Also this makes me really doubt the cheaper vta devices for Rega arms like expressimo and incognito. When you loosen the arm, change vta and then retighten, everything could have changed: The tonearm could slightly shift around in the mount changing cartridge alignment completely, you might hit an unstable thread on the mount, etc. Not the best method to get reproducible results.
True, and they're also sort of a PIA to use.
The bottom line is: If you want to bother about vta, you better do it right with a well-executed mechanism.
Are you sure you're a physicist? That sounds more like an engineer to me. ;-)
It's important to reiterate that we were driven to this by the demands of our ears. It was not theory driven nor, as Gregadd so aptly put it, a case of worshipping at some idol of theoretical perfection. It was only after we realized we could hear the differences that we went out, chased down the theory and sought out possible solutions.
That's important in this hobby I think. Hear as many different things as you can, talk to others and try to figure out if what they hear is what you hear. Then choose solutions that best execute your mix of priorities within your budget. As Twl so wisely pointed out on Artar 1's cartridge thread, chasing perfection for its own sake is endless, futile and ultimately sterile.
Yesterday Paul sent an email to a couple of friends describing a listening day with our new cartridge. Not a word about techniques or technology. He simply attempted to convey in words the intensely satisfying musical day he had experienced. :-) His unbridled enthusiasm and joy were utterly unlike his normally reserved self.
That's what I was hoping for when we came back to analog after 15 years in the RBCD wasteland. Twl told me this could happen and he was right. His passion and that of other early Teres adopters helped us rediscover ours. Your path and mine to that passion may differ and perhaps they should differ. After all, the only way to truly hear live musicians in your home is to host live musicians. Short of that it's important to remember, at least when talking here, that stereo is just an illusion.
But when the record spins and the eyelids close (mine do anyway)...