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Replacement Speakers for Ampeg B3158

Discussion in 'Amps and Cabs [BG]' started by deetah2, Jun 12, 2012.

  1. deetah2


    Jun 11, 2012
    I recently acquired a blown Ampeg B3158 amp. After I got the amp working, I discovered that both speakers were also blown. Reconing kits cost almost as much as some new speakers. So I'm wondering - what should I be looking for in replacement speakers for this amp/cabinet? Carvin sells their PS15 for $69 plus shipping. Any reason I should avoid this speaker? What freq range should I seek for the 8in driver? Is a full range speaker best for this? I've seen some "mid-range" 8" bass speakers that spec usable freq up to 5kHz, but the EQ sliders on the amp go all the way to 8kHz. Any advice would be appreciated. Thanks.
  2. JimmyM


    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    The typical high end rolloff in their cabs is 4 or 5k, so that would be fine. I'd throw a Beta 15a and an Alpha 8a in there. It's not doing it by the book, which requires lots of modeling in WinISD ;) but they're inexpensive and work well in vintage style cabs.
  3. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    Plug its specs and the cab dimensions into a speaker modeling program, comparing it against at least six other drivers to see how well it fares. That's the only definitive method of matching drivers and cabs.
    +1, assuming the OP doesn't have the ability to do driver/cab modeling.
  4. KOakley


    Sep 26, 2002
    Hampton Va
    I recently refurbished my 3158 after it sat for years due to being damaged when my truck was rear-ended. It is currently loaded with a Beta8 and a Carvin PC15. The Carvin farts out due to very low X-max. The Beta is great. I measured the cab and modelled several speakers with WinISD pro. Keep in mind that the 3158 only has 100W @ 4ohms for the low end which limits your choice of speakers. I've decided to install an Eminence Lengend CA154. It looks like the CA154 will drop right in and give a -3db point of 55hz and won't exceed X-max until 40hz at which it is down -10db with flat EQ. Net cabinet volume worked out to be 2.8 ft^3 with a tuning freq. of 56hz with the stock ports. YMMV, but all the numbers look good to me and max SPL@100W should average 115db in the plus/minus 3db range (power compression not factored in) which is waaaay louder than this old man wants to play. Anyway this is a long-winded post for me so feel free to PM me if you have any ?'s. Good luck.
    cornfarmer likes this.
  5. will33


    May 22, 2006
    I assume these have passive crossovers? Impedance matters, the CA154 is a 4 ohm driver.

    Edit: nevermind, I see they're biamped, which is cool.
  6. pauldog


    May 22, 2015
    Ok first timer here, I replaced my 8 inch with the alpha 8 the magnet is only 20 ounces the book specs call for a 30 ounce magnet do you think there will be any problems? Im expecting the eminence 15 inch 4 ohm to arrive any day, thanks for all the help paul
  7. JimmyM


    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Won't be any problems as long as you don't turn up louder than the speaker can take ;) I really don't know much about that cab, but just bring it up slowly at first, and if you any signs of distress, turn it down.

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