Regarding Dual 502 and similar models, be aware virtually no good sounding clone, counterfeit or replacement stylus for older cartridge types exists at this time for Shure, Empire (not great sounding anyhow) ADC, Stanton, Sonus AKG etc.
At this point only a few companies have genuine correct and a clearly better sounding true 3x7 nul stylus as in Audio Technica (best money spent) Grado, Ortofon and Oyster (not too bad of a deal) have real honest good sounding stylus. Some retailers are repackaging a $9 clone stylus at $30 and $90. The retail price does not make it better, it's dishonest. The simple fact is a correctly chosen better Audio Technica cart/stylus at $50 to $120 is a better product sonically than most $200+ price fancy name brand products.
Contact us for ordering information at sales@audioproz.com or (617) 926-8020