I'll take a slightly stronger position than Twl. If a cartridge comes to you new in that condition, strongly consider requesting a replacement.
My Shelter 901 (bought used) has two visible defects:
1. cantilever is not square to body when viewed from above
This was easily dealt with by aligning the cantilever, not the cartridge body. You should do this anyway, few cartridges have perfect zenith IME. A good mirrored protractor makes cantilever alignment easier and more accurate.
2. generator is both rotated and off-center relative to body and cantilever, when viewed from the front
This presents an insoluble performance/safety dilemma.
OT1H, as Twl said, the coils are not centered in the magnetic fields of the generator. This increases crosstalk between channels, which muddies voicing, imaging and soundstaging. My 901 measures 8-9 db of crosstalk, which is horrible for a $1500 cartridge. Cello's 901, which appears square, measured just 1.5 db when mounted on my rig. My three ZYX cartridges all measure around 0.2 db, which is almost surreal-ly good. (Is that a word?)
OTOH, the way you reduce crosstalk is by adjusting azimuth. But even if your arm allows this, you don't want to set your stylus significantly off straight vertical. You can imagine how bad that could be for the long term health of your groove walls.
IOW there was no satisfactory fix for my second problem except a replacement. Until then I set azimuth visibly for a vertical stylus. Anything else would have been unsafe.
My Shelter 901 (bought used) has two visible defects:
1. cantilever is not square to body when viewed from above
This was easily dealt with by aligning the cantilever, not the cartridge body. You should do this anyway, few cartridges have perfect zenith IME. A good mirrored protractor makes cantilever alignment easier and more accurate.
2. generator is both rotated and off-center relative to body and cantilever, when viewed from the front
This presents an insoluble performance/safety dilemma.
OT1H, as Twl said, the coils are not centered in the magnetic fields of the generator. This increases crosstalk between channels, which muddies voicing, imaging and soundstaging. My 901 measures 8-9 db of crosstalk, which is horrible for a $1500 cartridge. Cello's 901, which appears square, measured just 1.5 db when mounted on my rig. My three ZYX cartridges all measure around 0.2 db, which is almost surreal-ly good. (Is that a word?)
OTOH, the way you reduce crosstalk is by adjusting azimuth. But even if your arm allows this, you don't want to set your stylus significantly off straight vertical. You can imagine how bad that could be for the long term health of your groove walls.
IOW there was no satisfactory fix for my second problem except a replacement. Until then I set azimuth visibly for a vertical stylus. Anything else would have been unsafe.