The Diaphragm Goddess from Heil

The Diaphragm Goddess from Heil:

I had the pleasure of dining at the Nelson Pass household this week and told Nelson’s charming wife that once again the subject of Heil Air- Motion transformers has cropped up on the web.

There is only one person who ever was better versed in the particulars of ESS Heil Air Motion Tweeters and not surprising Oskar has nothing to say on the subject.

Nelson’s wife worked with the late Oskar Heil from 1972 on, first building the AMT diaphragms and later testing and passing judgement on each and every tweeter that came out of production. This was how she got to know Nelson, who was employed in R&D, and was responsible for the test setup.

According to Jill Pass there was an incredible variation in tweeters both with respect to performance and material choices. Each tweeter represented over 5 labor intensive hours to create and rejects ran upwards of 50 percent

Jill muses that the best diaphragms showed less than +/- 0.5 dB on the test bench. Without exception these were made of aluminized polyethylene from the airline food industry (peanut wrap), with one to three edge folds glued together. Jill had a private stash that tested perfect; these went to select friends. Absolute worst were later constructed of Teflon.

During those few years ESS went from two guys in a garage to a 20 million-dollar company with 300 employees.

With a bit of urging from the forum, I’ll bet Jill would be willing to tell us which transformers are hot. Might even flesh out some ribald stories concerning Nelson.


Cyclotronguy :p