Air Motion Transformers (Heil's) and New Diaphragms

EchoWars · 6th February 2003, 08:54 AM

I have had a pair of ESS Heil AMT's for many, many years. My latest speaker incarnation of them has them biamped with a couple of Dynaudio 20W75 in each cabinet (original woofers and cabs tossed out years ago...)

Anyway, my current AMT's have diaphrams that I bought back in about '82 or so. They have worked wonderful over the years and do not need replacing. However, I have found two much newer AMT's (the big ones, Great Heil's, as the ESS tech's call them) that have no diaphrams. I'd like to tackle another project with new AMT's but I am hesitant...

On another forum someone said that the new diaphrams that ESS sells are crap. More power handling, but bad rolloff after 10KHz. Seems odd to me.

These diaphrams are supposedly mylar or something.

I guess what I want to know is...who has heard the newer style of diaphram that ESS is now selling? Was I simply being bullshitted about how bad they are? How do thay sound to you??

EchoWars · 6th February 2003, 08:01 PM

I know there are guys in here that have experiance with the newer Heil's, so.......

--bump--

halojoy · 8th February 2003, 11:06 PM

I think you have got a point.

But all new things are not better,
but some really are.

So, I guess it could be done either way.
I am not sure, but ....

/halo - not quite sure but almost

SY · 8th February 2003, 11:23 PM

Here's a simple check- see if you can get diaphragm mass or thickness specs from the seller for the replacement parts. Compare it with what you've got. If it's substantially the same, you probably aren't going to have some mysterious HF rolloff. New diaphragms DO need to be worked in before frequency response comparisons should be made.

OliverD · 9th February 2003, 12:39 PM

@EchoWars, thanks for your reply in my transistor replacement thread

My AMT I are about 10 years old and I never had to replace diaphragms, but a friend of mine managed to damage one of his AMTs three years ago. He ordered two replacement diaphragms directly from ESS and first replaced only the damaged one to compare the sound of old and new. As far as I recall it, there were of course differences, but they were subtle and acceptable as his AMTs were also quite old. He then replaced the other one too and let them "burn in" a while. He still likes them and I account the only differences between the sound of mine and his mainly to his electronics.

Nelson Pass · 9th February 2003, 08:18 PM

As I recall the original Heil diaphragms were polyethylene,
not Mylar or Teflon. These later materials were tougher,
but never sounded as good.

The original, best sounding material was made from the
packaging material for airline peanuts, and may still be
in use in the food packaging industry.

EchoWars · 11th February 2003, 02:01 AM

Indeed, at one point I was told by ESS what my 'veiled' diaphrams were made of, but have long since forgotten. Hate to shell out $100 US to see if the newer ones are worth it, but perhaps that is what I may have to do.

As an aside, I can't imagine what it would take to smoke a Heil diaphram, besides some catastrophic amp failure. They get so loud with so little amp power that one would certainly have to be doing something stupid. I have used and abused mine for over 20 years, and they are still ruler-straight and sound like new, yet I have seen many Heil's on eBay with diaphrams that looked like they had been dragged behind a car...

OliverD · 11th February 2003, 03:51 AM

Overloading them is easier if you lower your crossover frequency.

/ AMT-Freak - enjoys his Heil's down to 800 Hz in a two-way setup

EchoWars · 11th February 2003, 10:05 AM

Indeed, I have a two way setup here also, but crossing them at about 2.3KHz, simply because the Dynaudio 20W75's do such a nice job up to that point...

800Hz. Wow...

tomtt · 12th February 2003, 01:36 AM

audio mart (on stateline rd in kcmo)was selling heils with
a pair of gauss 15"z ,x'ed at 800hz with cabnet in late 70s
demo-ed with supertramp's, 'school'
pant leg flappen good.

