JBL D140F (I found two NOS)

[Redbrangus]

I don't know for sure that it's relevant, but JBL introduced the Kapton bobbin when they introduced the K-series. K for Kapton? Then later, E for "Egads - that sure is a big ol' heavy magnet!"? Ultimately they did go back and issue a G-series, but it wasn't really a series of drivers for pro use. But you're right, their nomenclature didn't always make sense. They were hardly alone in that.

 

[puff father]

Hi, everyone.
I recently found two unused JBL D140F's

I looked around the forums for discussions about this speaker but couldn't find all that much. Do people like these? I have no need for them, I was thinking about posting them up on here. Could anyone give me more info? From what I was reading a high powered amplifier would blow them up. Would hate to do that.

jbl d140f - Google Search

 

[stretch80]

I had two in a home made cab in the 80s, powered by a solid state Sunn concert bass w/ ~ 165watts as I recall, and no trouble, and that was a loud rig !

 

[BassFishingInAmerica]

I had two in a home made cab in the 80s, powered by a solid state Sunn concert bass w/ ~ 165watts as I recall, and no trouble, and that was a loud rig !

Although it’s probably safe to stay in the 100 watt range, I don’t think the D140 would have much trouble handling closer to 150w. I know I’ve pushed mine close to that. The D140 was more heavy duty, in comparison to the D130. JBL even rated them for 150w.

 

[Ric Vice]

Bass Fishing in America,
Wow, thanks so much for posting that chart that includes the specs for the D130 JBL. I've been looking for that for years.
Conservatively, the JBL D130F in my B-15N is a great match for recording, since the B-15N is rated at 25 Watts RMS (probably closer to 30 Watts)
The B-15's were actually built primarily as Double Bass Amplifiers. As players transitioned over to EB, they were used on small gigs, but were never
all that popular once Rock, Pop and Soul started doing louder venues for bigger audiences. Even James Jamerson had a Kustom 200 for bigger gigs.
Just my take though.

 

[agedhorse]

While those are the MARKETING numbers, there are specific derating factors that apply to their MI speakers that address the limiting factors in those drivers.

For typical MI applications, where clipping, distortion, limiting, compression, or non-ideal box tuning, a derating factor of 50% is generally applied to the published power handling ratings (also caller continuous PROGRAM power). Note that these days, program power is also related to "RMS" power by the same factor of 2 when it comes to power handling. This is due to crest factor differences in the signal, the duty cycle and the acosutic loading on the drivers from non-ideal cabinets and acoustic loading.

THIS is why I made my comments earlier. For MI applications, they are rated at 75 watts.

Here's from the JBL designer's guide notes for MI applications (guitar and bass primarily):

 

[Altarofpigs]

My advice is the same as Agedhorse. The OP should consider this carefully and here is why: The highest and best use of these drivers is very possibly not as bass guitar speakers but rather HiFi speakers. The tube HiFi weirdo community has a small sub-group who are even more rabid than the rest. You see....most tube HiFi amps are push/pull and generate 20-30-40 Watts per channel or so. There is another kind of topology called Single-Ended Triode (SET) and these amps are often flea-watt units. 2A3 tubes are popular, and the amps that use them generate a paltry 3.5 Watts per channel! SET amp fans adore these flea-watt amps but they obviously require VERY VERY efficient speakers. These speakers sell for silly money. A brand new set of Klipsch La Scalas is about $17K.

I cannot find sensitivity specs on these JBLs but I have reason to suspect they could be in the neighborhood of 100db or better. If so, then someone would want them as badly as I wanted Cheryl Tiegs in the 1970s.

I also have a pretty pristine pair of these in 1x15 cabs that I would like to use as woofers/subs. I would love to know more about this, as I have no idea where to begin to put these to use and I’m kind of nervous to use them with as to not destroy them.

 

[Ric Vice]

Great Information,
So, assuming that we cut the "continuous power rating" of 100 watts for the JBL D130F in half and the 25 watts "undistorted output" rating of the B-15N(C) is half of that.
Since I never run the amp wide open, or play a 5 String bass through it, I'm not concerned about blowing the speaker.

 

[agedhorse]

I also have a pretty pristine pair of these in 1x15 cabs that I would like to use as woofers/subs. I would love to know more about this, as I have no idea where to begin to put these to use and I’m kind of nervous to use them with as to not destroy them.

I certainly wouldn’t recommend them as subwoofers, they would require a large enclosure to get that kind of low frequency extension.

