Thank you all. Yes, Albert's explanation is correct. Other analogue folk (not on this thread) have also confirmed it.
All TT platters I have ever seen are slightly smaller than 12" to allow the groove guard lip to over hang; thus, the playing surface can lay flat and "couple" with the platter more effectively. As I recall, even inexpensive TT's have smaller-than-12" platters--or a beveled one to account for the increased thickness of the g-guard at the disc's outer edge. Maybe the platters on record changers were the full 12" so that the GG could be used as GG was intended.
The record disc contact with the platter has already been pretty good on every TT I have had: Thorens TD-316, SOTA Sapphire, and VPI TNT 3.5. Has anyone found a non-record changer TT withOUT a platter that mitigates groove guard?
I wonder if the added bead of vinyl around the outside edge of the record increases the likelihood that some sort of resonance can propagate.(?) Doesn't the added thickness around the outer edge also serve to somewhat protect the playing surface from other interference such as the sleeve as one takes the record out or put back in?
Kinsekt, does your TT platter already allow for the GG either by its smaller circumference or a beveled edge? If it does not, I can understand how a non-groove guard record would sound better. Otherwise, I am baffled. I don't doubt that the non-groove guard records sound better. It would be nice to know on what kind of platters we're talking about hereĀ
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