Edison DD reproducer diaphragm link broken

[alang]

Does anyone know how to rebuild the little link string between the membrane and the stylus in a DD reproducer? What material to use for the threads etc? And how do I re-attach it to the membrane? How long should it be? I think I remember reading something a while ago, but I cannot find it anymore. For now I have a modern replacement in there, but I would like to fix the original if possible.
Thanks
Andreas

[JohnM]

I can't answer all your questions, but the linkage is woven silk with brass ferrules on the ends. Since DD reproducers are plentiful, it should be easy and affordable to locate a replacement linkage. Unless you are determined to rebuild it yourself, you may be better served to either simply buy another intact reproducer or to send it off to a competent restorer.

[gramophoneshane]

I've just copied and pasted this here. It's the responce I made to someone with the same question.

Most people seem to use dental floss to make replacement linkages, usually coupled with a new diaphragm.
I've only tried 2 replacement diaphragms. One I purchased off Ebay, and was a laminated cardboard with dental floss which was knotted on the top side of the diaphragm, with a loop to attach to the stylus bar at the other end.
The other was made by a fellow member here, Larry, and it uses some sort of vinyl material for the diaphragm, with a similar linkage as discribed above.
While the ebay replacement performed fairly well, Larry's diaphragm was better, and came very close IMO to sounding as good as an original. In fact, I'm still using Larry's in my A100, and it's still performing well after a couple years. The ebay example now sits in my spare parts box.

It is possible to make a replacement linkage, but it's a loooong & tedious process. I made one about 3 years ago...well, it actually took me 3 goes before I got it right.
I used some very fine wire and the items pictured below- a tassel from a cheap Chinese import shop, and the needle from a cartridge ink refill pack.
First, you have to remove the diaphragm, and then remove the linkage bolt that is attached to the ivory button on the top of the diaphragm. You'll find a tiny nut burried in the button under the shellac used to seal it all together. The diaphragm is extremely fragile, so you have to be very careful dismantling it.
Once that's out, you can start making the silk linkage.
I tried to reuse the original metal thread ends, but managed to split one trying to un-crimp it, and broke the loop off the other.
So, I cut a section off the needle, passed the ends of a U shaped wire through the needle, then drew the thread up into the needle tube. I then crimped it, and aded a drop of superglue to the cut-off end of the silk for extra support (not trusting my crimping skills).
Then I repeated the process on the other end of the silk thread.
I found that I had to make the new linkage a little over 1mm shorter than the original, as the new thread I used stretched under the tension of the reproducer weight.
Whether that could have been eliminated by pre shrinking or stretching the thread Im not sure. Apart from the colour, the tassel thread was identical to the original, and 3 years later, the replacement linkage is still doing service in my L35, and I can hear no audible difference from an original thread.
It is something I hope I never have to do again though.

[alang]

Wow, that sounds really involved. I guess I'll save that task for one of those long winter evenings. For now I have one of those eBay replacements installed, so I'm good. It sounds OK, but the bright white just looks plain ugly.
Thanks for all the information.
Andreas