Thread: Pass Labs XP-32

I have had an XP-32 preamp in my system for about seventeen days now. It has been playing music 24/7 on a digital loop as it continues to settle during the break in period. It will be replacing my XP-22. The improvement is significant and I will be posting my listening impressions of the differences between the two preamps later this week. Wayne Colburn should be commended for the design of this extraordinary three box preamplifier that is placed right below his flagship XS Pre. It is a truly remarkable piece of gear.

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Congrats Peter! I owned the XP-30 for several years and used it in conjunction with the XA-100.5 and XA-100.8 monoblocks. It was a terrific preamp. I’ll bet the XP-32 takes it several steps further. Enjoy!

Ken

Congratulations Peter!

Please keep us updated. All reports so far have been great.

Peter

What happened to the vibraplanes?

Very nice Peter! Look forward to your impressions.

Originally Posted by XV-1

Peter

What happened to the vibraplanes?

Hello XV-1,

The three Vibraplanes, their compressor, and four Townshend Seismic Sink platforms, as well as all acoustic treatments, have been removed from the system and room. I will be putting them up for sale as well as a couple of cartridges and my Transparent Audio phono cable and power cords. I am simplifying the system and experimenting with different gear support options.

Congrats on the new preamp. I waited and waited, but the release delays sent me another direction for a preamp.

Looking forward to your updates where it’s characteristics fall (20,30, or XS like..).

Originally Posted by PeterA

Hello XV-1,

The three Vibraplanes, their compressor, and four Townshend Seismic Sink platforms, as well as all acoustic treatments, have been removed from the system and room. I will be putting them up for sale as well as a couple of cartridges and my Transparent Audio phono cable and power cords. I am simplifying the system and experimenting with different gear support options.

WOW, you have almost been religious in your praises of the Vibraplane - that was a back flip I did not see coming - what happened? sounds better without I guess.

Didn't you have Jim Smith voice your entire room and system? that gone too?

DDK disease and Ching Cheng cables - fun times ahead.

Originally Posted by XV-1

WOW, you have almost been religious in your praises of the Vibraplane - that was a back flip I did not see coming - what happened.
Didn't you have Jim Smith voice your entire room and system? that gone too?

DDK disease and Ching Cheng cables - fun times ahead.

Tastes change, and systems evolve. Jim Smith voiced my old Magico Mini IIs to my room with all of its treatments. I replaced the Mini IIs with Q3s and changes were made. Jim Smith taught me how to do it myself. I learned a lot from him.

Audiophile nervosa is the desease, DDK advocacy for a more "natural" sound, is the cure. The full evolution is described on my system thread linked in my signature.

Originally Posted by XV-1

DDK disease and Ching Cheng cables - fun times ahead.

Hi Ian, nice to see you posting again!

Best,
Ken

Originally Posted by Alpinist

Hi Ian, nice to see you posting again!

Best,
Ken

Thanks, Ken!

Originally Posted by Alpinist

Hi Ian, nice to see you posting again!

Best,
Ken

Agreed. And it is on a Pass Labs thread no less.

Congratulations with your new preamp.

Thank you everyone for your congratulations. I will post my listening impressions in the next few days.

Originally Posted by Bruce

Have the Shunyata Venoms in situ at present-- and they are burning in nicely, but not convinced as yet they are superior to the Hirakawas--we'll see in time.

Venoms, while great, are entry level cables.

Pass Labs XP-32 Listening Impressions

Part 1

System Background and Goals:

I have owned many Pass Labs preamps. I bought my first in the late 1990s and have made steady upgrades ever since: Aleph P, X-1, X-20, XP-22, XP-32. I have always found these products good sounding, extremely well built, and very reliable. The rest of the system is as follows: van den Hull cartridge, SME V-12 and SME 3012R tone arms, SME 30/12 turntable, Pass XP-27 phono, Pass XP-32 preamp, Pass XA160.5 amps, Magico Q3 speakers, DIY cables.

I have owned and enjoyed the XP-22 for about two years. It is the generation after Wayne Colburn designed his flagship XS Preamp and is supposed to benefit from some trickle down improvements over the XP-20, namely a much better umbilical cord, the volume control from the XP-30, and lower noise. The improvement over the XP-20 was worthwhile, but it was more incremental than anything major.

Over the past few years, I have spent more time listening to live acoustic music. I spent five days listening to closed rehearsals at the Vienna State Opera followed by different evening performances from the Director’s box. My mentor and host wanted me to learn more about the sound of real thing and by more closely focusing on the energy of the sound leaving the both singers up on stage and the instruments down in the orchestra pit. I also attended quite a few BSO performances from the seventh row center and some small chamber recitals in a living room setting in Boston. Much of this listening was from a close vantage point where the sound was immediate and direct.

