Pass Labs XP-32

#1
Pass Labs XP-32 First Critical Listen
Prior to my comments below I had white and pink noise going thru the XP-32 preamp with its balanced outputs loaded with 22K resistor loads for a week. I alternated the noise sources every other day. Hopefully this will help reduce the break-in time some. With the previous XP22 preamp I used the noise source break-in for two weeks. I still felt it took nearly 2 months to fully settle into its final voicing. I play the system so seldom that this may another reason for the long break-in time that I observed even though it was powered on the entire time.

Some general comments first: I’m a rather critical listener, and less apt to say something sounds better just because it is sounds different. I do not expect my comments on this initial listen are going to be the final word on my thoughts going forward. I’ll likely formulate some of the preamps weaknesses as I listen to it more over time. Since the XP-22 was the most recent preamp being utilized in my system many of my XP-32 comments will likely reflect the differences I hear between these two preamps. I have used the Berkeley RS DAC as the volume control to get repeatability in level with the preamp set for unity gain (179). I have a varied list of music that I have volume level setting for DAC to get repeatability in my listening sessions. With the entire system now having 23 hours of being powered on the DAC and N10 Aurender unit clocks should be settled in better than the initial listen that I did yesterday. I’m using my XA-160.5 amplifiers and curious how the XP-32 will sound in this paring.

The Strengths I Noted with the XP-32 are as Follows:
1) This preamp makes it hard to peg it as a solid-state unit. The transparency of the unit would easily pass for SOA tube unit, but without the associated tube noise. This design surely has blurred the difference between SS and tube units, which is a first for myself.

2) This preamp has the best overall spectral balance that I have ever experienced in a preamp. I have not heard the Pass Labs Xs preamp, but at half the price, I suspect this unit would compare well. I now understand why Desmond would be willing to use this unit in his own system (as Wayne Colburn noted to me previously). An example: I have always questioned the sound quality on Keith Johnson’s symphony recordings. It always seemed like he had incorrect microphone placement, which caused many instruments groups sound anemic IMO. Playing some of this music today showed a well-balanced recording, which tells me Wayne has fixed my problem in the reproduction chain.

3) The harmonics of instruments are more fully flushed out than the XP-22. This is very evident in piano and string instruments. This brings a new level of realism to my system.

4) The timing of those harmonics and the amount of detail has improved. Everything sounds more realistic and playing in free space. Again, more tube-like performance. The decay of notes seems to linearly go blackness. The XA-160.5 amps are champs at natural sounding instrument decay in my book. Now with the XP-32 as the signal source the decay really brings noticeably improved realism to the picture.

5) The soundstage images have more equal weighting than I have ever heard before…what does that mean? The best photograph analogy would be the central images usually have good focus in a decent Hi-End system, but it seems they are taken with a wide aperture lens. The images deeper in the soundstage and off to the sides are there but not as well in focus. The outer images are not flushed out well with respect to the density of the sound in them and the full harmonic content and detail of the central images. The XP32 seems to be using a small aperture lens, so everything in the soundstage is in much better focus. The sounds are more saturated like the central image all across the sound stage depth and width. This brings improved realism and flow to the music. The soundstage portrays more saturated images in the soundstage with well recorded music. I believe this effect is highly related to the next effect I’m experiencing.

6) Now with all that acoustic energy being better focused (where it should be) the preamp seems to handle complex and loud passages of music more like a tube design. You do not get the urge to turn down passages because they get irritating and compressed sounding during loud and complex music. I found myself even seeking out music that I found irritating before and found the XP-32 allowed me to play them through to the end, which I had not wanted to do previously.

7) All these above traits come together to good effect. It is so easy to follow individual instruments or voices. The improved spectral balance and the added detail in the sound stage has made hand claps on live recordings sound much more flushed out and real. I use the well recorded Alison Krause & Union Station live album for one of my hand claps references (“Stay” cut and others).

Weakness?
The only thing I’m questioning with the XP-32, compared to the XP-22, is that maybe the dynamics seem a bit more muted. My thought process on this has led me to the considering that the sound energy is more uniformly spread around the sound stage (in the proper image locations) with the XP-32. The images having more body, spread more evenly/correctly, which makes the previously center centric image sound of the XP-22 sound more dynamic in comparison.

