Rich,
I don't know of a mirrored protractor for Stevenson. I imagine Wally could make one...
Nrenter,
1. The dual reflections that trouble you are what gives the TTB the advantage I described above. They are its best feature. You just have to practice using them. Whiskey helps. ;-)
If you're trying to sight down the centerline of an alignment grid, having two images makes it possible to get precisely lined up. The printed line and its reflection are either directly on top of each other or they're not. This degree of precision is impossible without dual images.
2. No need to guess at the second fixed point (the pivot). A length of thread makes aiming the TTB (or any universal protractor) simple and highly accurate.
A. Tape a length of thread to the beginning of the protractor's sight line. Make the thread long enough to reach across the protractor and over the top of the tonearm pivot.
B. Aim the protractor roughly and pull the thread gently taut, with the free end crossing directly over the pivot.
C. View the thread from directly above. Move your head back and forth to align the thread and its reflection from the mirror. This guarantees you're sighting exactly vertical.
D. Pivot the protractor until the sight line, the thread and the thread's reflection all line up. Voila! A perfectly aimed protractor. Simple, repeatable and exact.
(Thanks to Frank Schroeder for this tip.)
I don't see how an adjustable armboard affects the use of a cartridge alignment protractor. I have a Teres too. The function of the swivelling armboard is to set tonearm pivot-to-spindle distance. Once that's locked in you don't move the armboard again unless you change tonearms. By the time you're ready for cartridge mounting, the armboard is fixed.
If using a universal protractor, absolute precision in pivot-to-spindle distance is unnecessary. That's the whole point of an aimable protractor and headshells with slots. Pivot-to-spindle is a hair off? No problem. The protractor will automatically produce a pivot-to-stylus dimension to compensate. If the stylus is square at both null points your triangle is correct, by definition.
BTW, if you're using a Baerwald protractor with an OL arm, you may have better luck mounting the arm at ~220mm than the stock distance of 222.76. Regas weren't designed for Baerwald and some cartridges aren't long enough to reach the Baerwald null points with the arm mounted at the stock distance.
I don't know of a mirrored protractor for Stevenson. I imagine Wally could make one...
Nrenter,
1. The dual reflections that trouble you are what gives the TTB the advantage I described above. They are its best feature. You just have to practice using them. Whiskey helps. ;-)
If you're trying to sight down the centerline of an alignment grid, having two images makes it possible to get precisely lined up. The printed line and its reflection are either directly on top of each other or they're not. This degree of precision is impossible without dual images.
2. No need to guess at the second fixed point (the pivot). A length of thread makes aiming the TTB (or any universal protractor) simple and highly accurate.
A. Tape a length of thread to the beginning of the protractor's sight line. Make the thread long enough to reach across the protractor and over the top of the tonearm pivot.
B. Aim the protractor roughly and pull the thread gently taut, with the free end crossing directly over the pivot.
C. View the thread from directly above. Move your head back and forth to align the thread and its reflection from the mirror. This guarantees you're sighting exactly vertical.
D. Pivot the protractor until the sight line, the thread and the thread's reflection all line up. Voila! A perfectly aimed protractor. Simple, repeatable and exact.
(Thanks to Frank Schroeder for this tip.)
I don't see how an adjustable armboard affects the use of a cartridge alignment protractor. I have a Teres too. The function of the swivelling armboard is to set tonearm pivot-to-spindle distance. Once that's locked in you don't move the armboard again unless you change tonearms. By the time you're ready for cartridge mounting, the armboard is fixed.
If using a universal protractor, absolute precision in pivot-to-spindle distance is unnecessary. That's the whole point of an aimable protractor and headshells with slots. Pivot-to-spindle is a hair off? No problem. The protractor will automatically produce a pivot-to-stylus dimension to compensate. If the stylus is square at both null points your triangle is correct, by definition.
BTW, if you're using a Baerwald protractor with an OL arm, you may have better luck mounting the arm at ~220mm than the stock distance of 222.76. Regas weren't designed for Baerwald and some cartridges aren't long enough to reach the Baerwald null points with the arm mounted at the stock distance.
Now, if someone could help me print my protractor on some sort of paper-thin mirrored piece of plastic, I think we'd be on to something.That would defeat the major advantage of the mirror. See #1. :-)