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Ampeg B-25

Discussion in 'Amps and Cabs [BG]' started by register, Feb 10, 2003.

  1. register


    Mar 31, 2002
    I have an opportunity to buy an Ampeg B-25 all tube head from some time in the 1970s, I believe. It's rated at 55 watts, and is about $200. I'm looking for more information on tone, reliability, and how how to use its 2 channels. I was also wondering what the impedance was on the head, and what kind of cab it will take. I have an 8 ohm 4x10 cab, can I use it? Also, is 55 tube watts enough to gig with? Thanks!
  2. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    I'm assuming that each channel has two input jacks.

    To use both channels you need to have a short jumper cable (like the one used between stomp boxes) to go from one of the input jacks on channel 1 to one of the input jacks on channel 2. When you're using both jacks, they have the same sensitivity.

    Whether 55 watts will be loud enough depends on a lot of things...

    1. What kind of music?
    2. How loud do you want to be?
    3. Are you using an efficient cabinet?
    4. Are you playing 4 string, 5 string etc.
  3. register


    Mar 31, 2002
    I play indie rock along the lines of pavement/nirvana/other such things. Also what is the use of both channels? why not just use one? Thanks for responding!!!

  4. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Well, if the channels are voiced differently you can blend them...Hendrix did that with his Marshalls...

    55 watts (albeit tube watts and '70s tube watts) aren't going to go very far against thrashing guitars using the same amount of power.
  5. Boogie Boy

    Boogie Boy

    Jan 26, 2003
    I owned one in highschool (many moons ago). It was paired with the matching 2x15 cab. Back then it was "good enough" but I think you'd be better off with a bigger tube head (if $ isn't an issue) or a solid state rig. It had decent sound but I think you'll be yearning for more power. I hope this helps.
  6. [​IMG]

    I rebuilt this one, and I use it. Great sound! But will only hang with about 40 Watts of guitar, and unamplified drums, which is great for jamming, but not quite enough for insanely loud gigging. If you play at volumes people actually like to listen to, it's actually perfect. :D

    No need to jumper channels. Ch1 has less bottom end, kind of a rounder bouncier sound, and Ch2 has full sound with all the bottom. The Ch1 actually sounds better in the mix, like an old Fliptop.

    7027A and 5AR4 tubes can be expensive, but the ones that are in there will probably last for 20 more years. And it'll need new filter caps if it still has the original ones.

    It wants to see a 16 ohm load if you use the attached cord, or an 8 ohm load if you plug into the extension speaker jack.

    It's actually the perfect recording amp. Great tone, and it can get the slightly overdriven gravy without killing your ears.