A very unusal 050 system is being offered on ebay in three different auctions. From the date code serial numbers this would seem to have been assembled in late 1951 and early 1952.
The most unusual aspect is the crossover which has the high frequency
and low frequency sections built in separate boxes with unique model numbers! The high frequency section includes what looks like a continuously variable level control. Was this a custom crossover for a finicky client? An experimental system used by the JBL to determine values for the later N1200 with three position high-frequency attenuation? (I believe it was sometime in 1952 that the N1200 got it's knob)
The Low frequency section is house in a box bearing model number 1-1200A-3, there are empty holes in the platic plate where the terminals for the high frequency section would be.
The high frequency section is housed in a box bearing model number 1-1200A-4, the knob and a dial plate are positioned where the low frequency terminals would be.
in ebay auction:
http://cgi.ebay.com/2-JBL-1-1200A-3-...QQcmdZViewItem
from auction description:
A pair of 16 ohm crossovers.
Model numbers 1-1200A-3 and 1-1200A-4
This set came out of a cabinet with the JBL 130-B speaker and JBL 1217-1290 Horn, we have for auction at this same time
The description reveals the second unusual aspect of this system, a single 32 ohm 130-B is listed. And it is also unusual in posessing an aluminum dome? Another custom feature? A very old recone?
It's a little hard to tell in the picture but it looks like the wires connecting to the voice coil through the holes in the cone have not been glued down.
from auction description:
JBL 130-B VINTAGE 15" 32 OHM SPEAKER FOR REBUILD
The foam surround is in need of replacement and the voice coil rubs quite badly.
Sold as is for repair only
The 175 driver and 1217-1290 horn are the most pedestrian part of the system with the wide lip circular mounting flange and no acoustic lens.
But even this is unusual in that the driver and horn have different style cut-corners label. The 175 driver serial number 11239 has version of the cut-corners label with the name above and "Los Angeles" address below.
The 1217-1290 horn serial number 20280 has a no-name cut-corners label.
from auction description:
JBL 1217-1290 HORN WITH 175 COMPRESSION DRIVER
Both in very good condition as pictured.
It sounds very good too, with no problems.
16 ohms.
Includes front mounting flange.