JBL D-140F in Bag End S-15D cabinet??

Discussion in 'Amps and Cabs [BG]' started by andertone, Apr 14, 2004.

  1. andertone

    andertone Supporting Member

    Mar 22, 2000
    Southwest USA

    I've been trying awhile now to get a good low volume sound with decent bass for my 4 piece acoustic/electric group, and after trying an SWR Baby blue (great tone, but at it's limit), an Ashdown ABM-C100-300 (loud, but my E string on my Sadowsky breaks up when pushed), so I always go back to my 1967 Fender Showman and recently a Bag End S-15D cabinet.

    The stock speaker in the Bag End has great lows, but no snap like I'm used to with a D-140F. So, I plopped my JBL into the enclosure, and lost a wee bit of bass, but gained considerable clarity and tone.

    Question: I know the enclosure is way too small for the JBL, and the A-string sound is somewhat muted, but will I damage
    the D-140F by over-excursion in this tiny cabinet? But man, that tube only tone is so wonderful!

    Specs for JBL D-140F

    Fs: 37Hz
    Qts: 0.18
    Qms: 4.0
    Qes: 0.19
    vas: 10.5 ft^3
    Eff: 7.7
    Pe: 100W
    Xmax: 0.08
    Re: 5.7 ohms
  2. Where did you find the T/S on the D140F?

    Are they from a verifiable source? If so, I will add to my spread sheet.
  3. andertone

    andertone Supporting Member

    Mar 22, 2000
    Southwest USA
    Hi Bruce:

    I got the information from an ancient JBL site about 5 years ago, as far as I know it's reliable. I wrote it down thinking about making a cabinet or modifying one I already owned. BTW, the posts are reversed on that speaker (red=ground)


  4. These specs exactly match the JBL 130A driver. Nightbass claims they are the same. I dunno.

    Perhaps the F was just the musical instrument version of the 130A.
  5. Nightbass


    May 1, 2001
    Seattle, WA
    Just put "I dunno" in the comments section of your spreadsheet. :D

    I got the info from a fellow who used to work for JBL, so I have a bit of faith in it. If I was mass producing vintage cabs I'd just measure the params for myself, tho.

    The "F", as you know, is a designation for a widened gap in the magnet top plate to minimize voice coil rub. It was requested by Fender, and legend says that the "F" stands for "Fender". People used to over-torque the speaker mounting bolts against the flimsy baffles on Fender amps and bend the frame, causing the voice coil to rub against the top plate. The wider gap give the VC more leeway, as it were.

  6. All news to me. I used to use the F series playing as a kid in the 60's.

    I put "speculation" in my spreadsheet as to the source of the data.
  7. iammr2


    Jun 10, 2002
    I believe that speaker is a 2 ohm model. Reference at the top of page 3 here:


    Can probably use D140 T/S parameters with good effect,

    Almost forgot. There was a guy that used to play with the Allman Bros. that used cabs like those. Sounded great!
  8. VicDamone


    Jun 25, 2000
    I have nothing technical to ad. A long time ago, after the tear gas cleared from Telegraph Ave in Berkeley, I set out to build two large horn enclosures because there was nothing available to be heard over this ham handed drummer I was working with. These were the pre days, pre CBS, pre SVT, pre acoustic 360, and Marshall does NOT build bass gear. With plans supplied (for free) by the James B. Lansing Co. I constructed my first and last DIY enclosures. At almost four feet tall and with the driver baffle trippled in thickness they were truly awsome in the day. Powered by two Marantz 8B amplifiers (35 watts) and using the preamp section from a Dual Showman these did that magical tube thing and were loud. Of course I didn't realize that the tone was so magical until twenty years later.

    Bla bla bla...anyway, what I'm trying to say is the D-140F is capable of producing the sweetest midbass tone I have ever heard. If it doesn't work out build a big enclosure for at home, you"ll love the tone.

    The horns sucumed to the abuses of giging and the drivers were sold. The 8B's were sold to Japanees audio freeks at, what I thought was a huge profit, only to become more valuble with time. Oh well.