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I just bought a 400+

Discussion in 'Amps and Cabs [BG]' started by thirdeye, Jun 30, 2002.

  1. Damn...these things are the most awsome sounding beast.I was worried about not having enough volume to compete with my very,very loud band,I had the pre on 5 and master on 3 and a half and it was #$@!%*! loud.Love the tubey grind I get from it.

    Just one problem,it kept blowing fuses,never when i was playing just in between songs.I know it could be nothing to do with the amp,and just an outside power problem,but I'm new to tube amps and was just wondering if there could be something wrong with the amp itself?

    Just above where the fuse is on the front panel,there was a bit of shaped tape stuck over the fuse rating,looked like it was put there from factory.It says "8.0 AMP,SLO-BLO".The fuse that was in there when I bought it was a 3 amp,the only one I could find to replace it was a 15 amp,that blew aswell.

    The amp had new Peavy 6l6 power tubes installed,
    Could that be something to do with it?mabey something to do with biasing?

    Once again I don't know much about tube amps,so any help would be appreciated.Thanks.
  2. thelastofus

    thelastofus Guest

    Jul 3, 2002
    Bakersfield, Ca
    I recently ran into that same problem, my amp kept blowing fuses then i realized that the fuse was too big. dangit! now i'm just hoping i didn't mess it up really bad
  3. Big String

    Big String Supporting Member

    Apr 22, 2000
    Northwest Indiana
    I take it you bought the 400+ used????
    Peavy Tubes....???
    I would say have a good amp tech look at it before you get something seriously bad happening.

    If it were me, I would definatly call Mesa and tell them what is going on. They are very helpful.
    I would put the proper fuse in and get some spares.
    I would make sure you had the right tubes in your amp.

    400+ dosen't come with biasing adjustments, that is why getting the right mA (millamp) rated tube is important and that's why Mesa alway says to use their tubes; which I don't. I can tell you to get some Svetlana 6l6GC (20mA to 27mA range) and some 12ax7EH and you'll be happening.

    A wise tube guru once told me most tube suppliers have their own tube testing devices to measure the milliamps and match them close. There is supposedly no standard of tolerences to keep it consistant so one guys tubes might be a little hotter or cooler than the others. Not to worry though, just go to someone like Lord Valve or the Tubestore.com and you'll get quality parts and service. These guys know the needs of your particular amp design. Before you spend the money on tubes though ---- go see a good amp tech to check it out. Amen;)

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