• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Another ESS AMT-1a pyramid rebuild thread

I tried different compounds for filling grooves and pits on the various types of wood on mine. As essNeff pointed out, automotive filler ("Bondo") gives the best results and costs the most. I tried some 20 minute joint compound ("mud" to wallboard guys) mixed thin in some of the grooves. It was easy to sand, but definitely needs a good couple of coats of primer as it's kind of porous. Sand the areas to be patched with 60 grit. I also tried that Durhams Rock Hard Water Putty with the muscle man holding up the logo on front. It took a lot of elbow grease to sand, so apply sparingly. It shaped better on my curved surfaces than the joint compound did.
I also cheated a bit by using flat black spray on the final coat without sanding. Too smooth and shiny demands better prep work. Flat black hides stuff better.
I'm curious to hear about the German crossover if you find info. A good search of the term "AMT-1 biamp" pretty much leads to your YouTube video.
 
Last edited:
Get a load of this crossover over at eBay. How refined looking is that, compared to the haphazard tributes to crappy 70's manufacturing in my old crossovers? I take a small amount of solace in the fact that at least they varied the orientation of the coils when they built mine.
 
Last edited:
Porkloin said:
Get a load of this crossover over at eBay. How refined looking is that, compared to the haphazard tributes to crappy 70's manufacturing in my old crossovers? I take a small amount of solace in the fact that at least they varied the orientation of the coils when they built mine.
Click to expand...
At least they got the wiring color matched.
That Xo is for the birds...............CHEEP........CHEEP......CHEEP......CHEEP!
 
13stoploss said:
Went to 320, then 400, then 600, and got a near-mirror shine. So hopeful. Why do you build me up Buttercup, baby, just to let me down and mess me around?

23458981695_12c195a988_b.jpg


23432871386_babc92c9e7_b.jpg


So. Here I go. Gonna scrape it all down again with the heavy stuff. Primer like I should have in the first place. Then sand and wet sand.

Addicted? Yes, I'm in it for the long haul. I've basically decided to sell all my other speakers (AMT Monitors, Klipsch Forte I w/Crites goodies) and focus on perfecting these.

Anyone have any info on those German-made AMT-1e bi-amp'able crossovers? :rolleyes::biggrin:[/QUOTE

Welcome to "THE WONDERFUL WORLD OF SAND THROUGH"!!!!!!!!!!!!!!!!
Ain't know one who's never done it!!!!!!!!!!!!

Back to the Drawing Board.
Round Two coming up.
Click to expand...
 
essNeff said:
At least they got the wiring color matched.
That Xo is for the birds...............CHEEP........CHEEP......CHEEP......CHEEP!
Click to expand...
Easy for the guy with with the fancy-do-everything active crossover complete with pedigreed murderous guard dog to say.
Of course, I'm always a little overly impressed with nice PC boards when held up against hot-gluing components to a piece of chip board and calling it good. It takes your comment to remind me that those are some tiny caps and probably thin gauge wire on the coils. I only wish I had the gumption to convert my entire crossover to a big PC board rather than my partial approach with the caps on a prototype board.
 
My other dog feels slighted.
What's wrong with Hot glue?
We could all be a little thinner.............like those coils and hook-up wire!
 

Attachments

  • IMG_0904.JPG
    IMG_0904.JPG
    52.5 KB · Views: 51
  • IMG_0768.JPG
    IMG_0768.JPG
    114.4 KB · Views: 56
  • IMG_1079.JPG
    IMG_1079.JPG
    88.7 KB · Views: 55
Porkloin said:
Get a load of this crossover over at eBay. How refined looking is that, compared to the haphazard tributes to crappy 70's manufacturing in my old crossovers? I take a small amount of solace in the fact that at least they varied the orientation of the coils when they built mine.
Click to expand...

I emailed that guy last night. He's only got one, and he said he'd get a pic of the other side soon. I don't know how to read it or make sense of it...

essNeff said:
My other dog feels slighted.
What's wrong with Hot glue?
We could all be a little thinner.............like those coils and hook-up wire!
Click to expand...

My first thought, those wires!

