounds clearer and livelier than my new preamp at 125db costing usd9.5k , a unit which won a reviewers choice for that matter.

Anyone who read too much into the technology and spec is going to regret like i did.
Guys, never believe the high sn ratio crap.
It also means details are filtered away.
Leaving a lifeless dull sound
The folks at Pass are great and very responsive to questions. They would be your best source for that info, I would think.

BTW, I did not like the volume being set to zero when returning from theatre bypass so they made a special NXP controller for me so it now sets the volume at 50. How is that for customer service!
Hi all,

I am using bi-amping configuration. Do you think the "gain-control" of XP-30 will degrade the sound quality of "slave" amp.? Why or Why not?

Is the "gain-control" of XP-30 only to decrease the amp's gain , not to increase?

thank you!
The system consisted of the Sony flagship AR1 speakers, a Sony hi res streaming audio player, a top of the line VPI turntable , the Pass Labs vfet mono blocks and XP20 pre strung together with Kimber Kable. Simple yet delicious sounding. Definitely one of the top three systems at the show hands down! I wouldn't be so quick to rush into an XP30 based on what I heard the XP20 doing...
That is a very interesting comment. Love it! I've got the XP-20 and can't yet afford to buy the XP-30. What was in the rest of that system in NY?
I just listened to the "priceless" Pass Labs 40th Anniversary Sony Vfet amplifiers(only six in the world!) at the NY Audio Show. They were being driven by the XP20 which surprised me so I asked the Sony rep why they didn't opt for the XP30 in this cost no limit configuration? He said simply that they had initially used the 30 but found that the XP20 just sounded better and allowed the Vfet amps to really produce the magic that Nelson Pass knew that their output devices were capable of... If that's not a testimonial for the XP20, I don't know what is!?
The p20 does not use the so called feed forward tech sound engine yet still managed the same noise floor as p30 at 130db.
Yet the p20 performance is claimed to be 90% of the p30.
So much for the feed forward soundengine crap
Hthaller,
Thank you so much for your post!
Have fun with the Summit X´s!
I will try to listen to the SR2 myself.
Sorry - I don't check the forums all that often, but regarding the SR-2's ...

They sounded very good, indeed, but making a direct comparison is tough. The room environment was very different from my own and I was actively focused on the differences I was hearing in the electronics.

What I can tell you is that were no obvious flaws that drew attention. Very open, detailed, 3-dimensional, as you would expect from a dynamic driver system. Maybe missing a half octave at the bottom, though hard to say with the source material being used. I felt they were more seamless and "refined" than my Odyssey's, which are an older generation of ML technology, to be fair.

They are a bit pricey, though. I think retail is ~$18,000.

As you say - a bit off topic - but the last step in evolving my system was to trade the Odyssey's in on a new pair of Summit X's. I made two trips to Overture last summer and auditioned them against the Magnepan 3.7's and 20.7's. However, I did not audition any dynamic speakers that they carry. There were plenty to choose from, but was advised that to decisively better the Summit X's, I'd be looking at spending $25k and up.
Audiozen, I believe that someone is selling you a line of bull on the feed forward versus feedback argument. You can always achieve lower levels of measured performance with feedback loops. In critical control applications such as reactor design no one uses feed forward without having a feedback loop. With respect to amplifier design it's my understanding that you can get excellent measured performance with feedback designs. However, designs which use too much feedback don't sound as well subjectively.
You are naive if you believe Nelson Pass is unaware of these trade-offs.
Hthaller,
Even if its a bit off topic here: Could you please let us know your opinion on the Pass Labs speaker SR-2 which you heard at Reno Hi-Fi? How do they compare to your Martin Logans? Are they a perfect fit for pass amps what one might expect? Your opinion would be very much appreciated.
Many thanks in advance!
BoSo27
Philipwu..I would take the Hegel P-30 over the Ayre KX-R in a heart beat. The Hegel is warmer, richer and fuller than the Ayre. One thing I don't like about the Ayre is the loud clicking sound of the volume control when you raise or lower the decibel gain. Damn annoying. The other negative of the Ayre is the output impedance is 300 ohms balanced and 150 ohms single ended.which is too high for my blood. The output impedance of the Hegel is 75 ohms which makes it easier to drive amps with low input impedance. The Ayre has great resolution and detail and is very fast but is not as relaxed and organic as the Hegel. If your looking for an exotic sculptured space age looking piece of aluminum with an interior that looks like the circuit boards inside the dash board of a UFO, then the Ayre is for you. But if musical performance is paramount to your needs you will get a much better sounding Preamp with the Hegel and won't waste $18,500.00 on the Ayre.
Knghifi,

