Comparing the Pass Labs XA30.5 to the XA 30.8

As many here know, Pass Labs has come out with their new .8 series. However, to date there isn’t much written on the difference in sound quality between the XA.5 series and the new XA.8 series. I just finished an A/B comparison between the XA30.5 and the new XA30.8, two of their popular amps for those on a budget like me but still want the best class A sound possible for the money. I hope some of you will find this helpful who are trying to decide if you should upgrade to the .8 series.

Read no further: For those who just want the basic results that we heard, they are as follows in brief: The XA30.5 sound is more lush, very musical; slightly more pronounced in midrange; is holographic; has slightly more fine detail and texture in the upper midrange and highs and induces little to no listener fatigue. The XA30.8 sound is cleaner, more controlled with less noise, more dynamic and holographic, more accurate or convincing, constructs a deep, accurate soundstage, has excellent imaging and is also musically involving with little or no fatigue. Ok, so if you want to read on, please feel free; otherwise, that’s basically what we heard.

I haven’t written much on this forum at all, but have enjoyed the many posts by those far more experienced and knowledgeable than I. BTW, I am not a dealer of any audio gear; just a family man with bills to pay, a kid applying for college and a limited budget. I also have a relentless love for music. My apologies for such a long review; if you want to get to the chase, read the last seven paragraphs when you get a chance.

I have a good friend who is a sound booth technician and has managed the sound for countless live concerts and other events. He helped me in setting up this A/B test and I’m very grateful for his advice in this. All Pass gear was loaned (and eventually purchased) from Mark at Reno Hi-Fi (http://www.renohifi.com/). He and his staff saw to it that my auditioning and purchasing experience was absolutely flawless from beginning to end. I felt like I was his only customer. He really is as good as everyone says and I highly recommend him to anyone seeking Pass or First Watt products.

Anyway, here’s what we did to test the sound of the Pass XA 30.5 vs the 30.8: We let both amps run 24/7 for two weeks to be sure they were broken in. The amps were connected to a new (but also broken in) Pass XP 10 preamp. The IC’s used were by Mike Burley (Mike is a technician at Pass Labs). They are used by Nelson Pass himself, so I figured it was good enough for me! They can be purchased from Mark at Reno Hi-Fi. With my Harbeth SHL-5’s placed in the center of the listening room, side by side, 2 inches apart and 6’ from any walls, I connected the left channel to the Pass XA30.5 and the right to the XA30.8. All variables were isolated so the only differences in sound would be from the amps.

During the listening tests, I was able to instantly switch back and forth between the two channels using my balance controls on my laptop which fed into a Audioengine D2 (24/96 signal) and into the preamp. This quick switching allowed me to remember and detect subtle differences between the two amps.

For five consecutive days I sat and listened to many tracks of as much variety as possible, from solo acoustic instrumentals and vocals to classical, big band; drum solos; blues; Sanatra, pop; R&B; talk radio; acoustic guitar solos; sound effects; samba; Led Zeppelin; you name it, I threw it up there. I heavily dampened my listening room to isolate the pure sound of the speakers only. Digital was used because I do not yet have an adequate system for playing vinal. An example of some of the more dynamic tracks I listened to can be heard at //www.youtube.com/watch?v=WK5Z2FkEuGg&index=3&list=PLqD1T8J1i8jzU5UGW3Q7f0Bl06B4R7uhT

We also did listening tests with speakers in their normal positions and both channels connected to the same amp to get the true soundstaging, air, imagry, etc. From all of this listening, I and others who listened also made the following observations:

Lower and mid base: The XA30.8 produced an extremely clean, fast and solid lower and mid base sound that dug deep and was well defined on every track. Various instruments were very well separated. I was teased by its elusive quality, wanting to hear more of it. My Dynaudio C1’s (the original, not the SE’s which are base shy, IMO) came to life as never before and filled the room with very pure, clean, detailed base tones and they had texture as well, like you could tell what kind of woods the cello was made from. The 30.5 threw a very full, open and more lush sound which was also deep, solid and sounded very real, but not as detailed and defined. The .5 can become a drama queen with base tones, really dishing it out on some tracks and getting you more emotionally involved, which was fun to experience. Perhaps I was hearing some of the “noise” that was quieted in the design of the .8, but it was very delightful, involving and easy to listen to. When cranked to near full volume, both amps produced room filling thunder but the .8 rumbled my guts more, almost like the base and kettle drums were right there in the room. Under the .5, my Dynaudio C1 started clipping but not with the .8. Ok, so the .5 is extremely lively, emotionally full yet can cause clipping. The .8 never broke a sweat, was more dynamic and in control. I wish I could have both worlds here; the tubie, organic, full, involving base of the .5 with the clean, controlled, rock solid stability, dynamics and realism of the .8.

Lower midrange: Both amps sounded wonderful here, with the .8 coming out slightly “quieter”, yet still able to dig out a very natural timbre when called upon, all with concrete-solid control and slightly superior separation of instruments. The .8 renders such a realistic sound to any and all instruments and vocals, like you were “there” in the event. The .5 could become very flush with overtones at times, adding to the musicality and emotion. Again, the .8 made me want to hear more of what it was producing and had a very pure and “right” sound, not recessed, just more controlled which can give the illusion of being recessed.

