Dynaudio MD100 ferrofluid replacement

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I have these MD100's that spent 20 yrs in a car. I am getting very little sound out of them. They do move and have correct impedance, just make no spl. And maybe even missing some clarity.

Could they have dried out ferrofluid, and if so, can these be opened up and cleaned and new fluid installed ?

Thanks.
Srinath.
 
Oh, they looked great. The mids I pulled from the same car work extraordinarily well. Same doped fabric dome on it too. MD142 is the mid.
That's why I suspected that the position (in the dash) and orientation (face up) took more sun and more abuse than the door mounted mids.
I will check again, maybe find out if any others are having this issue.

Thanks.
Srinath.
 
Hi,

As a last resort there is something I would try before giving up on these speakers as there were well made.

Take some contact cleaner spray (that is rated as safe for plastics!) and spray out the voice coil area. Then try again and if working consider replacing the fluid.

I do not know of any fluid that won't evaporate and thicken over time. Suspect you have motion being hindered by gunk. IMHO.

Regards,
Greg
 
I have a number of the VOlvo c70 tweeters that are based from what I read on the Car audio forums as being a MD-102 Dynaudio unit driver. Man have some of them lived some harsh lives.

But out of the 14 I think I got? I only was able to get 2 of the 14 that were working.

One day, I am going to have to show the failure mode. But the odd thing is? The coil is not burnt. And I don't think the wire is borked anywhere. I think this has to do with something else. But they do measure has having no signal. So I can't tell you why they fail. I am about to unrap a voice coil on one and see if it is a broken lead in the coil, or what. But from what I can tell? It may have something to do with the ferrofluid gumming up and maybe the iron filings rubbing away the insulation on the coil till it breaks through the wire somewhere on the tweeter maybe?

Again, I am no E.E., but I think I can find the problem. Hopefully help some of you fix your gear.

I did order some China Domes to replace them. They sound good. But they are 8 ohms. Not 4 ohms. Also, they just don't sound the same as the Dynaudio Volvo c70 unit I have.

They are so good in fact? I don't think I can go back to anything else. This set the bar for me. So I'm no longer really interested in cheap tweeters anymore. Or cheap drivers for that matter.

I will order some cheap parts to try out, but if they don't meet the level of Dynaudio gear? Forget it.

I would love to order the domes from Dynaudio, but I don't think they sell them. I wish they did. I still have to ask them if they do repairs.


Anyways, love the thread on this. I will post here when I find anything that may help the rest of you keep your wonderful gear working.
 
The ones I have working are decent, but I'm more of a hard dome kind of guy I guess, or ribbon, or horn in some cases. In fact I don't like a few more of the softdomes I have including Marantz, Phillips etc etc either. Not just dynaudio. But yea a whole lot of them are knackered.
Cool.
Srinath.
 
I have unwrapped one coil all the way, and I did not find one break in the coil.
I have ZERO idea what the issue is with these and why they went out.

About the domes I bought. I purchased them on ebay. They are the 28mm domes, and they fit and work great. But are no where near as good as the OEM part. They sound good. But they are not in the same class as the OEM soft parts.

They are also less efficient as well.

They look like these. Mine are at 8 ohms.
1pair-28mm-6-ohm-Speaker-font-b-Voice-b-font-font-b-Coil-b-font-Silk.jpg


The sound is not bad at all. Its just not at the level or clarity or extension of the OEM part.

IMO, they have the same voicing as the the Cheap OEM car domes as the Philips units used by Volvo, VW, BMW, and others.

I really want to get back to fixing my Magnepans. And just stick with new drivers from now on as I have specific goals these days for installs.
 
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