 

[Altarofpigs]

I certainly wouldn’t recommend them as subwoofers, they would require a large enclosure to get that kind of low frequency extension.

Okay that’s a good point, thank you. A lot of good info in this thread. What about in general stereo speaker application? I have cabinets I can put them in but am kind of aloof on how to go about driving them correctly. I could just sell them, but I’d like to put them to use.

 

[agedhorse]

As a woofer in a 2 way cabinet, it’s a viable choice, but you might get more than they are worth than for this application.

 

[byacey]

I've run into more than a few of these with shifted magnets; perhaps it's exacerbated by transporting them in our cold weather. Does anyone have any experience with this happening in warmer climates?

At any rate, don't bounce them around too much, and transport them cone facing down, if possible.

 

[agedhorse]

Yes, it does happen sometimes, and in all climates I think.

 

[Mosthigh]

I've got a line on two JBL D140's in woofer cabs. They seem in pretty good condition. Comes with Altec horns, but I don't think I need those.

 

[Redbrangus]

I'd be willing to bet those cabs are built from the 1975 JBL Enclosure Kit plans. They look to be the 3.75 cu. ft. box, the smallest cab in the set, which also included 5 and 8 cu. ft. enclosures, and porting recommendations for all the JBL MI drivers. I believe that set of plans, and this cab in particular, was the... uh, inspiration (shall we say?) for the Alembic 'Wall of Sound' cabs. I built a fair number of those boxes myself; it was the first enclosure I ever built.

Those Altec sectoral horns were pretty standard equipment up until about 1980 or so, when newer radial horn designs began to displace them. Rap those aluminum horns with a knuckle or something and you'll hear a distinct ringing at about 800 Hz -- that resonance gave this particular horn a distinctive sonic signature, IMHO. That horn, with the Altec 808 driver, was used in the legendary Altec A-7 horn-loaded "compact" theater speaker system, among several other models Altec offered.

D-140s are great sounding drivers; I presume you've read the caveats above about the limited power-handling and difficulty sourcing recone kits, and have factored that into your decision about whether to buy these or not.

 

[Passinwind]

I'd be willing to bet those cabs are built from the 1975 JBL Enclosure Kit plans. They look to be the 3.75 cu. ft. box, the smallest cab in the set, which also included 5 and 8 cu. ft. enclosures, and porting recommendations for all the JBL MI drivers. I believe that set of plans, and this cab in particular, was the... uh, inspiration (shall we say?) for the Alembic 'Wall of Sound' cabs.

The bass cabs in the Wall weren't ported, so I kind of doubt that.

 

[Redbrangus]

The bass cabs in the Wall weren't ported, so I kind of doubt that.

View attachment 4386039

Huuh. I stand corrected. I've been laboring under this misconception for a LONG time. Dang.

 

[Passinwind]

Huuh. I stand corrected. I've been laboring under this misconception for a LONG time. Dang.

I know the feeling, especially when it come to Dead shows and the associated gear. I saw the Wall in action a few times, in my experience it was actually a very hit or miss proposition, much like the band itself.

 

[Jim C]

I had a Sunn 2x15 cabinet on loan for many years and it supposedly had D140's.
I remember them to be good but not great compared to modern speakers.
Am I remembering wrong, or does s the cult following put these drivers on a platform a little higher than deserved?
I feel the same way about pro series JBL studio monitors. They were tops in the day but not nearly as good as what's available now.

 

[Redbrangus]

I saw the Wall erected in Austin, but didn't get to hear anything other than a tape being played through what I imagine was the vocal system. (I had a gig that night, but word had gotten around town in the afternoon: "you gotta go see what they've built over at the Auditorium".) They just had a couple of Ampex tube-type mixers for FOH... that much, I remember. I worked as a hand on a Dead show in 1981, post Wall-era; Lesh still had a big pile of 115 cabs but I couldn't see the baffle boards for the tie-died grill cloth. What impressed me (or unimpressed me) at the time was he had four big Mac 2300 power amps that they carried loose and individually in some old Army surplus aluminum cases, and then just piled 'em up like a stack of bricks on stage. Even in 1981, that seemed like an inelegant and inefficient way to package and transport equipment that was designed to be rack-mounted in the first place. His Macs appear to be in a rack in the pic you posted, @Passinwind, so apparently someone somewhere had a change of heart about carrying that gear around in a rack. IIRC, a rack of four Mac 2300's wouldn't have been a particularly over-sized or over-weight package for the batch of gear they were carrying at that time, which included sound and lights.