Sophia II's and Pass Labs etc


I will buy a new amp set up for my Wilson Audio Sophia II's after the summer. I currently use a Burmester 051 integrated amp and a Burmester 061 cd player + a TW Acustic Raven w/Graham Phantom II arm will be ordered soon

I like the Burmester 011 preamp and Burmester 911 mk3 amp very much, although I have not tested the amp set on my speakers. The price for the set in Norway is NOK 276,000,-

The other options I am looking at are:

- Pass Labs XP20 and XA 100,5 / XA 160.5 mono amps, approx. NOK 210,000 / NOK 255,000

- Audio Research REF 3 preamp and REF 110 amp, approx. NOK 220,000,-

- Simaudio Moon P8 and Simaudio Moon W8, approx. NOK 245,000,-.

- Spectral DMC-30SS and Spectral DMA 360, approx. NOK 230,000,-.

And then you have Conrad Johnson, Mark Levinson, Luxman, Accuphase, MBL, etc etc.

Do you have any preferences of the amps mentioned. Do you know if Pass Labs XA 100.5 will be strong enough for the Sophia 2's?

I listen foremost to pop/rock/hip hop/electro/jazz/metal/etc, since I am a talent buyer within the festival circuit in Norway.

Thanks for your help.

Cheeers, ToffenG, Norway
The XA 100.5's have no problem driving the Sophia 2's to high levels with great control and finesse.

It is a very good combination.

I auditioned the Audio Research REF 3 and REF 110 with the Sophia 2's. I was looking for a new amp and linestage for my verity parsifals. I have heard the Sophia 2's a lot and felt that I knew their sound fairly well. With the Audio Research there was great air and imaging but the upper mids were a bit forced and I felt that the ARC gear did not fully take advantage of the Wilson's in the lower base, I have heard the Wilson's a bit deeper, tighter and with more "punch". I did hear them with Ayre and now that was really nice.

Thanks! I will try to get hold of Pass Labs for a review. It may not be possible as there is only one dealer in Norway. The same with Simaudio Moon. For Spectral I have to travel to Great Britain...

Cheeers, ToffenG

I have heard the REF 3 in the same system I talked about above and did not think it was a good match with the Sophia 2's. As you stated, the upper mids were forced and I also found the overall sound strident at times. There was no emotional connection to the music and I simply found myself not wanting to listen when the REF 3 was in the system.

I know the REF 3 has received great reviews, but I was very disappointed with how it sounded in this and my own system.


Thanks for your insight.

I will check out:

- Burmester 011 and 911mk3
- Pass Labs XP 20 and XA100.5
- Simaudio Moon P8 and Simaudio Moon W8

Have you any experience with Parasound JC2 Preamp and Parasound JC 1 mono amps on Sophia 2's?

Cheeers and thanks, ToffenG

Please also listen to VTL if you can. Very good combination w. Wilson if you can do tubes. The other great combination will be VTL for preamp & Lamm for amp.
For preamps the VTL 6.5 or 7.5/2
For amps the 450 Signature, S400 or the Lamm M1.2s.
MBL would excellent as well.
Luxman will be more lean, VTL more full and Lamm in between.


I have read lots of good reviews of the VTL and Lamm amps. I will check out who got them in Norway. MBL has a distributor in Norway now.

Cheeers, ToffenG
I have heard a friends Sophia 2 with Mcintosh and Ayre. The Ayre system he uses now is very good. K-1XE preamp and V-1XE amp. I would look into the even higher end Ayre products also.

Unfortunately I do not think The Ayre MX-R mono amps and Ayre KX-R preamp are within my budget as they cost NOK 350,000. The Pass Labs combo costs NOK 210,000 and Burmester NOK 275,000.

Cheeers! ToffenG
There is a review of the Pass XA 30.5 in the latest issue of Stereophile, May edition. Brian Damkroger was the writer and he used Wilson Sophia 2's. The article may provide some insight on the Pass Amps and the synergy with your speakers. Also, the XP-20 with the XA 30.5 is a great match in my particular system with Dynaudio. The XP-20 replaces a Conrad Johnson Act 2, Version 1.

