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FerroFluid aging

I know the topic has been discussed previously but this one is a tad more specific.

Did B&W use ferrofluid in the 800 matrix (801 - 805's) series (1-3) tweeters?

If they did, is there any known issues with the drying out of the ferrofluid in the 800 series specifically?  Yes I had some Vifa tweets that it happened to, but sadly my 805's died from other causes so I don't know if they would have lasted.

Any info would be appreciated.

troystg
erik_squires
16,245 posts
 

It's easy to tell if you disassemble the tweeter.  The coil will be crusted over with it and need to be cleaned.

troystg OP
5 posts
 

Page 1 section 2, last line on "the drive units" paragraph... It says they are ferrofluid cooled:

 

http://www.troelsgravesen.dk/BW-802s3/802s3-manual.pdf 

troystg OP
5 posts
 

Can the tweeter on the 802 s3 be disassembled?

 

 

knotscott's avatar
knotscott
954 posts
 

It’s easy enough to replace FF if you can open the tweeters up. Did it with my Seas H400 tweeters a couple of years ago, and was surprised that it made an audible improvement once replaced.

Once the voice coil is separated from the magnet, take a piece of index card or folded paper and scrape out the residue from the magnet gap. Refill it with fresh ferrofluid about 3/4 up. It’s useful to have a syringe or squeeze bottle with a fine fill tube for injecting it into the gap. It’s not rocket science, and there are plenty of pics and vids on Google.

 

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