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Problem with Mesa Boogie 400+ Please help!!!!!

Discussion in 'Amps and Cabs [BG]' started by Morris, Nov 7, 2002.


  1. Morris

    Morris Guest

    Oct 7, 2002
    Cardiff, Wales
    Oh no!! I've just returned from London all excited with my Boogie 400+ only to find it has a problem. I am really annoyed about this as when I tried it out in London (fairly extensively) it was fine. When I set it up in the studio it started making a really horrible humming noise centered around the 50 hz (uk mains) frequency. I tried revalving it with the new set that I got with the amp but that did'nt make a difference. With the amp in standby I can hear the hum originating in the power supply. My friend seems to think its one of the capacitors that has gone funny.

    Does anyone know how to fix this problem or has anyone else with a 400+ or similar had the same thing happen?
     
  2. Nope. Ask Mesa themselves. Make sure you swap all yer cords and try a different instrument to eliminate any possibility of a shorted wire . If it is fairly new, Mesa will no doubt help you with that stellar customer service thing they have going. They have always gone above and beyond for me.
     
  3. ihixulu

    ihixulu Supporting Member

    Mar 31, 2000
    getting warmer
    May sound stupid but try a different electrical outlet in the room or try plugging it in elsewhere. If you have dirty power, it may cause problems.
     
  4. Dirty power...I thought that was just bunk until I played a show in the middle of an island with generators providing AC. Wow...it completely sunk our set. Never experianced that B4. My Mesa M-2000 futzed nad spat, farted and rasped. Scared the hell outta me. that was the worst live set of my carreer i'd have to say.
     
  5. Does it do it with no bass plugged in? If it doesn't, the bass or cable is the problem. If so it's probably something simple like a cold solder joint/loose connection on a ground trace or wire. The power supply will hum a bit when the amp's powered up, that's normal. Keep us posted and good luck!
     
  6. Morris

    Morris Guest

    Oct 7, 2002
    Cardiff, Wales
    Firstly thanks everyone for the A1 advice. Let me get you up to speed. Unfortunately the problem is still there and yes, it does make the noise when there isn't even a jack plugged in. I have recorded the buzz and will post the sound file if anyone thinks its worth it. I have tried it out at numerous locations and with different speaker leads and plug sockets. The sound is definitely coming from the power supply. Well, if anyone out there knows what it could be I'd be incredibly grateful.
     
  7. Morris

    Morris Guest

    Oct 7, 2002
    Cardiff, Wales
    Does anyone know how long you should leave the amp on in standby before turning it on? Similarly should you put it back to standby and leave it for a while before turning it off? Cheers
     
  8. You need to leave the power on standby for 30s-1min to let the filaments of the tubes heat up before you turn on the high voltage. You don't need to let it sit on standby before you turn it off, you can just turn the power off. I usually leave the amp on during set breaks and turn my bass volume down. Not letting the amp sit on standby shouldn't cause the buzz you're hearing, though. It's probably a bad ground somewhere in the amp. I'd suggest taking it to a tech who really knows tube amps, I think that's your best bet.
    Good luck.
     
  9. Morris

    Morris Guest

    Oct 7, 2002
    Cardiff, Wales
    Thanks Mark.:)