BTW, looking at your pics, what are the common or specific values of ESS AMT model inductors? I haven't been able to locate that info...
 
essNeff said:
Here's the schematic:
Click to expand...
The only way I could figure to make that biam-able with the flip of a switch would involve two switches and the addition of your 45uF capacitor. My brain is on the verge of visualizing doing it with one DPDT switch, but I'll probably have to set up a visual aid on the computer and tinker with it.
 
I have been following this thread with interest. Someone donated a set of Heil drivers to me about ten years ago. They have been perched on top of my stacked Pioneer CS-99A since then.
Each crossover is nothing more than five Sprague 1.0 Mfd 600 Volt model 730P [dry] capacitors paralleled together. They sound extraordinary.The room the stereo was in before was smaller, so the crossover needed to have a 10 Ohm resistor. Even though this new listening area is much harder, I needed to eliminate the resistor as the room is bigger, and the new Scott amp is infinitely less pronounced in the highs than the previous amp, a Van Alstine MOSFET amplifier. I have got to say this about Frank Van Alstine- he builds things to last. But I guess that HH Scott did as well, as my Scott is 25 years older than Frank's baby.

And BTW, how does one phase the Heils to the 'push-pull' paper cone drivers?
 
Last edited:
Porkloin said:
The only way I could figure to make that biam-able with the flip of a switch would involve two switches and the addition of your 45uF capacitor. My brain is on the verge of visualizing doing it with one DPDT switch, but I'll probably have to set up a visual aid on the computer and tinker with it.
Click to expand...

Maybe this shows my automotive engine-swap roots, but why not just switch crossovers?

(btw, at work, so didn't/couldn't view the PDF)

Last night, I looked at my AMT Monitor crossover and the old, original, now-empty AMT-1a crossover board and--surprise surprise--they're the same size. And, we already know the two speakers use the same Heil AMT, the same 12" driver, and the same 12" passive radiator. On paper, they handle the same power, though for some reason, the AMT-1a is 91db and the AMT Monitor is 93db (the 1a has a mid L-Pot, the Monitor does not). I could just solder in some new hookup wire to the AMT Monitor crossover to cover the increased mounting distance inside the AMT-1a, and voila! Bi-ampable AMT-1a!

Right?
 
Bump, as I still need my question answered about proper phasing of these wierd tweeters to the cone speakers that reside in the wooden box below.
 
13stoploss said:
Maybe this shows my automotive engine-swap roots, but why not just switch crossovers?

(btw, at work, so didn't/couldn't view the PDF)

Last night, I looked at my AMT Monitor crossover and the old, original, now-empty AMT-1a crossover board and--surprise surprise--they're the same size. And, we already know the two speakers use the same Heil AMT, the same 12" driver, and the same 12" passive radiator. On paper, they handle the same power, though for some reason, the AMT-1a is 91db and the AMT Monitor is 93db (the 1a has a mid L-Pot, the Monitor does not). I could just solder in some new hookup wire to the AMT Monitor crossover to cover the increased mounting distance inside the AMT-1a, and voila! Bi-ampable AMT-1a!

Right?
Click to expand...
Yeah, why not? As long as the impedence on the woofer is the same, the crossover should work. But, as I've been stressing and essNeff has been practicing, you should have a protective cap in line with the Heil. It may behoove you to (actively) cross it over a little higher than the 900 Hz that the capacitor crosses it over at just to try and get as far from the effects of passive components that biampers work to avoid as you can.
But I could be all wet here - I've never seen a schematic of the Monitor crossover. I've only looked at photos and determiined, from what i could see, that the biamp terminals bypassed the crossover altogether.
 
NoTransistors said:
Perhaps no one here has an answer to the question, as it was certainly not meant to be rhetorical.
Click to expand...

I know next to nothing about designing cross-overs, but if it's wrong, you'll get a huge suck-out in the cross-over region. If reversing the leads eliminates or minimizes it, you're good. (measured at 1 to 2 meters)
 
NoTransistors said:
I cannot tell the difference with these things. They do not follow the rules of piston-type speakers.
Click to expand...

It sounds like you are using them like ESS ELITE'S except crossed over much higher.
I don't think I could listen to a Heil without at least some attenuation. (no L-pad)
(Although I don't know the sensitivity ratings of your Pioneer's.)
.
The Pioneers look like pretty nice vintage units.
 
Last edited:
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.
 
You must log in or register to reply here.
Back
Top Bottom