ESS AMT-1B restoration

saabracer23

Super Member
About a month back I received a random text from a number that I didn’t recognize. All it said was “do you want these speakers? Free” along with a photo of a portion of a speaker where I recognized a Heil AMT driver. I immediately texted back and then received a call. It was a nice older gentleman, they belonged to his wife and they were not being used. He said the surrounds went years ago and they’ve been sitting in a room since then unused.

I showed up to their house the following day where the husband showed me some of his other gear and I helped him lift and hook up his Pioneer CS-99As in his work shop. He poured me a glass of light lager from his kegerator and we sat outside and talked for a bit. He enjoyed talking audio, as did his wife. She was hesitant to let the AMTs go, one because she etched her social into each cabinet lol. I told her that she could trust me, and she could have of course, but I did end up using my knife to scratch the numbers from the backs of the cabinets. I also told her that if it made her feel better that I wasn’t taking them to flip them, that I planned to restore them and that she could come by to listen when she wanted to. I doubt I’ll hear from them again, but the offer stands.

anyways I got them home and in front of the garage. Took some pics to show my brother my new find.

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Quite the difference in veneer! First thing to take care of was the drivers and passives. I bought surrounds for the woofers and ended up buying new passives from ESS.
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I ended up buying a crap load (about 4,000 ft) of military surplus Teflon insulated silver coated copper wire of various sizes. I put some of it across this bar to hang so I had easy access and these speakers are my first use for it. It’ll be used throughout the cabinets.
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So next were the crossovers. All of the electrolytics were replaced with Audyn Q4 metallized polypropylene capacitors and the single sand cast resistor was replaced with a quality Ohmite. There were several push on clip connections on the crossover and to the drivers. All connections including to the drivers are now soldered.

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One down one to go.
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Dan
 
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Both crossovers are now finished. All of the silver coated wire was twisted as I’ve read it helps keep a clean signal. I went wayyyy bigger on the wire. It looks like they used 20 awg throughout and maybe 22 awg to the tweeter. I stepped it up to 14 awg on the input to the crossover, 16 awg to the woofer and 18 awg to the tweeter.
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Here is the crossover mounted into the cabinet on top.

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Here I have the wire coming through the hole on top for the tweeter. As I mentioned the original was about 22 awg and I stepped it up to 18 awg. I could barely get it to squeeze through the hole. It was seriously some work.

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The 14 awg coming through the bottom to the speaker terminals. I’d like to at some point out better ones in, likely to accept banana plugs. The originals were push on connected, now soldered.

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Soldered to the woofer terminal.
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Here is an example of how much bigger I went with the wire. This is the new 14 awg I put in vs the 20 awg that was in here originally. This was for the speaker terminal to the crossover board.
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Quite a size difference. Is the original ESS wire silver coated too? I didn’t get any pics, but I replaced the original stuffing with shredded denim cotton insulation. Love that stuff.

Next was cabinet clean up. All of the corners were scuffed and the paint had been removed.

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I got some oil based paint pens from the art supply store and they work a treat on black speakers.

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Dan
 
After getting the paint work done I wanted to take care of the veneer. The veneer was actually in very good shape, it just looked pretty thirsty.

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I grabbed my jar of Odie’s Oil and went to work. I apply this oil using a white colored scotch brite pad. This lightly sand it which cleans the veneer and gives it a decent full sheen. I love this oil, if you can try it out. A little goes a long way. This bottle will last me forever.

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While I was buffing the cabinets my little buddy was helping me out.

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I let the oil sit for about 30 minutes and then did a final buffing. Then they moved in next to the XPL200As. Don’t worry, the amps sitting on top are sitting on top of a 2” thick piece of Ultra touch denim insulation. The XPL cabinets are just fine.

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For testing purposes I hooked them up to a
Yamaha PC9501N power amplifier. Has more than enough power to drive these. And they sound MAGNIFICENT!!! I was a little worried about the crossover of a 12” 2 way (12” woofer being ran up to 1000 Hz), but they do sound quite good. They’re missing a bit of the midbass punch that the XPLs have, but overall can hold their own. They won’t be replacing the XPLs, but I’ll be proud to run them!

