As a point of interest given this extended discussion, 6moons.com just published a review of the Walker Proscenium turntable and an interview with Lloyd Walker. One of Lloyd's comments was about his design conclusions on adjustable VTA during play:
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Lloyd Walker: One thing we discovered right away is that adjustable VTA during play is probably one of the worst things you could ever put on a tone arm.http://www.6moons.com/audioreviews/walker4/sota_5.html
Reviewer: Why? I loved it on the Graham arm and it spoiled me. The ability to adjust VTA while playing is certainly convenient.
Walker: Well if you notice, when you adjust some arms while they're playing and you run the adjustment up and down from top to bottom over the whole range, you'll notice some differences but it's not huge. You change the butt of the VTA on our table 1/1000th of an inch and you can hear it plain as day. It's enormous but every time you set the VTA, it's locked in place. The arm cannot flex or move. To adjust an arm during play, something has to be left loose so the arm itself is wobbly. When you're talking about trying to read information in a groove that operates down into the micron size, iron-clad stability is critical. If you leave an arm loose enough for VTA adjustment during play, it will flex and you will lose dynamics, information etc. You just give up too much music for a few minutes of convenience.
Reviewer: But other arms which have adjustable VTA during play have tight locking mechanisms.
Walker: Doesn't matter. When you lock it back down, it's gonna move because that lock's going to torque it to one side and that's not only going to slightly change the VTA but it'll shift the azimuth as well since the whole assembly is flexing to one side.
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