Yes and I hear that the heil tweeter went through changes of material over the years. I believe these are the first searies with paper rather than milar or what. They should be a little softer sounding than the ones that came after. ESS has started making this speaker again but they call it the ESS Limited Eddition. The new woffer and passive are different now and may provide an inprovement in low frequency as well as blending the transition from the woofer to the heil. They have my attention for sure.
None of them were made of paper.
The earlier ones (Great Heil) where a bit clearer, then the later Teflon Mylar/screen versions.
The AMT3's where unique in that they had more pleats, and a bit more SPL, then say the AMT1 or Tower.
Some like the early versions, some the later.
They key is when replacing to make sure they are the same type, as there can SPL differences.
All versions can handle the same crossover points if they are the same size.
Using a transition driver between the woofer and Heil is the best way to get the most out of a ESS Heil.
But the 1a is a great speaker.
The ADS may be accurate, but the ESS is more musical IMHO.
I enjoy a few models of locally made DLK speakers.
The are very accurate, and I love 'em, but my AMT3's (2 pairs) are my preference most days.
Not sure how they will sound with the Dynaco.
The more low end power (and amp damping) you can get, the better IMHO.