mesa bass 400+ i the only one??

Discussion in 'Amps and Cabs [BG]' started by groovking, Feb 2, 2001.

  1. i just retubed my 400+ 12ax7a preamps and svetlana 6L6 454 GC outputs....all was fine for about 2 days and i lost channel one, found it to be a preamp tube closest to a transformer. in the dark all other preamp tubes had 2 glowing points visible except for the culprit, only one glowing point. i identified the culprit of the new set as jj tesla. replaced the tube with an old one i had just pulled and bingo channel one came back. that is problem one. NEXT during some hard playing about 3 weeks later i got a huge fire alarm type sound, just like in high school....again found another bad tesla preamp tube, MY QUESTION IS, how many other mesa 400+ owners have experienced similar situations? mesa claims they had a bad run of these tubes and they are the only ones in their experience that create this huge hum sound. sounds as if they have had complaints of similar types. if this is true id like to see how many other 400+ OWNERS HAVE EXPERIENCED THE SAME PROBLEM or PROBLEMS. all seems well when i replace the new teslas one by on with my old preamp tubes. is this purely a tube problem, it has been suggested to me by a reputable third party that this is probably due to other problems within the amp? very possible i no tech and am purely looking for other owners of this amp that have experienced the same it really the tubes is what im trying to find out, even though all seems well at this point with a mix of old and new preamp tubes in my preamp section......thanks all
  2. brianrost

    brianrost Gold Supporting Member

    Apr 26, 2000
    Boston, Taxachusetts
    I used to own a Mesa D-180. The Mesa heads have very high gain preamps and are VERY sensitive to the tubes in them. I did have some odd problems with the amp (like the master volume didn't work!!!) but all were solved by swapping in new tubes.

    I still own a Fender that hummed very badly when I got it. I was expecting to replace some power supply caps but the only problem was a bogus 6L6 power tube; I swapped it out for the hell of it and the hum disappeared!!! These sort of "bonuses" are pretty common when using tube amps.
  3. brewer9


    Jul 5, 2000
    I've owned my 400+ for almost exactly a year and havent had any problems and havent retubed.
  4. timv

    timv Supporting Member

    Jun 7, 2000
    Chandler, AZ
    I've owned my bass 400+ for about 6 years now and haven't had preamp tube problems at all. I have sovtek in it now. I doubt it is anything else in the preamp. It is a fairly simple preamp design and not much could go wrong with it. If it stays working for a while with the old tubes replacing the new, i would bet it was just the tubes. Where did you get the tubes from? If from mesa, they are known not to have the best tubes from some other reputable people, Lord Valve comes to mind.
  5. killer B

    killer B

    Apr 18, 2000
    Phoenix, AZ USA
    I've had my MESA/Boogie BASS 400+ for a about a year and half and have never had any major problems. I've had one pre-amp tube go microphonic, but hey that happens with pre-amp tubes. I've recently retubed it with all MESA tubes and everything sounds and works great. I say you just run across some bad tubes. In my expierience MESA build GREAT amps.
  6. I hate to be the one to say this, because I know that Mesa gear is probably one of the best. Maybe I was just unlucky.

    I bought my Mesa 400+ and Mesa 1516BE in 1992. On the second outing it fried all twelve 5881’s at an important gig, (luckily I was able to borrow a Trace from one of the other bands there)

    It went back to the shop who had to send it back to the UK distributors and I was without it for six weeks. It came back completely re-tubed and lasted for three more gigs until more or less the same thing happened again.
    This time I asked for a replacement amp but was told my one could be fixed, and also McCartney had had exactly the same problems with one of his , but they now knew what was causing this problem.

    The shop loaned me a Hartke 3500, which I used with the Mesa 1516 cab and I was very impressed with this set up.
    Four weeks later the 400+ came back, but I had lost all confidence in it.

    I bought the Hartke and used that set up for the next 8 years, without a single problem, the 400+ sitting in it’s flight case until I sold it recently.

    I must say that the Mesa cab has been used for many hundreds of gigs and has performed faultlessly. I now use it with an Ashdown ABM 500, which I am more than happy with.

    Hope that all you guys using the 400+ don’t have my luck with it.

    I’m not knocking Mesa gear, and know that mine was probably an unusual case.
  7. TCollins


    Apr 4, 2000
    Last Sept. I bought a brand new 400+ -I haven't had a bit of trouble with it. However, I also have a Mesa Basis M-2000 (also new) & I have had nothing but trouble with it --it is now on some "tech's" bench somwhere in Central New Jersey (it's been about two weeks). Mesa has sent me 10 12ax7 tubes for the runs ok for a while then starts making popping & cracking noise right in the middle of songs (very irritating). When the M-2000 is working right, it sounds great...but if I cannot get rid of the popping & cracking---I'm getting rid of it. I will let all you Mesa bass amp owners know how the repair turns out....