Blown marshal amp

Discussion in 'General Electronics Chat' started by mike s, Apr 8, 2010.

  1. mike s

    Thread Starter New Member

    Apr 8, 2010
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    0
    I've beem jamming out on a buddies marshal amp with my rp300 Digitec 300 about 5 nights, when I bent down to adjust the vol, on my peddle I handed my axe to him, when the amp went dead. He still had his axe straped on, Did we complete a connection? He's saying I shouldn't have plugged that digitec into something with a preamp in it. I'm thinking we're
    playing in a barn without proper grownding, and when we exchanged guitars we made a connection?
     
  2. retched

    AAC Fanatic!

    Dec 5, 2009
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    You may have made a "connection, dude". But not a circuit.

    The guitar cords only carry very low voltage and currents produced by the string vibrating in the pick-ups magnetic field.

    You probably blew an input fuse if you plugged a preamped signal into a preamp.

    I would look through google for fuse locations for that amp to see if the y are easy to change. Also, Is the power light still on?
     
  3. Mike33

    AAC Fanatic!

    Feb 4, 2005
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    +1 Retched.

    Don't get nervous...I've seen preamp pedals like that cause weird problems with amps. Mainly because they're turned up too much. I like to keep my Digitech RP350 set to <"80" or so on the main vol. output, and use my amp to turn things up. This protects the input circuitry. Should be a fuse that blew, maybe even the one you can access on the back of the amp. I too am curious if the pilot light is still on. If not, that indicates 'main fuse', probably in the IEC power cord receptacle. **ALWAYS replace with exactly the same rating fuse **

    Just diagnosed a Behringer bass amp - my bassist's friend jammed out with a pedal into it, blew the speaker and then the fuses went. So, $120 speaker is on the way. Gotta watch the output levels of those things! I don't think it's so much the 'using it with a preamp' as making sure you don't get over excited and turn the pedal up too much....if you're putting more than like 4.5VAC into the front end of an amp, that's probably too much IMHO.
     
  4. nomurphy

    AAC Fanatic!

    Aug 8, 2005
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    If you were both plugged into the same amp, then there is no chance that there was cross current through the guitars. You may have overloaded the input, fried an output, or just coincidentally lost a tube (if not solid state). However, if you were connected to different amps that have two-pin AC plugs then you were/are creating a dangerous situation. Reversed plugs and messed up polarity switches have been the cause of electrocution. Did you see any sparks flying, or experience any sudden involuntary twitching?
     
  5. retched

    AAC Fanatic!

    Dec 5, 2009
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    Not any more that is standard for rock-and-roll. ;)
     
  6. mike s

    Thread Starter New Member

    Apr 8, 2010
    2
    0
    Well my buddy said the power light does come on and the fans a blowing, no sparks a flying yet. They do have an electric fence for the horses witch was causing a on and off buzzing in the amps
     
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