Ken Fox
From:
Nashville GA USA
|
Posted 15 Sep 2013 2:32 am |
|
I borrowed this from another thread about 15" speakers. Mostly about power ratings, but he also talks about the F designation.
From: Harvey Gerst
Newsgroups: alt.guitar.amps
Subject: Re: How many watts can a JBL D-130 safely handle?
Date: Sat, 07 Sep 1996 01:41:09 -0700
>
> It's amazing about the variation in answers you'll get. Watts of what
> kind? RMS at 30 hertz? White noise? The question has almost no
> meaning without stating some parameters.
>
> If you look at the original spec sheet for the speakers in that series
> you'll see that the D-130 is rated at 25 watts. Since this appears on
> the rear of the pamphlet that gives dimensions for recommended B/R
> enclosures, one should assume that it is 25 watts when mounted in the
> proper cabnet.
>
> You should find that about 20 to 30 watts into one of these in a
> proper sized enclsure will drive you out of the room. If you put it
> in an undersized and over damped box like a Benson then the speaker
> will take more power, but it will need it to get the volume.
>
> The D-130 was/is an effeceint speaker. It doesn't need a lot of input
> to get a lot out.
On the other hand, I saw a lot of D130's come through with fried voice
coils that were running off a 12 Watt Williamson amp during the 50's and
60's. Integrated music from HiFi systems caused one kind of problem -
using the D130 as a musical instrument speaker created other problems.
That's why I suggested the D130F (which was a redesigned D130), made
expressly for musical instrument amps, as were the D110F (a totally new
design), the D120F (a redesign of the D131), and the D140F (a new design
using existing parts).
Power specifications for the F series were nominally 35 to about 60
Watts. How did I arrive at these figures? Pretty simple, I played guitar
and bass through them and kept increasing the power till they blew. Then
I downrated them from the power that fried them. Pretty hi-tech, huh? It
seemed to work pretty well (of course we didn't have synth players back
then).
The major amp manufacturers back then were Fender, Sunn, Kustom, and
Ampeg. Rickenbacher and Mosrite also bought some, but nowhere near the
volume of the other amp makers. All had JBL speaker options.
And yes, the "F" stood for Fender, since they were the largest single
buyer, and also distributed the F series to music stores. They had no
part in the design or the idea for the new series, I am solely to blame
for that.
let me take you back to the late 50s, early 60s. JBL was a small
company with their main offices above a candy store, and the manufacturing
scattered in a number of buildings up and down the street, near Glendale, on
Fletcher Drive.
They made the following speakers;
the D130 a full range 15",
the D131 a full range 12",
the 130A a 15" woofer,
the 130B (same as the 130A, but 16 ohms),
and the 150 - a 15" woofer with a heavier cone.
The D stood for a metal dome and the A and B were for woofers of different
impedances. I don't remember if we made a 131A. We also made a D123 (full range
pancake 12" speaker) and the D208 and D216 (both 8" speakers but with 8 and 16
ohm voice coils).
Fender was buying D130s for use in their Dual Showman systems, but they were
experiencing problems in surrounds drying out from outdoor use, and burnouts
>from improper mounting techniques. I wrote a memo to the president of JBL,
outlining a plan to let me design a series of speakers made specifically for
musical use and he agreed. My plan called for modifications to the D130 and
D131, plus an all new bass 15" speaker, and a new 10" speaker.
Since Fender was our largest purchaser, I did not want the headache of trying to
re-introduce a whole new series so I kept the D130 name for the 15" and simply
added an F (yes, the "F" is for Fender - don't know why to this day I did that,
but I did). Since I was making up new model numbers, I decided where possible to
keep it simple, so the 12" (originally the D131) became the D120F, and the new
10" became the D110F.
That left the new bass speaker. I didn't want to leave it in the 13x range
because it was different and the 150 was already being used by our theater
woofer. The 140 was not being used, so I named the new bass speaker the D140F.
After I left JBL, I understand they came out with the black crinkle finish and
renamed them E series. The first major modifications were made in the K series,
as I understand it. |
|