Another review is available for the XP-20 and the XA 160.5 in the latest issue of the Sensible Sound if you are a magazine type of person who reads them. Much luck in your search!
I have Sophia 2’s and Pass XA 100.5’s. They are a great match. I was worried that I wouldn’t have enough power and was thinking of the XA 160.5’s but my dealer talked me out of it. He was right to do so. The XA 100.5’s have 200 watts of power at 4ohms – and that’s just in Class A. The amps have a lot more power in A/B. That being said, it took playing rock at close to 100db before the meters on the front of the amps looked liked they were thinking of going over to the dark side. 

I replaced Theta Citadel 1.5’s which were also very good, but Class A power just sounds sweet and effortless.
How about posting some pictures of that awsome system of yours? I agree about the power of the XA100.5. I have Eggleston - 87dB, 4ohm min. - and they easily drive the speaker. The meters have never moved. They control my speakers much better than my old XA160s did. They double down in power as impedence is halved and they have more current. Plenty powerful with the sweet sound of Class A.
>>04-23-09: Madfloyd
The amps have a lot more power in A/B.<<

Well that's strictly conjecture as Pass does not publish any specs for Class AB operation. However, the amps will work into AB until power supply runs out of gas or the thermal circuit trips.

Regarding the meter staffs, they are not indicators of power output. They measure bias and will not move until the amplifier leaves Class A.

Dealer disclaimer.
Assuming the XA 100.5's behave in the same manner as the recently reviewed and measured XA 30.5's, I think it is fair to say that the amps have a lot more power in A/B.

In the Stereophile measurements section, it achieved its power rating of 30 watts in Class A with distortion at .015% and didn't clip (defined as reaching 1% distortion) until 130 watts!

As Madfloyd has already stated, you have to play music at same ear damaging levels to get the amps out of pure Class A mode, so people should just enjoy the Pass magic.

Slightly off topic...

Audiofeil, since you are both a Pass and Atma-Sphere dealer, any comments on how the XA-100.5's would compare to the Atma-Sphere MA-1's on appropriate speakers?

At some point Madfloyd will hopefully be bringing his XA-100.5's over to my place so we can compare them directly to my MA-1's on Vandersteen 5A's. Both are great amps and neither is really "better" than the other, but I am sure one will be preferred over the other depending on system setup and individual preferences.

Peterayer, you do believe XA-60.5 amps would have enough power to successfully drive Eggleston Andra II loudspeakers? My instincts tell me no, and comments from other Andra II owners suggest not, but I'd be interested in your opinion.
Hello Tvad,
That's hard to say. My gut says that the XA60.5 will be enough to drive the Andra II (89dB and 6ohm nom. load?) if the music is not too dynamic or too loud and the room is not too large. But that is a lot of "ifs". My Rosa is not as efficient as your Andra II and my XA100.5 seem like plenty, so they would be amazing with your more efficient Andra IIs. But then again, your room is probably bigger than mine as mine could not support the Andra's woofer. The Eggelstons love power and some Audiogoners use the X600.5 to drive the Andras. I have a small(15'x16'x7.5') room and my "gut" has been plenty wrong in the past. Do you have any way to audition them in your system before committing? There is always the XA100.5 or even the XA160.5, but the latter is getting quite expensive.
No, I have no way of auditioning Andra II, and I'd be purchasing them used rather than new.

I intend to keep the XA-60.5, so I'll be looking for other speaker alternatives with higher sensitivity specs. Daedalus models are under consideration.
Sorry Tvad,
I misunderstood you. I thought you owned the Andra II and were considering which Pass XA.5 to buy. Sorry for the confusion.
I have directly compared the XA30.5 to the XA100.5 on my Sophia II's. The XA30.5 sometimes runs out of steam, whereas the XA100.5s do not. The XA100.5s are better in every way than the XA30.5, it's not just a power thing. You get fuller, more stable imaging, better delineation, more articulation across the entire frequency and a much larger soundfield horizontally, vertically and dimensionally.

All that being said, I chose the XA30.5 for my Sophia IIs as my SS amp ( I use both tubes and SS amplification for the speakers depending on my mood ). At 1/3rd the price of XA100.5 mono blocks, the XA30.5 delivers maybe 85% of the sonics. I also found the XA30.5 to be a little sweeter with more "character" than the larger and more neutral monos. This sweetness created a more INVOLVING presentation, for me, with the Wilsons which certainly benefit from amplification that fully fleshes out harmonics. Th XA30.5 is also almost as transparent and textured as the XA100.5s, so detail freaks need not fret.

These amps heat up small rooms quite quickly, FYI. The monos produce about 3x as much heat as the stereo XA30.5 and suck just as much energy too.

