Proac Ribbon Tweeters Damaged

Weird. 

DC leakage on the amps won't cause this, because usually the tweets are protected by a capacitor. DC leakage would fry the woofers.

So, if you are _sure_ the issue is in the tweets, it's not DC, but it could be high frequency oscillation, which is hard to detect without a scope.

@gnoworyta,I use the same amp with my D48R and after your thread I am getting a bit worried. Did you try the amp with another set of speakers, if you have them? Did you switch off the complete system, wait for a few minutes (maybe an hour, etc), unplug the cables and connect back everything and try again? I am suggesting based on the good points that Erik is asking you.

Another possibility, in addition to those that have been mentioned (especially the possibility of an ultrasonic oscillation), is that a fault in the amp is causing a large but very brief transient at turnoff. (I assume, btw, that you are turning the components on and off in the proper sequence -- amp on last and off first).

I once had a high powered solid state amp, in that case a Threshold S-300, which developed a problem that caused it to put out what seemed like nearly a full power transient for a fraction of a second, about 20 or 30 seconds or so after it was turned off. In that case the transient was clearly audible, and produced visible movement of the woofers, but if such a transient is brief enough it might not be audible and might have sufficient high frequency content (corresponding to the rapid change in amplitude) to damage tweeters.

Also, what preamp and what phono stage are you using?

Regards,
-- Al

You may want to check for any DC offset at the amp speaker outputs.
Wondering, are the ribbon tweeters fuse protected? 
My MG 3.5’s have the ribbons fused. Additionally as others have mentioned, the ribbons are  fragile  and can be damaged by excessive air bursts from external sources. Could it be that someone has vacuumed cleaned the speakers?