Graham Phantom II 12" - dimensions and overhang


Hello guys,

I come from Europe and recently purchased Graham Phantom II tonearm with 12" armwand.I was missing specs for 12" armwand (in manual are specs for 9" and 10"),so I emailed to Bob Graham and asked him for specs for 12" version. The answer was,that 12" version should be adjusted same as SME V 12". Bob sent me document with SME dimensions as well.

So regarding this document specs are Leff 308,8, overhang 13,2, mounting distance ( Pivot-Spindle) 295,6.
To adjust mounting distance is easy using any quality protractor. I used Acoustic Solid.

http://www.acoustic-solid.de/html/schablone.html

So with mounting distance adjusted to 295,6,here comes the thing.
I should set overhang to 13,2 regarding to specs for SME V 12",but simply
elko

Showing 3 responses by geoch

I can not figure out what the fuss is all about, all you contributors of this thread ... you are very experienced analog afficionados and then you don't dare to improvise in this most creative and entertaining theme !
In my case I've had allways to deal with customised protractors for my 2 favorite tonearms (Pluto 9A & SAEC WE-308SX) but this is fun and never became a problem for me as far as I have this :

http://www.vinylengine.com/tonearm_alignment_comparator.php

I can choose whatever it pleases my LP collection.

Dear Suteetat, Clearaudio is not the same with the Denessen.
"This whole IEC standard r min thing" is the last inner groove that is recorded to your LP. So, depending on your LP collection you can choose an alignment which suits better your preferred inner groove and see the changes of the tracking distortion on the graphic above. The only problem (not every one has the patience) is that you have to design the 2 new null points on a paper which has to be accurately bored to your spindle according the Pivot to Spindle distance.
So :
1). First you have to draw the line from Spindle to Pivot.
2). With the compass tip to the Spindle point, draw an arc that represents your inner null point and a second arc for your outer null point.
3). With your ruler draw some closely spaced points (preferably with a needle)
counting from the Pivot point up to the Effective Length and progressively getting closer to the Spindle until you reach the Overhang.
*[This is your Arc Protractor]
4). With your ruler join the 2 points : from the Spindle point, up to where the small arc (of the inner null point) meets the Effective Length. Likewise join the 2 other points : from the Spindle point where the bigger arc (of the outer null point) meets the Eff.Length.
5). Draw the lines that are vertical to these two.
**[These are your 2 points for Zenith Alignment]
6). Now you can cut the Spindle Hole
(after some strengthening of this small area by using 2 pieces -as a sandwich- of self adhesive tape that we use for protecting the wall when painting)
exactly centered to this full stop point that represents your Spindle point
(preferably using a 2 pointed compass to cut smoothly).
***[This is your custom jig]

Before you start to design your own original protractor, you must have some experimental time with the VE comparator, enough for you to comfortably decide the graphic plot that suits your LPs. So pick up your 20 most enjoyable LPs and with your ruler find the innermost groove from the spindle point.

I'm sorry if Ι was tedious & boring but anyway this is what I am doing for my two quite distinctive tonearms.
To further promote this alignment theme, I'm taking the risk of saying that the tonearm manufacturer does not have to deal with the specific geometry of the designed tonearm, but only with the mechanics! And that's because he doesn't have to know what is the innermost groove of your LP collection. Neither he can enforce you to use only his prefered alignment, just because he gives you a jig or a specific Eff.Length, ONCE HE IS USING A SLOTTED HEADSHELL!
Within the physical limits of the tonarm & the armboard under use we can decide entirely free by our listening.
I have the Dennesen, the Clearaudio, the Pluto and the Project of this family of protractors. Even if the Dennesen was still available, (discontinued) I would buy the Clearaudio instead. Ιt gives the better sound (especially the r min=75mm) it has 4 options, it is fairly accurate and is a joy to use. But although I'm allways starting from here, it seems impossible to resist in making my own customised paper.
I'm starting from the furthest permittable Pivot to Spindle distance (on each particular armboard) and then I'm checking if I can reach the Effective Length which corresponds to this according the protractor. From this place, the VE comparator takes order to modify the curve of the plot to my own priorities. Usually I don't change the Pivot, but experimenting with the Offset Angle instead, watching the tracking distortion, and the innermost & outermost grooves in the plot of the VE comparator.
BUT ... even if you don't bother to make your own changes, (especially if you don't care to change the null points and stuck with the Baerwald alignment) it is worth to find a 2 point protractor, in order to adjust precisely the zenith! because this kind of protractors, they strictly offer only the inner null point and THIS IS NOT ENOUGH by all means!
In every other case you have to design your own paper with outmost care. It's fun and it helps to understand the whole situation that is taking place there and most importantly it gives you the essential self-assurance that nothing left to chance.