Thanks! I stand corrected. All I could get the other day was the U.S. highlighted in blue.
hi Audiozen, your emphasis on feed forward tech is noted here. could you describe more about sound character of P-30 or Hegel's "house sound"? i heard Amphion Argon speakers before so it's easy for me to relate your experiences.
If compare to ayre KX-R preamp, would P-30 be similar? as you had mentioned full, controlled & organic with 3D space, i assume it has more air and good at presenting complex orchestra passage without compressing musical notes, that would certainly come with excellent transparency right? higher octave is smooth without harshness, attack & transient of highs also have clean leading edge without roughness. is that the benefits of feed forward? i'm getting interested, thanks
08-13-12: Danielk141
Audiozen,

I'd be very interested in auditioning the P-30, or hearing it at a dealer.
When I go to the Hegel website, they don't even list their U.S. dealers.
Not a good business practice, IMO.
As long as they do business like this, they won't get an appreciable part of the U.S. market, no matter how good their gear is....
Danielk141 (Threads | Answers | This Thread)
There's a dealer link on the top of home page.

http://www.hegel.com/usa.htm
Audiozen,

I'd be very interested in auditioning the P-30, or hearing it at a dealer.
When I go to the Hegel website, they don't even list their U.S. dealers.
Not a good business practice, IMO.
As long as they do business like this, they won't get an appreciable part of the U.S. market, no matter how good their gear is....
hi has anyone compared XP-30 with JF Corus? i know of there is a price gap between them but it's not that big. just would like to know their sonic difference, if which one is more relax & sweeter, the leading edge attack and high's extension, which has more air around the notes etc.. thanks
Audiofeil..where is your brain?..I think you have too much mold in your bong. I was referring to solid state only relying on solid state engineered designs 35 years ago. I never brought up tubes vs. solid state. Thats another subject.
Peterayer..I have heard the Hegel P-30 and the H-30 mono-blocs hooked up to a pair of Amphion Argon7-L speakers. Stunning..rich..full..warm..very organic..very tight with outstanding bass. Have you noticed how different solid state Pre-amps sound bright, some with loose bass, muddy midrange, lack of 3D dimensional space? Heres why. Feedback looping in different Preamps creates more noise in certain frequency bands and less noise in the other bands. So the noise levels varies in different bands from one Pre-amp to another. If you have a Pre-amp that has very little to no noise interfering with the ten main bands, then you have a Pre-amp that will sound absolutely wonderful which is why feed forward Pre-amps will always sound better. The Hegel premium line came into the U.S. in August 2009 and have already picked up over thirty retailers in three years which is impressive.
No. I got the point. I personally prefer lower noise and less distortion too. However, I also have to like the way a component sounds in my system. That's why I have the components I have. I have not heard the Hegel P30 and can not comment on its sound. Sorry.
>>08-05-12: Audiozen
The idea that we stick to the past designs of 35 years ago is silly.<<

For example vacuum tubes vs. solid state and analog vs. digital?

Yeah, that's silly.
Your missing the point..the less noise and distortion thats achieved in a well designed Pre-amp means far less interference to the music signal that is passing through. Feedback designs have more vibration and noise problems which is why we use heavy isolation/absorbtion racks and shelfs and isolation feet to help control the vibrations in the components to improve the quality of the music. The idea that we stick to the past designs of 35 years ago is silly. Audio engineering always improves as the years go by due to better science and technical innovations that were not applicable 35 years ago. The reason why some Preamps are made up of two or three cabinets is to isolate the power supply from the control boards to keep the noise floor and distortion lower because these Preamps are using feedback designs. The best single unit Preamps in the world that have S/N ratios over 125db's using feedforward designs are actually quieter than two or three piece Pre-amps resulting in superior musical performance since obstructing the music signal is kept to a minimum. I have not heard the Pass XP-30 but use to own the X0-1 back in 2004 and at the time also owned the Musical Fidelity 308 Preamp and the Parasound PLD-2000. The Parasound was faster than both but thinner sounding. The Pass was fuller and more laid back and the Musical Fidelity was a piece of crap.
Zen, I have not had the opportunity to here the Hegel P30. It must be quite something judging from your raves here and on other threads. I have heard the XP-30 in my system for ten days and it is the best pre amp that I have had in my system.

Have you heard the XP-30? I know how specifications can mean everything to some readers. Listeners, on the other hand, form opinions about how components sound relative to each other.

