Originally Posted by
meestro
I just won a D130 from eBay with the serial 503169. Most likely May of 1950?
That would be my best guess Mike, thanks for adding your info here.
Here is my current hypothesis for interpretation of date-code serial numbers on the "cut corners" labels of JBL components (not cabinets):
First type, date only:
last two digits of year with month in the format yym or yymmJAMES B.LANSING SOUND INC., "name only" labels:
499 = September 1949 (D-175 & N-1000)
5002 = February 1950 (D-130B)
"no name" label:
5010 = October 1950 (D-130)
(The 5010 transitional label has no name and no address, but the layout of the "Model No.", "Impedance", "Serial No." type is the same as the earlier "name only" labels with a space between the "NO." and the following dash "-" that was eliminated when the address was added.)
"JAMES B.LANSING SOUND INC.", "LOS ANGELES, CALIF., MADE IN U.S.A." name and address labels:
5101 = January 1951 (D-175)
Second type, date and number:
last digit of year with month and suffix number in the format ymm## or ymm###, the suffix numbers increase irregulary over time, taking large jumps forward at different times on different components, but sometimes remaining unchanged for years.*
(N or No. were occasionally prefixed to serial numbers)10613 = June 1951, suffix number 13 (D-130-E)
10615 = June 1951, suffix number 15 (D-130)
10822 = August 1951, suffix number 22 (D-175)
10840 = August 1951, suffix number 40 (N-1200)
N30474 = April 1953, suffix number 74 (175)
205132 = May 1952, suffix number 132 (D-130B
212147 = December 1952, suffix number 147 (D-130)
309169 = September 1953 suffix number 169 (D-131)
311147 = November 1953, suffix number 147 (N-1200)
404153 = April 1954, suffix number 153 (1217-1290 horn)
405169 = May 1954, suffix number 169 (130-A)
407169 = July 1954, suffix number 169 (D 130)
510511 = October 1955 suffix number 511 (D-130)**
512170 = December 1955, suffix number 170 (N1200)
608713 = August 1956, suffix number 713 (D 130)
Third type, date code with unique, consecutive suffix number:
*the 150-4 is exceptional regarding the suffix numbers, increasing at a rate that would seem to be too accelerated for manufacturing batches or design changes and which I believe represents a transitional numbering scheme that is the first instance where each driver received a unique suffix number tacked on to the date code:311-342 = November 1953, suffix number 342 (150-4)
311-347 = November 1953, suffix number 347 (150-4)
411-711 = November 1954, suffix number 711 (150-4, 16 ohm unit should have been labelled "C")
502825 = February 1955, suffix number 825 (150-4C)
These 150-4 date-code serial numbers were the first to be hyphenated, probably to distinguish the different meaning of their suffix number. The only other hyphenated serial number I've found is on some 1217-1290s but there seems to be no significance to this since the "153" suffix is the same as other 1217-1290s.
The 375 driver introduced at about the same time as the 150-4 seems to have had consecutive serial numbers from the start. Maybe the date code scheme was maintained on the 150-4 because of the cast parts it shared with other cone drivers??
**510511 = could also be interpreted as May 1951 suffix number 11 (D-130) : But a later D130 labeled with serial number 608713 leads me to believe that at some point in 1955 D130s began to also be given unique serial numbers as the date code suffix like the 150-4s
And some anomalies:
32147 = February 1953 (N 1200):I believe this is just a typo, and was meant to be 302147
The only D123 with cut corners label I have seen has serial number 506. I think this may be a plain serial number like 375s from the same time. Like the 375 the D123 was a new and unique model that did not share parts with older models.
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