Mesa Boogie Bass 400 (not 400+) Info?

Discussion in 'Amps and Cabs [BG]' started by FatStrings, Dec 14, 2001.

  1. FatStrings


    Nov 16, 2001
    Southern NH
    Hi everyone, this is my first post. I've been checking out Talkbass for about five weeks now,
    and I've learned alot, thanks.

    I'm wondering if anyone has any experience with a Mesa Boogie Bass 400.
    A little info first:
    Mine is marked inside (I took the covers off to clean and inspect it)11/85 on the circuit board. I guess this means the amp was made in Nov of 1985.
    It has six large Svetlana power tubes and four small Sovtek preamp tubes.
    I downloaded the closest manual to this model from Mesa, Bass 400+, and it is basically the same exept the 400 has six EQ slidders, the 400+ has seven. And I think the 400 has less wattage, but I'm not sure.
    Oh yeah, and the 400+ has twelve power tubes.

    1. What's the wattage of this amp?
    2. Do you know of any common problems I should watch for?

    Thanks for any help, and please post any info you think would be helpful :)
  2. winston

    winston Supporting Member

    May 2, 2000
    East Bay, CA
    Welcome to TalkBass, FatStrings! I've got a Bass 400 and it's an excellent, underrated amp. From what I've heard, the 6-6550's put out 300 watts, like an Ampeg SVT. I've got Chinese Ruby power tubes in mine but if I retube it I'll get Svetlanas. I replaced the Sovtek preamp tubes with some old West German ones I got from an old Fisher tube stereo and they improved the sound considerably.

    I currently run it through SWR SOB 1x15 and Goliath Jr.III 2x10 and get a super rich, fat sound with my StingRay, Peavey Cirrus Fretless 5, or Chapman Stick. I played a really large club with this setup and the master on 2 1/2-and the soundman told me it was so loud, he took me out of the P.A.

    As for problems, before I got the SWR speakers I was running it through a homemade cab with a Carvin 15 or a Genz Benz with a super cheap 15 in it. Because the crappy speakers were very inefficient, I had to turn the master up really high to get decent stage volume. With the master cranked, the graphic EQ jacked up and the pull shift switches on the tone controls activated, the amp would blow fuses and shut down. I think this was a combination of the amp working really hard and the speakers not being able to handle all that juicy tube power (I blew several Carvin speakers). Ever since I got the much more efficient and robust SWR's this hasn't happened once, and the amp purrs like a kitten at shows or rehearsals.

    I'm not particularly happy with the FX loop; both the front and rear panel loops distort the Boss flanger and Rat pedals I use no matter where the input gains or FX blend knob is set, and it's tricky to dial in the blend, so I just run my pedals through the input. I suspect the loop is optimized for line-level rack FX.

    When I got mine about 3 years ago I called up Mesa and asked for the manual, but they also said they only had the one for the 400+. I'd love to get the correct manual and schematic diagram for this thing!

    I think putting the DI and Slave Out after the Master was also not the best idea-the DI is affected by any Master volume changes you make and can get pretty noisy. I've thought of changing my preamp tubes to lower-gain ones-7025's, perhaps, to see if it cuts down on DI noise. I also wish the graphic EQ had a level control to compensate for severe tweaks-they may have added that to the 400+.

    If and when I get mine retubed, I'm going to see if I can get someone to make a few mods-switching the FX loop to instrument-level serial operation; making the DI switchable to pre-master; and adding a couple of Speakon jacks and an impedance selector to replace the 1/4" speaker outs.

    Even in a wooden 4-space Grundorf rack mine only weighs about 60 pounds. The Bass 400 and one of the SWR cabs make a dastardly potent, fairly portable rehearsal/small gig setup. To tell the truth, my Ampeg B2R gets more use than the 400 because it's much lighter, sounds very good for a solid state head, and saves wear and tear on the all-tube Mesa. But on the occasions I do pull out the Boogie, I'm always glad I did.

    In case you're interested, the 400 replaced the D-180 which had 6 6L6/5881's and had two cascading input volumes, which allowed for serious smooth tube preamp distortion, like on Boogie guitar amps. Guitar Player magazine reviewed the D-180 around '83 in an issue with Segovia on the cover, and then reviewed the Bass 400 in one of the '87 issues. Michael Anthony of Van Halen appeared in an ad for the Bass 400 in which he said,

    "If it seems like a lot of amp, think of the caliber of bands you'd like to play know someone is going to get the gig. And if their tone is awesome while yours resembles A CAREFULLY EXECUTED FART, who do you think is going to get the call?"

    Uh...thanks, Mike. Couldn't have put it better myself!
  3. boogiebass


    Aug 16, 2000
    Great amp. A pretty decent bassist named Paul McCartney runs a 400 with two Mesa 2X15 Road Ready cabs as his live rig. Yer in good company!
  4. FatStrings


    Nov 16, 2001
    Southern NH
    Thanks for all that info guys! I've done searches on the web and in Talkbass and not come up with a fraction of that. :)

    Winston your name came up in the Talkbass search,
    so I was hoping you'd see this post.

    I haven't played the amp at practice yet (one of the band members is on vacation), but playing it at home, this thing sounds killer!
    I got the amp and a four space SKB case at Mars for $600. It needed a little touch up here and there on the outside, but the inside was surprisingly clean.
    Again, thanks alot
  5. I think you must have a much older 400, it's definatly not a 400+ which has 12 power tubes and 4 preamp tubes. I have the Svetlana 6l6GC and they are outstanding. It's heavy, but there IS no comparison to the tube sound in my humble opinion. Happy Holidays!
  6. FatStrings


    Nov 16, 2001
    Southern NH
    Thanks Big String. And yes I definately have the older 400 with 6 6L6's.

    I have some crackling at high volume on channel 2, so I spray cleaned the pot with cleaner conditioner.
    It almost completely corrected the problem.
    I'll keep messing with it, although I might have to retube at some point soon.

    Thanks for the post and have a great holiday yourself,

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