? about cartridge mounting

[gunut]

I have a couple Marantz turntables and in there instructions they say to mount the cartridge to the headshell useing the 45 adapter to gauge the needle overhang/alignment....I also have a plastic gauge that you attatch to the headshell that is supposed to be a universal cartridge alignment gauge that I picked up years ago from a electronics shop....The problem is that the two methods give me about a 1/2 inch differance in how far forward the needle is with the snap on gauge being the farther forward of the two methods....which one is correct????? and how do you tell???..... :scratch2:

thanks

 

[OvenMaster]

Myself, I would use neither, but instead download and print an alignment gauge from
http://www.vinylengine.com/manuals_tonearm_protractors.shtml (I used the Baerwald stupid and Chpratz with excellent results)
or
www.enjoythemusic.com/freestuff.htm
People swear by these, not AT them!
Tom

 

[brucered]

i myself have used the enjoythemusic one, really easy to use. DON'T MOVE THE PLATTER.

 

[Nat]

There is no such thing as a universal mounting gauge for headshells, since arms differ in length. I agree with the suggestion to download a alignment guide from Vinyl Engine, but you can also make a relatively decent one by taking a 3x5 card and cutting a V notch in it exactly lined up with one of the lines on the card, and then drawing a line perpendicular to that line at 2 and 5/8 inch, and one at 4 and 3/4 inch. A pin prick at the intersections will make it easy to set the stylus down exactly. Disable antiskating, and loosen the cartridge mounting screws. Align with the inner alignment spot, reset tracking force since moving the cartridge changes the down force, and check to see if it aligns at the outer point. Adjust back and forth until both are as close to perpendicular to the line as possible, always keeping in mind that the tracking force changes as you move.
If this is too much, just align on the inner spot, and go on about your business.

 

[vinylengine]

The problem is that the two methods give me about a 1/2 inch differance in how far forward the needle is with the snap on gauge being the farther forward of the two methods....which one is correct?????

Both are correct if you are using them correctly!

If you take a look at this picture over on the Analog Dept you can see that as an arm swings across a record the stylus is only parallel to the grooves at two points; these are known as the null points (points of zero tracking error). Depending on how far forward the cartridge is in the headshell, and at what angle, these points, and the amount the stylus 'overhangs' the spindle, change. Baerwald calculated that to minimise distortion across the average 12" record the null points should be at 66.0 and 120.9 mm. When you buy a 'universal' protractor most use these null points, and as long as you can get your stylus cantilever (or cartridge body) parallel to theses lines then you should have pretty low tracking distortion across the record. However, historically many tonearms are designed for different null points so the tool that came with the arm may align the cartridge at a different position in the headshell. Which should you use? If the cartidge is still fairly square in the headshell when you've aligned to a Baerwald protractor (measure the null point position to be sure it is Baerwald) then I'd go with that. However, if the cartridge ends up offset a large amount in the headshell or if you haven't got room in the slots to properly align at those points, use the manufacturers gauge. Just don't expect the two methods to agree with each other

PS IMHO the enjoy the music protractor is only suitable as a universal protractor if you rotate it to check the second point. If the protractor is kept stationary then you can only align at both points properly if you're arm is the same length as the one used in its design, which isn't stated on the site. Also the null points are a little unusual but don't let that stop you using it!