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Ampeg B25 vs B25b ?

Discussion in 'Amps and Cabs [BG]' started by Infa Red, Jun 5, 2012.


  1. Was wondering the actual technical differences (any and all) between the two. :help:

    Some say there is none other than the B25b was to be paired with another cab. (if this is the case, then what is the difference that makes that a "pair")

    Others have said there is a actual difference in the "Tone Stack" between the two... the "b" being more geared for bass.

    So whats the real deal here ? For real. :confused:

    Thanks -
     
  2. JimmyM

    JimmyM

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Straight from the Ampeg book, they are identical heads and cabs except for the speakers.
     
    GreaserMatt likes this.
  3. Thanks Jimmy for this info. If its straight from the Ampeg book, then I guess we have to believe that !

    I just find it completely strange that a company would have 2 of the exact same heads and yet name one something different than the other if there were no differences.

    I mean, why not just pair the different speaker'ed cab with the B25 and call that the "b" stack ? Opposed to making a whole different faceplate for one. Nuts.

    Which makes me wonder, ok, maybe the different speakers in the one cab has a different ohm'age ? Therefore meaning the B25B (meant to be paired with the cab with different speakers) had a different ohm rating than the B25 ?

    Could you check this possibility for me ?

    Cause man, if they are the same exact amp, plus even the same ohms, (meaning that cab with the different speakers had the same ohm rating as the other cab too), then this is a pretty funny and odd "run" from Ampeg if you ask me. Which hints to the possibility of something having to be different.

    Which came first ? The B25 or the B25b ?
     
  4. JimmyM

    JimmyM

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    The cabs were all 16 ohms since the B25 and B25B were built to run two 16 ohm cabs.

    As for the name, I believe the B25 and B25B were a package deal with head and cab, and even though the heads were the same, the cabs weren't, so the names make more sense if you look at it like that.
     
  5. coreyfyfe

    coreyfyfe Supporting Member

    Nov 19, 2007
    boston, ma
    They came out at the same time but the B25 guitar amp was discontinued in favor of the V2 amp a year later leaving just the B25B bass head for the remainder of the product's timeline. The V2 used the V series power amp/output transformer with the 2/4/8 ohm matching instead of 16 ohm business of the B series. The earliest B25B cabs were 16 ohm only, they later added a 4/16 ohm switching mechanism and marketed the cab for use with other amps. Hope that helps clear up some of the historical confusion.
     
  6. MegaSwing

    MegaSwing Your Obedient Bassist® Gold Supporting Member

    Nov 26, 2002
    Baltimore, MD USA
    Just bought an all-original B25B on a lark yesterday. Even though the 16-ohm rating doesn't seem to be a problem as far as volume and performance, it's something you can't forget about. Both speakers say '8 ohms' on them. How easy is it to re-wire them to make a 4-ohm cab?

    FWIW, it sounds quite awesome.
     
  7. JimmyM

    JimmyM

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    I always forget which is which, but if you wire it the opposite of what it is now (series vs parallel), it'll do 4 ohms.
     
  8. MegaSwing

    MegaSwing Your Obedient Bassist® Gold Supporting Member

    Nov 26, 2002
    Baltimore, MD USA
    It kinda takes me back, too. The only neighborhood kid with a hot bass rig when I was coming up had a B25 setup. It was only 60 watts, but it sounded great AND it was an Ampeg, which made it extra-serious.

    A real beeyotch to move around, though.

    Note: This freaking thing weighs 94 lbs.
     
  9. coreyfyfe

    coreyfyfe Supporting Member

    Nov 19, 2007
    boston, ma
    Parallel for 4 ohms (each speaker gets a positive and negative lead) or series for 16 ohms (wire is routed from jack, to one speaker, to the other, then back to jack).
     
  10. MegaSwing

    MegaSwing Your Obedient Bassist® Gold Supporting Member

    Nov 26, 2002
    Baltimore, MD USA
    What is the operational benefit of changing it to parallel, other than having a more standard resistance rating? Is the sound vastly different?
     
  11. RickenBoogie

    RickenBoogie

    Jul 22, 2007
    Dallas, TX
    The "sound" does not chang, only the load the amp see's, which is important. The B25B want to see a 16 ohm load, but can operate at 8 ohms by using a dummy plug in one of the spkr outs.
     
  12. MegaSwing

    MegaSwing Your Obedient Bassist® Gold Supporting Member

    Nov 26, 2002
    Baltimore, MD USA
    My Markbass LM2 seems to like it just fine. One thing is certain, I turn the output volume WAY higher than with any other cab I use, still nowhere near all the way. Life is good.

    Did I mention this thing weighs 94 lbs?

    Am I crazy?
     
  13. Mojo-Man

    Mojo-Man

    Feb 11, 2003
    :cool:

    One of my all time favorite amps, and cabs.
    55-60 watts of heavenly tone.
    A B25B cab loaded with JBL 140's is old school to the max.
    My first real good amp was a 1972 B25B.
     
  14. Ok, great ! Thanks for the info guys. Reason for this question is-

    I just cop'ed a real nice condition 1969 Blueline B25. As I am kind of a Blueline fanatic due to IMO their beauty. And well, I then learnt there was a such thing as a B25b, and I figured "b" stood for bass. And I wanted the amp mainly for bass guitar.

    I then was wondering if it was even worth selling it and then waiting and waiting to find a similar condition (near mint) blueline B25b for the bass.

    BUT, it sounds like this amp I got should do just fine. Considering there is no difference ! LOL. (except a letter in the graphics).

    So I thank you all kindly for the info and input on that.

    My next question would be, if one could make a dream custom cab for a B25 mainly for recording/tracking/mic'ing, what would it be ?

    Are the 400 Watt - Eminence Kappalite 3012HO Neo 12" Cast Aluminum Frame Drivers still the best speaker ? Back a while ago I asked, and lots of good things were said about them.

    I was thinking about a 1 speaker with horn cab (or 2 speaker with horn cab)... but wanted the best sound possible and of course a way to match the ohms I need.

    Or is a already made one of the market the best way to go ?

    Any suggestions ?
     
  15. JimmyM

    JimmyM

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    I've always believed that any good amp paired with any good cab will sound good. The traditional way to go with a B-25B is a 215 cab with ceramic speakers, but if you want a cab with 3012ho's, that's just as valid and would probably sound quite good IMHO. The options are pretty much endless.
     
  16. MegaSwing

    MegaSwing Your Obedient Bassist® Gold Supporting Member

    Nov 26, 2002
    Baltimore, MD USA
    Looking for a chance to take it out of the house. Sort of dreading it, too.
     
  17. JimmyM

    JimmyM

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    You only have to dread it in two minute doses. That's not so bad.
     

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