Good to see another fast spinner here.
While I have a fair number of 78s I do not as yet have any transcription discs. I do believe that most transcription discs are 16" diameter or more. I do believe that early transcription discs are close to standard groove (2.5 to 3mil) regardless of if they are 78 or 33 1/3 RPM. I'm guessing that after the mid forties they would be close to micro groove. I think micro groove would be rare for shellac records. Vinyl 78s can be standard groove or micro groove. I actually have some 78 vinyl records which were "audiophile" records which are 1 mil microgroove. The Label of some is actually "Audiophile". They do sound remarkably good. This is an example: [img]
I tried to search for a list of styli for various vintages of transcription discs but didn't find much. I did find that some are made of acetate which requires different care than vinyl or shellac. I found this: https://en.wikipedia.org/wiki/Electrical_transcription
There isn't much on stylis size but I'm sure the info is out there.
I believe there are calibrated microscope devices to measure groove size for choosing styli. I haven't yet got one, but I'd like to have one.
scrapjack+ wrote:I recently saw a 12" 78 RPM vinyl transcription disk from WW2, and was wondering if that would use a standard 78 RPM needle? I read another site stating 2.3mm and 2.0mm "often" yield better results with transcriptions, I assume they are referring to the 78RPM transcriptions. I've read that the 33RPM 16" transcription disks had wide groove and later micro groove variants. I thought I read their micro groove was somewhat thinner then standard.
What diameter needles would be ideal to play these 3 types of records?