Boils down to budget and what you're willing to spend to get that last ounce of performance. The XA30.5 is a great match with the Sophia IIs, and the XA100.5 are even better. I liked the price and involving performance of the XA30.5, so that's what I chose. The Sophia's are relatively efficient, so the extra wattage of the XA100.5s aren't needed for higher SPL, but mainly for CONTROL which equates to a better performing system (speakers and amps).

Give Pass Labs a call, Kent is extrodinarly helpful and quite frank about his opinions. For my situation, he heartily recommended the XA30.5 and discouraged the XA60.5s. When asked about the XA100.5s for my set up, he said it would be a bit better, but the XA30.5 really makes the best sense unless you just have to spend $15k +.

Hope this helps. I started a thread "Wilson Sophia2s demand better than AYRE V5xe, so" where I make comments about the XA30.5, FYI...

Oh, and I listened to the XP-20 which is a remarkable preamp, but it's not the most transparent or 3D, depth producing preamp compared to the best out there. I thought my Ayre K1xe was more transparent and textured than the XP-20. I liked the "sonic signature" of the Pass amps better than pre, and when put together, ALMOST too much of a good thing, but that's just me and I'm picky, so listen for yourself...
That was a great post, Hce4. I like your very "real world" consideration of price vs. performance. I don't often see comparisons between equipment which include a personal perception of value. You're right that Kent and others at Pass seem to express their honest opinions when discussing their products to potential customers. Thank you for sharing your thoughts.

I will also send a kudos on your post in the comparison between the 2 Pass amps. I also am a XA 30.5 owner and the XA 60.5's (don't need the 100's) still are in the back of my mind. Your post is a very pragmatic and sensible approach. I did keep the XP-20 though as I've never heard the Ayre, but perhaps a future endeavor.
Hce4, could you elaborate as to why Pass Lab prefers the XA30.5 or XA100.5, while discourages you from getting the XA 60.5? Thank you.
Hce4: thank you very much for that great post. Interesting to hear that you found the XA 30.5 sweeter.

I'm auditioning the XP-20 now.

Kent at Pass Labs mentioned that on my speakers, the XA30.5 and XA60.5 would perform quite similarly with the main difference in power and current. Kent made the point that the XA60.5s would outperform the XA30.5 at high volumes (100db+), while at normal listening levels there would be little difference. Kent mentioned that the XA60.5 are basically monoblock versions of the XA30.5 and were produced for people who desire monoblocks. He strongly thought the XA30.5 would be more than adequate for the Sophia II's, and the XA60.5 would be overkill and not worth the extra money (on my speakers). I should make the point again that those with slightly less efficient speakers would benefit from the XA60.5s.

Kent recommended the XA100.5s over the XA30.5, noting that in addition to power and current delivery, there are other improvements that put these monoblocks in another league sonically and when played at precisely the same volume (important point). At the same volume, sound output, I noticed specific differences between the XA30.5 and XA100.5 which I mentioned in my previous post. He did not elaborate much beyond that, but suffice to say he felt that for the Sophia II's the XA30.5 is a perfect match, the XA60.5s would be a sideways step, and the XA100.5s are the sweetspot in the XA.5 line (he prefered these to the XA160.5 and the XA200.5), so if I had the urge for Pass Lab's best, go for the XA100.5s, but the XA30.5 makes the most sense.

Having said that, I have not compared the XA30.5 to the XA60.5s and I have been told by Mark at Reno HiFi that he does not share Kent's assertion of the XA30.5 compared to the XA60.5s, even on Wilson Sophias. He feels that there is a significant enough sonic improvement between the two that justifies the price, even with efficient speakers. Also, I think I read someplace on the boards that one XA30.5 user found the amp to be inadequate with his Wilson Sophias, so as usual it depends on your situation, system and listening environment.
By any chance has anybody compared the XA100.5 to others in the XA.5 family, specifically for cases that don't have possible power shortage? There is just no way that Pass Labs intentionally designs their mid-level amplifier to be better than the upper 160.5 & 200.5. In fact before the XA.5 line exists, Pass Labs told me all XA's are made the same way, except for power difference. I can see the 100.5 be better than the 60.5 because there can be more to power than the ability to play it loud. But the other way around is a bit hard to believe.
I have only heard the XA100.5 in the XA.5 line. I have read people refering to a "sweet spot" in the various Pass lines. The Aleph 2 in the Aleph line, the XA 160 in the XA line, the X350.5 in the X.5 line, etc. I read somewhere Nelson Pass or one of the employees talking about this. I think they are refering to the price/performance ratio which can be a moving target depending on which generation of amps you're talking about. I don't think it is just more power or stereo vs. mono blocks.
Mark and I too exchanged email's on the differences between XA 60.5 and the XA 30.5 and he conveyed to me they were a worthy upgrade if you can justify the cost and have the floor space.

