How to set SRA after determining true vertical?

Actually, it's a right theory carried to a ridiculous extreme.

A simpler solution is a tonearm with adjustable height. Then you can use any cartridge you like and play any record you like, while matching SRA.

A simpler solution is a tonearm with adjustable height. Then you can use any cartridge you like and play any record you like, while matching SRA

Yes -- but by adjusting height you'll be changing the stylus overhang. As you note, having two arms is the right way -- but an extremist solution!

I am still looking for an article or picture that demonstrates that angled cutting head produces an angled cut. Has the angled groove been measured? All I have ever read is that it was just assumed.

Dear Doug, Gregm,

Base on what I understand from your answers, it is the SRA that is important, not the VTA (of course, the SRA and VTA are interrelated). As long as you can adjust the SRA to fit the angle of the cutting heads, it would be ok. So, any cartridge (no matter whether it has a build-in VTA of 20 degrees or 22 degrees) can be adjusted to fit any cutting angle. Am I correct?

Now, my friend’s “theory” actual goes one step further, which I have hinted but didn’t really state out clearly in my original question. It goes like this:

Going back to my original example “say an Ortofon, with 20 degrees build-in VTA, will fit the Decca, and another brand of cartridge, say a Clearaudio, with 22 degrees of build-in VTA, will fit the EMI etc.”, his theory is that with a Decca LP, an Ortofon (due to the fit of it’s build in VTA) will always sounds better than a Clearaudio no matter how you adjust the arm/cartridge (even if you adjust the SRA/VTA for individual records), assuming the cartridges are in a similar price range. And vice versa, an EMI LP will always sound better with a Clearaudio. So, if you want to ideally play back all the LPs, you will need one cartridge with a 20 degrees build-in VTA, and another one with 22 degrees build-in VTA.

Well, based on the answers I got from you guys, I guess this theory is false.

Thanks again,

Michael

SRA is very easy to match to the cutter head rake angle. True, there is/was no absolute standard, but the range of variation is very small, and so even if you don't have a tonearm with on-the-fly adjustable arm height, you can usually find a happy setting that fits most record grooves at least 90% perfectly if not 100% all the time. The trick once again is to find the absolute vertical point described at the beginning of this thread and then go from there.

VTA is another matter altogether. It is the angle of travel described by the cutter head as it moves up and down and depends on the design of cutter's torque tube (something like a cartridge cantilever.) There is some variation here also, but the big (and impossible to match) variation is among cartridges themselves. Cantilever length is all over the place among different cartridges, so it always struck me as folly to even attempt to match cutter VTA. A mismatch wil only create forth order harmonic distortion (if I remember my reading correctly) which is virtually inaudible, and so any attempt to "dial in" VTA by ear would be futile anyway. That's why I get upset when I hear the term "VTA adjustment" in any context. Call it whatever, but what's really going on is SRA adjustment.

Greg, adjusting arm height (in the range we're talking about here) has no effect on stylus overhang. That's function of the position of the tonearm base relative to the platter spindle -- with fine adjustment available via slotted headshell mounting holes, or in the case of SME, a sliding tonearm base.