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farleybob
05-09-2009, 05:51 PM
Hi, I just got what I thought was an early Altec 802 driver, but when I got it home and looked at it harder, it looked too big in diameter. It's 5" instead of 4.5". It has been pretty beaten and battered so I couldn't read the decal. According to the '43 Altec catalog the 901B is 5" in diameter, so I'm guessing this might be a 901B, cut I can't be sure. I can't find any photos of it. Can anyone recognize this driver? Also, it looks like the diaphragm is fried, so I was wondering if (and hoping that) an 802 diaphragm might fit.

hmolwitz
05-11-2009, 01:38 PM
The logo looks like Lansing Manufacturing to me.

Lansing

Manufacturing



Time for the real experts now.........

Earl K
05-11-2009, 02:13 PM
- The 3 attachment posts ( for the horn ) is a dead giveaway as to its' origin .

- I believe the library (http://<b>color=darkblue]library</b>) covers this off somewhere / ( it looks to me to be the PM version of the 801 Field-Coil ) .

>< cheers :)

farleybob
05-11-2009, 02:36 PM
Thanks, I checked the library and found that Lansing Mfg. offered the Iconic with permanent magnet versions of the drivers (it's just a mention tucked away at the bottom -- PM's available for an extra $25)

http://www.lansingheritage.org/images/lmco/bulletins/bulletin4B-4.jpg

but there's no description of the driver. In the 1943 Altec catalog I found a description of the 901B as a PM version of the 801B. The description matches, and I think that is what it is, but there's no photo

http://www.lansingheritage.org/images/altec/catalogs/1943/page07.jpg

I can't tell from the what's left of the decal whether it's a Lansing or an Altec Lansing. I'm guessing Altec Lansing since Lansing Mfg seemed to use metal ID plates.

I'm guessing this driver has literally "been through the wars" judging by the anchor stamped on it. Also, kind of neat how, at least at a quick glance, the structure looks a little like the early JBL drivers, with welded pipe and plate construction. Unfortunately, due to the bad diaphragm it's a very heavy paperweight ;)

Earl K
05-11-2009, 04:40 PM
Steve Schell will chime in eventually and give you ( us ) the low-down on what you have there.

- It's a nice find / even though the diaphragm isn't working / it's still really interesting / it has the original style half-roll surround as well as those "dock-loader" style stand-offs holding the voice-coil leads .

- I saw that red USN anchor stamp and thought the same as you .


>< cheers :)

Steve Schell
05-15-2009, 10:39 PM
I always crack up when I read a thread and someone says "Wait until Steve replies." Nice to be appreciated, just don't ask me about that newfangled post 1960 gear!

Farleybob, you do indeed have a 901B, the permanent version of an 801B. These Lansing and Altec Lansing pre 1945 permanent magnet compression drivers used an outer ring magnet, probably an older Alnico grade like II or III. Instead of an interior ring magnet like the 802 and 288, the early ones had to use a large outer ring magnet to achieve high flux density. RCA and Western Electric also built many drivers this way. Due to the black and white Altec decal, we know that this driver was built after the forming of Altec Lansing in 1941 and before the introduction of red, white and blue decals in 1945.

It is a shame that the precious original diaphragm is in bad shape. Note the spun rather than pressed aluminum and the half roll rather than tangential outer compliance. The voice coil lead out wires originally came through tiny holes die cut in the aluminum and formed tiny spirals up to the terminals, often with a bit of fluffy fiber inside the spiral for damping. Incredible hand work, the kind that had to end with the advent of high volume production.

Diaphragm replacement may be difficult. These early drivers had a tighter voice coil gap due to a smaller hole in the top plate. An original 801 diaphragm might fit but later ones probably won't. Altec's later service literature for early 802 and 288 drivers called for demagnetizing, remachining of the top plate to hog out the gap a few thousandths, reassembly and remagnetizing. This would be considerably more difficult to achieve on the 901B due to the spot welded top plate.

The Lansing small format drivers used the three stud mount from the first 801 in 1937 on. The change to the two stud mount was made in 1945, when Altec found a cheaper way of making the labor intensive H-808 tar filled multicellular horn. They cast a two piece horn, in a lousy orange urethane plastic during the war and later in aluminum, grinding the two identical halves flat and gluing them together. This design was incompatible with three studs so the change was made. Curiously, I have seen one 802 with RWB decal that still used three studs, and I have a tar filled H-808 horn (one of two I have seen) with large flange and two holes to fit the two stud driver. When Jim Lansing left Altec and began Lansing Sound Inc. he returned to the three stud mount for his D-175 driver and H-1000 horn. These pieces are compatible with the earlier three stud Lansing items.