Also, to enforce Kent's advise, when Stereophile (May 2009) recently reviewed the XA 30.5, the writer was surprised Mr. Pass sent the XA 30.5 rather then the more powerful monoblocks. The review was very positive for the XA 30.5, but the writer felt he would not buy the XA 30.5 himself with the Wilson Sophia II's he owns due to needing more power.

Speakers the reviewer used were NHT Super Zero's and Wilson Sophia 2's.

If you have not read the magazine, here are some snippets.

"Nelson's amplifiers, whether they were his earlier designs for Threshold or his later ones for Pass Labs, have always been on the my wish list, so I was delighted when the opportunity arose to review one of the latest Pass amps. I was a little surprised, however, at Nelson Pass's suggestion that I audition the XA 30.5. I'd expected a pair of X1000.5 monoblocks perhaps,, or maybe the XA 200.5s, fi he thought they'd do the job....but a nominally 30 WPC stereo amp? I double checked, and yes, he did know what speakers and other amplifers I was using, ansd yes, he was aware of the sort of gear I usually reviewed. Despite all that-actually, because of all that-he reiterated his preference that I audition the little guy."

"To be fair, I was running the XA 30.5 well out of it's comfort zone. Nelson Pass explained to me that the front panel meter, which indicates the amount of current being drawn from the wall, "Should sit somewhere in the middle" and "won't move if you running in class-A." During most of my listening sessions, the meter would bounce between the middle and, say, the three-quarters point of its range. When I was listening to and for large dynamic swings, the meter would frequently be pegged. This didn't seem to bother Pass when we discussed it though he did say, " you're pulling a lot of juice." Well maybe if I'd gotten those XA 200.5 monoblocks.."

"Plus in todays high-end audio world, the XA 30.5 is a steal. Compared to what else is out there, a price of $5,500 is low for an amplifier of this quality. No, I probably wouldn't buy one, but only because I think that a larger, more expensive Pass Labs model would work better in my system. Absolutely, positively, and enthusiastically recommended."
The XA-30.5 is the best sounding Pass amplifier in production at this time IMO.

That being said, it's difficult to designate any audio component costing $5.5K a "steal". Again IMO.

Dealer disclaimer.
Does anybody know if most models within the XA.5 line have their own design tweak different from the others? I really thought they all have the same design.

I too also heard that at low volume, the XA30.5 sounds superior than the more powerful models.
All I know is, my $10,000 XA-60.5 get no love, either from users here or from Pass Labs, apparently.

Boo hoo.

The ONLY hard/fast rule in Audio is there are no hard fast rules in Audio.

A softer/slower rule is that amps with fewer output devices seem to sound a little sweeter than their bigger brothers which may explain some peoples preference for the 30.5.

I believe I read with the Pass, the bigger the amp the more bias he applies which lowers distortion.
Beside current bias can anyone think of other differences between models of the XA.5 line? A theory is that given the XA.5 design, current bias level has its peak performance at certain marker. People at Pass Labs don't get into it because the reason why is not well understood. Just thinking out loud here.
Hi Toffeng,

I don't own the Sophia II's, but I am currently listening to a few different combination's of gear driving my Avalon Opus speakers (full range speakers at 87 dB efficiency in a rather large room). Among the amps and preamps are the Pass X250.5, the Pass XA100.5, the Pass XP-10 preamp, and the H2O Audio Fire preamp. I previously auditioned the ARC LS26 preamp, which I thought was strident in the upper midrange and rolled off in lowest frequencies when combined with the Pass X250.5. I also auditioned the Cary SLP05 with the X250.5, which sounded very nice although a bit colored (in a good way) in the midrange.

Different people respond to different aspects of sound quality, and components that work great in some systems don't work well in others. With this in mind I don't like giving recommendations as much as describing what works well in my system. That being said, the XA100.5 monos are proving to be really outstanding sounding amplifiers. They are powerful and delicate at the same time. They are warm with a full midrange, but no midbass bloat and very nice extension in both the upper and lower frequencies. Their full bodied presentation and power, along with their lack of distortion and noise results in an exquisitely beautiful sound.

