tonearm mounting and alignment

Like Dan_Ed, I like the TurnTableBasics. Its mirrored surface with top surface image and bottom surface reflection make it possible to achieve far superior alignments than any non-mirrored protractor ever can.

That said, I'd offer two warnings:

1) getting used to using the mirror drives many people batty or blind, if you're not the patient sort it might not be for you;

2) the Rega arm, when mounted at the stock 222-223mm, was not designed for Baerwald two point alignment (what the TTB protractor is designed for). With most cartridges you should have no problem, though the cartridge will be well forward in the slots and slightly twisted. A few cartridges with very short stylus-to-mounting-screws dimensions might not reach the Baerwald null points. Low probability risk but worth a mention. If you have the capability to nudge your arm in to 219-220mm then you can align any cartridge.

G'luck, and there are no stupid questions!
Doug

Any opinions on Van den Hul's Cartridge Alignment Gauge?

I finally picked up a Turntable Basics protractor. What a slick little device! I appreciate the suggestion.

That’s great. Don’t forget warning #2 in my post above. Assuming your arm is mounted at the Rega-standard 222mm from the spindle, proper use of the TTB will leave most cartridges well forward in the headshell slots and angled slightly inward. That’s okay.

BTW, the toughest part of using the TTB is accurately aiming the sight line at the tonearm pivot. Unless you aim it “perfectly” your results will be meaningless, but the aiming is tricky.

The best method involves taping a piece of thread to one end of the TTB’s sight line, at the side away from the tonearm. Now drop the TTB onto the spindle, aim it roughly and then pull the thread lightly taut directly over the tonearm pivot. Sight vertically down through the thread to the line, using one eye only. Swing the protractor L and R a few degrees and you’ll see the thread, the line and the reflections of each move in and out of alignment. When ALL FOUR images are lined up, your protractor is aimed just right. Now position your stylus on the outer alignment point and square the cantilever to the grid.

It's much easier to do than to write, so don't worry!

Doug, you're the bomb! Thank you very much for those hints. I was wondering how to accurately aim the line on the mirror at the tonearm pivot. I did my best by eyeballing it, but I'll do it again like you describe. A string makes perfect sense.

Regarding point #2, my cartridge is completely forward in the RB300 headshell slots and angled slightly inward just like you describe.

Now that I'm dialing in the cartridge accurately, I can't help but wonder whether my tonearm is mounted correctly. I know it's not because I mounted it and didn't measure the distance from the spindle.

Assuming your arm is mounted at the Rega-standard 222mm from the spindle

What points on the tonearm should I by using for this measurement?

Many many thanks!