Urei 811B schematic help needed

[rusty jefferson]

http://www.jblproservice.com/pdf/Vintage JBL-UREI Electronics/UREI-813B.pdf I have a friend who is starting to build a pair of crossovers for a diy 811B project. The only schematic he could find is attached (last page) and has a few unreadable values. Does anyone have a better schematic, or if you have a pair, could you please check the value of C3 and C4 and let me know? Thanks in advance.

[stephane RAME]

The "C" version
http://www.jblproservice.com/pdf/UREI%20Time%20Align%20Series/811C-L,R.pdf

Stéphane

[rusty jefferson]

Thanks Stephane, but he is looking for the "B" version.

[stephane RAME]

http://www.jblproservice.com/pdf/Vintage%20JBL-UREI%20Electronics/UREI-811.pdf

Stéphane

[rusty jefferson]

Thanks again, but he is looking for the "B" version for use with the 801B Urei drivers.

[eso]

https://dl.dropboxusercontent.com/u/4500648/Audio/811B crossover.pdf

While it doesn't say so, this is the 830 crossover schematic which is the correct crossover for 1 801B duplex in an 811B enclosure. The Crossovers are made in 2 parts with a large umbilcal cord connecting the sections. The time delay section is in the back panel with the signal binding screws and the high pass section, fuses, lights and trim pads are in the front panels. The light bulbs are important too. I'd really recommend going with the 813 with the helper woofer. They really kick.

This might come in handy too: https://dl.dropboxusercontent.com/u/4500648/Audio/UREI driver%3Ax-over matrix.pdf

Here's my 813Bs:

https://dl.dropboxusercontent.com/u/4500648/Audio/813BRepro.jpg

And one of my hardwood horns for these:

https://dl.dropboxusercontent.com/u/4500648/Audio/Rosewood.JPG

eso

[stephane RAME]

https://dl.dropboxusercontent.com/u/4500648/Audio/UREI%20driver%3Ax-over%20matrix.pdf

Stéphane

[rusty jefferson]

ESO,

Thanks very much for the schematic. Just what he's looking for.

Your second link didn't work, however.

I'm rebuilding a pair of 813Cs right now and have been talking to a few people about wood horns for them. I'd like to discuss your horns and will pm you later. Thanks again

[eso]

ESO,

Thanks very much for the schematic. Just what he's looking for.

Your second link didn't work, however.

I'm rebuilding a pair of 813Cs right now and have been talking to a few people about wood horns for them. I'd like to discuss your horns and will pm you later. Thanks again

Try the link now. For some reason it didn't post correctly the first time.

eso

[Earl K]

@ESO ( or Rusty since you downloaded the file some 10 years back from a now dead link )

Would you please attach into this thread the Urei 811B ( or 813B ) schematic ( talked about earlier ).

& Yes, I have the same 813B User manual version with the impossible to decipher C3 and C4 values ( found on the last page ).

Thanks <> Earl

PS; this is nice work ESO ( I'm glad that you eventually posted these pics elsewhere, here on this website > unlike your earlier postings which all went poof!! into the ether )

https://www.audioheritage.org/vbulletin/attachment.php?attachmentid=79369&d=1513354404
https://www.audioheritage.org/vbulletin/attachment.php?attachmentid=79370&d=1513354904
https://www.audioheritage.org/vbulletin/attachment.php?attachmentid=79371&d=1513354999

[hjames]

@ESO ( or Rusty since you downloaded the file some 10 years back from a now dead link )

Would you please attach into this thread the Urei 811B ( or 813B ) schematic ( talked about earlier ).
Suspect this is the one you are referring to that is missing the far right side :

[Earl K]

Suspect this is the one you are referring to that is missing the far right side :

@Heather

Yes Thanks ( though I have that one, as did Rusty the thread starter ).

The missing part of the page ( far right ) isn't really a deal-breaker for me.

The issue(s) are the need for additional confirmation pertaining to the uF values belonging to capacitors C3 and C4 ( which seem somewhat questionable >> without me running some sims ).

:)

[rusty jefferson]

Earl, naturally I didn't do the right thing and download and post it here for posterity, I just copied the links ESO posted and forwarded to my friend. I just sent him an email asking for a copy if HE downloaded it, or to let me know the C3 and C4 values. He still has the speakers so I should hear something shortly.

[Earl K]

Thanks Rusty!!

I really do appreciate your attention to this matter.

:)

[toddalin]

Drool!

https://images.craigslist.org/00l0l_gaGbUjyJNsG_0CI0t2_1200x900.jpg

https://losangeles.craigslist.org/lgb/ele/d/long-beach-speakers-super-urei-811a/7686187550.html

[Mr. Widget]

Drool!

YES!

Very pretty, thanks for posting the pic. I rarely click on links.


Widget

[rusty jefferson]

Earl, Sorry for the delay. My friend hadn't apparently downloaded the link ESO posted but had a couple drawn out schematics. One of them matches the schematic in this link I just found and is legible. The schematic Heather posted appears to be the 813A schematic, not the 813B. Check this link and see if it looks right to you, it does appear to be the 830 network for the 811B. It might be worth a PM to ESO to see if he agrees as he's built several of these I believe. If it is right, perhaps Rob could get it into the library with a link in this thread to it?

https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://robertmelchers.nl/images/robert/luidspreker-boxen/Urei_811B/jbl_urei_811b_813b_815b.pdf&ved=2ahUKEwiT2OqEzNWCAxX8mYkEHVPLCWAQFnoECA8QAQ&usg=AOvVaw2rrG8RlYvFEbrg_NCQ5AkZ

[rusty jefferson]

I just noticed the link I posted a few minutes ago isn't to a JBL Pro or Harman server but a restoration guy in Europe I wasn't aware of.

https://robertmelchers.nl/index.php/nl/

[Earl K]

Hi Rusty,

Thanks Much !! for your efforts.

What you've found here makes more sense for the C3+C4 values in the woofer section ( plus overall, it's a clearer scan of what Heather has posted > which had the added "Helper-Woofer" LP section within it ).

I'm going to model this eventually, once I get given some measurements ( which are in the works but waiting on some HF parts to arrive ).

If it doesn't model well with these updates C3+C4 values ( being 10uF and 14uF respectively ) I'll ask ESO what he in fact used.

Thanks Again!!

:)

[rusty jefferson]

Earl, You are correct, Heather did post the 813B, not 813A schematic. My bad. Too many UREI combinations. :-)

[Earl K]

And now:

Some more pics of eso's spectacular work ( before they get lost in the ether ).

:)

[Mr. Widget]

Absolutely magnificent!

Thanks for sharing!!!!


Widget

[eso]

Here's the parts matrix for the Urei models, and a partially cleaned up schematic for the 840 network for 813B monitors.

There are significant differences in the time correction between each different series from the Altec 604 8G through the full JBL version. There are also other differences in both the LF and HF sections between the 811, 813 and 815 models as the duplex cone does not need to extend as low and the HF section needs less padding with greater woofer output.

I'm also supposed to receive a pair of the earliest 824 networks to upgrade for a customer and reverse engineer while I have them. These were an aftermarket offering for upgrading existing 604E monitors that is a 16Ω version that would time align 604E and earlier goemetries.

BTW, That fiddleback anigre pair of 811A is still available if anyone is interested.

eso

[eso]

Here's a parts list I did years ago for the 840 (813B) network.

In the '00s I did verify this with the former JBL archivist. I think his name was Everett. He was a good guy.


eso

[eso]

Really, I can read... I just now realized that this is asking for the 811B–830 network...

Here's a clearer copy:



eso