@sameyers1 "A number of people who posted comments have dissed the concept of neutral. A simple view of neutral is that a device (preamp, amp, dac, speaker, cables, whatever) does nothing to change the recording. It’s not complicated"...
Following your lead, here is a simple view and question, and not too complicated. The XP12, XP22, XP33, each sounds different. And for some audiophiles, the next version is better than the last, and so they upgrade and sell the prior version.
-or- If anyone else cares to respond, feel free to chime in -
Are the earlier versions less neutral than current versions, and what makes the latest versions of Pass Labs preamplifiers more neutral, or better, or different enough to want to make the next-level-up upgrade?