I'm wondering, though, if these are the original 90+ year old rubber gaskets, or some that might have replaced the originals, say 20-30 years ago. Originally, the #2 sound box was equipped with a single reddish burnt orange colored gasket, with a split running down its center to accommodate the mica diaphragm. If the sound boxes are fitted with (separate) front and rear gaskets, then they are not original.Cody K wrote:...These two soundboxes seem to have made it through the decades with the gaskets still in good condition, not shrunken or hardened.
I'll add my support to those who say it's a good idea to replace the gaskets, especially if there are signs that the rubber is starting to harden.
On the other hand, I also agree that if you're dealing with an Orthophonic pot metal sound box that shows signs of deterioration or metal fatigue, then it might be best to leave it alone if it plays okay. (You can normally change the ball bearings, and replace the "throat gasket" without fear that it will fall apart in your hands.)
Unlike the earlier sound box designs, the Orthophonic sound box's diaphragm does not depend on soft gaskets for flexibility. The gaskets are there primarily to clamp the diaphragm's edge firmly in place, and isolate it from the sound box's shell--and to provide an air-tight seal.
The one I have used for about 16 years on my Orthophonic VV-4-40 is basically as-found. I painted over all of the hairline cracks with Krazy Glue, which not only plugged them, but seems to have stabilized the pot metal, since no new ones have formed since I've owned it. Other than re-seat the throat gasket in silicone caulk, the only thing I've done to it is swish some "Goo Gone" around the very edge of the diaphragm. For whatever reason, this improved the sound quality. Possibly it caused the rubber gaskets to moisten or swell; I don't know. It did make for a great improvement in overall bass response, while reducing surface noise. Save for a Waltrip Wondertone rebuild I used to own, it's about the best sounding Orthophonic sound box I've ever had.
JDS