I would not replace a Shelter 501 with a Denon 103 AND the 103 is not a good cartridge for that light to med weight tone arm. A much better choice would be a Dynavector 10X5 MC (2.5mv) for that arm, IMO. Lots of jump factor with this cartridge, you cant go wrong. Keep your tonearm and change to a proper cartridge is my advice. Also, I agree re tipping the Shelter might be the best option IF your changing your tonearm (only use Soundsmith for that, imo), but that Dynavector is really nice with that arm.
Matt M
Matt M