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Roscoe,

Any chance you downloaded those UREI schematics from these links 10 years ago? Someone else at Lansing just asked for the same information you did and those links are dead. Naturally, I didn't download and post the readable schematic there at the time for posterity. If not, can you tell me the C3 and C4 values? Thanks

I’m pretty sure I have it around here somewhere, let me see what I can find….

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I can explain it to you, but I can’t understand it for you.

I've got two different ones, on paper only (that I can find), and C3/C4 are different values, and different places in the circuit, for both...

For this one:

C3 10uf/50v, C4 14uf/50v
For this one:

C3 2uf/50v, C4 32uf/50v.

Roscoe

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I can explain it to you, but I can’t understand it for you.

Roscoe, thank you very much for digging those up. Per our text exchange it does appear the first one is the 830 network for the 811B. I shared that link at Lansing Heritage and we're looking for confirmation from a member there who has built several 811B crossovers with high quality parts.

Which version of the driver was in the 811Bs?

Roscoe

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I can explain it to you, but I can’t understand it for you.

The 'B' Series was the PAS coax woofer (instead of Altec) and the JBL 2425 compression driver (instead of Altec)

An excellent chronology of the 604/UREI development is here:

https://www.technicalaudio.com/pdf/Dupl ... UPLEX.html

Those are the ones I have

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I can explain it to you, but I can’t understand it for you.

Oh, like these? Here's a little 811B porn for you Roscoe.

Not quite in that kind of shape.... Or in such nice cabinets, or as well-built crossovers...

Roscoe

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I can explain it to you, but I can’t understand it for you.

Yeah, that guy does really nice work including making those wood horns to replace the blue plastic ones.