Thoughts On Turntable Clamps And Weights

I digested all of your information and bought a lightweight clamp.  It arrived yesterday and I did the "with" and "without" test on a few albums and noticed improved sound quality on all of them.  Instrument separation improved, lower frequency sounds became fuller and highs were clearer.  And some of the background muzziness went away. 

In the evening I played a few more albums and my wife, who is a passive bordering on indifferent listener, even noticed the improvement with the clamp.  She said she could hear each instrument more clearly. 

So the clamp was money well spent.  Thank you for your advice and observations.

@jrcotner Excellent report on your early experiences.

There is more to come if you work with the Platter Mat.

I have VPI HW-40 turntable which is direct drive. It came with a very nice weight and peripheral ring. I prefer to use the Stillpoints LPI weight. It is heavy at 848grams. The HW-40 is a beast and I seem no issue with this heavy weight. I have never used the ring FWIW.

My TTW Gem V2 came with a 1kg weight. It makes a noticeable improvement.

@pindac  Suggest that you rest the record directly on the Delrin, as Delrin and vinyl couple very well (speed of sound is essentially the same). Also, you might do better with thinner Delrin, as thick pieces can be heterogenous.

Also, consider an air bearing. More trouble, but lots less noise. Best is air in all dimensions, like a thrust bushing from New Way.

Balancing is important, and easily done by machining an oversize cylinder. Thing is, it's easy to find an approximate centre of a cylindrical billet, so turn around that approximate centre, and shave off the excess to give you a perfect centre. Keep the cylinder on the lathe chuck and let it settle. Mark that point, and rotate it to the top. If it stays there, your cylinder is balanced. If not, remove a little material from the bottom, until the cylinder stays in any position. Then you have a static balance. 33 RPM is not enough to require a dynamic balance IMO.

This requires the lathe to have low stiction bearings. Also, be very careful to fit the spindle in the exact centre identified above. Repeat the balancing procedure with the spindle in place, if possible. This works with a massive platter. If the platter is light enough, go directly to turning and balancing on the spindle.

BUT - your machinist may have better ideas. It's his profession, after all, and I'n just an amateur.