Mid and upper midrange: Starting with female vocals, through the .5, I could hear the subtle nuances of the vocal chords, oral cavities and breathing patterns. The .5 midrange is a little more present and responsive here. The .5 renders all of this fine detail with such naturalness and ease; like a good quality tube amp. The .5 dishes out more air around the players, more inner detail and a smooth, dry, almost crispy texture. But with the .8, all of this air and nuance is slightly quieter, yet more authentic and convincing. The .5 was overall the most non-fatiguing at higher volumes (not that the.8 is in any way fatiguing, just that it has higher micro-dynamics which made me want to reduce the volume a little on some female vocals because they were so intense but that’s just my ears here). With the .5, I was able to understand more about the nature of the skins on which the brushes were moving. This same experience repeated itself with most of the other instruments and voices I heard as well: I was able to hear the valves opening and shutting on brass instruments so clearly I could tell you what kind of material they had on their surfaces. Background noise was picked up easier. Whispers and wine glasses tinkered on some live tracks more clearly. The .8 was not able to retrieve this information as well, being slightly more quiet and controlled, yet projected a more dynamic and convincing atmosphere. With the .8, I could understand more about each instrument as a whole and how it interacted within the recording venue. The .8 managed to get the tones so eerily correct including the voices that it fools the mind into thinking you’re in the event. If you like to hear artists breathing and guess how many nose hairs the singer has, the .5 would be better for that. Perhaps in an attempt to reduce noise (which was a major goal with the designing of the .8), some of this fine nuance and inner detail was diminished a bit but these differences were slight and both amps did a wonderful job of bringing me into the music, IMHO. I don’t know if any of the higher XA.8 models can bring out more detail than the 30.5; it would be fun to hear from anyone on this.

On acoustic instruments: Over the last 30 years, I have played many acoustic guitars and am quite familiar with the signature sound of the various makers and the tone woods typically used to build the instruments. So in solo guitar tracks, I can say that the .8 series renders a slightly more true to life presentation of these instruments and with more dynamic energy across the frequency range. Both amps throw a very deep, musical, detailed and emotionally involving soundstage. The .5 sounded warm, airy, crisp detailed and weighty all at the same time. The .8 did a better job of allowing me to guess what kind of woods the guitars were made of. It brought out that “nutty” essence on some woods, for lack of better words. Cedar sounded like actual cedar. Spruce was warm and crisp over deep, dark rosewood. And Hawaiian koa was warm, dry and oh so sweet as it should be. And that inner air and echo was so right on each piece I heard. Both amps created the illusion of the guitar being there in the room, with the .8 rendering slightly better pinpoint imaging. Someone remarked that the .8 imaging was slightly smeared; I did not hear any smearing at all; both the .5 and the .8 can cast pinpoint imaging when the recording dictates it.

The above observations were made over several hundred switches and sweeps between the two channels and the results were consistently the same, no matter which speakers I used or the volume levels. I also switched the channels. I also tried various USB cables and IC’s from Audioquest and Gabriel Gold and the results were the same except for some very slight differences.

Mid highs: much the same as I have described above, with the .8 being slightly more dynamic, cleaner, realistic and “pure” sounding. The .5 has a delicateness, airiness, crispiness and dryness of tone and timbre, very easy to listen to that the .8 does not present quite as much.
Highs: The .8 has very smooth subtle, liquid, clean and real sounding micro-dynamics yet very slightly more tamed compared to the .5. Cymbals take on more weight, substance and air around them with the. 8 which I preferred, but the .5 digs out more “tink” and crisp detail of the metal. Occasionally with the .5, I would hear more whistling and hiss from someone when pronouncing the letter, “s”, but for me, I’d rather have that level of detail than not. Here both amps were very easy to listen to, not fatiguing at all.

Soundstaging: The .8 throws a very “correct” stage, placing instruments and vocals where they should be, all with very realistic air and echo, all in a deeper, slightly taller area with sound extending well beyond the speakers (the speakers disappear completely). With the .5, overtones flew out freely into space in a coherent manner that sounded true to the character of the instruments which also had very good placement in the room. With the .8, vocals, piano strikes, plucks and snare drum strikes, etc. seemed to come forward (or bring me in) with more intensity, creating a slightly more dynamic and holographic effect. I had the sensation that I had been transported into the live venue more than with the .5. The .5 seemed to cast more overtones and echoing effects which accentuated the venue with all of its air and the “noise” of the recording area. With both amps, instruments had excellent placement in the room, were wonderfully detailed, lively and real sounding. The .5 can create a holographic effect as well, with the right recordings.

In conclusion, the Pass XA30.5 and XA30.8 are both marvelous amplifiers, each with their own attributes, each able to serve up the music with such realism, fine nuance and involvement, all in a very non fatiguing way, IMHO. My friend the sound technician agrees. I chose to keep the XA30.8 as it just seems to float my boat more. It has been a thrill to listen to the two and compare them and I hope I have helped someone who might be trying to decide between the two.

Gear:
Listening room: 14’ X 19’ X 11’ tapered to 8’ ceiling, customized and dampened as needed.
Power: Pure 12 Gauge copper from meter with HQ copper outlets and Groneberg Quattro Reference power cables.
Preamp: Pass XP 10
Amplifiers: Pass labs XA30.5 and XA 30.8
Spekeres: Harbeth Super HL5 Anniversary Editions. Also tried Harbeth Compact 7ES3, Harbeth P3ESR, Dynaudio C1, C3 and Contour 1.3SE’s.
Velodyne DD15 Plus sub
Transports: PS 1 player, Laptop with Audioengine DAC-2 connected with Audioquest Carbon USB cable: Audioquest Carbon, Forest and others
IC’s: Burley Wire balanced IC’s (built by Mike Burley of Pass Labs and used by Nelson Pass) Gabriel Gold Reflection, GG Rapture R Audioquest King Cobras and AQ Cheetah (PSS)
Speaker cables: Gabriel Gold Rapture R