I know that in the era of 78's that the grooves consisted of vertical peaks and valleys. With the advent of 'microgroove' recording the bottom of the groove is flat, whereas the walls of the valley wobble from side to side. Nevertheless I've never had any real problem playing them on modern gear.

EXCEPT that I no longer own a 78 rpm turntable. I remember seeing some Wave file software years back which would speed up 33.45 rpm recordings to 78 rpm. Any clues where to find it today?

BTW I wouldn't recommend using your finest transcription turntable with expensive cartridge and stylus to play 78's, but being a bower bird I have some crappy old machines ideal for the purpose.

Regards, John