"Old school engineering" is why people still love horn, tube, vinyl components. Specifications are great, but listening is what matters to most of us.
The XP-30 has a low S/N ratio of only 110db's which is a poor number for a three piece system. Why? Old school engineering. Since the early eightie's many designer's including Nelson Pass use local or global feedback technique where the signal current is looped and fed back ("feedback") several times through the Pre-amp then to the ouputs which increase the gain level to the output. The best Pre-amps on the market that are pricey all have S/N ratio's above 125 db's since they are not using feedback looping into the Pre-amp but using a more current technique called feed forward which does not loop the signal current.
The feed forward design was pioneered by FM Acoustics. Feedback results in noise and higher distortion from the parts and boards. The founder and designer of Hegel Audio in Norway, Bent Holter, who has a degree in micro electronics with the emphasis on transistor engineering, took the feed forward technology from FM Acoustics and further enhanced it to a better design he calls his patented Sound Engine technology. The Hegel P-30 Pre-amp uses the Sound Engine feed forward method and the Pre-amp has a S/N ratio of 132db's, the highest ever achieved of any Pre-amp costing up to $20K and higher. The P-30 costs only $7500.00 and performs like a $40K Pre-amp since the noise and distortion is so low which is typical in the best and costliest Pre-amps made.
Tonyptony - If you read reviews I referenced, you'll get the differences ("Secrets" nails it and also mirrors my preferences - e.g. some tubes in the signal path are a requirement for me). To me, the XP-20 was better in several areas than the X0.2 - noise, bass, clarity and to a lesser extent sound stage. I really wanted to like it (heck I bought it!), but it just didn't sound natural in my system. Perhaps it will in yours. Despite it's shortcomings, I liked and kept the X0.2 and sold the XP-20. However, I never felt quite the same about the X0.2 again having heard what was possible in the areas where the 20 excelled. The XP-30 may fill those gaps but I haven't heard it.
As you noted, you can read the comparison of the XP-30 to the XP-20 and to your X0.2 on Dagogo or Secrets of Home Theater Hifi. The descriptions of the XP-20, which I owned for a few months, are spot on (I also owned and liked the X0.2). I didn't care for the XP-20 in my system. I replaced it with the ARC Ref 40 Anniversary and for me it was a significant upgrade (Of course it should have been it was $25K!). Like Ed Momkus I found the XP-20 too clinical although a liked the dead quiet background and bass. However, if your power amp is on the warm side it may be just the ticket. The ARC Ref 40 has more warmth, better sound stage, and just a bit of texture resulting in a very natural sound to me. While the bass is very good in the ARC, it will not match the XP-20 for sheer impact if that's important to you, although it has a tactile quality the 20 doesn't have. I have not heard the XP-30 although reviews suggest that I would really like it. You don't say what amp you're pairing the preamp with and that is a major consideration. My tube hybrid Counterpoint NP220 (mid-tweets to 240 Hz) is dead neutral, very immediate and very revealing. Oh, you may have a difficult time finding a used Ref Anniversary as they were a limited run dicontinued since Fall of 2011. If you're seriously consider ARC get the 5SE as it has the bigger power supply and the teflon output caps. These recent upgrades as well as new tubes and transformers are the major drivers of the change in the ARC house sound and the the reason ARC is enjoying a bit of a resurgence. Happy listening and good luck.
I'm curious how the XP-30 (or XP-20) compares with the ARC Anniversary Reference (or the Ref 5). When I upgrade my X0.2, these are the linestages I'll look at based on fit with the rest of my system. Another preamp that I'm very interested in is the Esoteric C-03. Heard it at a few audio shows and was quite impressed with it.
FWIW there is a new review,

http://www.dagogo.com/View-Article.asp?hArticle=1060

The reviewer compares the XP-30 to the MBL 6010d which is arguably the best preamp I have ever heard.

You don't know what you're missing until it's there.

While I'm not sure the XP-30 is the most (M)usical preamp I have heard, Peter's system, with the XP-30 added, offers a presentation so sure and engaging that I am still hearing and 'feeling' the music of last night's listening session.

Characteristics are rich and solid vocals, stunning speed, a newfound soundstage breadth, a substantially greater transmission of complex symphonic passages, more persuasive imaging and this listener's life-list level of timbral accuracy.

The complementarity of the XP-30 with Peter's other system components is disarming: even with flawed recordings the music can somehow survive. That's a feat.

the other listener in Peter Ayer's thread (two entries above)
Very, very insightful discussion...

Having ordered the Krell Phantom (two-chassis, 17500 USD retail), presumably a model comparable in features and quality to the XP-30, I would be interested to know more on comparison between Pass and Krell preamps, generally, and if possible, on Pass XP series vs Krell Evo preamps.

