What makes a good tonearm?

I'm entering the world of decent analog and believe I understand why the turntable design is critical (e.g., vibration isolation, balance and speed stability) but am scratching my head a little about tonearms. What makes a good tonearm good and a great tonearm great? The resulting sound is always the key, but what design characteristics contribute to that sound? Tonearms are a big investment and can be tough to change later so I'd like to understand more about them before I buy anything. Thanks in advance.

Showing 1 response by orpheus10

If you're low on cash and have moderately skilled hands, buy a used (meaning cheap and old) Rega Planar 3, and rebuild it; plus, do all the tweeks, thereby turning it to the equivalent of the "Sota Saphire". You also get the tone arm with the TT, which can be upgraded with new wire.

All the instructions for doing this are on this forum.