Ferrofluid questions

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Doublej

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Ferrofluid questions
« on: 9 Apr 2017, 07:15 pm »
I have a few questions about drivers with ferrofluid. I ask because there are lots of decade + old speakers out there that can be had for a seemingly great price but how do you know what you are purchasing.

(How) can one tell if a the ferrofluid in a driver is dried out or drier than when when it was new? Is there any measurement that indicates the state of the ferrofluid in a driver?

Will the ferrofluid in all drivers eventual dry out? Over how many decades?

FullRangeMan

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  • All Tweeters look like a target, then shoot them!
    • Never go to a psychiatrist, adopt a straycat or dog. On the street they live only two years average.
Re: Ferrofluid questions
« Reply #1 on: 9 Apr 2017, 07:37 pm »
By what I know ferrofluid was used only in tweetzzz in the past century, the fluid had a time life by time/years not by used hours, w/years the fluid will dry.
The oil fluid will aged after some years, how much I dont know.
The fuid was to colling purposes only, so when they figured a better colling it was no more used.

nickd

Re: Ferrofluid questions
« Reply #2 on: 17 Apr 2017, 04:07 am »
Older tweeters that are fluid cooled will often sound dull or burn up after a few years. As I understand it the fluid gets thick/dirty and some evaporation or leaking is possible.

The old fluid can be removed and the gap cleaned out. You do need to know how much new fluid to install when rebuilding. Much like oil in an engine, there is a correct amount. There are some rebuilders that offer the service if you search around.

The easy way is to replace the tweeters if you can find the exact replacement from the manufacturer. Although that can be expensive (I.e. Dynaudio or Scanspeak)

andycsb

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Re: Ferrofluid questions
« Reply #3 on: 17 Aug 2017, 07:12 pm »
Hello. Anyone know if it could...instead of dullness... go the other way and sound piercing and bright. Thanks.
« Last Edit: 17 Aug 2017, 09:00 pm by andycsb »