Tnx
Petrushka, That is indeed very interesting and helps to explain its high performance. I had a friend over tonight to do some more listening to the XP-30. He brought over some of his favorite LPs and was very impressed with the improvement over my XP-20. He knows my system well. One of the topics we discussed is the polemic that audio reviewers espouse, namely that a component usually falls into one of two camps: the accurate (read analytical, hyper detailed and often sterile) or the musical (read euphonic, warm, beautiful).

My friend and I have always been puzzled with these seemingly opposed camps. To us, something that sounds accurate, ie. like real music, is by definition "Musical" with a capital "M". It is highly resolving and beautiful at the same time. The XP-30 is an example of a component that does just that. There is such a level of resolution, lack of distortion and great detail, and dare I say "accuracy", that it is the most "(M)usical" pre amp that I, and my friend, have heard.

It was a most memorable evening.
Hi Peter: I don't have personal experience with these linestages as I haven't listened to the XP-30 and I don't do vinyl, but this is what Pass told me about the XP-30. It was originally a prototype for their inhouse needs of chaining amplifiers with different gains to a single preamp. (They didn't say what for, but it might have to do with the new Xs amps.) As a byproduct of this design requirement, they managed to get the noise to an extremely low level; the noise of the new volume control even exceeds the resolution of their test instruments. In order to ensure that this level of performance is always available (and not masked by distortions / noise brought about by fluctuations in AC quality), they gave the XP-30 a massive power supply and extensive voltage regulation that would have been considered very overengineered just a few years ago.
07-17-12: French_fries
i can understand producing a new top-line preamp as a match for the newest amplifiers (cost no object). HOWEVER, i cannot understand with all the latest technological advances why you would need THREE boxes for TWO channels.
there are a number of VERY good preamps out there that have more than adequate isolation-techniques that still are just a single unit.
Pass Labs used to make the one-box Aleph P which was pure class-A and built without regards for cost ($4k) was compared to a passive unit and sounded "slightly" less transparent. anything they make is fine with me because they are absolutely dedicated to great sound, but OTOH i would rather they upgrade the XP-20 to a 20.5 and perhaps generate even more enthusiasm.
French_fries (Threads | Answers | This Thread)
Consumer demand?

I was speaking with a highly regarded and well known designer, he said market demands have a LARGE influence in his designs and some of the features are just for show. I'm sure most thinks 2 chassis are superior to 1, 3 are superior to 2 ... and also the more chassis, the more you can charge. Some buy to satisfy their egos and not their ears. Like any successful company, you build what the consumer wants.

BTW, I'm not accusing Pass of this practice. As a matter of fact, Nelson Pass is one of the good honest guys in this industry based on personal experiences.
Petrushka, Thanks for sharing those comments about the various models. I'm wondering what the bigger improvement would be with the following two choises:

1. Upgrade from the XONO to the XP-25
2. Upgrade from the XP-20 to the XP-30

The XP-25 has the front controls for convenience, but has far fewer settings. The two inputs don't matter to me because I only have one arm/cartridge. The XP 30 is great, but it would be a more expensive upgrade.

French_fries, I owned a used Aleph P and it was great for the money, but the PASS X-1 that replaced it was much better, IMO. And the XP-30 is much better still. It does seem like overkill to have all of these boxes and cables. Consider the XP-25, XP-30 and a pair of the new Xs amps. That's nine (9) boxes with lots of connectors. Imagine the space needed. You could certainly buy a one-box integrated amp with built-in phono circuit instead, but the sound would not be as sweet.

After listening to the XP-30 for a week, the added rack space needed for the three boxes is a small price to pay for the glorious sound. If they could upgrade my XP-20 to a 20.5 which sounds like the 30 for a small fee, yes, that would be fantastic, but I doubt that option will ever be available. Perhaps in a few years there will be a small one box preamp based on the SIT chip which will change the whole game and footprint.

They certainly are "...absolutely dedicated to great sound...."
i can understand producing a new top-line preamp as a match for the newest amplifiers (cost no object). HOWEVER, i cannot understand with all the latest technological advances why you would need THREE boxes for TWO channels.
there are a number of VERY good preamps out there that have more than adequate isolation-techniques that still are just a single unit.
Pass Labs used to make the one-box Aleph P which was pure class-A and built without regards for cost ($4k) was compared to a passive unit and sounded "slightly" less transparent. anything they make is fine with me because they are absolutely dedicated to great sound, but OTOH i would rather they upgrade the XP-20 to a 20.5 and perhaps generate even more enthusiasm.
Great review -- thanks for sharing.