Summary/Comments:
This preamp definitely has the effect of pulling you into the music. Your brain just does not have to work as hard to fill in the mental sonic gaps. We are asking our brains to do this all time. We have to mentally complete the music as we know it from our past live performance experiences. The XP-32 IMO achieves a few steps towards a more realistic and enjoyable experience.

On the surface the XP-32 looked like it offered move balanced inputs and the useful additional buffered Slave outputs. Given the large price-point difference, I was hoping, but not really expecting to hear this much of an improvement with the XP-32. Wayne Colburn has managed evoke some magic in this unit and needs to be commended. Even a jaded, performance orientated, audiophile like myself is likely to become more of a music lover with this unit in the system.

I admit that was a little worried, given that the XP-32 was likely designed with the PT 8 amplifiers in mind. This might have meant that it would not mate up as well with the sonic character of my older XA-160.5 amps. I find that my old XA-160.5 amps were able to portray a higher level of detail and finesse with the XP-32 feeding them, which banished my initial reservations. I find it interesting that the amplifier was not the weak link and allowed me to hear the much improved signal the XP-32 was generating. More time is need to see where the XP-32 finally ends up sonically. I do not think it will be leaving my system any time soon….
 

jackelsson

Well-Known Member
Dec 1, 2013
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#2
Maxpwr, thanks for this most interesting write-up. Myself I went from an XP-20 to my current XP-30 some four years ago and what you write could have been written pretty exactly like this by me back then to explain the difference between the XP-20 and the XP-30. Seems the general difference between the 20’line and the 30’line has stayed the same.

Did you have any chance to compare the XP-32 to the XP-30? That is something I would be highly interested in.

Care to post a picture of the XP-32?

IMG_4512_Pass-stack_web.jpg
 
Likes: Gene 15352
#3
jackelsson, I unfortunately do not have any experience with the XP-30 preamp.

I have attached a picture of the business end of the XP-32. The front looks exactly like the XP-30. As you can see they are now uing the new circular connectors for power and control signal. The XP-30 power/control pass-thru feature for adding additional channel expansion has gone away. I assume not many utilized this feature.

One of the nice new features is that the volume control has 0.5 dB resolution, which makes the balance control much more useful. There are 199 Volume steps, the first 20 are 1 dB increments with the remaining 179 steps 0.5 dB steps. I convinced Wayne Colburn this would be a desired upgrade and he agreed. Needing more display digits to achieve this the "L" and "R" volume indications are now gone. I surely do not miss them as the position on the preamp display makes this automatically intuitive.
 

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PeterA

Well-Known Member
Dec 7, 2011
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#4
Hello MAXPWR, I must commend you on a very well written and comprehensive description of the new XP-32. Congratulations. As an owner of an XP-22, I found this very interesting. I suspect your thoughts may evolve slightly, and I look forward to reading more of your impressions in the future.

I have two questions:

1. When you describe the spectral balance as being the best you've heard and that instruments from RR recordings no longer sound "anemic", I presume this means they have more weight, are less thin sounding, etc. Perhaps more harmonic content and a good frequency balance from lows to highs. Is this in direct comparison to the XP-22? If so, would you say the latter preamp is thin sounding, or emphasizes the mid to high frequencies more at the expense of the mid to low frequencies?

2. Dynamics: You write that the XP-32 sounds as though more instruments across the stage have a more realistic relative weight and that the center image is not the focus. This certainly is more how real instruments sound, but is that dynamics or something else? Have you had a chance yet to listen to something like a string quartet? Does it sound more dynamic through the XP-32 across all four instruments spread across the stage relative to how the XP-22 sounds? I find with recent changes in my own system that there is much more energy coming off of the strings/bow of all four instruments. The wood resonance is more alive and the sound just fills the room more. Your description makes it sound as though the emphasis is more towards the center of the stage with the 22 and more equally distributed across the stage with the 32. Is that correct?

This is a really excellent piece describing a component that I would love to own. Thank you for that.
 
