Cartridge Alignment, Protractors
Proper cartridge alignment is obtained by aligning the cantilever. Therefore, it is unnecessary and a waste of time aligning the sides or body of a cartridge. That really serves no purpose.
The easiest cartridges to align are the “nude” (body-less) designs. Their cantilevers are fully exposed and easy to see. Cartridges with smallish bodies like a ZYX are also quite easy, for the same reason. The hardest cartridges to align (properly) are those with long, square bodies, like many Koetsu’s. You can square the body easily enough, but you can hardly see the cantilever at all.
The two trickiest aspects of using an alignment protractor effectively are:
- making sure the protractor is aimed correctly (if the design requires it) and;
- making sure you’re viewing exactly down the center of the alignment grid when squaring the cantilever. The tiniest head motion will throw you off, and with most protractors you won’t even know.
If a protractor requires aiming, it usually has a line you’re meant to point at the tonearm’s pivot point. This is easier said than done (accurately), yet even a small error will throw your results off. If your protractor has such a line, there’s a good trick for aiming it accurately.
Tape a piece of thin thread to the end of the line that’s further from the tonearm pivot. Aim the line roughly and then pull the thread taut, holding it directly above the tonearm pivot point. Now view the thread and the protractor’s alignment line from directly above. If you keep the thread taut and move the protractor slightly back and forth, you’ll be able to judge when the line and thread are parallel. This is more accurate than merely aiming the line itself at some point in space.
MAKING SURE YOU”RE LOOKING SQUARELY DOWN THE CENTER GRID LINE
This is readily solved, but not with just any protractor. To be certain you’re viewing squarely, the only really effective tool I know is a mirrored protractor. There is a very expensive ($150) one that can be custom made for any tonearm and that takes months to get, but for just $20 you can have a similar one in a few days.
The TTB protractor is based on the widely recommended Baerwald two point geometry, which is quite similar to the geometry of most Helius tonearms. The TTB should be compatible and I highly recommend it.
A mirrored protractor makes alignment much more accurate. The built in parallax (dual images) effect makes it easy to tell when you’re sighting exactly down the centerline of the grid – and when you’re not. It also makes the thread trick explained above still more effective. With four images to square up (the thread and its reflection, the printed line and its reflection) it’s almost impossible to mis-aim the protractor. I recommend this tool for any compatible tonearm.
Beyond the above, the best way to become comfortable and adept at cartridge alignment is (you guessed it!) by doing it… repeatedly. Align a cartridge. Then loosen it and align it again from scratch. Practice really does help with this delicate but critical task.
Note: make sure your VTF (downforce) is close to correct before beginning, then fine tune it after the cartridge is snugged down in place.