Based on what I've read and my communications with the folks at Pass, it seems that sonically the XP-30 benefits from a new volume control that is very quiet and a massive power supply that makes it quite immune to power line noise and anomalies. Overall, the sound is supposed to be extremely detailed and resolving without sounding harsh.

Back in 2010 I visited Pass' booth at CES. At that time, they hadn't decided if they would top out their line at XP-20. The two-piece XP-20 already edged out the older, 3-piece X0.2 in performance and it wasn't clear if the addition of a third box would bring meaningful benefit. It's interesting that they did finally find a way to improve things. This was how they described the differences to me:

- the XP-15 edged out the Xono slightly; the XP-25 was better than the XP-15 by quite a large margin

- the XP-20 was slighly better than the X0.2; the XP-10 is a touch less resolving than either and had slightly less articulate bass, but it did have a very pleasing, musical balance that some people preferred
I've been given the opportunity to borrow an XP-30 for a few days. I own an
XP-20 and figured the only way to really know how they differ is to
compare them directly in my system. As Petrushka mentioned, the XP-30
benefits from at least 24 hours of warm up. I've been listening now for five
days and have a sense of how it compares to my XP-20.

First, it is quieter. The noise floor is lower. I only listen to vinyl and the
backgrounds are slightly blacker than with the 20. Of course, this
increases signal to noise, so micro details are more easily heard. Overall
resolution is higher than with the XP-20. But also, there seems to be less
distortion allowing me to listen a bit louder with absolutely no fatigue.
Timbral accuracy is improved and there is slightly more hall information.
I've never heard the cello as played by Starker sound so pure. Tone is
simply beautiful. The definition of instruments in space is also clearer.
Some or all of these improvements may be due to the separate gain chassis
for each channel. The effect is not unlike when I compared an Aleph 5 to a
pair of Aleph 2s. Channel separation increased and crosstalk diminished.

The frequency extremes also seem slightly more extended. The bass is
better and the midrange is a bit fuller with more weight, but this is
balanced by better high frequency extension and detail, so I would not
really describe it as warmer. It still seems well balanced. The increased
clarity and extension is more noticeable in my system than is a shift in
tonal balance. Bass, in particular, seems more articulate, deeper and better
defined than it is with the 20. This reminds me of when I switched from
the SME V to the V-12 arm. The latter sounded more relaxed and
moredetailed at the same time with a better articulated bottom end.

Soundstage width is about the same as with the 20. Depth is
slightly better, but more important is the improved sense of layering and
image location, definition and solidity. The sound is also slightly bigger. It
projects more into the room making the music more present.

These differences are not subtle, but they are clear and definite. At the
same time, they are not huge. I've learned not to expect such things. It is
not so much a case of diminishing returns as it is a case for incremental
and steady improvement. After a certain level, to some of us any
improvement is worth celebrating. The improvement is quite noticeable
and the XP-30 is certainly the best preamp that I've had in my system. I
think the degree to which one thinks the 30 is better than the 20 will be
very dependent on the resolution of his or her system. Whether it is worth
it to upgrade will depend on available rack space and how much of a
difference one is able to hear. Because the 30 is considerably more
expensive than the 20, I will leave the issue of value to everyone to decide
for himself.

In my system, the XP-20 sounds great and I'm extremely happy with it.
Perhaps it was a curse to hear the XP-30, but I could not resist the
opportunity. It is definitely better, as one would expect for the additional
cost. I think that the XP-30 is the best preamp that Wayne has designed. It is
a real achievement and he should be commended.
I think you answered your own question -- the problem must lie not in the preamp but how it was set up.

All of Pass' preamps require 12 - 24 hours of on time before they reach their normal operating temperature for the class A sound and they are not meant to be powered off (hence no switch.) Was your unit adequately warmed up before your audition?
I currently have one in for audition with a Pass X350.5 amplifier. I have compared it head to head with a Conrad Johnson GAT tube preamp. The CJ positively smokes the XP30.
The CJ is open and spacious, where the XP30 sounds dynamically and spatially constricted. The CJ has a full round natural tonality and is beautiful to listen to. The XP30 is thin and reedy with no bloom. I am not certain why some reviewers have called this a tube-like sounding pre. To me it sounds like solid state on a diet. Very strange and rather lean. Not bright in the treble, but lean nonetheless. For my money, at $16K, there are a world of choices out there that make more sense. I auditioned the XP-10 with the same amp a while back and actually prefer it to the XP30. Sorry folks. Hate to piss in the punchbowl,but that's my honest opinion and I've listened to a few things in my day.