nkonor,
I am using a ring that I made myself, following the example of a discontinued model. It is a constrained layer damped ring consisting of two .080" thick stainless steel layers that sandwich a .125" acrylic layer, all bonded using a more ductile cyanoacrylate glue (Loctite 480). I had the ring CNC machined from large squares that I bonded together. It is "one of a kind", to be sure, but it seems to work very well. It would be fun to compare it directly to the same ring sizing made simply from stainless steel alone (I will probably try this at some point), just to see if the damping addition matters much, because it does increase the hassle and expense of making one to add such layers.
I am using a Stillpoints Ultra 5 LP Isolator as my center weight, and my mat is a 5.5mm acrylic mat that sits on top of a 1.5mm foam silicone rubber for damping and adhesion to the platter surface. I really like the total combined affect, with the ring making the final adjustment that brought it all home. It seems that the ring just ensures that the LP surface is in nice contact with the mat so the mat can do its job of draining the energy from the needle's vibrations.
Placing a ring is futsy, no question; and you need a spot to store it safely between plays. My ring is not perfectly balanced, as its overall thickness varies by a range of .005" around the circle; but the direct drive of the Technics does not care one wit - - power to spare, by far, and the servo correction makes it steady, regardless, it seems. I hear tonal purity and sustain on piano and organ notes that I have never before heard on vinyl.