6th February 2003, 08:54 AM	#1
EchoWars diyAudio Member Join Date: Dec 2002 Location: Left of the Dial	Air Motion Transformers (Heil's) and New Diaphrams I have had a pair of ESS Heil AMT's for many, many years. My latest speaker incarnation of them has them biamped with a couple of Dynaudio 20W75 in each cabinet (original woofers and cabs tossed out years ago...) Anyway, my current AMT's have diaphrams that I bought back in about '82 or so. They have worked wonderful over the years and do not need replacing. However, I have found two much newer AMT's (the big ones, Great Heil's, as the ESS tech's call them) that have no diaphrams. I'd like to tackle another project with new AMT's but I am hesitant... On another forum someone said that the new diaphrams that ESS sells are crap. More power handling, but bad rolloff after 10KHz. Seems odd to me. These diaphrams are supposedly mylar or something. I guess what I want to know is...who has heard the newer style of diaphram that ESS is now selling? Was I simply being bullshitted about how bad they are? How do thay sound to you??

8th February 2003, 11:06 PM	#3
halojoy On Hiatus Join Date: Nov 2002	yes I think you have got a point. But all new things are not better, but some really are. So, I guess it could be done either way. I am not sure, but .... /halo - not quite sure but almost

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6th February 2003, 08:01 PM	#2
EchoWars diyAudio Member Join Date: Dec 2002 Location: Left of the Dial	I know there are guys in here that have experiance with the newer Heil's, so....... --bump--

8th February 2003, 11:23 PM	#4
SY diyAudio Moderator Join Date: Oct 2002 Location: Austin, TX Blog Entries: 1	Here's a simple check- see if you can get diaphragm mass or thickness specs from the seller for the replacement parts. Compare it with what you've got. If it's substantially the same, you probably aren't going to have some mysterious HF rolloff. New diaphragms DO need to be worked in before frequency response comparisons should be made.

9th February 2003, 12:39 PM	#5
OliverD diyAudio Member Join Date: Nov 2002 Location: Germany	@EchoWars, thanks for your reply in my transistor replacement thread My AMT I are about 10 years old and I never had to replace diaphragms, but a friend of mine managed to damage one of his AMTs three years ago. He ordered two replacement diaphragms directly from ESS and first replaced only the damaged one to compare the sound of old and new. As far as I recall it, there were of course differences, but they were subtle and acceptable as his AMTs were also quite old. He then replaced the other one too and let them "burn in" a while. He still likes them and I account the only differences between the sound of mine and his mainly to his electronics.

9th February 2003, 08:18 PM	#6
Nelson Pass The one and only Join Date: Mar 2001	As I recall the original Heil diaphragms were polyethylene, not Mylar or Teflon. These later materials were tougher, but never sounded as good. The original, best sounding material was made from the packaging material for airline peanuts, and may still be in use in the food packaging industry.

11th February 2003, 02:01 AM	#7
EchoWars diyAudio Member Join Date: Dec 2002 Location: Left of the Dial	Indeed, at one point I was told by ESS what my 'veiled' diaphrams were made of, but have long since forgotten. Hate to shell out $100 US to see if the newer ones are worth it, but perhaps that is what I may have to do. As an aside, I can't imagine what it would take to smoke a Heil diaphram, besides some catastrophic amp failure. They get so loud with so little amp power that one would certainly have to be doing something stupid. I have used and abused mine for over 20 years, and they are still ruler-straight and sound like new, yet I have seen many Heil's on eBay with diaphrams that looked like they had been dragged behind a car...

11th February 2003, 03:51 AM	#8
OliverD diyAudio Member Join Date: Nov 2002 Location: Germany	Overloading them is easier if you lower your crossover frequency. / AMT-Freak - enjoys his Heil's down to 800 Hz in a two-way setup

11th February 2003, 10:05 AM	#9
EchoWars diyAudio Member Join Date: Dec 2002 Location: Left of the Dial	Indeed, I have a two way setup here also, but crossing them at about 2.3KHz, simply because the Dynaudio 20W75's do such a nice job up to that point... 800Hz. Wow...

12th February 2003, 01:36 AM	#10
tomtt diyAudio Member Join Date: Aug 2002 Location: kansas city mo, and on occasion, around the world ... Blog Entries: 15	audio mart (on stateline rd in kcmo)was selling heils with a pair of gauss 15"z ,x'ed at 800hz with cabnet in late 70s demo-ed with supertramp's, 'school' pant leg flappen good.

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