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Thread: Trash find from the mid-80s.

  1. #1
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    Trash find from the mid-80s.

    Howdy! My first post on this forum. I found you all yesterday while I was searching for more info about 3 Urei 539 eqs that I've been using for the past couple of years.

    The forum prompted me to dig out an old speaker that I had since the mid-80s. I found it piled up with some trash at a house a block up from where I was living off-campus. I asked if I could take it, and the man who put it out said sure.

    I haven't found too much info regarding Ampex stuff from this piece's period (not even sure what it's period is...), but browsing here yesterday filled me in on what type of speaker this box has in it. It also might add to the Ampex/JBL threads I read, as well. Yes, it still works and sounds pretty good for a small enclosure.

    If anyone can provide more info, it would be greatly appreciated. I searched for LE8-6 and couldn't find anything....










  2. #2
    Senior Seņor boputnam's Avatar
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    Quote Originally Posted by Superreverb View Post
    I searched for LE8-6 and couldn't find anything....
    I don't know the "-6", at all.

    It looks identical to the LE8T, a "full range" transducer JBL deployed in a number of cabinets. It is a beauty. It is 8 ohms; I see that "-6" is 16 ohms...

    One thing for sure - you're going to need to replace the surrounds on those...
    bo

    "Indeed, not!!"

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    Thanks for the reply!

    Yeah - I figure the surround is probably past its "due date," but it is still relatively supple. The speaker didn't/doesn't get much use. I hooked it up yesterday to test it, though.

    One thing: This speaker has a whizzer cone. Did the LE8T have the whizzer? The one in the hot-linked pic doesn't.

    Regards - Ed


    Keeper of:

    (1) JBL loaded Ampex box
    (1) pr. of L20Ts

    And recently traded away (last week....):

    (1) pair 4691B cabs

  4. #4
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    Here's a post that might interest you

    http://www.audioheritage.org/vbullet...6&postcount=15

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    Senior Member Steve Schell's Avatar
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    Nice score, Superreverb. The history of JBL and Ampex are heavily intertwined. Ampex used JBL speakers in their theatre sound products beginning in 1952 or so, and by the mid '50s they tried seriously to purchase JBL outright. Company owner and president William Thomas ultimately decided not to sell, so Ampex set up their own factory in North Hollywood to build JBL designs on a royalty basis to meet their considerable needs.

    When Ampex began building consumer open reel tape machines, a popular accessory product was a unit that incorporated a small tube power amplifier and 8" speaker. Your speaker may be an accessory unit from the early stereo era; you could probably research it further on some Ampex sites. Over the years there was a wide variety of these Ampex units with various 8" speakers. I'd say you've probably got one of the better ones.

    Here is the Sales Model Drawing of the LE8-6 from the JBL archives; it indicates that your speaker dates to 1965.
    Attached Images Attached Images  

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    Color me jealous

    Maybe I don't do enough dumpster diving! I'm getting a pair of LE-8T today, but not for free!

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    Nice drawing Steve , thanks very much for posting that . I would have guessed that the whizzer varietals would have been gone by then .

    And some more proof ( as I see it ) of JBLs' "Z-speak" / when it comes to their older labelling conventions of a transducers' working impedance .

    >< cheers

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    Older and wiser- a retouch on alnico v. ceramic

    Those aren't 80s but 60s, just for those who haven't picked up on it yet. By early 80s, JBL was making the LE8T-H AFAIK. These generally haven't been as highly regarded as the Alnico versions.

    Is this nostaligic hoo-doo-voo-doo? As I lay wondering this issue last evening, I had some thoughts. The nearly 1/2" top plate of the LE8T, which was required to get the underhang they needed for approx +/-4mm xmax (of course, underhung exceeds this more gracefully than overhung) requires a LOT of magnet behind it. With AlNiCo, they were able to do this in a big honkin' magnet structure. With ceramic, this had to get bigger still, since it's a much weaker material. So, to keep the magnet size and cost down, the silver machined (I'm making an assumption here) shorting ring was traded down for a thinner copper plating on the polepiece. This allowed the polepiece to ride closer to the coil, at the cost of a (slight?) reduction in shorting ring performance. The drawback of demagnetizing is a non-issue in an underhung motor, so that advantage of Ceramic is eliminated, leaving us with just a slightly better motor in all respects.

