Alignment tool for SME V + Shelter

Hi Nsgarch
ok, ok, ok, so VTA is totally, utterly, completely, unrelated to SRA you say. So you'd be then saying that the stylus is also unrelated to the cantilever?!
And maybe then the stylus' contact-line is unrelated to the stylus?
Oh, oh, please gimme THAT link so I may also partake in this 'current fantasy'.

And in any case *SRA* is wrong also, since it should be then called *SCLRA* Stylus-Contact-Line-Rake-Angle, since the 'stylus' is only doing that picking-up via its 'contact-line' touching the groove, yes?
And as it so happens, the angle of the contact-line maybe just as unrelated to that 'clump' of stylus also!

As to the spring-steel finger lift --- you do recall that we are amplifying that pissy cart signal by 1000s of times and THAT - will make you hear a fly fart when sitting on your head shell, promise :-)
Greetings,

I have the SME V and my dealer never installed the finger lift when he set up my arm and installed the cartridge saying that it made for a less direct connection between the mounting bolts and headshell. Is it audible? Probably not. I simply hold the headshell when I need to move the arm.

Can one hear the difference between the fixed SME V headshell and the detachable SME headshell (used for quick cartridge swaps and azimuth adjustment)? I never tried. It probably did contribute in small part to why my SME V sounds better than my old 309. I like the theory that the more rigid the headshell/arm interface and the headshell/cartridge interface, the better.

Axel, here again is the link:
http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1140840022&openmine&Nsgarch&4&5&st0

And in any case *SRA* is wrong also, since it should be then called *SCLRA* Stylus-Contact-Line-Rake-Angle, since the 'stylus' is only doing that picking-up via its 'contact-line' touching the groove, yes?
And as it so happens, the angle of the contact-line maybe just as unrelated to that 'clump' of stylus also!

Technically you have a point, however, the usual fabrication of line-contact styli (except the Shibata) produces a shape that is symmetrical when seen from the front or the side. Thats why it's so relatively easy (as my photographs show) to determine when the "line of contact" is perpendicular to the record surface. Getting from there to a useful rake angle is a fairly simple calculation, and with some tonearms, a fairly simple procedure (NOT the SME unfortunately ;-(

The idea of properly setting the SRA (again, only an important issue with line contact styli) is to have the ridges on each side of the stylus 'lean' forward at the same rake angle as the cutterhead (or did you think cutterheads were positioned straight up and down? Ever try using a chisel that way ;-)

Ah the fingerlift again. Well, I don't care if you amplifiy it a million times, you won't hear it ;-)

Hi Nsgarch,
maybe we have to set out our trades/professions for some helpful insights?
I'm a trained mechanical engineer and actually have even WORKED with chisels on METAL.
Next, I do furniture- and speaker-building, so again I use wood chisels (even Japanese double laminate ones --- and I sharpen them too, ho, ho). 25 deg. main angle and 30 deg. honed angle mostly, and depending on the cutter AND the tool.
Variations of 10 - 15 deg. depending on the application are not uncommon.

Yes, I did read that thread, not that it changes what I understand, but what I actually disagree with is the statement that the cutter-head is/was at ~ 1.5 deg (obviously tilted forward of the 90 deg. makes 88.5 deg. or 91.5 deg. so take your pick). In fact some 2-7 deg. seems closer to what has been the case when cutting lacquers or DMM masters.

This does in no way explain your take, that SRA is supposed to be NOT related to VTA...
VTA, is the angle between the flat record surface and the line the cantilever makes --- and the cantilever is bonded to the stylus at some angle greater than 90 deg. -- but it is then FIXED! So, how can the two then NOT be related, hallo?!

You are an architect you would understand what I try to get at, and I'm not talking just some numbers not being related here.
Depending on the angle between the stylus' contact-line to cantilever you can get either SRA or VTA, AND in fact those cart manufactures 'stupidly', 'stupidly', quote VTA (if they do it at all) and all then wait for us 'clever' audio-dudes to re-express it in SRA angle terms, wow.
If a cart manufacturer quotes 22 or say 25 deg. VTA you actually know squat about SRA -- because you do not know the angle that was used between the cantilever and the line-contact, or do you?
Do you know what angle the lacquer was cut at for the LP? No way, so you go fiddle your SRA or VTA angle until it sounds the best to your ears - and the rest of it is just a case of intellectualizing what we truly don't know, in terms of the actual degrees.
So you see, that's why I got a-plenty of VTA and SRA by now. Eish!
Axel

Typical cutterhead angle is 1.5 deg. +/- depending on the lathe operator. I confirmed this with Stan Ricker, a well-known mastering engineer and lathe operator (Cardas Test Record.)

The precise angle of the cantilever to the record surface is irrelevant for playback. It can vary from zero deg. (for strain gauge cartridges) to 90 deg. (Decca cartridges) and everything in between.

However, ensuring that a line contact stylus' edges line up with the angled groove undulations is essential, no matter how it's attached to the cantilever, or what the VTA winds up being. Don't worry about those things.

It's nice to be able to adjust SRA on the fly to compensate for different record thicknesses and lathe operator preferences, but 1.4 degrees seems to be a good average if 'on the fly' is not possible (e.g. SME arms.)

If you set up your arm geometry carefully and adjust for close to the correct SRA (or exact SRA if your arm provides) that is at least 90% of the job.

It's then easy enough to check for correct azimuth with a test record, and for VTF by ear. Anti-skating force settings for line contact styli is about 25% that necessary for spherical or elliptical styli because of lower friction and groove drag.

If you'll follow this strategy, you can be confident you are getting the most out of your tonearm and cartridge.