How much difference if the tonearm is mounted 5mm

Calvin, thanks for the clarification. It sounds like you are correct about the arm being off spec. The only other logical conclusion is that the Feickert protractor is off spec. If the Feickert works fine on other arms then that would rule it out as a suspect.

Assuming you can mount the arm where ever you want. With a Feickert protractor (own one myself) you can just mount the arm where you end up with the cartridge in the middle of the head shell slots, and still get the stylus in the middle of the cross marks on the protractor. This is where the arm should be mounted. The only draw back is the head shell offset may be a little off if it was designed to work with a 212 mm P2S distance. If this is the case do not aligning the cart offset to the head shell. Just align the cantilever (front to back) with the marks on the Feickert protractor, which should be done regardless.

This would work for any arm you do not know the P2S distance on as long as you are using the Feickert protractor, or one that is of the same design.

Regardless I would contact the manufacture and try to get a replacement if the arm is not to spec, because this would make the arm impossible to resell if it is off. Someone else may not have the flexibility to mount the arm at a different distance than what is specified.

The db protractor finds correct null points from pretty much any pivot-to-spindle distance within the range of your headshell.

Good morning,
Thanks to all of you who have answered to give advises in this matter. Yesterday, I mounted the arm 5mm shorter than manufactor reccomedation. The result was terific. I will run it for a few days to breaking in and will report back. In the mean time, does anyone know is there exists any head shell which has the mounting distance further than normal? All I can find is the Ortofon LH 9000 and the zyx headshell. I an leaning to the zyx but it is too expensive (700 retailed). How effective of a good design headshell soundwise?
Thanks
Calvin

The ''Zupreme'' sold by LP/Gear has the slots quite a bit forward.  This head shell is Magnesium  with the screw for azimuth adjustment.  Litz leads and are the same head shell as the Sumiko's.  Their just not branded as such and sell for $50 instead of the $90 that Sumiko's get!
In my opinion, the best head shell available!
Regards,