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The Original 10" ESS AMT1 Full Restoration, Alnico Re-cone. Heil Restoration.

zastin17

Active Member
Hi everyone. I have not posted in quiet a while and have been unbelievably lucky and have found tons of amazing finds for cheap. I was on Craigslist 4-5 months back, and saw these old speakers ive never seen before for $150. Little did I know, this cheap purchase would completely end my search for speakers. They simply destroy everything I have ever heared. Martin Logan's, doesn't matter. Never in my life could I be prepared for how good these would sound after the recone.

I got them home, the cabinets where splitting a little bit at the corner seams. The Heil was slightly rusted on the surface, but all the drivers where perfectly preserved. The early Teflon Diaphragms where in perfect shape, and so where the woofers. I gutted the cabinets, glued, and clamped all the seams down with 8+ bar clamps. Then I masked out the pyramid and painted it satin black. One of the Heils had a manufacturing error, Few extra wave guides where thrown into a stack on a tweeter. I removed the putty, and the diaphragm. And tapped around the Heil with a rubber screw driver. Within seconds it broke at the seams into 2x halves. I pried up the stack which was very difficult, uncrimped the delicate, thin aluminum rod crimped on either end. Removed the plates 1x1. Then re-stacked them correctly. Since there where a few extra plates, this gave me some extra wiggle room to re-crimp the aluminum rod. Using a vice, and crimper, I crimped it until it matched the other stack in tightness and size. I reinstalled it into its location, and the Magnet violently ripped it into place, and smashing my fingers between the guides!!:no: So after that incident, I restored the plates using a 3M pad. Look brand new now! Due to the Heil breaking apart so easily, I didnt trust the Old Epoxy, so I decided to replace the Epoxy on the other Heil as well. So I purposely broke the other Heil, and reglued it using bar Clamps, strong feet, and Strong epoxy. Scraped the old glue off when a razor blade. The Diaphragms putty was old and crumbled after removal. I am currently using Blutak to hold each end of the diaphragms place at either end of the Heil, it worked a treat!

I called ESS because I some some questions about my speakers, as I heared they are very helpful. I called, it starting ringing, and a very nice man named Rick answered. Little did I know I was speaking to the CEO of this fantastic company. No front end, no automated "information" line. If you call, you will be talking to the CEO. He answered all my questions. Apparently my diaphragms are made of Teflon, not Mylar like the new ones. and that there is no need to replace with the new replacements as there is no difference in sound. He could have sold them to me and lied, but instead, he said, (if they are working, don't replace them) An amazing trust from ME to ESS Laboratory's is instantly obtained from this. All I can say is the way Rick runs this company is amazing, in terms of the care for the customer, people, and personal, warm way he speakes with you.
He also stated that ESS is like "Burger king" "Have it your way" you send us whatever parts you want, and we rebuilt it and bring it to our current standards. AMAZING!

I wanted to replace the woofers in my AMTs, as the original Alnico cones where pretty poor, worn, and the spider was sagging immensely. He said the new ESS woofers don't work with the early 10inch AMTs, and that they are a different woofer and voice coil entirely. He said if I want the best possible sound, which I've found to be true, to send my Alnico woofers into them, they would remove the Magnet, demagnetize, and then re-magnitized it. And completely recone the woofer using a really nice voice coil and cone specifically made for the AMT1. I got my invoice, paid the $200 flat fee, and they where on there way.
They arrived in their OEM 10inch woofer boxes. It was like unboxing a brand new pair of woofers. The cone is a beautiful paper pulp purple color that I really dig. My AMTs are now like bass cannons when they need to be, the low midrange transition has improved to pure and utter perfection. The transition to the Heil is flawless. Incredibly impact full sounding bass. Doing a sweep, audible down to 30hz with little variation is volume until it drops off. A smaller room drops at about 40HZ. Extremely accurate woofers, but not too boomy or overpowering to the Heils transition. They are incredibly fast. When a low bass note hits them, there is no sense of hesitation next to the Heil.

