Last night Ian (MadFloyd) invited me and two other good audio buddies over to compare the Pass Labs .5 amps to the newest .8 amps. He uses an entire Pass Labs chain of electronics: XP25, XP30 and XA160.5. I also have an all Pass chain consisting of the XP25, XP20 and the XA160.5. But the similarities end there. I have the limited range Magico Mini 2 speakers in a small enclosed space while Ian uses full range Wilson Alexias in a large, open space. The sound of our systems has always struck me as quite different, but that impression has been radically changed after last night's listening session. More about that later.
Ian has in for audition a pair of the newest XA160.8 mono blocks. He has had them for just over a week and they have been either playing music or plugged in for almost all of that time, so they should be just at the end of the break-in period. He told us that the sound has stabilized. The four of us were eager to compare the sound of the two amps. We are all familiar with Ian's system so it was with some excitement that we sat down to listen. We started off with the .5 listening to familiar digital cuts and then to some vinyl. There were perhaps eight cuts in total with a variety of pop, jazz and classical. We then switched the input and speaker cables and listened to the .8 amps using the same cuts in reverse order starting with the vinyl and ending with the digital.
When we were finished, Ian asked: "So, do you guys have a preference?". Two of us said "yes" without hesitation. The third friend said that he wanted to hear more music before commenting. Well, thinking that the one guy and I were in agreement, I figured that there was a clear preference and all that we would discuss was how they differed and perhaps guess about why that was the case. To my surprise, the other fellow preferred the .5 while I preferred the .8. So that was rather interesting. As the evening continued that preference for the .5 was for one of the formats, either digital or analog, but I forget. Apparently, after the less committal friend and I left, Ian and the remaining friend stayed to listen for a while longer and again this morning. They now both prefer the .8 for reasons they may explain on the forum later.
For me, the differences were pretty clear. What I find interesting is that the reasons I liked the .8 more than the .5 in Ian's system is precisely because the .8 made his system sound more like what I enjoy about my system, namely, a relaxed, non-fatiguing sound, an ease and flow to the music, convincing dynamics, a sense of palpable presence, and a sense of natural timbre and tone.
As many may remember from reading these forums, Ian has always loved Wilson speakers. He has had his Alexias now for about eight months, with Sofias and Sashas before then. In my opinion, he has had difficulty finding electronics, and specifically amps, which can control and mate well with the Wilsons. To my ears, there was always an inability to control the lower frequencies which resulted in a loose, inarticulate bass, a slightly lack of clarity on complex passages and often a rather strident treble with the occasional glare. Tonally, Ian's system always seemed a bit recessed in the midrange and somewhat emphasized in the frequency extremes. With his Sashas and now Alexias, I have heard amp/preamp combinations from Lamm, Ayre, Doshi, D'Agostino and now Pass Labs. These are arguably all first rate products, but for me, and perhaps there is considerable bias involved regarding Pass Labs, Ian's system benefitted tremendously from the introduction of Pass gear.
His system had reached a high level the last time I was there about eight weeks ago when he had introduced the XA160.5, XP-30 and a few weeks later, the XP25. The midrange had become more fleshed out and the overall tonal balance was more neutral that it had been with all of the other electronics combinations. But there was still a slight looseness to the lower frequencies and an obscuring veil over the sound. His Transparent Audio cables had been configured for the tubed Doshi gear and he had different power cords and a different DAC.
Well, all of that changed last night. The Transparent Ref XL speaker cables and ICs are now reconfigured for his Pass gear, he introduced Shuyata PCs and has a new Playback? DAC (which I know nothing about). The system sounded very good when we started listening to the .5, but once we switched to the .8, the Wilsons were, for the first time in my experience, really happy with the amplifiers. Here is how I would summarize the difference between the .8 and the .5:
1. Lower noise
2. Greater dynamics
3. Better control of lower frequencies
4. Increased clarity
5. Smoother, sweater sound
I don't pretend to really understand how or why I heard these differences, but I think it has a lot to do with the lowering of noise. My theory is that at this point in the evolution of top tier gear, the manufacturers have solved lots of the issues involving distortion, bias, and clean power delivery. The next frontier in my view is the lowering of noise. With a lower noise floor, one hears more detail, better clarity, greater dynamics, all the things which I associate with live classical music in a great hall.
The two LPs which really clarified my opinion of these amps are the Sheffield Drum Track and Vivaldi's Four Seasons: Winter. I had never heard in Ian's system before the explosive dynamics and tight control of kickdrum thwacks and snare drum strikes and cymbals as I heard last night. One member of our group is in fact a drummer, and he heard more nuance between the different drums, perhaps preferring the .5 in some of the ranges.
In fact, Drum Track LP, one of my acid tests for a system's quality, always sounded kind of soft, dull and boring in Ian's system before. (Sorry Ian) But last night, it was incredible, and improved even more with our later introduction of Stillpoints under his speakers. More about that later in another thread. I had thought that the soft rendition of the Drum Track in Ian's system had been a result of the rather long rubber belt stretching when his cartridge hit a massive transient in the LP. But last night's experience shattered that theory. It was the amps (and perhaps the cables and PCs also) all along and the earlier versions being unable to control what is clearly a very difficult load at low impedances in the Alexia speaker. All of those other great amps, including the 160.5 could not handle the speaker load. Surprisingly, the explosive dynamics and tight control, and even the crisp clear transients of the cymbals now resembles what I hear from the sealed enclosures and easier load of my Mini 2s with my XA160.5.
The massed strings in the Vivaldi had a clarity and truth of timbre that I had not heard through the Wilsons before either. Sound was more open and clean than it was with the .5s and they sounded sweeter. The soundstage seemed slightly bigger and deeper with better defined edges. This overall clarity really went a long way to making it sound much more like the real thing at my reference hall, the BSO and to what I'm used to hearing in my own, mini monitor based system, which is known for clarity.
One area in which the system did not do as well though, is with imaging and scale. The images were a bit diffuse and often larger than life. The sound was slightly bigger than with the .5 which was welcome on jazz and classical, but individual instrumental images were a bit too large. I think this is more a matter of speaker fine tuning than the amps though and it was recording dependent, so it's not too big a deal. I think Ian could work on the speaker placement slightly over time to improve the imaging.
There is no question that for my taste, Ian's Alexias and system in general have never sounded better than with the Pass gear, either the .5 or the .8. I don't know how the .8 would sound in my system, because the attributes that I heard last night in Ian's system really remind me about what I already hear in my own system with the .5. So without more exposure to the .8, I can't be sure if they are better in an absolute sense, but last night, boy did they sound great in Ian's system. It is the best I have ever heard his system sound. The XA.8 is a real achievement and I think they will be a popular line for Pass.
Congratulations Madfloyd.
