ericar said:
How do you explain the difference in feel between 2 and 3 springs with same gauge strings, same trem , same guitar , and floating setup?
I did have to adjust the tension of the springs but there was a difference in feel and force needed to drop the notes afterwards.
Spring tension is rarely linear. With coil springs, if you graph tension vs. extension or compression, you'd see there's a curve to it. That is, the farther you stretch or squeeze a spring, the more tension or compression it takes to stretch or squeeze it to move a defined distance. So, if you only install two springs, then in order to balance against that 130 pounds or so of string pull, they've got to be pulled out to where they're screaming. Add a spring, and you can relax all three a bit. Add another, and relax even more, and so on.
So, if you want to counterbalance 130 pounds with two springs, you need each one to be pulling back 65 pounds. If there's three, then they each need to pull back ~43 pounds, and so on. Thing is, because of the non-linear response curve, it's easier to stretch a spring that's nearly relaxed than it is to stretch one that's under great tension.
Few people use all five springs allotted for most vibratos. Most use three, as far as I've been able to tell. Seems to be a happy medium. I haven't done a great deal of experimentation, because I just don't care that much. Three works for me, so I don't tempt fate <grin> But, I suspect 5 is really the number to use. Problem I can see with that, though, is they're liable to fall out of the "sustain" block when you remove all the strings, because they'd be under almost no tension at all.