I also asked why they don't make the 3x way AMT3 Rock Monitors. Its because the newer cones are perfectly capable of delivering those frequencies in a timely matter. The diffrence would be pointless and negligible. But only if the Heil is implemented correctly with the woofer. An ESS AMT exhibiting this issue will have a lower midrange gap, and as if there are 2x separate sources of sound. The larger, vintage 12inch models inherently have this issue more often as the woofer is simply larger. I have tried all the woofers I have seen recommended on forums, ect. and none of them seemed to integrate with the Heil to the perfection the ESS woofer did. I have a ESS Professional Eclipse 2242 Electronic Crossover and Have experimented with a midrange cabinet, lots of different woofers. The best sound I got from these was everything set to flat, the Heil crossed at factory 700hz crossover with the Reconed Alnico, crossover knob set to normal.
You do not want a woofer that is too powerful, or goes to high, as it seems to take away from the Heil. These reconed woofers are truly the only ones I've tried that blended perfectly with the Heil, lots and lots of very fast, impactfull, accurate bass detail. Not boomy, and not too weak. Not too extensive in the mids. Everything is precisely where it should be! There was an obvious break in period. Seems after only a few hours of working them out, the bass extended lower, and the spider/surround felt less stiff. Great! After a few months of music, they now extend even deeper. I use damping in the center of the wall to reflect rear reflection into the center of the room. I had to align the speakers perfectly in the room. Even a few cm off messes with the sound due to their speed.

To this day, they are the best speakers I have ever heard, or owned, period! I will cherish them for the rest of my life, and pass them onto someone that will take care of them, even though I'm young. These speakers are revelations that will never be competed with. Completely within there own category of transparency.

Here are a few SOUND DEMOS

Before
HklrKga.jpg

After Full Restoration!
ewCx9JN.jpg

aRowKAu.jpg

UqOp96q.jpg

SzAR9Cp.jpg

VhfPQ0C.jpg

y1fBzsT.jpg

EarFxaA.jpg

daTRg7K.jpg

bWZfTqh.jpg
 
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That's not a bad price for reconing, especially considering it was done by the original manufacturer. Glad to hear that ESS isn't gouging their vintage customers like some other (*cough* Shahinian *cough*) manufacturers.
 
There is NOTHING like an Air Motion Transformer, but I'd pit the Rock Monitors with their "transition driver" any day against one of the two ways. Rick needs to take advantage of the modern day crop of buttery-smooth full rangers and develop the "Rock Monitor Nuevo."

AMT3Nuevo.gif
 
There is NOTHING like an Air Motion Transformer, but I'd pit the Rock Monitors with their "transition driver" any day against one of the two ways. Rick needs to take advantage of the modern day crop of buttery-smooth full rangers and develop the "Rock Monitor Nuevo."There is NOTHING like an Air Motion Transformer, but I'd pit the Rock Monitors with their "transition driver" any day against one of the two ways. Rick needs to take advantage of the modern day crop of buttery-smooth full rangers and develop the "Rock Monitor Nuevo."
View attachment 1908603
Ive built little full ranges with various drivers like that. The transition driver was the fix for the issue with the very original woofers disconecting with the Heil due to woofer manufacturing limitations at the time, and the unprecedented Heil. They don't do it because it causes more issues with the manufacturing process, and space, than it solves, which isn't mutch at this stage in time, their newest 10inch AMT1 woofer cone is absolutley sublime. I would say extended, crystalline and forward in the lower mids. The original cone was not however, it had a very poor lower mid transition. So did many of the older 12inch models. Not these Reconed AMTs though, these are seamless in sound. And so are the newest models they currently sell which are crossed even higher. If you take a listen to the fairly accurate video, you'd hear the lower midrange is very mutch forward, present and all accounted for, same with the Rock monitors.
Its all because of the limitation and implementation of the drivers at the time they where made. That time has long passed. There is no practical need for a transition driver anymore. But it may make it easier in a diy setup if you want something a bit more seamless without needing to worry about finding ridicuosly specific woofers and crossover components.

