Hi! I play a 1925 gibson mastertone ball-bearing tenor i bought from John Bernunzio. All original! I have done some research and found the ball-bearing set up is NOT to keep tension on the head {although its one benifit} But its to keep the tone ring FLOATING on the ball- bearings and springs so not to touch the rim. This makes the tone ring "SUPER SENSITIVE". And it WORKS! A very SWEET tone with good volume! I love it! The only reason they stoped on this tone ring method is because VEGA felt it infringed on one of thier patends.