Rerurn to Romy the Cat's Site

Not one to fix too firmly on a given implementation, I rdecided to futz around with my vacuum holddown this weekend.

The power was not very good, but I was none the less able to determine conclusively that [within the context of my rig] although the sound certainly benefits from the vacuum (as opposed to no vacuum), there is such a thing as too much vacuum suction, which, past a critical point, begins to vacuum away ambience, where it would otherwise be part of the program, and likewise bass harmonics suffer when I overdo the vacuum.

I do not conclude from this that a lesser LP-to-platter coupling is better, because I am not certain if the coupling is wholly directly proportional to the vacuum, or perhaps there are other factors at work having to do with reflections, or new transmission paths, or vacuum leaks, or whatever.  Certainly this phenomenon could be peculiar to my TT - as opposed to all vacuum HD rigs - but even if this is the case I find it interesting.

Anyway, just in the interest of science (in its humorous guise).

I was also thinking some more about speed control and wondering about the "perfect platter bearing", whether it would indeed be friction free or perhaps it should acyually have a certain controlled viscocity/drag, in order to offset motor stepping?  I wonder if in practical terms a quite heavy platter with no perceptable drag would overcome motor cogging and related belt response?  In the case of less-than-very-heavy platters I suspect that some sort of damped "drag" might be a good thing, and perhaps best applied at the spindle as "oil", maybe multi-viscocity oil.

Lastly, if a "fully-levitated platter" is already 100 lbs. of - say - lead, then why should it have a "ground"?  Why not just let it serve as a sink all by itself?

Paul S

Rerurn to Romy the Cat's Site