You really do need ESS woofers with the Heil to sound correct. I've tried everything, Altec, dayton, goldwood. One 5inch, 2 diffrent 6inch midranges crossed with the Heil at 700hz with the ESS Eclipse 2422 Electronic crossover, woofers at 200hz. The reconed ESS woofers seamlessly blended with the Heil far better than all of the combinations I tried. Everything is precisely where it should be. Far more image coherence and homogenization in a 2x way with the New woofer cones. Little difference could be heared in the lower mids with an added midrange transition box that the setup wasn't worth the result. The new 10inch cone is perfectly capable of handling those frequencies with every ounce of detail available in a very impactful manner. But no other woofer I've tried that was recommended as replacements blended with the Heil so seamlessly near the perfection of the ESS reconed woofer does. Again the original cone does not count, as it was indeed, poor in performance.
 
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A good story and very nice work. I have also had good experiences talking to Ricky. Welcome to ESS Heil ownership. My only speakers for 45 years.
Next project. Try making a Trans Bass module. Another AKer has made these and loves them.

ESS Trans bass 1.jpg
 

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Hi everyone. I have not posted in quiet a while and have been unbelievably lucky and have found tons of amazing finds for cheap. I was on Craigslist 4-5 months back, and saw these old speakers ive never seen before for $150. Little did I know, this cheap purchase would completely end my search for speakers. They simply destroy everything I have ever heared. Martin Logan's, doesn't matter. Never in my life could I be prepared for how good these would sound after the recone.

And Oh by the way. Those diaphragms are quite original. 17 pleats, no silicone rows, no bridal veil. I have a few of those myself. Take good care of them.

I got them home, the cabinets where splitting a little bit at the corner seams. The Heil was slightly rusted on the surface, but all the drivers where perfectly preserved. The early Teflon Diaphragms where in perfect shape, and so where the woofers. I gutted the cabinets, glued, and clamped all the seams down with 8+ bar clamps. Then I masked out the pyramid and painted it satin black. One of the Heils had a manufacturing error, Few extra wave guides where thrown into a stack on a tweeter. I removed the putty, and the diaphragm. And tapped around the Heil with a rubber screw driver. Within seconds it broke at the seams into 2x halves. I pried up the stack which was very difficult, uncrimped the delicate, thin aluminum rod crimped on either end. Removed the plates 1x1. Then re-stacked them correctly. Since there where a few extra plates, this gave me some extra wiggle room to re-crimp the aluminum rod. Using a vice, and crimper, I crimped it until it matched the other stack in tightness and size. I reinstalled it into its location, and the Magnet violently ripped it into place, and smashing my fingers between the guides!!:no: So after that incident, I restored the plates using a 3M pad. Look brand new now! Due to the Heil breaking apart so easily, I didnt trust the Old Epoxy, so I decided to replace the Epoxy on the other Heil as well. So I purposely broke the other Heil, and reglued it using bar Clamps, strong feet, and Strong epoxy. Scraped the old glue off when a razor blade. The Diaphragms putty was old and crumbled after removal. I am currently using Blutak to hold each end of the diaphragms place at either end of the Heil, it worked a treat!

I called ESS because I some some questions about my speakers, as I heared they are very helpful. I called, it starting ringing, and a very nice man named Rick answered. Little did I know I was speaking to the CEO of this fantastic company. No front end, no automated "information" line. If you call, you will be talking to the CEO. He answered all my questions. Apparently my diaphragms are made of Teflon, not Mylar like the new ones. and that there is no need to replace with the new replacements as there is no difference in sound. He could have sold them to me and lied, but instead, he said, (if they are working, don't replace them) An amazing trust from ME to ESS Laboratory's is instantly obtained from this. All I can say is the way Rick runs this company is amazing, in terms of the care for the customer, people, and personal, warm way he speakes with you.
He also stated that ESS is like "Burger king" "Have it your way" you send us whatever parts you want, and we rebuilt it and bring it to our current standards. AMAZING!

I wanted to replace the woofers in my AMTs, as the original Alnico cones where pretty poor, worn, and the spider was sagging immensely. He said the new ESS woofers don't work with the early 10inch AMTs, and that they are a different woofer and voice coil entirely. He said if I want the best possible sound, which I've found to be true, to send my Alnico woofers into them, they would remove the Magnet, demagnetize, and then re-magnitized it. And completely recone the woofer using a really nice voice coil and cone specifically made for the AMT1. I got my invoice, paid the $200 flat fee, and they where on there way.
They arrived in their OEM 10inch woofer boxes. It was like unboxing a brand new pair of woofers. The cone is a beautiful paper pulp purple color that I really dig. My AMTs are now like bass cannons when they need to be, the low midrange transition has improved to pure and utter perfection. The transition to the Heil is flawless. Incredibly impact full sounding bass. Doing a sweep, audible down to 30hz with little variation is volume until it drops off. A smaller room drops at about 40HZ. Extremely accurate woofers, but not too boomy or overpowering to the Heils transition. They are incredibly fast. When a low bass note hits them, there is no sense of hesitation next to the Heil.

