Another ESS AMT-1a pyramid rebuild thread

[Porkloin]

You may have a number mixed up. The AMT-3's were a three way system with a 6.5" cone transition driver between the two 10" woofers and the Heil. If it's any help to your phase cause, the Heils in that model had a 3rd order crossover and were wired phased with the second order crossover woofers. The midrange was second order and wired reverse phase. The manufacturer published that they were crossed over at 250 and 750, but if you plug the numbers into a crossover calculator and work backwards, it looks more like 500 and 2000. It makes me wonder if publishing bogus specs is some form if intellectual property protection and they throw numbers out there for guys that can't be happy with what their ears are telling them.
I look forward to getting out of the present poorhouse and doing a bit of tri-amping with some tubes.

 

[NoTransistors]

Correct, the Heils were in a 2-way system with passive radiator. No mid-range driver.

 

[Porkloin]

If the high pass leg of a 2nd order crossover took the tweeter 180 degrees out of phase in one direction and the low pass leg took the woofer out 180 degrees in the other direction, given that both drivers were wired up the same, would they be in phase, but one cycle off from one another? Which brings up the question: which is more important, phasing or that cycle relationship? What about the bandpassed driver in the middle?

 

[Porkloin]

Like the Heils, the Pioneers are of high sensitivity. Might explain my preference for no attenuation. These odd drivers are the dipoles from AMT-3 2-way speaker systems. I have heard a few speakers from this company, and always thought that the Heil drivers were crossed over way too low. These boxes needed a separate mid-range driver. My stereo sounded dreadful, until I tossed the transistor stuff in favor of the H.H. Scott valve integrated amplifier.
You know what they say about valve amplification? Well, even if you don't, try it once and you'll never go back to transistors.

Something you may look into: A popular phenomena amongst the Heil crowd is to put foam "wings" on the sides of the Heil, with the belief that the dipoled waves getting around the front too early have some interfering effect on the upper midrange. It may be your answer as opposed to phase.
I tried it and couldn't discern a difference, unless I went with the most extreme form, which blocks the side vents. As a big fan of sound squirting in all directions, I didn't like the effect.
Below: An image of the "wings".
Artist unknown.

 

[NoTransistors]

I thought I was the only listener why had to deal with stairs in the 'main room'. In my case, the couch is against the iron railing, and the speakers fire at it from across a narrowish room that has floors of the ugliest Italian-tile. Not like the previous house, with lots of large rooms, lots of space, lots of walls, and lots of carpeting. Replacing the tile with carpet would be great if my dog didn't leak and my birds did not toss food everywhere. Tiles are easy to clean and they get swept/mopped every day.
I may get a Japanese screen to place behind the couch.
Red Bull gives you wings.
Maxi-pads have wings.
And Heil drivers may need wings.
Cute.

 

[Porkloin]

My other dog feels slighted.

Both of my "guard dogs" would happily load the Rock Monitors into the back of your truck for a cheeseburger.

 

[62sunbeam]

Where in LA are you? If you are near Shilpark paint in Hollywood or Marks Paint in North Hollywood go there and get a few Mohawk touch up markers and use them to blend the patches. Van Dyke Brown, brown mahogany and maybe a burnt umber will get you where you want to be. DO NOT get the minwax ones. They're oil based and useless.

If you decide to reveneer let me know and I might be able to hook you up.

Good luck

Eric

 

[13stoploss]

I look forward to getting out of the present poorhouse and doing a bit of tri-amping with some tubes.

I look forward to hearing more about this.

Where in LA are you? If you are near Shilpark paint in Hollywood or Marks Paint in North Hollywood go there and get a few Mohawk touch up markers and use them to blend the patches. Van Dyke Brown, brown mahogany and maybe a burnt umber will get you where you want to be. DO NOT get the minwax ones. They're oil based and useless.

If you decide to reveneer let me know and I might be able to hook you up.

Is this comment for me? I left SoCal in Summer 2013, now living in MD outside DC.

When you say Van Dyke Brown, you pique my alternative photographer heart. I used to make photo prints under the sun with this process...

As soon as I finish painting the top cabinet, I WILL be veneering the cabinets. I've already bought the walnut veneer.

 

[13stoploss]

Gentleman, I present to you ESS' bi-amp goodness: the new-old stock 2241-AM active electronic crossover with fixed 800hz crossover point. This is available, unopened, new-old stock from Ricky at ESS in both 120 and 240. In Winter '12/'13, I paid $125. He had a whole pallet of them in the shop. I guess the more pressing question is How many AMT series speakers were bi-amp'able? The AMT-1a/1b/1c/1d were NOT (the 1e was, but it was developed by ze Germans post-USA sale), and the AMT-3 wasn't either (bi/tri; Rock Monitor was passive crossover only). Plus, what other ESS AMT speakers were both bi-amp and two way and could utilize an 800hz fixed crossover? Thus, is this a product for only one speaker in the lineup?

Manual

 

[13stoploss]

OK, and now for the bi-amp'able AMT Monitor crossover, which I want to translate to the AMT-1a that I am rebuilding:

 

[13stoploss]

AND, for shlts and giggles, I present to you this model brochure, maybe the last that ESS ever produced? I stole this from my old man. In December 1994-1995, on our way to visit friends in Redding, we stopped at ESS in Sacramento for some new AMT Monitor drivers. I guess my dad picked this up then.

 

[Mojo Warrior]

I bi-amped my ESS AMT-1 Towers and believe you me it was worth it. Completely bypass the crossovers, they can only degrade the sound. If you can add a subwoofer you will have a speaker that will beat most anything out there less than $2000. The ESS AMT-1a,b weak spot was deep bass, essential for rock music, unnecessary if you only listen to classical. We sold a lot of them in the 1970s.

