One difference is that you will need a mahusive plinth - as fitted to my Goldring '88' - to accommodate its 3012 arm. I can imagine a few slight advantages and disadvantages but never heard an informed explanation.
Yes, not all arms are 12 or 9 but they were common lengths.
Yes, not all arms are 12 or 9 but they were common lengths.
I believe the 12" tonearm was originally designed to accommodate 16" radio broadcast transmission discs.
BBC 16" transcription disc
The 9" tonearm was adopted for domestic use with 12" discs.
BBC 16" transcription disc
The 9" tonearm was adopted for domestic use with 12" discs.
The longer the length of a tonearm the more "Tracking Error Distortion" is reduced due to the reduced ARC of stylus across the grooves.
( of course this requires appropriate distance mounting of the pivot )
( of course this requires appropriate distance mounting of the pivot )
Fascinating stuff. So for once in life we have a standard (9" arms) that's a sensible choice rather than something that was convenient. How unusual...