With the memories of these live music experiences in my mind, I began to make some major, some might say radical changes to my audio system in an attempt to better capture that sense of incredible energy, clarity, and natural sound of live music. My system was somewhat artificial and not that natural sounding. It was a bit too “hifi”. It lacked the sense of “life” and energy that I heard live. I did not fully understand what was lacking until I started to experiment and make some changes.

I removed all pneumatic isolation platforms from under each component and replaced them with 14” X 18” X 1” 75 lb. stainless steel plates supported by large rubber O rings. I removed all acoustic treatments from the room, with the exception of one small absorption panel on the back wall 14” behind the listening seat. Upholstered chairs replaced absorption panels at the first reflection points. I played around with the location of the rug. Four 16” tube traps were removed from the front wall corners. I replaced expensive audiophile signal cables and power cords with DIY cables and Ching Cheng cords. Finally, I repositioned my speakers and slowly reduced toe-in to zero, or facing straight ahead.

I wanted to simplify my system, but I was also trying to achieve a more “natural” sound, one with more energy and life. The system is located in my formal living room. For years I sacrificed aesthetics for audiophile accessories and what I thought was my preferred sound. The more I listened to live music, the more I realized it was time for a change. These changes resulted in a less artificial, less focused, less “hifi” sound. Space opened up, timbre and dynamics improved. The sound became more alive and more natural. I was satisfied that I was moving in the right direction.

I made two equipment purchases during this time. I designed and had machined an outboard arm pod for a new SME 3012R tonearm, and I bought a van den Hul Colibri Master Signature cartridge. I mention all of this as background to explain that I think the sound of my system has changed pretty dramatically over the last year or so, but also to suggest that the system sounds less restricting and I think it is very likely that the differences between the XP-22 and XP-32 are more clearly audible than they might otherwise have been without these changes to my system. It is also an attempt to describe the type of sound I am trying to achieve.

Part 2

Evaluation protocol and design features:

The XP-32 arrived in its large box one evening. I unpacked the outer box and each of the three inner boxes. No damage. I removed the XP-22 from the rack and plugged it in at a different location to keep it warm and ready for future comparisons.

I placed the three XP-32 chassis in the rack. The controls are housed in the power supply box, so that went on the bottom shelf next to the power supply of the XP-27 phono stage. The two separate gain channel boxes were placed on the second shelf below the control/gain box of the XP-27. This arrangement keeps the gain and signal boxes furthest away from the noise of the power supply boxes. I used the same Ching Cheng power cord for the XP-32 that I had been using for the XP-22, so there was no break-in of a new stock power cord which would have been a complicating factor. I hooked up all of the connections and powered on the units.

I only listen to vinyl records in my system, but I do have an old Thule CD 150B digital player which I hooked up for break-in purposes. I ran a variety of CDs 24/7 during the entire seventeen day evaluation period. This preamp needs a lot of break-in, despite the suggestion that it simply needs to be plugged in for five days. I heard regular settling changes to the sound for two weeks. Another owner has told me that he heard changes for a couple of months until it reached its final voicing.

For the first few days, I listened only to old and familiar CDs. They had never sounded so good in this room. I had not heard digital in my system for years, and I suspect that some of the improvement in sound was due to the other recent changes I had made to my system and not to the new preamp. This was confirmed later during the evaluations when I switched back to the XP-22 and briefly listened to digital.

The XP-32 continued to break in and after a few days I began to listen to some familiar vinyl records. I did notice a few odd things. The center image that had been shifted slightly to the left with the XP-22 was now slightly to the right, both on digital and on vinyl. Strange. The shift to the left I had attributed to the wear on the SME internal arm cable because fiddling with the DIN socket does shift around the image. (That arm is due to go back to SME for maintenance and cable replacement)

Because this image shift issue could be heard on both digital and vinyl, I figured it was something other than the tonearm cable. I discovered two things. The XP-22 has an issue most probably with the volume control, and second, the resolution of the XP-32 allowed me to hear the very slight image shift to the right which I discovered was due to imprecise speaker positioning.

My house is 225 years old and has soft wide pine floor boards that, it turns out, are not precisely perpendicular to the walls. I lined the speaker footers up with the edge of one floor board but a very precise measurement with a laser and architect’s angle indicated that the left speaker was indeed 9/16^’” further away from a reference spot on the back wall centered in the room directly behind the listening seat. The zero toe-in was also off by fractions of an inch. After moving the left speaker forward slightly and adjusting toe angle to match the other speaker, the center images were precisely placed in the center and more solid than before. I did not hear this inaccuracy in speaker position with the XP-22 which had been getting worse over time. I had been simply adjusting the balance control to center the image thinking it was the tonearm wiring. With this mystery solved, I began more serious vinyl listening.

