On 1/14/2021 11:40 AM, Karl Miller wrote:
> I have some recordings made in 1935. They are vertical cut, ten inch,
> recorded at 33 rpm. While the labels are covered, I am assuming they were
> embossed on one of the Victor home recorders.
> After trying six different needle sizes, I found that a
> microgroove needle seems to work the best! I am trying to track it as
> lightly as possible. I recall that these discs were pregrooved and embossed.
The Victor "home" disc recorder embossed the sound on pre-grooved pressings
using a 6 mil conical "needle" to both laterally emboss and play recordings.
I confirmed this a while back when I obtained a pair of the actual "needles"
sold by Victor for the purpose. I had Expert Stylus in the UK re-tip a Stanton
stylus assembly, duplicating the size of the original Victor "needles", to use
for transferring these recordings.
The embossing happens on the upper edges of the "U" shaped groove and if you
use a smaller stylus it falls the the bottom of the groove where there is no
audio to be found! The playback "needle" must ride on the top of the groove to
"hear" the audio.
> Do any of you know what sort of fluid might be the best (safest) to clean
> the discs.
Kodak Photo-Flo 200 diluted 1:200 is probably the safest. It can be mixed in
other ratios 3:200 and 6:200 if need be to make the resulting mixture
properly "sheet" on the disc.
The Disc Doctor's velvet brushes are excellent for the cleaning job.
... Graham Newton
Audio Restoration by Graham Newton, http://www.audio-restoration.com
World class professional services applied to tape or phonograph records for
consumers and re-releases, featuring CEDAR's CAMBRIDGE processes.