#5
PeterA Q1) When you describe the spectral balance as being the best you've heard and that instruments from RR recordings no longer sound "anemic", I presume this means they have more weight, are less thin sounding, etc. Perhaps more harmonic content and a good frequency balance from lows to highs. Is this in direct comparison to the XP-22? If so, would you say the latter preamp is thin sounding, or emphasizes the mid to high frequencies more at the expense of the mid to low frequencies?

Answer 1) Yes the XP-32 portrays more weight, harmonic content and a better top to bottom frequency balance than the XP-22, This is what I’m calling spectral balance. I do not believe the XP-32 is emphasizing any frequency extreme at the expense of another. At first I thought the upper midrange was not as detailed, but after listening to multiple female vocal cuts the increase in harmonic content and overall weight in all the images just makes you think there is less upper midrange content/detail than the XP-22. The overall improvement in spectral balance (over the XP-22 and the Berkeley RS DAC driving direct to the amps) just makes the overall listening experience more realistic. The two RR cuts that I listened to the instruments had more weight and correct harmonic content, more like you would hear in an actual concert. The 3D placement of the instruments on the sound stage was more apparent. In a past life I did symphony concert recordings for PBS radio stations. The improvement I hear is much like finding that “best compromise” location of the microphones to get all the instruments to sound the best. The XP-22 seems to emphasize detail more without totally flushing out the harmonic content as well as the XP-32. The XP-32 sound more fluid and flowing more like music. Instead of calling the XP-22 thin sounding or emphasizing the mid to high frequencies my first thought is that with the XP-32 the sound energy is better focused in the individual images, or more energy is being resolved; thus, flushing out the images in a more realistic manner.

PeterA Q2) Dynamics: You write that the XP-32 sounds as though more instruments across the stage have a more realistic relative weight and that the center image is not the focus. This certainly is more how real instruments sound, but is that dynamics or something else? Have you had a chance yet to listen to something like a string quartet? Does it sound more dynamic through the XP-32 across all four instruments spread across the stage relative to how the XP-22 sounds? I find with recent changes in my own system that there is much more energy coming off of the strings/bow of all four instruments. The wood resonance is more alive and the sound just fills the room more. Your description makes it sound as though the emphasis is more towards the center of the stage with the 22 and more equally distributed across the stage with the 32. Is that correct?

Answer Q2) Comment: Multiple questions to answer here. I can see how when I tried to answer what I thought was happening with the XP-32 dynamics maybe seeming muted over the XP-22 I may have been confusing. In answer to,” This certainly is more how real instruments sound, but is that dynamics or something else?” No I do not think dynamics. I believe it has more to do with my explanation I did in the last few sentences in my Q1 answer. I did not listen to small group quartet music yet. I listened to 4 full orchestra pieces. A violin concert (Ann Akiko Meyers, The Bach Album with the English Chamber Orchestra) is the closest I could make an example of at this early date. The violin string work seemed more intricate and involving. The instruments across the display were very even in weight, with very good dynamics. I believe the detail and spectral balance was better, but really did not notice a dynamics difference. If the dynamics on the XP-22 was a bit better, like I noticed on some other music, I did not notice it with this violin piece. The added realism of the instruments is what I noticed the most. This piece would not have been as closely miked as a quartet would be done. Another cut I played to sense the evenness across the stage was Michael Jackson’s Thriller, at the beginning when the door opens and someone walks across the floor,. This resulted in a very even image as they walked across. In answer to your last question, yes the XP-32 presents a more equally weighted images across the stage, with the XP-22 seeming sounding more center stage weighted by comparison.
 
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PeterA

Well-Known Member
Dec 7, 2011
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North Shore of Boston
#6
Thanks for the clarification, MAXPWR. I am balancing center image weight v. whole stage even distribution with new efforts to position my speakers. I continue to marvel at how much this can affect the sound.
 
#7
Thanks for the clarification, MAXPWR. I am balancing center image weight v. whole stage even distribution with new efforts to position my speakers. I continue to marvel at how much this can affect the sound.
PeterA, from all the posts I know you have a lot of experience trying things to make your High-End rig sound better. As you know everything matters! The key is to understand what the effect is of the changes you are trying. Trying to understand the various effects can be time consuming and frustrating to many. The results can be very rewarding when finally find the best compromise. The placement of speakers in the room and toe-in are huge variables compared to the high quality level of equipment most of us are using. In the engineering world we utilize a methodology called "Design of Experiments" (DOE) when we are trying to zoom in a solution that has a multitude of variables.

