@divertiti
I hesitate to say anything because if my impressions don’t measure up to what appears to be the consensus of others, I start to wonder that maybe I’ve done something "wrong" when auditioning. But because you’ve asked, FWIW, here goes.
I brought in the Pass Labs XA25 because Terry London had written how much of an impression it made on him with his chain/room/etc (as compared to the Linear Tube Audio) so I was curious to see if it would have an impact on my listening configuration. As you probably know, in addition to the myriad differences in his vs my chain he uses the more expensive Tekton speaker.
When asked, Eric suggested that I might try either a Parasound or Peachtree Nova amp because apparently others had reported "success" with those products. I couldn’t get a Parasound in as quickly as I would have liked but had no problem getting the Peachtree within a few days.
Many people report being impressed with Pass Labs products; and the XA25 is reported by some to be the closest thing to the "tube" sound that an SS amp can get. It just didn’t play out that way for us. Yes it delivered a pleasant rendering of our selected content but when swapping between it and the PrimaLuna or the McIntosh or the LTA it was so obviously apparent how it renders noise differently. With the XA in the chain, playback seemed "flatter" than with the pure tube or hybrid. It wasn’t "bad" but it wasn’t as expressively "palpable" (to quote Terry London) as the PL or Mc or LTA gear. Believe me when I say that we spent A LOT of time with the XA25 trying so many configurations in our attempt to reproduce what others reported.
It’s probably important to stress that I prefer a bouncy, sponge-like rendition when I hear content. To me it’s that "sponginess" that makes performances seem more palpable. When a drum head is hit, the sensation I want is not only to feel the depression but also the skin bounce back -- the warble. That gets me engaged physically and emotionally. This was the key element that differentiated the Triode Masters. They can deliver the warble with effectively convincing imaging and the others could not. No doubt by design, the Triode Masters pressurized our room in such a distinctive manner that to us was and is seductive. This is the sound that I’ve been chasing. The result was true regardless of the chain components but clearly more pronounced with PrimaLuna in the middle.
[All the speakers we heard gave varying degrees of "warble" but the TMs deliver it in spades. When finished, we all just looked at each other, shook our heads and said, "There’s no comparison". What’s more, the TMs can deliver warble almost anywhere in our room. They are a placement dream. The others were very finicky placement-wise so much so that I would call them one-dimensional in this regard.]
In our chain, the Peachtree was the worst of the amp bunch and left a bad impression on all of us. It detracted instead of augmented.
If we were to rate amps in terms of the "warble" factor from highest to lowest (when paired with the TMs) it’s PL, LTA, Mc, XA, PT.
With respect to how we heard the PLs, for us, we know that it’s mostly in the tubes. We didn’t change out what was sent to us in the LTAs even though I tried to find the tubes that Terry London recommended but no one had them in stock (and as of the writing of this reply no vendor has notified me that they have them in stock).
What made the PLs stand out was how it produced a more "meaty" (?) presentation, a more "flesh on the bone" reproduction regardless of the tubes rolled.
To compare: a note got struck on a piano, and with the LTA/Mc/XA it’s there and feels "real". A note got struck on a piano, and with the PLs it’s there but it felt "much more real", more tangible. When we heard it on the PL it conjured up a vivid image of a decaying oscillating string. It was as though we were standing at the back of the instrument looking down actually watching the decay (as opposed to sitting in front of the piano watching it get played but only hearing strings get plucked. Yes we heard decay but it felt two-dimensional by comparison). Maybe for others this is too subtle a distinction to matter. But because we weren’t able to ignore it, we all noted it. So the PLs gave us that "looking inside" impression and did it with all content. Again, it did it with the benefit of the TM’s deep warble.
Everything that we brought in (with Peachtree as the lone exception) was capable of delivering a satisfying aural experience. I know that if I heard these components in isolation without benefit of comparison I probably would have been happy to have any of them. Yet they wouldn’t have "nailed it" for me. I would have been left with that lingering "What if?" or "How about?" So I felt the need to do what I did to resolve any doubts once and for all (in the price range that I wanted to spend). It was a great learning experience that clarified A LOT of things about audio and audio claims.
I would end this note by saying that what I’ve written barely touches the tip of our evaluation iceberg. We also tried a variety of ICs and speaker cables and that was a great learning experience too. In addition, we spoke to many manufacturers and vendors, and that too was quite an interesting experience on its own.
