Question! are these cabinets original JBL4520?

[OLDGEN]

here are some pictures about two pair of cabinet.
I have not seen original JBL in my life, but I always wanted a pair of original.
I have found a guy who has these pairs of JBLs??? , but I can not decide, are these original JBL4520 or not.
I hope here on the furom the "EXPERTS" could see on the details, about the cabinets.
Please help!

[OLDGEN]

the 6.

[scott fitlin]

They could be, they appear to have had the bottom pedastals removed. The rear bracing inside the scoop flare appears the same. The angle of the board where yours says JBL appears the same too.

Heres the JBL catalog picture for comparison>>>>>>


http://www.lansingheritage.org/image...pro/page08.jpg

[scott fitlin]

Your pair appears to have had a second skin built on to them, which tells me, besides the casters, these moved around alot.

Not that I don't like scoops, I love em, Can you get to hear these fiirst?

Just to make sure they dont rattle and buzz!

What do you wan to do with these?

You might have wayyyy too much fun with them, they are PUNCHY AS HELL!

Oh, yeah, the drivers? JBL, yes?

If you need new woofs, 2226H works damn fine in these! Real good!

[Fangio]

It's been a while that I have seen originals in person but would dare to doubt it.. at least for one pair, obviously the 2 pairs are built with a different angle for the panel below the woofers.

The seller himself doesn't claim to offer originals and stated the constructors are unknown. They have 2226H's (german ebay ad).

[Hoerninger]

Maybe this is of any help:
http://www.audioheritage.org/vbullet...ead.php?p=9995
___________
Peter

[scott fitlin]

It's been a while that I have seen originals in person but would dare to doubt it.. at least for one pair, obviously the 2 pairs are built with a different angle for the panel below the woofers.

Your right!

I just went back, originally Im studying the pair in the 1st pic, now, Im scrolling between 1 and 2, and THERES A BIG difference in the angle of the panel under the woofers.

Doesn't mean they wont work though, back in the days EVERYONE cloned these things!

[subwoof]

(1) Originals were particle board ( at least the pro 4520/A ) with some internal panels made of plywood ( never baltic birch )
(2) They had a riser
(3) Material was 1" thick, doubled all around front edge.
(4) Precise routed cutout on lower back for the passive ( IE: 3110A ) Xovers on the singles and most doubles - this had a plate with push terminals supplied. NOBODY who cloned them did this..
(5) No handles anywhere
(6) Different internal bracing over the years so no "one" style is correct.
(7) Internal panels were dado'ed into the sides - look for sloppy fit ( hey - it was the 70's ).
(8) Real scoops have more chips that chocolate cookies within 1 year of use. And suck up moisture like a sponge ( wood gets pregnant ). look at the joints.

I also made a boatload of clones and used all screws to assemble ( factory had staples ).

sub

[demon]

whoever made them, they just look so happy..!





mikey

[jcrobso]

I have seen some copies and they just don't look like that. John

[OLDGEN]

I have decided, I leave this "copies".
I will finish my D31050 copyproject, I will load 4 2231A

[OLDGEN]

I want to install into the cabinet 4 2231A and I want to use 2440A with 2395.
my new question, which xover could be good for them?
or if somebody can post a drawing of xover

[scott fitlin]

Gee, lens horns, straight front loaded horns, IF you put the scoops under the 15in front loaded horns you would have SCOTTSTACKS!. Just like the stacks in my corners at Eldorado!

[Fangio]

...4 2231A and I want to use 2440A with 2395... new question, which xover (-point?) could be good for them?

Nice project and tasty design so far. Hope some experts can advise on your question.

Now that you've hijacked your own thread it would certainly give some of us pleasure to see a new one, with the full story and completion of these. Or perhaps the mods could split it later.

Are these a customized copy of a JBL/Altec cabinet, or? Which plans were you using?

[OLDGEN]

Are these a customized copy of a JBL/Altec cabinet, or? Which plans were you using?[/QUOTE]

i have book about the old enclosures, and I have made almost a similar than JBL 31050, bunt only the bass side, and I have leaved the horn side, because I hope th 2395+2441 could be better for my tube system.
I have the actual amplifier, a EL156 Singele Ended monoblocks with fully telefunken old tubes and with two rectifier circuit (450volt/280volt) with 850 watts output transformers and 550 watts powertransformers. I know this is overdimensioning, but for the bass need a big output trax.
the sound is amazing, it is not a chinese garbage! oldstyle german sound!