The Talking Machine Forum — For All Antique Phonographs & Recordings

I replaced the diaphragm and gaskets on my brass no.4 several years ago and don't remember an aluminum ring such as that, and I would certainly noticed it if there was one. It had a hardened and old-looking no.2 style single gasket and showed no signs of ever having been worked on. I used a mica diaphragm made to fit a Columbia reproducer. My advice is to leave your 4A alone if it sounds good. I have owned some that looked like they would crumble from the vibrations if you played a record with them but actually sounded quite good.

Jim

If I recall correctly, the original brass No 4s from Victor started with a full mica diaphragm held between two rubber gaskets, and that sometime toward the end of the 4 / beginning of the 4A Victor switched to a diaphragm that had a metal ring on the edge, again held between rubber gaskets.

HMV used a full mica diaphragm for the entire time their No 4 was in production, 1925 through 1931 or so, but used a single thick rubber gasket that was slit on the inside edge, into which the outer rim of the diaphragm was inserted.

Thank you all for your help. I think I will leave the reproducer alone for now.