ESS amt 1 tower drag home

i heard the AMT towers when they first came out. i spent 3 hours one afternoon listening to nearly every kind of music. afterward, knowing how much they cost then and realizing that my 60 watts per was not going to cut it, i left very depressed for weeks. i had wished they had the B139 oval woofer ESS used to employ in their speakers but the bass extension was still okay, down to about 32 hz..

depressed, i tried to duplicate the transmission line enclosure from a reveal of the inside of the cabinet but failed miserably. what i came to find out is you cannot use just any woofer that fits the hole to substitute for the original. t-lines are matched to the woofer and precisely designed.

looking at the photos of the woofer, i seem to recall that ESS used a woofer from the the first Heil speaker that had a cast frame that resembled the 1044 driver from their earlier speakers (non-heil). these look like stamped frames?

glad to see the OP wants to restore them. some of these legendary speaker wind up in landfills :eek:
 
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NOOOOOOOOOOOOOO! Oh that hurt. Oh well, just have to move on and keep going, how hard and expensive is it going to be for me to find what belongs in here? I'm going to take a look at everything else in there, haven 't done that yet. btw I had to make this tool to get that glued basket out of there. I paid $150 for these so I'm OK spending some $ on them.
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But they do tend to loosen up with use.

I’m curious what the woofers were replaced with.

These speakers can take quite a lot of power! Mine (1aM) were rated for max 275 watts.

What version of McIntosh do you have?

I have the MC7106 and MX130. I can't even find the picture porkloin posted on the internet, probably going to be a while before I find what I need.


what i came to find out is you cannot use just any woofer that fits the hole to substitute for the original. t-lines are matched to the woofer and precisely designed.

looking at the photos of the woofer, i seem to recall that ESS used a woofer from the the first Heil speaker that had a cast frame that resembled the 1044 driver from their earlier speakers (non-heil). these look like stamped frames?

The basket diameter is 10 3/8 inches, the Realistic fit in there just right.
 
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I think I would take a listen with the Realistic woofer in there before shitcanning it. It may actually sound pretty decent. It's not like the original was anything special.
 
What was originally in there, something like this, https://www.amazon.com/ESS-Factory-Replacement-Speaker-689-1012/dp/B00CFOZUS6 (I don't think they are the correct diameter), or the older looking alnicos that Porkloin posted?
It looks like someone did the same thing that those monkeys that assembled speakers for ESS did. A rule of thumb to live by is never use anything that starts out wet to seal a speaker.
Your AMT-1s came with the driver that I pictured above ESS Part # 690-0007. The present driver sold by ESS is not comparable. A more modern replacement would be the Eminence 1040SF, which was discontinued a couple of years back and would be a little difficult to find in the used market. @tarior probably offered the most pragmatic solution, which would be to listen to what you have for awhile. You may actually enjoy it, if you can get beyond the nagging audiophile doubt about the drivers you have not being stock. Tarior was right in that the original was nothing special - I bested them with a new after-market driver (now discontinued also), but they are in a case ported per the T/S parameters of the driver and my enclosure size. Predicting how a given driver would function in a transmission line is a whole different ballgame.

Stock ESS 10" drivers (left) vs. Dayton ST-255-8 - to my ear, it's no competition.

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Dayton ST255-8 (left) vs. ESS # 690-0010. A giant magnet and a stiff suspension made for a good tight musical match to the Heil.

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OK haha, yeah that's going to eat at me. I'm not going to give up on them though. I think what I'll do is take the advice here, refurbish the crossover, clean up a little more and put the Realistics back in until I find a better replacement. I will leave both grills off, fix those in the mean time and only put those back on after I find a better replacement woofer and put those in. I'd be completely lost without this site and the internet as most people would. Here's the crossover btw.
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I've got Rock Monitors with the original (re-foamed, same as what should be in the OP's speakers) drivers, and IMO, they are pretty weak-kneed and bass shy. But then again, I'm comparing them with various JBLs from the same era.
 
Okeeee ....dokeeeee, just those two caps? I'm OK spending $200+ on some good woofers for them, just sayin. It's fun to get good deals but it's not like I'm broke, I just think it's fun finding good deals. Sometimes you just have to pay up and I do now and then. I should be buying a new car but this is more fun. I thought it was unusual the frame diameter cut is 10 3/8 and the cutout is 9.25. I guess a 10" frame would be OK. How about these? https://www.amazon.com/ESS-Factory-Replacement-Speaker-689-1012/dp/B00CFOZUS6 Porkloin, you are saying "these" aren't very good, that the Eminenence 1040SF is better than the 689-1012? https://www.amazon.com/gp/offer-listing/B01A9CF58U/ref=dp_olp_0? ie=UTF8&condition=all Oh OK, yeah I found the tower speaker version, beefier looking, hard to find.
 
