Big STAX amps, almost there.

Sorted yet?
The other is, but they’re super busy and have not come to get this one to match one to the other. I also have not called to remind them in over one month. This one needs a bias anyway and for the startup sequence to match. But yes, we are talking finishing touches.
They will also be bringing the Levinson 432 back at the same time. It’s fixed.
 
The other is, but they’re super busy and have not come to get this one to match one to the other. I also have not called to remind them in over one month. This one needs a bias anyway and for the startup sequence to match. But yes, we are talking finishing touches.
They will also be bringing the Levinson 432 back at the same time. It’s fixed.

I am sure I am probably missing something......but, if it took this place 3 years to get one amp repaired and it takes them over a month to adjust the bias, why would you take the ML to them??

edit:

Wait, I missed the comment about the ML being already fixed...
 
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very interesting design.
It looks like two individual amps in BTL, inside each of the mono-blocks. Similar to Yamaha BX-1.
Is there another board inside? do you have a few closer shots to those drivers and dual transistors?
You could imagine that close-up shots of the internals of these uber rare birds are pretty much non-existent. You would do the ultimate favor to curious minds by taking and sharing a few more...if it does not too much of an effort.
 
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very interesting design.
It looks like two individual amps in BTL, inside each of the mono-blocks. Similar to Yamaha BX-1.
Is there another board inside? do you have a few closer shots to those drivers and dual transistors?
You could imagine that close-up shots of the internals of these uber rare birds are pretty much non-existent. You would do the ultimate favor to curious minds by taking and sharing a few more...if it does not too much of an effort.

It is exactly as you said, two amps in BTL. This also runs in two classes, about 125 in class A, then to AB. On the bottom side of the amp block, there is another board, looking much the same. I’ll try for more photos of the lower board, but the bottom plate of this amp does not come off. It is 8 mil or so plate steel. Usually, getting to that board requires removing the amp block, which is a standard procedure with these. It is required to bias it properly.
 
I am sure I am probably missing something......but, if it took this place 3 years to get one amp repaired and it takes them over a month to adjust the bias, why would you take the ML to them??

edit:

Wait, I missed the comment about the ML being already fixed...
Many shops have gone under, and they are slammed with biz. I could have pushed to have him come and get this one, and deliver the Levinson, but I’ve been busy. They are good guys and really gone above and beyond to undo some terrible work with all original parts. It’s been like restoring a rare car. He wanted it done exactly correctly.
 
very interesting design.
It looks like two individual amps in BTL, inside each of the mono-blocks. Similar to Yamaha BX-1.
Is there another board inside? do you have a few closer shots to those drivers and dual transistors?
You could imagine that close-up shots of the internals of these uber rare birds are pretty much non-existent. You would do the ultimate favor to curious minds by taking and sharing a few more...if it does not too much of an effort.

Also, check page two of this thread. I had uploaded more close ups of the insides.
 
It is exactly as you said, two amps in BTL. This also runs in two classes, about 125 in class A, then to AB. On the bottom side of the amp block, there is another board, looking much the same. I’ll try for more photos of the lower board, but the bottom plate of this amp does not come off. It is 8 mil or so plate steel. Usually, getting to that board requires removing the amp block, which is a standard procedure with these. It is required to bias it properly.

Thanks,
Yes, I can see the photos on the earlier pages, but I was trying to make out individual components such as the input stage (fet) differential pair(s), outputs, etc
The schematic of this thing would be really an interesting document to study.
 
Thanks,
Yes, I can see the photos on the earlier pages, but I was trying to make out individual components such as the input stage (fet) differential pair(s), outputs, etc
The schematic of this thing would be really an interesting document to study.
I have a copy somewhere.
And next time I’m in it, I’ll get closer pics. Probably next week.
 
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