ESS AMT-1D schematic/upgrade?

[speakerdoctor]

Can anyone confirm the attached schematic is indeed for the original -1D model?
I have read ESS upgraded the -1D. Can anyone provide information on the upgrade? Particularly any schematic that may exist.
Thanks,

 

[JohnL]

I'm a bit of a historian on the AMT stuff and I have that schematic in a folder marked AMT 1D crossover. I see your copy has 'old schematic" marked on it, maybe it is the original before any upgrade.

 

[speakerdoctor]

I'm a bit of a historian on the AMT stuff and I have that schematic in a folder marked AMT 1D crossover. I see your copy has 'old schematic" marked on it, maybe it is the original before any upgrade.

Sorry John. I wrote that stuff on there and should have mentioned up front to disregard it.
So, I guess from your post this is the 1D xover. I'm going to rebuild some damaged ones and just wanted to know if there indeed was an upgrade and details on the design. On one of the original boards I have, there are (were) two 10 ohm resistors wired in series to make the 20 ohm bypass around the woofer's 100 uf cap. However, the board exploded right in the area of the two 10 ohm resistors. There's just a black hole left there.
Any ideas on what might have happened? Is this a familiar problem with the 1D?

 

[JohnL]

Well, my guess would be too much power. I'm really not so much an electronic circuit designer. This crossover uses some things outside the normal highpass, low pass, zoebel and l-pad stuff, but if things are fried that's typically too much power. I've not heard of this being a common issue.

 

[Inductor]

To make a good repair I would change both Res. in both speakers, and look at stepping up the Watts. Maybe the recommended 400W (lower than 4ohm@100Hz) was the culprit.
(note: I'm not the rights owner of the imp file)