The Talking Machine Forum — For All Antique Phonographs & Recordings

MicaMonster wrote:The floating reproducers are VERY sensitive to the geometry of the sapphire stylus. Look at it under a microscope or loop. If there is ANY flat whatsoever, the sound quality will be terrible because the sapphire will be riding the shoulders of the groove instead of the bottom of the groove. Ron Sitko has excellent 2-minute sapphire replacements for these.

Lucius1958 wrote:Well, I've rebuilt the reproducer (an early #2) on my AT, and it's still pretty coarse in sound.

Whether it's because the reproducer was designed for brown wax cylinders, or that the modern suppliers use a thinner gauge of mica, I do not know…

Bill

Yes: I had examined the stylus with a good loupe, and could not find any sign of wear.

Interestingly, what appeared to be the original diaphragm (when I purchased the machine, it had a frozen carriage, and did not appear to have been tampered with for a long time) was a single piece of mica - not stepped.

Is it possible to re-create the stepped diaphragm by splitting a thicker sheet of mica to the correct gauge and laminating it? What would the original specifications have been?

Bill

I agree with most of the observations made here so far but once Edison moved to the large carriage reproducers and, I guess, Columbia concentrating more and more on disc, it became hard to beat the Edisons.

It is possible to split full thickness mica diaphragms to repair stepped diaphragms. However, I know of no source for the 2 smaller diameters - only the full size ones that Ron Sitko and others sell. I recently had to rebuild a Columbia floating reproducer with a full thickness diaphragm and would like to be able to try a stepped one. I have rebuilt stepped diaphragms where the large section was the only one damaged. I split the 2 smaller sections away from the larger one, then made a new section by splitting a standard replacement with a razor blade to get the proper thickness, using a micrometer for measurement. I used superglue to hold the sections together. It works quite well that way. If you used a glass diaphragm in a Columbia floater, how would you melt the wax around the perimeter without the possibility of damaging the glass from the heat?

Jim

With glass you should instead coat a regular rubber gasket, and coat it with rubber cement and place on top, will sound better than waxing in place.