Replacement tweeter diaphragm/coil

[Eichberger]

I am thinking about replacing one of the tweeter diaphragms in a pair of B&W DM11 speakers i have been playing with and wondered if anyone has had any success doing this?
I have seen someone on Ebay selling them for quite a few old units but they aren't cheap and i have no idea if they are quality parts.

 

[swechsler]

If the parts are OEM then they should be the same quality as the originals. But if yours still work, why are you looking to replace them?

 

[Eichberger]

One of mine has a very low output. I thought originally it was the crossover but i re-capped them and the same tweeter was low. I have swapped them over and even swapped the magnets so i'm pretty sure it's the coil.
The parts aren't OEM unfortunately - i don't think you can get them for the TW 26's anymore. I have just found some cheaper diaphragms on Ebay but they are from China so not sure on the quality of them either - They are cheap enough for it to be worth a punt mind.

 

[Nat]

Dried up ferrofluid maybe?

 

[swechsler]

Dried up ferrofluid maybe?

I don't think these use it. There's been lots of discussion on AK regarding the tweeters from the DM-600 series, since, being aluminum, they appear to be a magnet (yes, I know that aluminum is non-ferrous) for damage. No recommended solution has been found. There are Chinese manufacturers that sell supposed replacements of just the dome and voice coil, so that's a bit more of a difficult fix compared with the B&W replacement, which just screws on and is obviously NLA. The difference with the Chinese version is that it uses a cloth surround rather than foam like the original. While I do have a dome that's creased, it otherwise still works OK, and I'm not willing to damage the tweeters to try the replacements, since with those, there's no going back.

I know that none of the above really helps much, but unless you can find someone selling correct NOS (new old stock) replacements, I'd say that the Chinese versions are your only hope. If the replacement is a full diaphragm, where you just unscrew the old and apply the new, you probably don't have much to lose except the cost. Theoretically with eBay you can get your money back if they won't work properly, but with the long shipping times I've been seeing lately from overseas sellers, there's a decent chance that the return period will run out before you receive them.

 

[Eichberger]

Yes, i think these 80s tweeters were pre-ferrofluid. I swapped the magnets anyway and the fault followed the voice coil.

I think you're right @swechsler , the Chinese option is about all I've got. The one tweeter is so poor it is worth the risk. As far as i can see from reading a few posts on the matter, it is a bit of a fiddly job. There seems to be a few different opinions on the right glue for these old silk domes but i'm not even sure that the replacements will be the same material. Plenty of time for research though with those shipping times!