ESS AMT replacement diaphragms

[Sjef]

I know there are guys out here using the AMT-1 tweeter, so please help.

I have bought a pair of old AMT-1 tweeters but they don't even nearly sound as good as my Jordanow Ribbon/horn tweeters wich tend to have a lot more airyness and micro detail.

The sound is kind of rough, gritty and harsh compared to the Jordanows, (even after a DEQX calibration) although it is dynamic it is not exactly "as clear as light". Actually they remind me a lot of the Electro Voice T-35 tweeters.

Is that the way they sound ? or could it be that the diaphragms need replacement. I tried searching the net about aging of the diaphragms but could not find any usefull information. I have also heard that ESS used different kind of materials for their diaphragms troughout the years, is that true and would the newer ones be better ? Anyone any experience on that ?