    This all assumes a change in gap geometry, but at the very least, the shorting material was changed from silver to copper. Silver's a better performer, not only does it have superior thermal and electrical conductivity, but also, silver oxide is an equally good conductor, where copper oxide is an insulator.
    Last edited by badman; 04-22-2009 at 10:23 AM. Reason: clarification

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    Senior Member Steve Schell's Avatar
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    All good points, badman. I haven't seen all the JBL drivers apart, but in the ones I have like the compression drivers the "silver shorting ring" is accomplished with silver plating on the center pole.

    I regard all these 8" efforts at a wide range driver to be descendants of the earliest moving coil cone speakers as used with radios from 1926 on. The early field coil units had a powerful motor, very light seamed paper cone and supple suspension. Such a strong motor will provide thrilling transient response and high efficiency, but also typically a rising response. This is why, beginning with Paul Voigt in the late 1920s, so many have used these speakers with rear horn loading to bring up the low end. When done well the results can be very good, and preserves the undeniable coherence of the crossoverless speaker.

    Earl, whenever you need a Sales Model Drawing of one of these 1960s speakers just let me know. I scanned two complete books of them in the JBL archives, both standard and non-standard models. They don't provide too much information but do provide clues as to manufacturing date and often the customer.

  10. #10
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    Quote Originally Posted by badman View Post
    Those aren't 80s but 60s, just for those who haven't picked up on it yet. By early 80s, JBL was making the LE8T-H AFAIK. These generally haven't been as highly regarded as the Alnico versions.
    Who's doing all the regarding?
    I've never heard anyone complain about an LE8T-H.

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    Man, you guys are fantastic!! I'm soaking up the info, and loving it! I'm a touring live audio guy by trade and the esoterica of gear has always been an interest of mine, especially "vintage" stuff (which is why I prefer my Urei 539s for my personal system as opposed to most newer EQs...)

    And if that is Boputnam in his avatar picture behind the Yamaha desk, I'm wondering if I might have crossed paths with him when the guys I work with play in NorCal.

    Thanks, again, guys!!!

    Ed

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    Senior Member 4343's Avatar
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    Cool

    Quote Originally Posted by Steve Schell View Post
    ...

    When Ampex began building consumer open reel tape machines, a popular accessory product was a unit that incorporated a small tube power amplifier and 8" speaker. Your speaker may be an accessory unit from the early stereo era; you could probably research it further on some Ampex sites. Over the years there was a wide variety of these Ampex units with various 8" speakers. I'd say you've probably got one of the better ones....
    Did any of the consumer tape decks come in a rack mount case? Looking at the cabinet above, it appears to have rack mount "ears", and I'd bet it measures 19" wide. It may have come from a quad video tape recorder console. I have a 3RU stereo set from a 1" Type C VTR, 80's vintage that has a pair of Poly-Planars in it, obviously sound quality was not the priority it once was... I used it for years as a center, mounted in the rack that held up my video monitor.
    Mike Scott in SJ, CA
    Drive 'em to the Xmax!

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    The cabinet does indeed have rack ears. When I had a small Porta-Studio setup in my room at college, the box lived in rack in front of me with a small power amp underneath it. I would use it to collapse the stereo mix to mono to check for phase problems. The last time I really used this speaker must have been around '88. Been hauling it around ever since, but now have a new-found appreciation for it - thanks to y'all

    Regards - Ed

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    Best Regards!

    Quote Originally Posted by 4313B View Post
    Who's doing all the regarding?
    I've never heard anyone complain about an LE8T-H.
    I'm just speaking from my collected info researching these drivers (sold myself on picking up a nice, clean pair from craigslist today). Certainly I don't wish to beat up on the ceramic version, which I'm sure is a very good widerange.

    I'll stick with the AlNiCo myself, since that's what I've got

    Steve:

    Thanks for the insight on the pole pieces. I knew that the compression drivers were usually plated, but was going on the use of the word ring in the product lit. The LE8T-H spec sheet specifies "the pole piece is plated with a copper ring" so it really could go either way, certainly plating is the easier technology, and would explain why the steel oxidizes white on the top plates on some of these older motors- maybe all steel in them is silver-plated (huzzah if so, it'd be like classic JBL to include such a feature. After all, a thin plating isn't expensive).
    Last edited by badman; 04-22-2009 at 01:44 PM. Reason: Resolved foam question

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