Cartridge Alignment Protractors

Hi Reuben,

This is not rake angle. Rake refers to the angle the stylus makes with the surface of the record. It's the same for practical purposes as VTA which is tonearm height. Raising the tonearm and lowering it changes the rake angle. The standard rake angle is around 92 degrees plus some decimal point which I forget. Some people use a microscope to view the stylus angle and adjust so it's exactly this angle. Of course this would change with record thicknesses so I don't really see the point but that's another discussion.

Also as per your previous post I'm wondering how your dad and that guy in England set carts to the spindle point. As far as I know all carts have an overhang measurement differing from cart to cart but there nonetheless specified by the manufacturer. Which means the stylus has to sit in front of the spindle not at it. Not sure how a proper alignment would be achieved without achieving this specified overhang distance?

Also the DJ who uses no offset probably is using an S curved tonearm where the offset is already built in with the curve of the arm and the cart itself is lined up straight achieving proper offset. Was this the case? Cos you simply cannot play a cart without offset and achieve any aligning there will be distortion all throughout!

Regards.
yea, but actually the spindle trick served them well, on another note, the straight tonearm i was referring to, can be seen in this video
 
I hope Amit, you now have an idea about turntable tonearm and cartridge calibration. Moral of the story, find a way that works best for you and you'd be happy. As with most things audiophile, the trick in it is to understand that under all circumstances, the "means" justifies the "end"....with the focal point being the "end". Dont get stuck with the "means" :) and dont forget to keep it simple :)
 
Thank you everyone for your valueable recommendations. I will read through the links provided by all of you.

I m sure I m going to have some more doubts and will be needing more guidance.

Regards, Amit.
 
Hi Amit, I don’t wish to add to your database of links. But generally, it may help to keep the following in mind.

The tonearm would be designed to achieve one of a variety of objectives – e.g. minimize peak distortion, minimize total distortion while traversing from outer to inner groove etc.

At the end of any of these objectives, the result will be two null points. The most common one is the 66mm and 120.08mm set. That is what I have in my protractor that came with the tonearm as well as other (Shure) protractors.

For a given objective of distortion minimization the null points will be independent of the length of the tonearm. E.g., given identical designs, the SME 3009 and SME3012 will have identical null points.

When tonearms are designed for a different set of null points, what is different in the tonearm design is the offset angle (there are only two variables – stylus pivot distance, and offset angle – that define the position and path of the cartridge/stylus and one of them, the stylus pivot distance is usually the same, i.e. 9”).

If you choose the 66mm null point but your tonearm is not designed for that, then by varying the stylus – pivot distance, you may achieve alignment at that null point, but you won’t be able to achieve at the other null point i.e.120.08mm. But for an SME tonearm, the other null point alignment will be automatically achieved as the tonearm is designed for that set of null points, such is the offset.

If your tonearm base cannot slide back and forth, like in SME, then you might want to use the headshell type with rails where the cartridge can slide back and forth. They can also allow some flexibility in the offset. But between the whole lot, you will create so much variation that even if you start out with an SME, if you finally get the 66mm alignment, you may not get the 120.08mm alignment.

If you are in the habit of experimenting with tonearm cables (like I am) then you too will be cursed with the need to keep redoing all the above, plus follow up with azimuth + SRA adjustment etc. before you can get your TT singing.

This article is one of the best articles for understanding this topic. jls001 forwarded me this piece many years ago.
 
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Hello Forum Members,

Hope all of you are doing well in your life and staying safe in these unprecedented times.
I have been out of the HiFi world for the last few years due to family and work commitments, Now slowly trying to get back to this wonderful world of music.

I came across Cartridge Alignment Protractors online, certain websites selling them and then few free printable versions also. I did search through our forum and found some bits and pieces of information on the subject. I thought it might be worthwhile to have information about Cartridge Alignment Protractors in one single thread.

Actually till a few days back I didn't not even know that these protractors existed. Cartridges of the two TTs that I have were aligned by esteemed forum members before they were sent to me. So coming back to the basic question, are these protractors really required?. Now I understand there are different types of protractors available, how should one choose which one to follow?. Also do we use the free downloadable versions or buy the commercial ones?

Requesting forum members who have expertise in Turntables to give their view/suggestions.

Regards, Amit.
It is not the cartridge, but the cantilever that should be aligned.
 
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