• Please note that Audiokarma will be offline briefly for updates early on Monday morning, September 28th.

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

I've been listening to them since last night. All day today, as I worked outside with the screen door open so I can hear it. They don't go down as low as I would like, and I'm hoping the Misco's will go down lower and fill the low mids bettter. My stepdaughter was here yesterday, and she thought they sounded great! And they do. Avril Lavigne SK8TR BOI is my test song for lows.

And, because I am like a squirrel, I also pulled out the Infinity 1500s I got last week for the cabinets. I have 4 X 8 inch B&W woofers that like a port. I just need to find tweeters that physically fit in the Infinity's. Then I can play with them as well.

I haven't opened up the ESS yet. I'm enjoying listening to them too much.
 
I've been listening to them since last night. All day today, as I worked outside with the screen door open so I can hear it. They don't go down as low as I would like, and I'm hoping the Misco's will go down lower and fill the low mids bettter. My stepdaughter was here yesterday, and she thought they sounded great! And they do. Avril Lavigne SK8TR BOI is my test song for lows.

And, because I am like a squirrel, I also pulled out the Infinity 1500s I got last week for the cabinets. I have 4 X 8 inch B&W woofers that like a port. I just need to find tweeters that physically fit in the Infinity's. Then I can play with them as well.

I haven't opened up the ESS yet. I'm enjoying listening to them too much.
Sure-from about 250-to 500 they should have a bit of a bump-given your cabinet volume (guessing 1.25 cu ft) -so I'm thinking they should fill the lower midrange nicely.
You should get a little extension in the bottom end-the limiting factor is the cabinet volume.
The FS is 28hz-and a impressive impedance curve...just like old school woofers.
I always liked the bass boost on my Proton AP1000
10db@40hz is perfect for sealed speakers.
 
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.
I agree
Nice work
But what other woofers have you tried?
Seems you skipped that part.
I agree the AMT1 and its 10 is a better match to the Heil the a 12 “ woofer...but even a 10” midrange would issues in the crossover range... becoming a bit directional for one...
IMHO it more of the slight dip in the midrange of the Great Heil 2-ways wasn't a big issue for a lot of people buying these speaker in the past.
That’s why they stuck with 2-ways.
No practical need, in avoiding the mid deep would ideally be a 8” woofer that could cover the mids better, or a 3-way, with larger woofers.
In my experience, many modern drivers clearly out perform these vintage drivers, even reconed ones.
The advantage is this driver was made with the cabinet in mind, and the crossover ( hopefully) designed with the woofer electrical properties in mind...which in part goes away with a new voice coil, suspension and cone.
So in part, you effectively replacing this driver.
Regardless, like to hear the other woofers you tried, pics if possible- thanks.
 
Last edited:
I've been listening to them since last night. All day today, as I worked outside with the screen door open so I can hear it. They don't go down as low as I would like, and I'm hoping the Misco's will go down lower and fill the low mids bettter. My stepdaughter was here yesterday, and she thought they sounded great! And they do. Avril Lavigne SK8TR BOI is my test song for lows.

And, because I am like a squirrel, I also pulled out the Infinity 1500s I got last week for the cabinets. I have 4 X 8 inch B&W woofers that like a port. I just need to find tweeters that physically fit in the Infinity's. Then I can play with them as well.

I haven't opened up the ESS yet. I'm enjoying listening to them too much.
So-did you ever get the woofers installed.
Hopefully they are "akin" to the Eminence 1040sf's
The detail, depth of response-and textures and tones-well I haven't really heard bass this good before in such detail.
Certainly not from plastic cones.
But even the Dayton ST255-8's while very good-lacked the quickness and texture of detail.
They had more of a clean bass sheen to them-sort of like a poly cone-a bit "slow sounding".
Too much damping from those rubber surrounds.
It's amazing-even listening to a good FM station.
These definitely give the Heils a run for their money with super detailed low distortion bass!!
Just listening to a live track of my bother in laws 90's band-and the bass lines-was like standing right there by the amp-pretty cool stuff.
My wife was equally shocked as well!;)
I gotta get my "Super Set" done (same woofers)-can't imagine them being able to0 best these beast-but in audio-like life-no firm absolutes!
 
Last edited:
So-did you ever get the woofers installed.
Hopefully they are "akin" to the Eminence 1040sf's
The detail, depth of response-and textures and tones-well I haven't really heard bass this good before in such detail.
Certainly not from plastic cones.
But even the Dayton ST255-8's while very good-lacked the quickness and texture of detail.
They had more of a clean bass sheen to them-sort of like a poly cone-a bit "slow sounding".
Too much damping from those rubber surrounds.
It's amazing-even listening to a good FM station.
These definitely give the Heils a run for their money with super detailed low distortion bass!!
Just listening to a live track of my bother in laws 90's band-and the bass lines-was like standing right there by the amp-pretty cool stuff.
My wife was equally shocked as well!;)
I gotta get my "Super Set" done (same woofers)-can't imagine them being able to0 best these beast-but in audio-like life-no firm absolutes!

@automojo I did.