Here is all of the original wire removed from the cabinets.

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Got the original manual too!
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Considering doing the grill material with a standard black material. Thoughts? Would it be a crime to remove the original material when it’s in great shape?

Dan
 
Very nicely done. Very nice crossover work. And they were in very clean condition to start with. And of course, nothing beats free. Had you considered just replacing the passive with a flat disc kit what is I'm sure what it originally had? My grills are original like yours. They match the rest of the speakers in the collection and I'm good with that look. I do think that black would be a sharper more modern appearance. ESS sells the whole replacement grill in black, but its pricy. In any event, enjoy these. I think its a great speaker.
 
...My grills are original like yours. They match the rest of the speakers in the collection and I'm good with that look. I do think that black would be a sharper more modern appearance. ESS sells the whole replacement grill in black, but its pricy. In any event, enjoy these. I think its a great speaker.

That's exactly what I did for mine. Got those free too from a guy who neglected them, they needed a complete restoration, I even had to fabricate new emblems : https://goo.gl/photos/HRJonKUKSTucWXgb8

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That's exactly what I did for mine. Got those free too from a guy who neglected them, they needed a complete restoration, I even had to fabricate new emblems : https://goo.gl/photos/HRJonKUKSTucWXgb8

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I looked at your photos. WOW! and OMG! What beautiful work! You even upgraded the circuit breakers. But the logos. Never saw anybody do that. You even sewed the grill cloth. And yes. I think I like the black better. I have 2 pair of AMT1a's with original grills and overall, the speakers are in decent condition. But not like yours or the OPs.
 
... You even upgraded the circuit breakers. But the logos. Never saw anybody do that. You even sewed the grill cloth.

Thanks for the good words. Whenever I restore legends like these I try to go as far as I can. For these, I would say that I rebuilt them, litterally, they were in such a sorry state that i could'nt let them go to the junkyard (which was indeed their fate).
 
As a fun fact, these ESS AMT1s were stored in the attic of the very house where lived Lionel de Wandonne, the captain who arrested Jeanne d'Arc (Joan of Arc) on May 23rd 1430, thus leading to her being burned after a faked trial. You can see some beams of this attic on the first picture of my album. But this is another story...
 
Considering doing the grill material with a standard black material. Thoughts? Would it be a crime to remove the original material when it’s in great shape?
No, I'd do the same. IMO the original grille material is stuck in the 1970s, and it belongs there. The 70s were not exactly the height of fashion (speaking as someone who lived through them)..
 
Thanks for the good words. Whenever I restore legends like these I try to go as far as I can. For these, I would say that I rebuilt them, litterally, they were in such a sorry state that i could'nt let them go to the junkyard (which was indeed their fate).
What is the product you used to fill in the broken out cabinet corners? Looks like you were able to blend it very well with the wood grain.
 
What is the product you used to fill in the broken out cabinet corners? Looks like you were able to blend it very well with the wood grain.
I used wood filler and let it harden for two days. When completely cured I carefully sanded it and I applied cherry wood stain on it with a small brush.
 
Great work on the AMT's, I am restoring 1Bs also and noticed your configuration for the crossover. Looks like you kept the connector length which you soldered the caps and resistor to. How did you get the caps to attach to the original board? did you use hot glue and do you think they will stay in place without zip ties ? Hadnt thought on how to position the caps, standing them up does solve my dilemma on how to fit them on the board.
Thanks.
 
Great work on the AMT's, I am restoring 1Bs also and noticed your configuration for the crossover. Looks like you kept the connector length which you soldered the caps and resistor to. How did you get the caps to attach to the original board? did you use hot glue and do you think they will stay in place without zip ties ? Hadnt thought on how to position the caps, standing them up does solve my dilemma on how to fit them on the board.
Thanks.

First I wouldn't want to hijack saabracer23's post, so if admin prefers, we can start another thread.

Now, to answer your questions, I used hot glue. However I preferred to cut fresh MDF boards to replace the original masonite ones, which were really tatty in my opinion : https://photos.app.goo.gl/mKP6YSpk1NpmJNHb8

Also, I paid attention to coils orientation relative to each other to minimize mutual induction.
 
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