In addition to the higher resolution of the XP-32 allowing me to hear some minor issues with speaker positioning, I was also able to hear that the two cartridges and tone arms were not optimally set up. I made some minor adjustments to VTA which in turn led to readjusting the VTF and finally some very minor adjustments to the alignment.

The XP-32 is separated into three boxes. The controls for input switching and volume as well as display are housed in the power supply box. There are three transformers, one for each channel, and a third for the volume control. The power supply does not seem to get warm. The two gain boxes are slightly warm. By contrast, the control boxes of the XP-22 and XP-27 get pretty hot when left on 24/7.

This preamp runs much cooler but uses more energy than does the XP-22. Heat dissipation is excellent. This separation of the noisier parts of the preamp out of and away from the two independent gain channel boxes surely contributes to the extremely low noise that I am hearing which in turn leads to specific sonic improvements.

The XP-22 has 1.0 dB volume steps. The XP-32 has 0.5 dB steps making it easer to find the right volume for the music and to level match between sources. The three chassis do take up some rack space, but it is a price well worth paying in order to realize the sonic benefits, IMO.

Each gain chassis also has a secondary volume knob with for a linked secondary output. If I ever get around to experimenting with powered subwoofers, these may be very useful.

Near the end of the evaluation, I reinstalled the XP-22 and listened to three LPs. I then removed it again and reinstalled the XP-32 which had been plugged in staying warm. I listened to the same three LPs and confirmed my earlier impressions. The differences were indeed significant. I had heard all I needed to hear to decide which preamp to keep.

For the evaluation, I listened to acoustic music, mostly large and small scale classical, some choral music, some solo vocal music, and some jazz. Here is a list of some of the recordings:

1. Beethoven, Violin Concerto, Arthur Grumiaux, Philips
2. Holst, The Planets, Los Angeles Phil., Mehta, Decca
3. Cantata Domino, Proprius
4. Schubert, Death and the Maiden, Quartetto Italiano, Philips
5. Hindemith, Crumb, Solo Cello, Frans Helmerson, Bis
6. Bach, Sonatas and Partitas for Violin, Kuijken, Harmonia Mundi
7. Bach’s Trumpet, Don Smithers, Philips
8. Schubert, Winterreise, Schreier/Richter, Melodia
9. The King Singers, A French Collection, EMI
10. Holst, Savitri, Argo
11. Brown & Almeida, Moonlight Serenade, Jeton
12. Johnny Hartman, Once in Every Life, Beehive
13. Art Pepper+Eleven, Contemporary

​Part 3

Listening Impressions:

I often tell people that the one overwhelming impression I get when listening to the Boston Symphony Orchestra is one of “clarity”. Every instrument sounds so clean, so immediate, so present. The connection with the energy of the sounds produced by the musicians in command of their instruments is profound. One just absorbs the sounds and becomes lost in the music.

Here is a long list of specific words I can use to describe the differences between the two preamps, but more importantly, how the XP-32 brings me closer to the real thing: clarity, energy, natural resolution and dynamics, low noise, ambiance, texture, weight, body, harmonic content, tonal density, layering, decays, space, air, nuance. These attributes are all better with the XP-32 in the system, but it is the gestalt, the whole presentation, the sum of the experience which is meaningful, not the individual attributes making up parts. I only mention the parts for specificity in an attempt to explain differences. Were I not writing a report for others to understand what I was experiencing, I would simply describe the XP-32 as having greater “clarity” and presenting the sound more naturally. That is the essence for me.

For others, to whom such a description is too vague, here is more: the tonal balance and voicing of the XP-32 is very similar to that of the XP-22. From there, the differences become more pronounced. With larger scale recordings of orchestra and choir, there is a greater scale and cleanness to the sound. Individual instruments and voices are more distinct. There is less homogenization of the sound. It is more grand. There is more air between, around, and above the players. The sounds decay and reflect off of the stage boundaries more realistically. My listening room disappears more and the speakers disappear more, as the musicians take on more presence. On smaller scale music, if the solo instrument is on a large stage, that space around the instrument is more defined because decays hang in the air longer and move away more audibly toward the boundaries. Both the stage and the cello, or piano, or voice, is more present. The setting is more clearly audible.