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Caps are cheap - replace all three. So are the resistors. Contrary to the penny-wise/pound-foolish nature of the average audiophile ("if it aint blackened and melty......."), resistors are a wear item. Parts Express has cast resistors similar to the ones on the ESS crossover for about $1.38 each. Or you could go nuts and get the Mills wire-wound resistors for $4 - $5 each.
I just noticed the marking "8 Ohm" on your Realistic driver. I believe that the original driver was 4 ohm. If the associated crossover components weren't modified (halve C1, 1/4 C2, double L1, double R1) the Realistic woofers would be crossed over (cut off) at half the frequency of that for the stock 4 ohm woofer, meaning that there would be a bigger midrange gap than the 2-way ESS speakers are already reputed to have. The original C2 and R1 are designed to equalize the impedance of a 4 ohm woofer - I'm not sure what the effect would be on an 8 ohm driver.
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Okeeee ....dokeeeee, just those two caps? I'm OK spending $200+ on some good woofers for them, just sayin. It's fun to get good deals but it's not like I'm broke, I just think it's fun finding good deals. Sometimes you just have to pay up and I do now and then. I should be buying a new car but this is more fun. I thought it was unusual the frame diameter cut is 10 3/8 and the cutout is 9.25. I guess a 10" frame would be OK. How about these? https://www.amazon.com/ESS-Factory-Replacement-Speaker-689-1012/dp/B00CFOZUS6 Porkloin, you are saying "these" aren't very good, that the Eminenence 1040SF is better than the 689-1012? https://www.amazon.com/gp/offer-listing/B01A9CF58U/ref=dp_olp_0? ie=UTF8&condition=all Oh OK, yeah I found the tower speaker version, beefier looking, hard to find.
't know if he'd know it or not as the AMT-1 was before his time, but you may look up ESS-USA and call Ricky and see if he knows their 4 ohm driver to be a good match for your speakers.
 
Caps are cheap - replace all three. So are the resistors. Contrary to the penny-wise/pound-foolish nature of the average audiophile ("if it aint blackened and melty......."), resistors are a wear item. Parts Express has cast resistors similar to the ones on the ESS crossover for about $1.38 each. Or you could go nuts and get the Mills wire-wound resistors for $4 - $5 each.
I just noticed the marking "8 Ohm" on your Realistic driver. I believe that the original driver was 4 ohm. If the associated crossover components weren't modified (halve C1, 1/4 C2, double L1, double R1) the Realistic woofers would be crossed over (cut off) at half the frequency of that for the stock 4 ohm woofer, meaning that there would be a bigger midrange gap than the 2-way ESS speakers are already reputed to have. The original C2 and R1 are designed to equalize the impedance of a 4 ohm woofer - I'm not sure what the effect would be on an 8 ohm driver.
I don't know if he'd know it or not as the AMT-1 was before his time, but you may look up ESS-USA and call Ricky and see if he knows their 4 ohm driver to be a good match for your speakers.

Yeah!, duh, what was I thinking, ...I wasn't. Just contact ESS about it! I will contact them, I already emailed Eminence for suggestions. I think I'll go all out with what you said there, don't see any reason not to for a few more $. But before I go there, I want to find out what kind of woofer I'm able to get, I'll get more fired up about it again if I know I can get a good pair of woofers. And even if the tweeter diaphragms are OK and I end up really liking these, I might as well spend the money and get an extra pair to store, never know when they won't make them anymore.
 
Yeah!, duh, what was I thinking, ...I wasn't. Just contact ESS about it! I will contact them, I already emailed Eminence for suggestions. I think I'll go all out with what you said there, don't see any reason not to for a few more $. But before I go there, I want to find out what kind of woofer I'm able to get, I'll get more fired up about it again if I know I can get a good pair of woofers. And even if the tweeter diaphragms are OK and I end up really liking these, I might as well spend the money and get an extra pair to store, never know when they won't make them anymore.
Not to badmouth Ricky as he's a very friendly, attentive guy, but take what he says with a grain of salt. Your monitors were a bit before his time. I'm skeptical about ESS' documentation on their old stuff - it's just not in their interest to put that much into servicing the vintage stuff as us cheap old vintage freaks aren't the demographic for the pricey new ESS stuff. I think that the AMT 1 monitors are even before Nelson Pass' time.
It may be that you'll have to pursue information from the transmission line gurus and actually one-up OEM, which to me, is a far more noble cause. The common question will be "Who are you to second guess the engineer that built these things?" to which you could answer, "The beneficiary of 45 years of technological forward progress." Computer modeling and testing has become accessible to the hobbyist in the 21st. century. The only limitations are one's gumption and imagination.
It could be that the "pro" drivers that are presently in good favor with ESS guru @automojo may be a good match for transmission line enclosures. Hopefully, he'll see the reference and chime in on this.
 
Porkloin: I like your comparison pics of an original AMT3 vs your updated version. Looks like you replaced your particle board front baffle with MDF and rear mounted your new drivers. I guess the port is relocated as well. Nice clean appearance with beveled cutout edges. Could not have been easy to do. I'm afraid my 3's will just have to sit with refoamed original woofers.
 
I think you got those fairly cheap, shoot, a pair of AMT's alone goes for more than that. You have some room to put woofers in when you find them.
 
OK, well I'm really leaning toward the ESS 4ohm 689-1012. I mean it can't be that "bad". It's probably pretty good, most complaints come from wanting to make "good", better, the nature of us humans. So I may buy those and see if something better comes along later.
 
OP, congrats on getting a worthwhile project, I’ll be following your progress. IMO, it’s well worth the effort. There’s magic in those Heils.

Damn do I want (at LEAST to hear) a pair of Rock Monitors! DAMN! Damn! Damn! :rant:

You’re location shows you’re practically a neighbor to me (in Midwest terms). If you ever get down to Iowa, you are welcome to listen to my pair of Rock Monitors. We also host an AK gathering here in September if you can make it.
 
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