It's business as usual - all systems fully operational throughout Covid lockdowns. No account needed to shop.


Your Basket is Empty


Ferrofluid Tweeter Repair Kit

For restoring old tweeters.

APG O87, an ester based fluid with a saturation of 250 Gauss and a viscosity of 750 centipoise. Manufactured by Ferrotec USA .

Other available formulations, contact us for details:

CDF 2250 (Ester based): 220 Gauss, 500 cP

APG 1134 (Hydrocarbon): 220 Gauss, 1000 cP

These are the specific fluids used by major drive unit manufacturers.

Beware: some unscrupulous sellers are offering the cheap, commonly available science project type ferrofluid as an audio product. This results in an overdamped output and can soften drive unit adhesive - always double check the origin and the specification.

Ferrofluid is a cooling / damping compound used in the magnetic gap of many tweeters to increase power handling and smooth out the frequency response; it has a tendency to thicken with age, gradually reducing tweeter output to zero. Many old tweeters from the 1980s/90s can be restored to perfect working order by carefully dismantling and cleaning out the old coagulated fluid then replacing with fresh.

This refill kit comprises a high accuracy syringe pre-filled with Ferrofluid specifically formulated for high fidelity tweeter application. There is sufficient in the syringe for 2 tweeters & a micro applicator nozzle is supplied.

Willys-Hifi Ltd, the UK speaker specialist.

Helpline 01702 523999