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ampeg v4 and b25

Discussion in 'Amps and Cabs [BG]' started by sugarmagnolia97, Dec 13, 2012.

  1. sugarmagnolia97


    Aug 4, 2012
    I was just wondering what the differences were. theres alot of threads on them individualy but non comparing them. Anyone have some info? thanks
  2. RickenBoogie


    Jul 22, 2007
    Dallas, TX
    Well- B25 is 55 watts and wants a 16 ohm load, V4B is 100 watts and happy with 2/4/8 ohms- for starters.
  3. sugarmagnolia97


    Aug 4, 2012
    What about sound wise?
  4. sugarmagnolia97


    Aug 4, 2012
    thanks. I think i like the v4 better
  5. I sold the B25B because it wasn't loud enough for me. The V4B is plenty loud, and I use it when we play outdoors.

  6. sugarmagnolia97


    Aug 4, 2012
    Thanks Chris
  7. gerryjazzman

    gerryjazzman Supporting Member

    Dec 31, 2006
    New Jersey
    Also, the V4/V4B has a mid-boost/cut control at three selectable frequencies of 300 Hz, 1000Hz, or 3000 Hz which the B25 doesn't have.
  8. JimmyM


    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Both are very cool amps but the B-25 is a little on the esoteric side with its 16 ohm dealio. Definitely would go with a V4 or V4B over it given the choice, but if a deal popped up on a B25 for you, might be worth it to go take a look at it.
  9. Regarding the Ohms thing, on my B25 schematic, drawn 8/21/96 by Joe Piazza, the Ext. Speaker jack is clearly shown to be an 8 ohm tap from the OT. I have often used mine into an 8 ohm cab with no issues, though it sounds great with the orig. 16 ohm cab.
    Can't really comment on a tone comparison since I have not had the pleasure of playing through the V4, Obviously the power will be a big factor though, the B25 being only just enough for rehearsal and smaller blues or classic rock gigs. Unless mic'd.
    One other thing, V4 is twice the weight of a B25 head, 70lbs compared to 35 give or take.
  10. sugarmagnolia97


    Aug 4, 2012
    I've heard you need to put a dummy plug to use an 8 ohm cab. Do I put the dummy plug in the extension cab out or in the normal out?
  11. coreyfyfe

    coreyfyfe Supporting Member

    Nov 19, 2007
    boston, ma
    I believe the reason for the dummy plug trick working is that ampeg used shorting jacks on the speaker outs. If you don't plug into the "main" out and only use the "ext" out you won't get signal, but having both connections in switches the connections to the right transformer tap. Works that way with the SVT as well. If you're using a 8 ohm cab on the 16 ohm main tap you're likely overworking your tubes/transformer a bit, though with tube amps they're supposed to tolerate a lower rated mismatch better than a higher rated, so you might be ok.
  12. Russell L

    Russell L

    Mar 5, 2011
    Cayce, SC
    That is one cool control. Very effective. Select before you play, though, since it requires using the switch AND the knob.
  13. Europebass


    Mar 22, 2010
    I'm a happy 2nd half 70-ies SVT user. I use 2 own made 4x10 cab's. Together they are sized as 1 square-/flatback 8x10. I put 8 1978 SVT (=ceramic Eminence) speakers in there. I'm currently looking for a bit lower powered amp. A friend of mine has got a late 70-ies B25b. With just 1 cabinet (indeed with the dummy plug in the external speaker socket since 1 cabinet is 8 ohms) it sounds outrageous, but just not loud. So ideal for studio/rehearsing. This weekend I was able to try a (also late 70-ies) V4b and hooked it up with my 2 cabinets. I was quite disappointed especially after reading all the raving reviews. The volume was perfect for this 200 cap club. I didn't even have to turn up 100% but the low end wasn't happening for me. Yes, it's there, plenty. But it's not together, not tight, not ballsy. The character is totally Ampeg, very warm, very tubelike, but I missed the punch. The low end seems open on the lower frequency side like it's flushing down the toilet or something. Don't know how to describe it any other way. Compared it a day later in the studio directly to the B25 and later also to the SVT: same thing. Too bad, it seemed perfect. Maybe it’s just this particular V4? It’s got a new 220 volts PT since it’s originally an US version (and I live in Europe). The SVT and the B25 are both export models carrying original 220 volts transformers. That’s the only major difference I can think of apart of course from different basic design (the V4 is after all first designed as a guitaramp).
    Hope to hear some more experiences from the field!