Yikes,
Since Everett Hull would never have put a "F" on the end of one of his amplifiers, it likely was a D-130, the speaker I have in my B-15N(C) is a D-130F. It's very confusing sorting
this stuff out, many of the D-130's over time have been re coned with a D-140F kit. What I think I do know is that the D-130(F) had a copper clad aluminum voice coil, while the D-140(F) had
a copper voice coil. So they sound a bit different at the midrange.
Not really confusing, but I went through the JBL recone school back in the very early 1980's and we learned quite a bit about the history.
JBL wouldn't sell the original D-130 into the MI market due to the high number of failures, there was a white paper regarding de-rating of speakers driven into distortion which is the norm for MI speakers. The D-130 was a very short wound voice coil with a short bobbin and a soft spider with a (doped) paper surround, not a good choice for a bass guitar speaker. Virtually every D-130 used in the MI world was the F variant.
You can't recone a D-130 with an F kit and get the same performance as the F variant. The magnetic gap width is different which was part of the problem with reliability... it was too tight for the thermally unstable paper bobbins at that time.
The D-130F had an aluminum VC, not copper clad. Some of the aftermarket recone kits use copper clad or plated wire, some even use copper wire, and also use round wire rather than edge wound ribbon, but this is because it's cheaper to assemble and bond to.
The D-140F as well as the 2220 used copper ribbon wire, the 2220 used a cone very similar (if not identical) to the D-130F but with a paper dust cap
AG,
Thank's for verifying that for me, I thought that was the case. I do know that Ampeg had some issues with blown D130's at least that's the story I heard. But that was so long ago, who knows. According to the JBL Spec's for the D-130F I can find, it was rated at 25 watts.
According to Ampeg:"The Story Behind the Sound. Ampeg used the JBL D-130F"
The original D-130 would be rated to about 25 watts RMS by today's standards from about 40Hz on up, but from say 80Hz on up the power rating improved to almost 50 watts RMS. This is because of the mechanical limitations of the suspension components as well as the imprecise methods of cabinet design combined with low damping factor tube amps.
The D-130F increased the power rating to roughly 100 watts continuous average power, but this is deceiving because for musical instrument applications there is a 50% derating required. Still, it's about double that of the original model. This is guitar applications though, where the low frequency limit was ~80Hz. As frequency decreases, so does the power handling. Used to 40Hz, the original limitations (more or less) still applies.
The D-140 power handling was increased to roughly 150 watts continuous average power but did not need the derating for frequencies below 80Hz which made it a much better choice for higher powered bass guitar applications. They did still need the derating for musical instrument applications however which made this a solid 75 watt "RMS" driver and would hold up ok with more power if the amp was not overdriven or no compression was used.
You have to remember that back then amps were pretty small by today's standards, it was uncommon to have enough rig for the gig so amps were often overdriven in general.
