12-22-07: StringreenA couple months ago I added the KAB fluid damper to my Technics SL1210 M5G, and that is EXACTLY what I got. When I first filled the trough about 2/3 full, the presentation was quieter, but it was also deader, with initial transients and high treble info missing. I lowered the fluid level in the trough to about 1/3 and voila! Magic!
I...discovered that a bit of the damping fluid is a good thing. ... Too much oil will deaden the highs....The results are improved midrange - more depth and air between the notes, and improved low bass. ....
I got the same improvements you mentioned--improved midrange, more depth and air between notes (especially noticable in better stage depth and decay of notes), and improved bass.
It also tracks like a mo-fo. Hideously warped records don't phaze it at all.
So my conclusion is that a *little* damping is an improvement over no damping, but too much damping (and you'll know it when you hear it) sucks the life out of the music.