The Misco drivers are a little smaller than the originals, and I am going to have to figure out a way to fill the gaps, because my AMT 4s are no longer sealed. And they sound much better. The mids and lows are much better. Deeper, more full would be descriptors I would use.

My wife and stepdaughter also think so. Earlier this week, my contractor came over to do some more work. He comes by about once a month. He is working to pay off a system I put together for him. Win-win for both of us. The speakers I sold him are Tangent RS8 and they sound excellent. But he was fascinated by the AMT4s so I gave him a quick demo after he finished for the day. He also really liked them.
 
@automojo I did.

The Misco drivers are a little smaller than the originals, and I am going to have to figure out a way to fill the gaps, because my AMT 4s are no longer sealed. And they sound much better. The mids and lows are much better. Deeper, more full would be descriptors I would use.

My wife and stepdaughter also think so. Earlier this week, my contractor came over to do some more work. He comes by about once a month. He is working to pay off a system I put together for him. Win-win for both of us. The speakers I sold him are Tangent RS8 and they sound excellent. But he was fascinated by the AMT4s so I gave him a quick demo after he finished for the day. He also really liked them.
I'm glad you really like the new Misco woofers and that everyone else does as well. Yeah. I found out about the slight size difference between the ESS stamped basket woofers and other 10 inch woofers when I needed to buy the outer cardboard gaskets when I was refoaming a pair. I had never actually measured them and the gaskets I bought from simply speakers just didn't cover the entire circle.
So I called SS and they said that's because your ESS woofs are really 10.25 inches in diameter and we only sell a gasket that fits a 10 inch frame. So I measured mine and sure enough, 10.25 inches. DUH!!!
So I had to space the 4 gasket quarters around the frame with little gaps in between. Looks OK from 5 feet away at 100 miles an hour.
 
That's great!
Surprising how more modern woofers really improve ESS AMT speakers.
I think alot has to do with a more power motor system.
Interesting on the size issue.
The AMT3's use standard spec 10" woofer frames-even the bolt holes are the same.
Hopefully Misco will make a equivalent 8ohm woofer at some point.
As it would easily be the go to woofer for AMT3's
They only draw back is at some point they will need a refoam.
But the quality of sound-IMHO is work it..
Even if they were cloth surrounds-most last about as long as a good foam surround till they become either stiff, or sloppy (gravity issues) and cause voice coil rub.
The knock on the Dayton ST255-8 was they would sag with their Snaoprene surround and have to be realigned.
Seems alot of people are also happy with the ESS woofer-if they fit-so if Misco does get a nice 8 ohm version out there-ESS refurbers are set.
 
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
Great Job! Very impressive.
I have a pair of AMT-1's that my stepmother was going to put out on the curb *GASP*
I've had them for about 20 years now and am about to send them back to ESS for a full refurb as they desperately need it.
I have been looking for a power amp that will give them what they need to sound as good as they possibly can.
Probably going to use them as rear channels in a 5 channel surround system, possibly with goldenear triton 5's as the front mains (if i can ever afford them).
One of AMT-1's has a woofer that isn't putting out any sound. Hopefully they are the original woofers and ESS will give me the same treatment they gave you :)
Cheers...and again, great job!
 
Great Job! Very impressive.
I have a pair of AMT-1's that my stepmother was going to put out on the curb *GASP*
I've had them for about 20 years now and am about to send them back to ESS for a full refurb as they desperately need it.
I have been looking for a power amp that will give them what they need to sound as good as they possibly can.
Probably going to use them as rear channels in a 5 channel surround system, possibly with goldenear triton 5's as the front mains (if i can ever afford them).
One of AMT-1's has a woofer that isn't putting out any sound. Hopefully they are the original woofers and ESS will give me the same treatment they gave you :)
Cheers...and again, great job!
Most any power amp worth its weight will do the job. I did try my McIntosh MC2205 with mine and it wasn't a good match. My Yamaha M-40 can manage, but more power of that type (such as from an M-70 or M-80) would be better. I am using my Bose 1801s for my currently hooked up big speakers.
 
Great Job! Very impressive.
I have a pair of AMT-1's that my stepmother was going to put out on the curb *GASP*
I've had them for about 20 years now and am about to send them back to ESS for a full refurb as they desperately need it.
I have been looking for a power amp that will give them what they need to sound as good as they possibly can.
Probably going to use them as rear channels in a 5 channel surround system, possibly with goldenear triton 5's as the front mains (if i can ever afford them).
One of AMT-1's has a woofer that isn't putting out any sound. Hopefully they are the original woofers and ESS will give me the same treatment they gave you :)
Cheers...and again, great job!
CoreyU. First, welcome to AK! Plenty of people here follow ESS products. I am wondering what you will send back to ESS? If the Heils are working, no need to change the diaphragms, but that you can do yourself. So the xovers and the woofers. If you can post some pics of the woofers, we might be able to tell you if they are original. If they are not original, I don't know if ESS will touch them. In that case, there are plenty of good aftermarket choices. I would say an amp of about 200 wpc continuous would be a good choice to operate these cleanly to their potential. Make sure your 2amp fuses are correct. Good luck with your project.
 
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.
Can you please repost your videos?
Thanks
 
Back
Top Bottom