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oldsoundz
05-08-2009, 11:15 AM
Recovered these from a pair of homebuilt Karlson enclosures. Found coupled with the a 16 ohm n2400/075 upgrade.

What can you guys tell me? No model number label like I've found on other early Lansings. Are these cones original? STEVE, WHERE ARE YOU!? I think I've determined these were built in 47-48 (Venice tags).

Is the handscribed number the serial? Were these speakers built by Jim?

oldsoundz
05-08-2009, 11:21 AM
a couple more

John
05-08-2009, 11:21 AM
I would vote non jbl. :blah:

but they look old or stored with out any care that they deserved.:(

oldsoundz
05-08-2009, 11:45 AM
You mean the cones don't look JBL?

By the way... these speakers came out of the studio of the late Dale White III, actor on the Jack Benny show, and also has credit attributed to the soundtrack for the show.

JBL Dog
05-08-2009, 11:51 AM
You mean the cones don't look JBL?

By the way... these speakers came out of the studio of the late Dale White III, actor on the Jack Benny show, and also has credit attributed to the soundtrack for the show.


Those are definitely aftermarket cone kits (Waldum??, or, however it's spelled).

oldsoundz
05-08-2009, 12:15 PM
Those are definitely aftermarket cone kits (Waldum??, or, however it's spelled).

Waldum? I'm not familiar, at all. Are they an old company? What are they known for?

JBL Dog
05-08-2009, 12:36 PM
Waldum? I'm not familiar, at all. Are they an old company? What are they known for?

I have the spelling wrong, it's Waldom. They make aftermarket kits for use with a number companies. If the part number on the backside of the cone starts with a "W", it's a Waldom kit. They've been around for years.

oldsoundz
05-08-2009, 01:00 PM
Thanks Dog!

Too bad. I was hoping they were original of course:banghead:

Any idea as to why there are no id labels for model and serial#?

Any cone kits that would be appropriate exist?

JBL Dog
05-08-2009, 01:20 PM
Thanks Dog!

Too bad. I was hoping they were original of course:banghead:

Any idea as to why there are no id labels for model and serial#?

Any cone kits that would be appropriate exist?

The only factory JBL kit that you may be able to get away with is a C8RE120. edgewound or Giskard are the guys that can advise you on this.

Steve Schell
05-09-2009, 11:04 AM
Oldsoundz, you have a pair of what I call "flat back, no hole" Venice D-131s. At the time Jim Lansing only had two or three employees, and was doing much of the work himself, so he most likely had a hand in these. His business was located in the Marduardt Aircraft plant in Venice from some time in early or mid 1947 to mid or late 1948, when he moved with Marquardt to Van Nuys.

Slightly after your drivers were built, while Lansing was still located in Venice (I think), he began venting his motors with a hole through the back plate. Those would be "flat back, with hole." Hal Cox, who knew Lansing, told me that Jim had mentioned that the idea to vent out the back had come to him in a dream. All of these early motors were constructed from pipe and plate; the sand cast motors were introduced as a cost reduction in 1953.

AFAIK those hand-scratched numbers were added later, maybe by the reconer. Drivers as early as yours had no serial number.

I'm afraid your drivers have been somewhat sloppily reconed with Waldom aftermarket parts. The original aluminum dust caps were replaced with paper, probably with the intention of using them in two way systems as you found them.

I never cease to be amazed at how much of this late 1940s JBL product still surfaces. Jim was working like a madman during those years trying to get the company off the ground. Sadly for him, success didn't come until later under the business leadership of William Thomas.

oldsoundz
05-11-2009, 03:19 PM
Hi Steve

Thanks for the history lesson. I am always amazed at your endless knowledge on this subject. Do you have an idea of how many speakers were produced from day to day?

I was pretty sure they were early, but was not aware of the re-cone. Too bad about that.

Then again, maybe not. At this point I have an early pair of baskets that Jim may have handled. Way cool!

Plus they have their own history as I think the gentleman who bought them new, may well have bought them straight from Lansing. He also mixed many pieces of music and some video on these speakers in his private basement studio. I was told by his grandson that at some point, grandpa had sent the speakers somewhere for upgrading. Oops.

