Urei 813b project

[Robh3606]

One of the last challenges will be sourcing the blue foam for the mouth.

It reminds me of the foam they use too make the pool noodles.

Rob

[Mr. Widget]

One of the last challenges will be sourcing the blue foam for the mouth.

The folks at Foam Trends might be able to help... they seem pretty resourceful and are excellent at attention to detail.

They may be able to fabricate something out of a white foam and tint it... just a thought.


Widget

[speakerdave]

Foundation sill form, maybe? It's nominally 1/4 inch, and folded over it might make about the right outside bend, or you could bend it around a former. Some of it's blue.

[Oldmics]

N.O.S.

Which ones do you need???

Oldmics

[Robh3606]

Hello Oldmics

Can you post a picture of the flip side to see how they attach to the coax driver.

Thanks

Rob

[eso]

N.O.S.

Which ones do you need???

Oldmics

The two on the left. P.M. me please.

eso

[Oldmics]

Ther Ya Go .


Also have these 800 W woofers currently on eBay

http://cgi.ebay.com/ws/eBayISAPI.dll...STRK:MESELX:IT

[Robh3606]

Thanks!

Ok so the metal transition through the pole piece is completely within the pole piece on those horns. You bolt up through the top plate.

Rob

[doodlebug]

Be aware, though, that the cone's spider must be removed in order to mount the horn. The inner circumference of the spider is attached to that large circle where the screws go through the base of the horn.

I'm looking at my 809s right now as I write this. IIRC, the Altec 604 version does the same thing but the spider also has felt on it. Seems to me from the pics of the JBL-based versions I've seen didn't use felt but the more standard spider system.

BTW, on the ALtec 604 versions, the blue horn - sans the foam lips - was glued to the standard mounting base and could be removed without dinking (a technical term that!) with the spider. This is how I ship or move my UREI/Altecs in their box.

Cheers,

David

[speakerdave]

Be aware, though, that the cone's spider must be removed in order to mount the horn. The inner circumference of the spider is attached to that large circle where the screws go through the base of the horn.

I'm looking at my 809s right now as I write this. IIRC, the Altec 604 version does the same thing but the spider also has felt on it. Seems to me from the pics of the JBL-based versions I've seen didn't use felt but the more standard spider system.

BTW, on the ALtec 604 versions, the blue horn - sans the foam lips - was glued to the standard mounting base and could be removed without dinking (a technical term that!) with the spider. This is how I ship or move my UREI/Altecs in their box.

Cheers,

David

The horn in the original UREI version incorporates what looks like the base for the stock 604-8G horn. That is screwed to the pole piece with a spacer and the felt bridges from the cone to the mounting flange of the horn base. The woofer spider is not in any way involved with the mounting of the horn. Are you really referring to the felt?

[doodlebug]

Yes, I was referring to the felt. Frankly, I've never peeked around back of it so made an assumption. Thanks for keeping it straight.

Cheers,

David

[eso]

Have any of you ever built/rebuilt one of the Urei crossovers? I'm having a hard time finding the l-pads as called out in the 840 schematic: 30-25ohm/25watt for the H.F. Trim and Drive and 50ohm/25watt for the Mid trim. Any Ideas?

I was searching around in the archive and most here seem to favor Solen caps. The Urei schematic calls for mostly 100V caps and the Solens are 400V. Is this going to affect any of the desired values?

Also, any input on Resistor types? I'm currently leaning towards Mills 1% from Parts Express.

Have any of you thought about or tried to implement Charge Coupling these networks? Does it sound like a good idea here?

Any input on these items would be greatly appreciated.

******

Playing with these is a big stretch from my years as a low-power-SET-amp-BIG-horn-system guy. Following some guidelines in the Urei manuals I've located a decent sized amp (McIntosh MC2200) and just hooked up the 809s I got for the first time. They're fun. The entire presentation is different from what I've lived with for years now. Even with the little 12" monitors I'm pleasantly surprised by the transient response.

The NOS horns for the 15"s should be here any day, and then I need to get the 800Ws down to Orange County Speaker for re-foaming. It's all about getting the Crossovers built now. The cabinetry for these is a no-brainer.

[Robh3606]

Hello Eso

I have a picture of my 811C crossover. I used Mils ressistors, Solens and Elctrolytics for the large values. I did that network a year or more before we were talking CC networks. I don't see why you couldn't especially on the compression driver. For the pots I used 2 legs of the standard 8 ohm 25 watt pots.

Rob

[eso]

Rob,
That's the crossover with the tapped inductors, isn't it?

[Robh3606]

Yes it is.

Rob