Congratulations on scoring the ESS electronic crossover. If it does not work out you can purchase a used Behringer CX2310 2 way crossover form Guitar Center or Musicians Friend for cheaper than the ESS. I am running a Crown XLS 2500 for the woofer, a Carver TFM-6b for the Heil and a Sunfire subwoofer with the Behringer crossover. Very, very clean sound. Great dynamics and punch. And very musical.

 

[Porkloin]

Gentleman, I present to you ESS' bi-amp goodness: the new-old stock 2241-AM active electronic crossover with fixed 800hz crossover point. This is available, unopened, new-old stock from Ricky at ESS in both 120 and 240. In Winter '12/'13, I paid $125. He had a whole pallet of them in the shop. I guess the more pressing question is How many AMT series speakers were bi-amp'able? The AMT-1a/1b/1c/1d were NOT (the 1e was, but it was developed by ze Germans post-USA sale), and the AMT-3 wasn't either (bi/tri; Rock Monitor was passive crossover only). Plus, what other ESS AMT speakers were both bi-amp and two way and could utilize an 800hz fixed crossover? Thus, is this a product for only one speaker in the lineup?

So you're saying that you just picked on up or you picked one up three years ago? I'd like to pick one up just to hermetically seal it and hawk it on eBay in a few years.
The answer to your question: Technically, all of them. It's just a matter of how ambitious one is with a soldering iron. The rock monitor would be easy to actively crossover as it has a pretty good protective capacitor in place for those willing to cross over a bit higher, which is pretty good benefit of that transition driver.
Nice collection of images by the way.

 

[essNeff]

Nice post.......................Thanks for the Pix!!!!!!!!
I did not know that the Monitor came AFTER the AMT-3.
I wonder why the step backward?
I never have heard of the High Dynamic Series either.
I wonder if spreading their product line out so extensively helped lead to their demise.
Enjoy your project and Thanks again for the info!

 

[Porkloin]

Nice post.......................Thanks for the Pix!!!!!!!!
I did not know that the Monitor came AFTER the AMT-3.
I wonder why the step backward?
I never have heard of the High Dynamic Series either.
I wonder if spreading their product line out so extensively helped lead to their demise.
Enjoy your project and Thanks again for the info!

Isn't ESS up and running again, or was it sold to someone else who got to keep the name? The speakers seem pricey enough to absorb the cost of Heil and the fit and finish look a whole lot nicer than the 70's models.
It is surprising that the "transition driver" only wound up in one model.

 

[Mojo Warrior]

Something you may look into: A popular phenomena amongst the Heil crowd is to put foam "wings" on the sides of the Heil, with the belief that the dipoled waves getting around the front too early have some interfering effect on the upper midrange. It may be your answer as opposed to phase.
I tried it and couldn't discern a difference, unless I went with the most extreme form, which blocks the side vents. As a big fan of sound squirting in all directions, I didn't like the effect.
Below: An image of the "wings".
Artist unknown.

I tried this and was not pleased with the sonic results.

 

[13stoploss]

I bi-amped my ESS AMT-1 Towers and believe you me it was worth it. Completely bypass the crossovers, they can only degrade the sound. If you can add a subwoofer you will have a speaker that will beat most anything out there less than $2000. The ESS AMT-1a,b weak spot was deep bass

Disagree. I think 30hz is plenty low, even if it's slower than the Heil AMT. The weak spot has always been the mids.

Congratulations on scoring the ESS electronic crossover. If it does not work out you can purchase a used Behringer CX2310 2 way crossover form Guitar Center or Musicians Friend for cheaper than the ESS. I am running a Crown XLS 2500 for the woofer, a Carver TFM-6b for the Heil and a Sunfire subwoofer with the Behringer crossover. Very, very clean sound. Great dynamics and punch. And very musical.

It works pretty well, actually, but it's limited to 800hz fixed crossover.

So you're saying that you just picked on up or you picked one up three years ago? I'd like to pick one up just to hermetically seal it and hawk it on eBay in a few years.
The answer to your question: Technically, all of them. It's just a matter of how ambitious one is with a soldering iron. The rock monitor would be easy to actively crossover as it has a pretty good protective capacitor in place for those willing to cross over a bit higher, which is pretty good benefit of that transition driver.
Nice collection of images by the way.

I picked it up a few years ago.

Secondly, what I meant was from the factory. That I can tell, only the Monitors had a built-in, from-the-factory bi-amp posts.

I did not know that the Monitor came AFTER the AMT-3.
I wonder why the step backward?

No, the Monitors came before the AMT-3.

The Monitors came from the 70s, sometime after the AMT-1x, but before the AMT-3. I have a feeling not many people used the bi-amp capability of the Monitors. And by then, it was already well-known that they lacked mid-range, so they added the 6.5" driver for the AMT-3, which didn't have a long production run and which wasn't bi-/tri-amp'able.

Isn't ESS up and running again, or was it sold to someone else who got to keep the name? The speakers seem pricey enough to absorb the cost of Heil and the fit and finish look a whole lot nicer than the 70's models.
It is surprising that the "transition driver" only wound up in one model.

I explained this in earlier posts in this thread.

 

[13stoploss]

Nice weather update: four coats!

 

[Porkloin]

Nice. You gotta be happy with that.

 

[essNeff]

Way to go! Nice spray job.
You have some Thirsty lookin' Walnut veneer!
At least a few coats of Tung or Danish oil for them.
Those oils do smell bad though, maybe let them dry outside!