Hi,
1mm change in VTA will affect 0,19 degrees of SRA, so no it will be less than 1 degree. Warps produce more.
1mm change in VTA will affect 0,19 degrees of SRA, so no it will be less than 1 degree. Warps produce more.
Showing 3 responses by petg60
Hi, @cleeds, i don’t have a formula though below made sense to me. VTA is an angle but changes by upward/downward arm movement in mm. Greater changes in SRA are created by VTF than VTA. The VPI is a 12" arm, but as we’re in the 21st century let’s go metric :-) For ease of maths lets say the VPI is 300mm effective length. That means that if the arm pivot is seen as the centre of a circle the stylus describes a circle, diameter 600mm. That gives a circumference of the circle as 1885.2mm (600 X pi (pi taken as 3.142)). Thus in a full 360 degrees the stylus will travel 1885.2 mm. To alter the stylus angle (SRA) one degree the pivot must move 1885.2/360 = 5.23mm. Here remember that relative to the cartridge the pivot will not go just upwards but describe an arc, but for our purposes I think it acceptable to say that a 5.23mm change in arm height will alter SRA by 1 degree. Likewise we can calculate what SRA change a 1 mm change in arm height will produce i.e. 1/5.23 = 0.19 degree, about a fifth of one degree. As an aside it’s interesting to apply this formula to a cartridge cantilever, which is less than 10mm long (as little as 1.5mm) - just think of the huge, massive, GIGANTIC! SRA changes the tiniest movement due to warps will produce... https://www.tnt-audio.com/sorgenti/vta_e.html |
Hi, as i have no formula to prove when 1 degree of VTA= 1 degree of SRA please enlight me if wrong. How long should be the arm or the cantilever for this to happen? In normal arms, never, 1 degree change in VTA would correspond to much less than 1 degree of SRA, so not close enough. So all depends from the arm and the cantilever. |