I also asked why they don't make the 3x way AMT3 Rock Monitors. Its because the newer cones are perfectly capable of delivering those frequencies in a timely matter. The diffrence would be pointless and negligible. But only if the Heil is implemented correctly with the woofer. An ESS AMT exhibiting this issue will have a lower midrange gap, and as if there are 2x separate sources of sound. The larger, vintage 12inch models inherently have this issue more often as the woofer is simply larger. I have tried all the woofers I have seen recommended on forums, ect. and none of them seemed to integrate with the Heil to the perfection the ESS woofer did. I have a ESS Professional Eclipse 2242 Electronic Crossover and Have experimented with a midrange cabinet, lots of different woofers. The best sound I got from these was everything set to flat, the Heil crossed at factory 700hz crossover with the Reconed Alnico, crossover knob set to normal.
You do not want a woofer that is too powerful, or goes to high, as it seems to take away from the Heil. These reconed woofers are truly the only ones I've tried that blended perfectly with the Heil, lots and lots of very fast, impactfull, accurate bass detail. Not boomy, and not too weak. Not too extensive in the mids. Everything is precisely where it should be! There was an obvious break in period. Seems after only a few hours of working them out, the bass extended lower, and the spider/surround felt less stiff. Great! After a few months of music, they now extend even deeper. I use damping in the center of the wall to reflect rear reflection into the center of the room. I had to align the speakers perfectly in the room. Even a few cm off messes with the sound due to their speed.

To this day, they are the best speakers I have ever heard, or owned, period! I will cherish them for the rest of my life, and pass them onto someone that will take care of them, even though I'm young. These speakers are revelations that will never be competed with. Completely within there own category of transparency.

Here are a few SOUND DEMOS

Before
HklrKga.jpg

After Full Restoration!
ewCx9JN.jpg

aRowKAu.jpg

UqOp96q.jpg

SzAR9Cp.jpg

VhfPQ0C.jpg

y1fBzsT.jpg

EarFxaA.jpg

daTRg7K.jpg

bWZfTqh.jpg
 
Yea they are original! The early ones where made of Teflon while the later version where Mylar. This was simply done for heat resistance. As at over driven at high current, the Teflon diaphragms tended to stick to itself. They do have far more pleats than the new replacements. I did notice that. While the diaphragms itself is held in place with a clear silicon like glue near the bottom and top to keep the pleats aligned and perfect. while the pleats themselves freefloat in the air. According to Rick, he could have lied sold me replacements, but he said not to replace them as they are identical in sound. Haven't personally tried them though.
 
The reconed ESS woofers seamlessly blended with the Heil far better than all of the combinations I tried. Everything is precisely where it should be. Far more image coherent in a 2x way with the New woofers. Little difference could be heared in the lower mids with an added midrange transition box that the setup wasn't worth the result. The new 10inch cone is perfectly capable of handling those frequencies with every ounce of detail available in a very fast manner. But no other woofer I've tried that was recommended as replacements blended with the Heil so seamlessly near the extent of the ESS reconed woofer does. Again the original cone does not count, as it was poor in performance.

I can hear the peak. ;)

Took some doing, but I got rid of it with my diffraction lenses and doing some "creative crossover manipulation" to take advantage of them.

