How to get 100 accurate azimuth?

You can't.

Nor is that level of precision necessary.

I use the Wally Analog shop, and even with that, at some point you have to say "good enough".

As Riffer says, 100% perfect azimuth is impossible, unless by chance your cartridge is 100% perfect. Since no cartridge is...

That said, I agree with Rushton's excellent post. I own a Wally Analog Shop, but over the years I've found I can adjust by ear just about as closely as the Analog Shop can measure, and enjoy listening to music while I do it.

Hi Rushton

Thank's a lot. Seems I've got some reading to do:-)

Theo

Freshpuma, you're welcome. There's a wealth of discussion. Just be careful to sift through it with an appropriate "hooey filter" in place. :-)

I eventually abandoned the mirror method in favor of one that seems to work a little better - play a record at night and shine a bright flashlight at the record where the stylus makes contact. A black vinyl record will reflect the stylus and cantilever nicely. The cantilever and it's reflection should form a straight line when viewed from directly in front of the cartridge. That being said, your eyes can play tricks on you and you may find yourself tilting your head in order to get the reflection to line up! I'd recommend a mechanical method (test record, Wally tools, etc.) unless you are really going to tinker with this setting often enough to learn to do it by ear.