People just hoping to buy new equipment to cure their concerns is not the answer in most cases.
 

PeterA

Well-Known Member
Dec 7, 2011
6,113
1,096
310
North Shore of Boston
#8
PeterA, from all the posts I know you have a lot of experience trying things to make your High-End rig sound better. As you know everything matters! The key is to understand what the effect is of the changes you are trying. Trying to understand the various effects can be time consuming and frustrating to many. The results can be very rewarding when finally find the best compromise. The placement of speakers in the room and toe-in are huge variables compared to the high quality level of equipment most of us are using. In the engineering world we utilize a methodology called "Design of Experiments" (DOE) when we are trying to zoom in a solution that has a multitude of variables.

People just hoping to buy new equipment to cure their concerns is not the answer in most cases.
This has been my experience too. Thanks. I want the gear to get out of the way and get to what's in the grooves with the equipment and room not being obvious contributors to the sound or experience.
 
#9
Pass Labs XP32 Update #1

It has been a week since my first critical listen to the XP-32 preamp. In that time I have been able to listen to it multiple times. Each time I hear less of an electronic signature to the sound. It seems to be becoming even more transparent to the music. Just “getting out of the way” would be a good way of describing what I’m experiencing. The effect is somewhat like what we experience with MOSFET based power amplifiers as they warm up over time becoming more transparent. In this case the new XP-32 is breaking in and it sounded rather transparent to begin. As I mentioned in my initial impressions, it sounded very tube like with respect to transparency and music flow. As it breaks in the transparency of this unit is continuing to improve. The lower frequencies seem to show the most improvement.

The improvement in transparency I’m experiencing seems to be created by an improvement in image focus. The preamp seems to be taking energy that was dispersed around the soundstage and now this energy is now better focused in the individual images. Blacker space around the images and better definition of the edges of the individual images, which I relate to better focus and the resulting transparency improvement effect I’m trying to explain. Individual strings on a guitar are more evident as is the varied fingering effects and tones of those strings. I’m hearing more information on all my recorded music. Even non-HD recordings are offering more detail. The bass lines are better focused in the soundstage. The individual bass notes are better delineated. I’m hearing multiple bass line inflections, where the individual note changes were not noticeable previously. Even more impressive is that those bass notes in the soundstage are much better defined. Again, this added focus results in overall transparency improvement. With the bass frequencies coming into focus better the air effect of the soundstage and reverberation on well recorded acoustic material makes the overall effect more realistic. The ability of the XP-32 to present high to low frequencies in the soundstage images, in such an even handed manner, is better than I have never experience and results in realism.

As I listen to more material I find myself listening to all the cuts on an album vs just a few select ones. The added detail and overall focus has made everything more interesting and compelling. Another obvious effect with the XP-32 is that going from album to album the overall sound of the system changes more to reflect the original recording venues. This also happens from cut to cut when there was a recording change. There is just less of my system’s equipment signature apparent and the artistry of the music is more evident and compelling.

I remember a very good Audiogon forum post where the author compares the XA-160.5 and XA160.8 amplifiers in a single word. The author described the XA-160.5 as “PRESENCE” and the XA160.8 as “AIR”. The XP-32 has surely added a good dose of “AIR” to my system along with significantly more detail, focus and realism. The overall effect of having the XP-32 in my system is that I’m listening to music more than to my system. This jaded, performance orientated, audiophile is enjoying music more, instead of trying to figure what is the next thing I need to try to improve. It’s a nice change for me is all I can say…
 
Likes: PeterA
#10
XP-32 One Month Update:

Just as with my past experience with the XP-22, the new XP-32 preamp has continued to break in during the period I have had it in the system. If you have not read my initial review, I will mention again that I had white and pink noise going thru the preamp for a week prior to installing it into my system. The XP-32 has now been powered up for about 5 plus weeks. I typically do not get to listen to the system very often, but I have tried to get a few listening sessions in each week to access the progress and performance of XP-32 during its break in period.