DSC_00171.JPG
DSC_00151.JPG
DSC_00122.JPG
 
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Yea they are original! The early ones where made of Teflon while the later version where Mylar. This was simply done for heat resistance. As at over driven at high current, the Teflon diaphragms tended to stick to itself. They do have far more pleats than the new replacements. I did notice that. While the diaphragms itself is held in place with a clear silicon like glue near the bottom and top to keep the pleats aligned and perfect. while the pleats themselves freefloat in the air. According to Rick, he could have lied sold me replacements, but he said not to replace them as they are identical in sound. Haven't personally tried them though.
Yes. As I have said many times, if your old original diaphragms are working properly, there is no reason to get rid of them. For awhile in the years before Ricky was there, in the early 90s, they used the Dupont product Kapton for the diaphragm substrate. Yellow in color. Is supposed to have higher heat tolerance. Were also single circuit with conductor only on one side of the diaphragm. Cost $30 each back then. I have several pair in use and can't hear a difference. There is a pair for sale now on ebay for the outrageous sum of $300.
 
I can hear the peak. ;)

Took some doing, but I got rid of it with my diffraction lenses and doing some "creative crossover manipulation" to take advantage of them.

DSC_00171.JPG
DSC_00151.JPG
DSC_00122.JPG
Whatcha got going on their? I need to see more! What's it mounted on top of? Also, peak?
 
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Yes. As I have said many times, if your old original diaphragms are working properly, there is no reason to get rid of them. For awhile in the years before Ricky was there, in the early 90s, they used the Dupont product Kapton for the diaphragm substrate. Yellow in color. Is supposed to have higher heat tolerance. Were also single circuit with conductor only on one side of the diaphragm. Cost $30 each back then. I have several pair in use and can't hear a difference. There is a pair for sale now on ebay for the outrageous sum of $300.
I saw those on Ebay aswell haha. They are not even dipole? Wonder if they where for the ESS Bookshelf speakers? Where the back half of the Heil is covered up. I use kapton tape on my 3D printer for the hotend/nozzle. So it's one of the most heat tolerant plastics out there for sure! I've been planning tracing my own diy AMT Diaphram onto Mylar. 3D printing a pleat alignment jig, using silicon to secure the pleats. Really want to build my own experimental diaphram that would fit the Heil. I've built small Planar Electrostatic panels and tweeters before with great results. So it's just a matter of adapting my method. Luckily, I dont even need to buy any magnets, as I have the Heils to use.
 
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Ah, yes. The low midrange peak is very mutch present on these reconed Alnicos for the Heils transition. Here is a video of the ESS AMT1s with both of the Heils compeltly disconnected. Just the woofers are playing. Very crystaline, inert, fast, and very impactfull lower mid peak! :) Very cool btw! So many fun tweaks and experiment's with the Heil.
And another demo with Fleetwood Mac. You can really hear it with headphones.
 
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Whatcha got going on their? I need to see more! What's it mounted on top of? Also, peak?
Toddalin started a very interesting project to mount a wedge deflector directly in front of the Heil lense area. I'm surprised he didn't link the thread to his post. It's called something like Give Oskar a Wedgie. An interesting read and not too difficult to make.
 
The Klipsch guys seem to think there's not really a peek but what your noticing is there's actually a dip in midbass response due to the waveguide opening of the heil not being long enough.
They also go into double stacking the HEIL to extend the low frequency crossover point.

Either way, it's worth reading...

https://community.klipsch.com/index...s-amt-1-with-wings-possible-kit-for-heritage/
The thing about the Heil is it will change in response, and in sound with the slightest change is implementation or position. One room will quiet litteraly make the Heil respond far diffrent than another room would. Specifically the upper midrange. The Heil excels in this area more than any driver I've heared, but if you have them spaced incorrectly or don't give them enouphe air to breathe on the rear. The upper midrange begans to break apart very quickly. The original issue was the dip/disconnect in the transition with the low midrange woofer, and transition to the Heil. The new woofer solved the issue. That was a really common complaint with the ESS AMTs earlier woofers. The true measured response of a correctly implemented Heil does not show an upper midrange dip. Nor can I hear it on my speakers. The AMT1S are the most difficult speaker to place, I have ever laid my hands on. I had to use a measured out string to align the speakers in the room, and to keep a perfectly balance image due to their speed. Reflect onto the rear walls, then onto the damping blanket. The Heil is a strange beast, and gets directly effected by the woofer its crossed with.
 
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Very cool conversation - thanks for all the inputs!
 
I’m seeing a pair of these used and neglected near me for $350 ... pockets itching ... I know they would require work and I don’t have the experience and tools that some of you fellows have.
 
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