Dried up Ferrofluid?

quincy196 posts03-14-2020 12:44pmThank you George!
My tweeters are Kef pn SP1353.
They do contain ferrofluid.
I am going to attempt a R & R. Seems straight forward.

👍
And if not old enough yet or sounding ok, just like doing preventative maintenance.

I used contact cleaner to FLUSH OUT the old ferrofluid. Paper tape will not remove all the old gunk.

I think even petrol would be fine for the magnet gap, but anything on the voice coil something milder as the coil insulation lacquer needs to be looked after. 

Cheers George

Is all ferrofluid the same or is there different types?

I would use this one from Parts Express (audio parts specialist) you'll know it'll be good quality.
https://www.parts-express.com/ferrofluid-100ul-general-purpose-for-1-diameter-vc--340-540

Cheers George

pops
Thanks George, I believe Thiel does in fact have ferrofluid per Rob at Coherent Sound .

This correlates now with what many older Thiel owners are now finding and starting threads saying their speakers are harsh and/or have no sparkle. Their tweeter have lost a couple of dB’s and hf extension, and are now working very non linearly.

And this happens over time so you don’t even realize the tweeter performance is slowly degrading, and you enjoy your music less and less blaming your own age, your amps, your source ect ect

When all you need to do for $10 and a little labor-love is to clean out and change that ferro fluid in the tweeter.

https://www.speakerrepairshop.nl/en/instructions/replace-ferrofluid-in-tweeter/c-36

Cheers George

Dumb question, do all tweeters have ferrofluid?

No, you'll have to ask the manufacture if your does, it served two purposes, a way of getting heat away from the voice coil via the ferro fluid to the magnet which acts as a heatsink, also it served to damp"oil can" resonance at hf especially in metal dome tweeters.

Cheers George

So, how does one know if their ferro fluid is no longer viable?

The ferro fluid starts getting thicker after 10-15 years, especially in a hot environments or if driven hard, it becomes non linear (distorts) and yes as ljgerens said  looses it's efficiency "sparkle".

Cheers George

Dried up Ferrofluid?

I posted this up 6 months ago, why some were complaining about harsh Thiel tweeters that get non-linear distortions with sticky old Ferro Fluid that’s gone like tar, it has to be cleaned out, just don't add new fluid to a gummed up voice coil gap, you'll be wasting time and effort  

A lot cheaper than buying new diaphragms. $10 for new fluid vs up to $200 each for new diaphragms, and they could be clones/fakes.
Still have to clean out the old fluid doing either.

Tweeter Ferro Fluid and how to change it.
https://www.parts-express.com/ferrofluid-100ul-general-purpose-for-1-diameter-vc--340-540

https://forum.audiogon.com/posts/1843203

https://www.speakerrepairshop.nl/en/instructions/replace-ferrofluid-in-tweeter/c-36

Cheers George