Thanks again!

Earl K
05-11-2009, 05:11 PM
I was pretty sure they were early, but was not aware of the re-cone. Too bad about that.

Then again, maybe not. At this point I have an early pair of baskets that Jim may have handled. Way cool!

It's entirely possible the "Waldom upgrade" only consisted of a new cone & surround / leaving the original voice-coil & spider intact .

- Buy WT2 from Parts Express and measure the TS / particularly the Bl factor .

Post the results and others can start to interpret what they mean for you .

- Alternatively, send them to GPA for remagging and TS testing .

>< cheers :)

oldsoundz
05-14-2009, 10:41 AM
It's entirely possible the "Waldom upgrade" only consisted of a new cone & surround / leaving the original voice-coil & spider intact .

- Buy WT2 from Parts Express and measure the TS / particularly the Bl factor .

Post the results and others can start to interpret what they mean for you .

- Alternatively, send them to GPA for remagging and TS testing .

>< cheers :)

Hi Earl

I think I will get the WT2 as you suggested. I think it's time I begin learning a bit more of the technical aspect of this "hobby".

In the meantime, I wondered if you would give me an idea of what may be deduced from this testing and if this could possibly answer as to if they still had the original v/c. I assume that if the v/c is original that it might be easier to re cone to a more correct state. If that makes sense:blah:

Thanks for the input!
Chris

Earl K
05-14-2009, 12:56 PM
I think I will get the WT2 as you suggested. I think it's time I begin learning a bit more of the technical aspect of this "hobby".

In the meantime, I wondered if you would give me an idea of what may be deduced from this testing and if this could possibly answer as to if they still had the original v/c. I assume that if the v/c is original that it might be easier to re cone to a more correct state. If that makes sense:blah:

Thanks for the input!
Chris


- The problem here is that ( from my perspective ) the original spec. isn't necessarily known .

- As a for instance , your pics seem to show a thicker top plate than what became standard on the later back-vented 131s . If what I see is not just a misinterpretation of the picture / then there's also reason to believe the voice-coil may not be the same as the type as the next generation .

- The strength of the motor ( measured in Bl ) driving a cone of a certain mass ( measured in Mms ) will result in a speaker with a certain dynamic character . These sonic characters were to become JBLs' signature sound .
- From the history lessons mostly given by ( Steve S. ) one can see that J.B. Lansing started his last company by making speakers that were highly dynamic ( according to some specific formulas I use ) . He seemed to pack as much drive ( Bl ) into a motor structure as was technically possible . ( Waldom would not have done this ) .
- Since Bl is also related to magnet strength / one would want the magnets remagged to make sure one was getting a true Bl reading .
- The weight of these after-market cones may be just fine / essentialy giving the driver a sonic character somewhere between a 2202 and the 2206 .

cheers >< :)

oldsoundz
05-14-2009, 03:21 PM
That was exactly what I was looking for. Now I am fully intrigued and will have to look further into this.


Thank you Earl!

grumpy
05-14-2009, 03:27 PM
Clarification:

I can heartily recommend the usefulness of this company's product "WT2", and have
experienced helpful support from the proprietors:

http://www.woofertester.com/

Parts-Express is selling "WT3"... a similar-looking and named product, but my
understanding is that is is an unrelated product... not a progression in a series.

Others may have compared the two for usefulness vs. value. I have not.

Steve Schell
05-15-2009, 09:59 PM
My guess would be that the voice coils and spiders have been changed owing to the amount of brown glue adjacent to the spider gluing surfaces. I have heard that the Waldom replacement parts used copper voice coils instead of aluminum, and round wire instead of ribbon wire wound on edge, but I have not seen this for myself.

Jim Lansing was definitely trying to achieve high gap flux density in these drivers. There is a correspondence file in the JBL archives between the company and Arnold Engineering in Chicago, their magnet supplier. Jim Lansing had apparently sent them dimensional drawings of his proposed new D-130. Jim was trying to achieve 13,500 gauss flux density, but the reply from the engineer at Arnold said that by his calculations only 12,000 would be achieved with the magnet specified.