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Ampeg B-15 Speaker Replacement Recommendation?

Discussion in 'Amps and Cabs [BG]' started by Thor, Oct 10, 2006.


  1. Thor

    Thor Gold Supporting Member In Memoriam

    My friend Funkster has a Ampeg B-15 with a blown driver.
    The existing driver is a JBL K140. I need to double check
    the impedance but I am virtually certain it is 8 ohm.

    I have no idea if this was the stock driver. The cab
    is a sealed and measures 12" x 19" x 19" or 2.5 cu. ft. The
    'flip-top' probably does leak a little air. The cab pic is labelled B-15n.

    A driver recone is about $125 from the estimates I had gotten
    locally.

    I ran WinISD on a Eminence Delta 15 ProA and got a bit of a
    hump around 130 hz, about 2 db, and a gradual rolloff with a
    -3db point around 60 hz.

    I am concerned that the EBP listed on the site is around 95
    or so, and I was under the imoression this was a value where
    the ratio suggests it would be more appropriate for a vented cab.

    I can buy that for under a hundred.

    My questions here are:

    1) Is the JBL K140 the stock speaker for that unit? I am
    very suspicious it was a retro fit.

    2) Do you TB tech Heads have any suggestions as to
    an appropriate replacement driver for this size box.


    This is an older 'flip top' unit, and I don't expect it to be rated f
    or more than 100 watts. Unfortunately, Ampeg took down
    all the schematics and specs, so getting the info has been a
    bit more difficult. Anything you know about this amp would
    be helpful.

    A pic is enclosed.

    Thanks,
    Thor
     
  2. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    I doubt that the JBL was original. All the B15s I saw back in the day with original drivers were loaded with square magnet Oxfords and CTS. Model the Kappalite 3015LF, the Qts is almost the same as the Delta Pro and it has twice the xmax, half the weight. No law says you can vent that box either. Yes, lower EBP drivers are better for sealed cabs, but the volume you're dealing with is less than half what you really need for a sealed box in any event.
     
  3. madlee

    madlee

    Sep 9, 2006
    Philadelphia
    I believe you can find a replacement speaker from places like fliptops.net

    you should also call this guy:

    http://www.vintage-amp.com/

    he will be able to find you a replacement for a good price.

    also, look for these:

    CTS 15"

    Eminence 15"

    Altec 421A
    Altec 418B
     
  4. jbrew73

    jbrew73

    Dec 24, 2006
    i thought those cabs were ported at the bottom.?.
    i believe some b15's came with a jbl as a factory upgrade but if you call fliptops i'm sure they would know.
     
  5. Alivefor5

    Alivefor5 Supporting Member

    Jul 17, 2006
    Indiana
    The B-15 is a vented design but not in any traditional way.
    If you pull the speaker and look toward the grill cloth you will see a double baffle board with a space around the entire circumference of the hole. This space is connected to the volume of air in the cabinet by small slots on either side of the speaker when it is mounted. Rear cone movement sends air through the slots to the front of the speaker in phase with the front cone movement.

    Sounds confusing but in short - it is ported into the same opening that you view the speaker from in front.

    Just one of many features that made these amps Cadillacs then and now.
     
  6. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

     
    May 7, 2021

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