The groove width of a 78 compared to a 33 and 1/3 LP is readily apparent to the eye! No need for a magnifying glass!
Which stylus is correct for a Shellac LP
I found some older LPs which I believe are shellac (because they are stiff, not "bendy" like vinyl). Should I use the wider 78 stylus (3mm?), rather than a stylus typically used for LPs, (eg., .08?) because of the physical composition of the record? I’d rather know in advance than experiment and ruin a record, or a stylus.