String texture is better, and its contrast to the instrument’s hollow wooden body is more clear. With instruments that have complex harmonics like viola de gamba, harpsichord, or French horn, the sheer harmonic content is intense. It is more complex, more colorful, more nuanced. It is also more accurate in terms of distinct timbre. Separate sounds are more easily heard, but they are also richer tonally, instruments and voices are more timbrally distinct and identifiable. Energy is released more easily. The sound is freer. There is less strain, more relaxation. The listener does less work.

Cymbals are less splashy, less white, more colored, more metallic, more defined. Wooden string instruments are more hollow, more resonant, more “woody”. Clarinet and saxophone are more “reedy”. Drums have more impact and are more defined by skin, size, and extension. Dynamics were always excellent with the XP-22, but with the XP-32, they are less stark, and less bold, more nuanced and realistic.

I used to think of the distinction between the source of the sound up on stage and the sound that is created and moves outward into space. The XP-32 so clearly and naturally conveys the two that paradoxically, they sound more as one and not distinct. They are more complete. They are more whole. The instrument or singer has more weight, more body, and is spatially better defined. It is more present. And yet, the sound produced is more nuanced, more atmospheric, more energized. It is a part of the presence, intimately related to the source, and it leaves or explodes away moving to fill the space. This sense of completeness is so well conveyed that I often lost the impression that I was listening to reproduced music. It was pure energy naturally thrust into the room.

Part 4

Conclusions:

After more than two weeks of continual playing, I reinstalled the warm XP-22 and played music through it for a couple of hours before comparing its sound to the XP-32. I played three LPs: Beethoven’s Violin Concerto, Cantata Domino, Solo Cello. My first impression was that the XP-22 sounded considerably better than I remember it sounding. Then it occurred to me: the slight improvements to speaker position and cartridge set up. That explains the better sound than what I remember. The XP-22’s resolution level prevented me from hearing those setup issues before.

In direct comparison to the XP-32, Grumiaux’s violin was not as present, not as emotional, not as convincing. The massed strings did not soar as high, or fill the listening room with quite the same energy. The sound was flatter, and a bit greyer. The chorus on Cantata Domino actually sounded excellent and pretty similar to the XP-32. That recording has an incredible ambiance and could probably sound fantastic on most systems. Here it sounded grand and quite beautiful, but not quite as natural or quite as sublime. Decays were shorter. The images were similar, but the hall was less defined. The individual voices were not quite as distinct.

The solo cello as portrayed by the two preamps sounded perhaps the most different. I find solo instruments make it easier to focus on one or two particular attributes of sound because one is not distracted by other instruments. I was taken back to Vienna where my mentor told me to pay attention to the “energy” from that solo cello in the pit. In my room, years later, it was clear that the XP-22 simply could not convey the same energy, weight, nuance, string texture, hollow body, or ambient hall information - all the things that made that cello come alive in my room with the XP-32.

We often hear people say that one does not know what he is missing until he hears it for the first time. Putting the XP-32 back into my system has made this comment more relevant. I knew what I was missing because of my reference to the real thing, real music in a real space. I heard that live cello sound years ago in Vienna and again a few times in the Boston chamber setting. I am now, for the first time, hearing something much, much closer to the real thing, right in my listening room. The increased clarity, and the lower noise and distortion, allows me to increase the volume which goes a very long way towards making it sound more convincing. The system and room changes, including the new arm and cartridge leading up to this evaluation, certainly helped to create a setting in which the XP-32 could more clearly demonstrate its capabilities.

Wayne Colburn should be commended for this fine achievement. The XP-32 is all about clarity and presenting the music in a more natural and convincing way. It brings me much closer to the music embedded in my precious vinyl LPs, and it more often enables me to forget that I am actually listening to an audio system. What more could one want? The XP-32 has made me realize how much a really good preamp can improve the sound of one’s system and bring him closer to the music.

Peter, excellent write up. Thank you for sharing. The XP32 is a wonderful preamp from a great American company.

A very thorough approach and excellent write up Peter. Congratulations on the XP32 and all of the changes you’ve made in the room and system.

Wow, Peter, what a thorough and entertaining write up. VERY nicely done!!!

Originally Posted by madfloyd

Wow, Peter, what a thorough and entertaining write up. VERY nicely done!!!

That ^ just like Ian said it above ... entertaining read-up.
That's what it's all about...the pursuit of happiness.

Very best journey to you Peter.

Thank you everyone for the kind words. I find it is easy to write when I know what to say. This was a pleasure, and I hope that others get a change to hear this excellent preamp.

Does anyone know if the XP-32 modules can be stacked on top of each other? I’m sure they are better separated but is there any sound penalty for stacking?