Regarding preamps, my favorite with the Pass amps is the H2O Audio Fire. I recently described this preamp in a different thread so I don't want to repeat myself here other than to say it mates very well with the XA100.5. Another contributor to this thread will be trying one out with his XA100.5 amps, so maybe he can chime in with his results after he's listened to it for a while. The drawback is that it is a big two box affair that will be expensive to ship to Norway from the U.S., but it is also not as expensive as the others you have been thinking about.

P.S. I will be traveling to Norway in August. I've never been, so please let me know if you have any advice for areas that are not to be missed.

Good luck with your search,
I called Pass Labs describing the Audigon discussion. His answer about "sweet spot" is just what Peterayer said. It's a personal taste on value based on price and whatever else the person think is important. It has nothing to do with design. Although bias and power supply size are changed as you go up the power rating, the design is the same. Basically you want bigger amp as you have more demanding speakers. Gee, for a moment I thought I bought the less desirable model of the XA.5 line.
I used to have Watt Puppy 6s with a Pass X350 and found it a good match, especially in the bass, which was natural and listenable and well integrated. In showrooms, I also thought the WP6s paired well with Levinson 33Hs and BAT amps. Hope this helps, even though these were not Sophias.
For the original poster's benefit:

I would recommend the XA100.5, but not the XP20. Although I voiced my opinion clearly for the XA30.5 with the Sophia II's, I think compared to the rest of your system, the XA100.5s would be the best fit. I think you would appreciate the difference between an XA30.5 and the mono XA100.5s and you would be willing to pay for the improvements. In my situation, the XA30.5 fit the bill just fine both financially and sonically (and it allowed me to purchase a tube amp to swap out during winter months or when the mood was right). The XP20 is very good, but you really should pair the XA.5 series with a tube preamp as it will only add to and enhance the sonic purity of timbers/harmonics you get from the XA.5 series.

Hope this helps. really should pair the XA.5 series with a tube
preamp as it will only add to and enhance the sonic purity of
timbers/harmonics you get from the XA.5 series.

Hope this helps.
Hce4 (Threads | Answers)

Care should be taken that a tube preamp used with the Pass Labs gear does
not have high output impedance, as it may result in rolled of bass and treble.

I used a Lamm LL2 Deluxe (fully tubed) and Lamm L2 Reference (tubed power
supply) with excellent results.

Which tube preamp are you using, Hce4?
Hi all!

Thanks for all the advise! Much appreciated.

I have got some quotes from the various dealers now, and two pieces are standing out:

- Mark Levinson No 432 amp and Mark Levinson No 326S amp (very nice quote indeed)
- Burmester 911mk3 demo

I also got nice quotes from Pass Labs, and the Krell, Simaudio Moon, Plinius & Audio Researc dealer is also keen.

How is Krell compared to PassLabs? Krell Evolution EVO 302 and Krell Evolution EVO 222? The dealer told me that the Krell sound is the most smooth one, as Simaudio Moon is more of everything, the Audio Research is great midrange and treble, but lacks punch. And he reccommended Plinius a lot. I will travel up to him (2 hrs flight) to check out all with a Wilson Audio 2. He is lucky for me also a dealer for Wilson, the only one in Norway.

Cheeers and thanks, ToffenG
I don't know if Balanced Audio Technology is available in Norway, but I can strongly recommend the VK-52SE vacuum tube preamp and the VK-600SE solid-state amp with Wilson Audio Sophia Series 2. I am blown away with this combination!
Hi everyone,

I am driving my Sophia 2's With XA30.5 without any issue,my preamp is
ARC Ref3.You can suggest ref3 for its wide and fantastic soundstage with XA30.5.You can 'see' every performer right at it's place-very 3 dimensional.
I have tried XA30 with many pre's such Aesthetics,Boulder 810,but Ref 3 is the right one for me.Indeed match XA30 with a tube pre,works.
Compared XA30 (ClassA)with Boulder 1060(A/B) , thought they are different.
Any who like mellow ,soft,3D,musical amp should suggest XA30..
One who likes strict ,punchy instruments at the right place of soundstage can stick on 1060.
I listened to the Sophia iii with an Ayre ax-7e and the Sasha with Ayre mx-r's, and both setups were among the best I've ever heard.