Check if head shell is parallel to vinyl surface.
Rega tonearm is set for the catridge of 14 mm height
I think you need to raise tonearm with 4mm spacer for ortofon (18mm height).http://lpturntables.blogspot.kr/2011/06 ... -rega.html
Also you may need longer bolt to install spacer.
If you gonna use Grado, consider height difference and get appropriate spacer.