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??
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??
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.
@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.
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.
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.
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.
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...
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...
I had a buddy who worked there in the late 70's. He is actually the one who suggested I get the studio monitors that they had after he put a couple of the small Heil's into his AMC Pacer. Sounded great, I was hooked. Bought the Heil's and have considered my midrange and high-end covered ever since, though I have gone through many versions of woofers trying to find a match...
Have crossed mine over at a variety of freq's, and the Dynaudio/Heil combo sounds best letting the Dynaudio's do the work up to 2300 or so (it should, the Dynaudio's were hella expensive).
///kinda suprised anyone remembers Audio Mart from back in the day...
Have crossed mine over at a variety of freq's, and the Dynaudio/Heil combo sounds best letting the Dynaudio's do the work up to 2300 or so (it should, the Dynaudio's were hella expensive).
///kinda suprised anyone remembers Audio Mart from back in the day...
RTR woofers? Hmmm...by 1986 I was in Boise, ID. In the 70's the only decent woofers McGee had were Eminence, and they left a bit to be desired.
My buddy was Steve Galpin(sp?) Used to play in a local band, and I ran their sound. He was drummer, about 5'10'' or so, a bodybuilder, and a cool guy. Always wondered what happened to him...
My buddy was Steve Galpin(sp?) Used to play in a local band, and I ran their sound. He was drummer, about 5'10'' or so, a bodybuilder, and a cool guy. Always wondered what happened to him...
I was browsing the forum for some information on magnet material in my AMTs just to discover someone asked me a question about my speakers!
Hope you don't mind me taking about a year to reply:
It's an active 24db Linkwitz-Riley XO since the woofers I'm using are great until about 800 Hz but have a large peak soon after 1 kHz, so... Also helps to reduce the load on the AMTs. Finding a low frequency counterpart for these tweeters is a tough job and I've seen many bad sounding speakers (including the original ESS). Having tried many expensive drivers I think you should definitely go two-way and let the AMTs play as low as possible.
Now for something completely different:
Does anybody happen to know what magnets they used in the old AMT-1 (the big ones)? I can only measure dimensions, but what about the material?
Hope you don't mind me taking about a year to reply:
It's an active 24db Linkwitz-Riley XO since the woofers I'm using are great until about 800 Hz but have a large peak soon after 1 kHz, so... Also helps to reduce the load on the AMTs. Finding a low frequency counterpart for these tweeters is a tough job and I've seen many bad sounding speakers (including the original ESS). Having tried many expensive drivers I think you should definitely go two-way and let the AMTs play as low as possible.
Now for something completely different:
Does anybody happen to know what magnets they used in the old AMT-1 (the big ones)? I can only measure dimensions, but what about the material?
Not sure if this is the BEST place to purchase them, but it is A place...
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=14993&item=3070017491&rd=1&ssPageName=WD1V
Hope the link works. If not, search ebay for "heil diaphragm". By the way, I have never used them and do not have any information on the differences between the various incarnations of the heil diaphragms. It is a source, though...
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=14993&item=3070017491&rd=1&ssPageName=WD1V
Hope the link works. If not, search ebay for "heil diaphragm". By the way, I have never used them and do not have any information on the differences between the various incarnations of the heil diaphragms. It is a source, though...
new heil diapragms
i have just obtained a replacement set of d/phragms from the west coast of the states and they sound just like the originals in my 1980 AMT'S from ESS..I obtained them as spares to my original that still work fine..(all are teflon/mylar units..I cant tell any difference in sound quality..
Steve in nz
i have just obtained a replacement set of d/phragms from the west coast of the states and they sound just like the originals in my 1980 AMT'S from ESS..I obtained them as spares to my original that still work fine..(all are teflon/mylar units..I cant tell any difference in sound quality..
Steve in nz
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