Beginner_N
Well-Known Member
Hi Amit,
I dont have extra. I can give it on loan if you want. Manufacturing guy made this sample for me and stopped responding completely.
Regards
Nishant
Cartridge Alignment Protractors
- Thread starter AmitKumar
- Start date
I dont have extra. I can give it on loan if you want. Manufacturing guy made this sample for me and stopped responding completely.
Regards
Nishant
reubensm
Well-Known Member
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
The guy in the video says he realized only later that the manual said to offset the cart. Straight arms are ok. But the cart has to be offset.
reubensm
Well-Known Member
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
and dont forget to keep it simple 
Gerry_the_Merry
Well-Known Member
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.
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.
Last edited:
vinyl
Active Member
It is not the cartridge, but the cantilever that should be aligned.
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