About two weeks after installing (three weeks after first being powered) the preamp exhibited a break in characteristic similar to what I have experienced with interconnects and speaker wires. The characteristic I noticed was an exaggeration of the bass up to lower midrange frequency spectrum. Information in this frequency range came forward in the sound stage to give a somewhat bloated sounding effect. The good news is that this effect greatly diminished the next time I listened and totally absent the next time I listened. I will qualify this observation with the fact that to install the 3 chassis XP-32 in my system I had to completely rearrange the position of the equipment in my two racks. This required that the interconnect cables also be moved. I could be experiencing the interconnect cables de-stressing, or the preamp breaking in, I cannot be sure; thus, my full disclosure here.

The XP-32 continues to impress me with the extra detail it finds in recorded music. Its ability to extract low level information and place/focus this new information in the soundstage has surprised me on music that I’m very familiar with. Not only are background instruments and vocalists more evident, but there are more of them than I have experienced previously. Subtle low level signals are not only more evident, but they have focus that can rival the presence of the higher level information. This new low level detail that was not noticed, prior to the XP-32 in the system, can even exhibit very noticeable dynamic level contrasts in their reproduction. The one word description that keeps popping into my head about the XP-32 is “ARTICULATION”. I have muted the system many times because I thought I heard something happening in the house. We have all done this when listening to unfamiliar/new music, but I’m doing this with music that I have used for equipment comparisons for many years.

In my initial review I previously described how well the XP-32 has unraveled music that was complex and loud. Given the added low level detail, described in my previous paragraph, I’m now going to describe another revelation. In music I previously found rather boring all the new found low level detail has elevated this music to a higher quality level than I thought possible. A mediocre sounding solo vocalist with acoustic guitar (16 bit, 44.1 kHz) album was transformed for me. The guitar had so much more low level information, which resulted in much more added presence and character. The guitar’s new range of tones and the intricate finger touch effects now available with the XP-32 transforms what was a rather boring accompaniment to the vocal. The added articulation and harmonic content in the vocal just draws you into the performance. The acoustic space of the recording is now evident and involving. Now the real kicker, I’m talking about an album streamed from Tidal (Not MQA). Since I like this artist, I have listened to this album many times prior to the new XP-32 preamp installation. I now have much more appreciation for the artistic content that was captured in this recording. This is an example of what I have been experiencing with much of the music I have been experiencing with the XP-32. Maybe I should say re-experiencing…

When I was considering purchasing the XP-32 one of the negative aspects was the fact that it was a three chassis implementation, which presented issues for me physically implementing it my system. The space between my shelves would allow the two amplifier chassis to be stacked, but not enough room to allow adequate cooling or implementation of any isolation devices if needed. I needed to use up two shelves for the amplifier channels and still had to find a home for the Power Supply/Control chassis. My thinking now is that the three chassis not issue, let me explain. I have to think that the significant improvement in low level information retrieval and imaging has to have something do with the separate amplifier channel units and getting the control out of the amplifier units. I would not have questioned the three unit placement hassle now knowing the sound quality improvements that I’m experiencing with the XP-32 in my system. If this is a compromise that must be taken to achieve the sound quality I’m now experiencing, I’m all for it!
 
#11
Pass Labs has finally added the new XP-32 Preamp to their equipment pages on their site.

https://www.passlabs.com/preamplifier/xp-32

XP-32 Specs:
Power consumption 70 watts
Gain 9.6 dB
Balanced Output Impedance: 25 Ohms RCA, 50 Ohms XLR Input Impedance: 22K Ohms
Frequency response: +/- 0.05 dB 20Hz to 20KHz -2dB @ 150KHz
Crosstalk > 110dB
THD < 0.001 @ 1V 1Khz Max out 23V RMS 0.1%
Residual Noise 500nV RMS, SN -150dB ref max out
Dimensions: 17”w x 12.5”d x 4”h times three
Weight: 62.5 lbs Shipping weight: 78 lbs

It has been 2 months since I received the new XP-32 preamp. In a week or so, I will post another update on how the unit is sounding now that it has had a decent amount of time for a break in period.
 

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