I'm still not convinced that SRA should match VTA(cutting stylus) necessarily. What shape is the cutting stylus vs. the many different playback styli? How many different cutting stylus shapes are there?
Stylus Rake Angle
I am trying to set up my new VPI 3D arm as close to perfection as I can. On the Analog Planet, Michael Fremer gives one opinion, however, a different opinion was voiced by Harry at VPI, and Peter at Soundmith. I've been discussing this with them....Fremer says that SRA should be adjusted even if the back end of the arm is WAY high up as needed, whereas Harry, and Peter said to start with the arm in a horizontal position and move it slightly up and down to find the sweet spot. Peter said that my cartridge (Benz LPS) and some others have an additional facet in the diamond so bringing the arm up in back would be exaggerating the proper SRA. When I wrote back to Fremer, he answered with an insistance that he was correct. Does anyone want to add to the confusion??
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Raul The analog medium is full of imperfections and we have to deal with in the best way we can. Sometimes I think is an endless enterprise. Yes, I agree all is compromise with regard to set up, especially with regard to SRA and VTA which are decided by the cartridge manufacturer. It is up to each listener to decide what is acceptable to them, and to be aware of why it is so. Csontos For all intents and purposes, VTA and SRA are virtually the same thing because it is impossible to perfectly maintain standardized specs. This is why the only way to match the two is by 'listening' and at best, listening on the fly. The issue isn't that there is or isn't a standard (if recommending anything between 15 and 25 degrees for VTA constitutes a useful standard), but that it appears that the SRA parameter is variable depending on the mechanics of record cutting, and is at best an approximation of between 91 and 95 degrees, and can vary across a record. It also varies with downforce, and with offset, which in turn depends on chosen geometry and the accuracy with which it is set. Until someone makes a headshell which allows variation of VTA/SRA without altering overhang and downforce, then those will be factors... More info - old articles- here . |
John, What do you think is meant by the first sentence in that article you referenced?: "Adjusting the cartridge for optimum SRA may alter the VTA away from optimum. Or vice versa." I usually think of VTA as a useful surrogate for SRA, but I guess that a separate function of VTA, apart from its direct effect on SRA, would be to alter the angular relationships between magnets and coils, but that is a major function of VTF. The cantilever/magnets/coils are fixed in space except for the effect of VTF to re-position the cantilever, if too much or too little VTF is applied. Which takes me back to my question; what are they talking about? |
There actually is a standard cutting angle. It was changed from 15 degrees in the '60's, to 20 in the '70's. I think you've reiterated the pertinent points I've already made. However my conclusion is still that the best compromise is the ability to adjust SRA on the fly. That way the manufacturers and cutting engineers can go fly a kite:) |
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