Help!! With cartridge alignment

[Tom-Brown]

Hi all you knowledgeable folk :) I've just got my RB250 arm back after a complete re-wire and want to fit a new Ortofon Blue cartridge to it - but I have no idea how to ensure the alignment is correct :( I've got the ortofon alignment protractor but don't have any idea how to use it!!!
I've searched the interweb and it all sounds like techno talk to me :(
Can any one help with a plain English instruction :)

Cheers
Graham

[Ammonite Audio]

Is the cartridge a 2M Blue? Assuming that you have the arm mounted at the correct distance (222mm from platter spindle to the arm pivot point, eg centre of mounting hole), I think I'm correct in thinking that the outline shape of the Ortofon 2M cartridges deliberately matches that of the Rega's headshell. So, just align the cartridge so that its edges follow those of the headshell. and you're pretty much there. If you want to be really thorough/obsessive, download and print a Rega alignment protractor from Vinyl Engine.

[NRG]

plagiarised from the world designs forum, credit to Greg for getting the low down on the Rega arms, he spent a lot of time getting to the bottom of this...

"....I've made some progress on Rega arm set up which I hope will be helpful. I sourced some information from http://www.audiomods.co.uk/ which I also believe would be endorsed by Jonny at Audio Origami as he has acknowledged that original Rega set-up geometory is incorrect.

Audiomods (Jeff Spall) states that (regardless of the Rega factory rounding up the figures) the Rega arm and it's derivatives require a Pivot to spindle distance of 222.25mm. The cartridge offset angle is 23 degrees. The 'effective length' or stylus to pivot point is 239.5mm. Therefore, stylus overhang is 17.25mm."

HTH

[Tom-Brown]

Cheers for that guy's makes more sense than the stuff I've read so far. I'll be building it up tomorrow and I'll let you know how I get on :)

Graham

[awkwardbydesign]

Do you understand "overhang"? That's the term that seems to cause the most confusion.

[Tom-Brown]

Do you understand "overhang"? That's the term that seems to cause the most confusion.

I think so?? but if you'd like to give me a description I'd be happy :)

Graham

[hifi_dave]

You needn't worry about overhang, you just need the appropriate Rega alignment gauge to adjust the cartridge by. Very easy to do.

[Ali Tait]

Here's the protractor you need. Just make sure it's printed out to scale-

http://www.audiomods.co.uk/protractor.pdf

[Ali Tait]

You needn't worry about overhang, you just need the appropriate Rega alignment gauge to adjust the cartridge by. Very easy to do.

Well no, you need the Audiomods one to do it correctly.

[NRG]

The Ortofon one he has got will also work. I thought the instructions where printed on it?

http://ortofon.com/images/Accessories/Cartridge%20alignment%20protractor.pdf

The overhang will be set correctly by aligning the cartridge to the null points on the protractor, as the Ortofon is set to Baerwald AFAIK you may find the cartridge has to be pushed quite far forward in the headshell to get it aligned.

[hifi_dave]

Well no, you need the Audiomods one to do it correctly.

If the Audiomod is a modified Rega arm, then the geometry is the same.

[Ali Tait]

Not if it's mounted using the Audiomods dimension surely?

Not saying it won't work.

[Barry]

Both the Audiomods protractor and the Ortofon protractor have the two null-points at 66mm and 121mm. They thus follow the Baerwald arm geometry.

For an arm of effective length (stylus to pivot) 239.5mm, the overhang and offset angle can be calculated ("http://theartofsound.net/forum/showthread.php?20109-Tonearm-alignment) to be 17.28mm and 22.96 degrees respectively.

These values agree with the values quoted Jeff Spall of Audiomods:

"... regardless of the Rega factory rounding up the figures, the Rega arm and it's derivatives require a pivot to spindle distance of 222.25mm. The cartridge offset angle is 23 degrees. The 'effective length' or stylus to pivot point is 239.5mm. Therefore, stylus overhang is 17.25mm."

It therefore follows that either the Audiomods protractor or the Ortofon protractor will allow the cartridge to be correctly aligned within the arm.

As others have said, the instructions printed on the Ortofon protractor (I use one) make it clear how the set up the arm and cartridge. It's quite easy.

[Tom-Brown]

Wow!! Now my head really hurts :eek::lol: Thanks guys, looking at the protractor again It makes more sense now!! Looking forward to putting it all together tomorrow now :) Pics of my new deck will follow.....

Graham

[Ali Tait]

Thanks for the explanation Barry.

[struth]

I just use my Geodisc and to hell with it ;)

[Tom-Brown]

I just use my Geodisc and to hell with it ;)

Ouchhhh £40!!!! Think I'll stick with my Ortofon one :)

[Barry]

The Ortofon alignment protractor will be perfectly OK. Just follow the printed instructions and you won't go wrong. :)

[Tom-Brown]

Thanks for all the help guy's!! Lined it up on the arm and using the protractor it only needed a small "tweak" running sweet - pic's in the gallery :) :) I'm over the moon,, sat listening to The Who Live at leeds at the mo!!!!!

[Eagle owl]

Thanks for all the help guy's!! Lined it up on the arm and using the protractor it only needed a small "tweak" running sweet - pic's in the gallery :) :) I'm over the moon,, sat listening to The Who Live at leeds at the mo!!!!!

That's excellent Graham. I've fairly recently bought a turntable and returned to vinyl, setting up the arm and cartridge is pretty stressful I reckon.