Audiodisc Recording Blank - What Needle To Use For Playback?

[hydnar]

Hello,

I found a few recorded audiodisc recording blanks in a lot of 10" 78 rpm discs that I picked up at an estate sale. The discs they are with are mostly from the 1940's. How can I tell what needle I should use for playback (33, 45 rpm or 78 rpm)? Did the disc cutting machines cut at both groove thickness? The band that is recorded on these disc originated in the 1940's.

Any information is appreciated.
Thanks in advance!

hydnar

Here's some pics:

[Lucius1958]

Definitely 78. I assume you're using a (relatively) modern turntable?

- Bill

[hydnar]

Definitely 78. I assume you're using a (relatively) modern turntable?

- Bill

Yes. I’m using a BSR record changer to play the late 1940’s, early 1950’s 78 rpm recordings that I’ve found. Older discs I play on a suitcase acoustic phonograph that I found. This disc feels like a 1980’s vinyl lp. It is fairly thin and flexible compared to a 10” shellac 78 rpm disc. How can you tell which groove was cut in it? I’ve seen YouTube videos of these disc being played at 33 rpm with a thin stylus and 78 rpm with the wider stylus. Any idea what years these discs were used?

Thanks for the information!

hydnar

[tim w]

If these are from the mid forties, I doubt they were using microgroove cut yet. You should be able to use a standard 78 stylus. Lightweight preferably. Some have said you could use trailing needles on acoustic machines but I wouldn’t trust it. These still look nice & shiny. There are some people that use these discs today.

[hydnar]

If these are from the mid forties, I doubt they were using microgroove cut yet. You should be able to use a standard 78 stylus. Lightweight preferably. Some have said you could use trailing needles on acoustic machines but I wouldn’t trust it. These still look nice & shiny. There are some people that use these discs today.

Thanks Tim! I decided to try them at 78 rpm with the 78 rpm stylus. I used an old BSR record changer that I found at a sale. Here is a youtube link of one of the three discs I found. I was pleasantly surprised at the quality of this disc so many years. Who knows when it was last played.

[YouTubeHD]
https://youtu.be/dY3WSeCaI30[/YouTubeHD]

Thanks again!

hydnar