Jennings Electronic Industries D4 speaker cabinet (4 x 12") - 1969-1975
100 watts handling, 4 ohms total impedance
A wall of D4 cabinets for Rod Argent and his band, pictured in the "Jennings News" newspaper-format catalogue of late 1969.
The music trade press carried the news in January 1970.
The D4 was developed during the latter part of 1968 and had evidently reached a finished enough form to be photographed in early 1969. It was designed initially to accompany the J100 solid state amplifier. JEI valve amps did not come until later.:
Detail from "The Jennings Scene" brochure, printed to accompany the company's display at the Frankfurt Trade Fair, February 1969. Note that no model number for the speaker is cited.
A couple of months later - in July - amplifier and cab were still presented as a set:
July 1969. The Jennings users explicitly named overleaf are Dave Clark and Hank Marvin.
However, by the time of the Russell Hotel Trade Fair in late August, the cab had become the D4, presented on its own as well as in conjunction with the J100 and J200 amplifiers:
Detail from the "Jennings News" newspaper-format catalogue.
The design of the D4 was vanishingly simple: birch ply construction, two sizeable backboards with straight edges, and four 12" Celestion T1217 greenback or blackback speakers - 25 watts handling, 15/16 ohms apiece - wired in parallel for a total impedance of 4 ohms. Two openings in the sides were provided to aid carrying. Encircling the outside, which was covered in black basketweave vinyl, two lines of silver piping, much as on Vox cabs of the late 1960s and early 1970s. Last but not least, stuck to the baffle inside, a printed paper slip warning the user that tampering with the wiring might harm the J100 amplifier.
1969 to late 1973
The Vox logo is naturally a later addition.
One of four original speakers from a relatively early D4. The date code for its manufacture is "8 JB" which should mean 8th September 1969. The cab was probably ready for sale a month or two later.
Late 1973 to 1975
A JEI D4 speaker cabinet from late 1973, repaired (in some way) by Alan Pyne at 119 Dartford Road in the summer of 1977. The original drivers will have been Celestion Greenbacks. The amps normally paired with this cabs in this livery (introduced in the late summer of '73) were the JEI V100 and the JEI FR100 and AP100.
