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oops! did I do damage something?

Discussion in 'Amps and Cabs [BG]' started by K-Funk, Mar 11, 2008.

  1. K-Funk


    Sep 24, 2007
    Auburn Hills, MI
    actually it's "do damage TO something", but moving on.....

    Well, we started rehearsal and in a total "state-of-dumbass" I forgot to plug the cabinet into my 400+. I turned it on, but it was only on for about 10 seconds before I realized my error. Played and sounded just fine afterward. I think I lucked out, but is there any more concerns I should have (besides never doing that again!)

    Also, how long does it take a tube amp to destroy itself when running without a cabinet?
  2. Don't worry. You did not hurt anything in 10 seconds. Check with one of the Mesa "gurus" on the forum. Mesa may provide protection for un-penetrated speaker jacks anyway. Safe thing with heads is to just get in the habit of plugging in a speaker cable before you do AnyThing else.
    Your Head Is Fine :)
  3. TrooperFarva


    Nov 25, 2004
    New City, NY
    Well, most of what you said there is wrong. It takes far less than 10 seconds to seriously damage a tube amp not connected to a speaker load. The 400+ does not have any kind of protection for when cabs aren't connected. I know both of these for a fact, because my guitarist blew mine up when I used to have one. He powered it up and took it off standby when it wasn't connected to the cab.

    If, at the time, your master volume was at 0, then your head will be fine, the 400+ manual specifically says that if you leave the Master Volume at 0, you can take the amp off standby with no load connected.

    But if you haven't experienced any problems since it happened, then your head is likely in good shape. If you didn't smell anything bad at the time, and when you open up the bottom of your amp, you don't see any burn marks, and all your tubes still light up, then I'd say you're fine.
  4. K-Funk


    Sep 24, 2007
    Auburn Hills, MI
    yeah, there's no burn marks and the tubes all glow.

    If I recall correctly, when I turned it on it was in standby and the master was at zero. I took it off of standby and turned up the master to about 3, and noticed there was no sound. I immediately shut it off and plugged in the cabinet.

    So the amp was in the "danger zone", off standby and with the master on 3 for about a total of 5 seconds, tops.

    If there are burn marks, where would they be located? I may have missed them. But regardless, the amp works perfectly fine, nothing smelled funny and all the tubes lit up.
  5. Rob Mancini

    Rob Mancini Guest

    Feb 26, 2008
    I wouldn't worry about it then. While Trooper is right, the real world truth is that many of us have forgotten to plug in our tube amp's speakers before for a short time and not had a problem. Not something you want to make a habit of, though.
  6. ezstep


    Nov 25, 2004
    north Louisiana
    Nope, you are all wrong! Your head is now worthless. Ship it to me and I will be happy to take it apart and separate the parts for recycling. That's about all it's good for. I'll even help with the shipping.


    I actually did the same thing one gig (and only one) where we were really rushed to hook up the p.a., monitors, mics and cables and d.i.', and I had forgotten to put a speaker cable on the cab. When I tried to tune, I got nothing. I, too, played around for maybe ten seconds - maybe less - before I figured out what I had forgotten. The head worked quite well for the next seven or eight years before I sold it (19 years altogether).
  7. TrooperFarva


    Nov 25, 2004
    New City, NY
    If you open up the bottom of your amp, there's a lot of resistors and such, if there's any burn marks under them, that'd definitely be an indication of a problem. Unfortunately, I don't have a picture as an example.
  8. Tim1


    Sep 9, 2005
    New Zealand
    Did the same thing once with my 400+ with no problems ensuing. Stupidest thing I ever did was trying to figure out why my sound was so muffled - it took a few minutes before I noticed that I had not taken the front cover off my Road Ready Diesel 215 case, it was effectively a 100% sealed cabinet with nowhere for the sound to come from!! Much hilarity from my bandmates.
  9. K-Funk


    Sep 24, 2007
    Auburn Hills, MI
    a bit off topic.... but does anyone know where I can get a solid 4U rack for my 400+? Preferably a genuine Mesa, and how much would it cost? Upon checking out the bottom, I noticed that the claws on my Gator case had been gouging the hell out of the paint. Arrgghh!! I hate watching expensive stuff get scraped up!

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