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Why my Mesa Tubes blew?

Discussion in 'Amps and Cabs [BG]' started by Colarndo, Nov 12, 2004.


  1. Colarndo

    Colarndo

    Mar 7, 2004
    Singapore
  2. Benjamin Strange

    Benjamin Strange Commercial User

    Dec 25, 2002
    New Orleans, LA
    Owner / Tech: Strange Guitarworks
    Tubes break sometimes. It happens. Get some new tubes and try again.

    By the way, define "blow".
     
  3. Colarndo

    Colarndo

    Mar 7, 2004
    Singapore
    "Pop" Sound.
    Than silence.
    Used the term as "blew"? or went bust?
     
  4. Colarndo

    Colarndo

    Mar 7, 2004
    Singapore
    The question is, whether it's safe running from line out cos my dealer told me I should have ran out from the speaker load output. That's why the tubes blew, cos they needed a load out?
     
  5. ChenNuts44

    ChenNuts44

    Nov 18, 2001
    Davenport, IA
    There's no output transformer, so you don't have to run the speaker output into a load. You should be able to operate the amp using only the line out without problems.
     
  6. Colarndo

    Colarndo

    Mar 7, 2004
    Singapore
    Hmm. My dealer said the reason why my tubes blew was because I didn't give a load out so the tubes couldn't take it. He said I must take the signal from the speaker output instead of the line output.
    I am really confused right now. That means if my tubes don't get a load out, they're not gonna last long. it's less than a month now and i blew the tubes.
     
  7. I'm going to take a wild guess.
    Are the preamp tubes (12ax7) the tubes going out?
    Are the preamp tubes the LPS type?
    If so...
    Even though I was using a Mesa 400+ at the time and I know that is a completely different amp but.... I had installed at least 6 12ax7lps preamp tubes before we figured out the Mesa's don't like these tubes which I think were relatively new a few years back. I was also told there were some bad tubes of that type issued and the problem was fixed. ??? I never tried them after that though. If you are unsure you really really need to cal MESA they will get back to you. I would'nt trust what the dealer says even though he may be right or have good intentions. Call Mesa.
     
  8. nonsqtr

    nonsqtr The emperor has no clothes!

    Aug 29, 2003
    Burbank CA USA
    Agreed. I think your dealer is wrong. A solid state amp without a power transformer should not require a speaker load to operate correctly. My guess is, there's a problem in the power supply. Both tubes shouldn't pop at once for no reason. I agree, before putting in a new set and trying again, call Mesa. Then have a tech do a thorough electrical inspection of the power supply portion of the amp (or do it yourself if you're electronically inclined). Then if all checks out, replace the tubes and try again. There is the possibility that one tube blew and took out the other, stuff like that can happen. Fortunately, 12ax7's are cheap and readily avaiable. :)
     
  9. Colarndo

    Colarndo

    Mar 7, 2004
    Singapore
    Thanks guys. Appreciate it. Well there's no way i can send it back. I stay in a small island called Singapore....
    I'll have to do some international calling to Mesa
     
  10. I wasn't sure if it was a SS amp but I see it is. As the others have stated you should be able to run the amp without a load form the speaker. Let me see if I've got this correct. You're running the Mesa into a combo amp right? Were are you running the line out from the mpulse into the combo? Are you going into the input or the loop return if it has one? Can you run the speakers from the combo into the speaker out of the mpulse possible with an adapter and bypass the combo head?

    Please give a run down of your signal chain.
     
  11. Colarndo

    Colarndo

    Mar 7, 2004
    Singapore
    I took the line out Frm M-Pulse into a Eden Nemesis Pre-amp input. The Nemesis Pre-amp powers a 2X12' cabinet.
    I can't bypass the combo head.
    Cos it isn't my combo amp. I just pay $$ to rent it for a weekly 2hr jamming session with my band.

    Great, I don't know how to make international calls from Singapore. Rats.
     
  12. Benjamin Strange

    Benjamin Strange Commercial User

    Dec 25, 2002
    New Orleans, LA
    Owner / Tech: Strange Guitarworks
    Yup, your dealer is way wrong. The tubes in that guy drive the preamp and the mosfets, not the power.

    A popping sound makes me think that you blew a fuse, rather than a tube. Did you check that?
     
  13. Colarndo

    Colarndo

    Mar 7, 2004
    Singapore
    Hmm. Guess I'll have to wait till i can get an electric screwdriver to open it out. Cos there's these screw that cannot be manually be opened by a hand welded screwdriver....
     
  14. Believe it or not one of my many gear trials included an Eden Nemeis... Here is what happened. At the time I was using an SWR Basic Red 350w amp run into a SWR Henry 8x8. I had bought a new Nemisis and wanted to use them together on a bigger venue. I ran the LINE OUT of the SWR to the input of the Nemisis and shortly there after smelled something cooking....it was the Nemisis and it was fried. I sent it back to Eden and they repaired it. Yikes... maybe you shouldn't continue.
     
  15. notanaggie

    notanaggie Guest

    Sep 30, 2003
    And, please repeat, just how do you know "the tubes blew"? The dealer said so? 99% chance the dealer is full of dhurri. (if I have spelled that close enough, you'll know what I mean)

    I have fixed an awful lot of tube stuff, and i have YET TO SEE a "blown" preamp tube. Plenty of weird stuff with output tubes, but you don't have any.

    That dealer sounds like a prize turkey. Maybe you should find a decent technician and get a truthful report on what the real problem is.

    Ther clearly isn't enough info to make any decent guess from what you can see outside and have explained here. Not your fault, no shame in that, there are musicians and there are techs.....

    Oh, and:
    Warranties are fine, but from Singapore, it might be cheaper to just fix it, as opposed to shipping and so forth. Does mesa pick up international shipping on warranty? Do they actually warranty overseas stuff from their USA office?
     
  16. Bridge Cables

    Bridge Cables Gold Supporting Member

    Mar 23, 2003
    Southern N C
    I think you may want to give your dealer a second chance on this one.

    Was looking at the Mesa manuals site and the way I read it on all M-Pulses they do require you to have a recommended load on the head before switching it on. It is listed in the Precautions & Warnings page just after the table of contents. That will include the 750, 600, 360 and Walkabout since Mesa lists them all as the M-Pulse line.

    http://www.mesaboogie.com/manuals/user_manuals.htm

    I'm definitely not a techie at this end so I may be reading it wrong. In the places I play I've always needed a cab whether going to the board or not so I have never played my 600 or for that matter my D-180 without a cab/load.

    Maybe some of the more advanced here on the board can translate what Mesa is saying in their manuals.

    BC :cool:
     
  17. nonsqtr

    nonsqtr The emperor has no clothes!

    Aug 29, 2003
    Burbank CA USA
    Looks like boilerplate verbiage to me. Note that the warning is in the same section as: "Your amplifier is louid! Exposure to high sound volumes may cause permanent hearing damage." :D

    Reading note (2) in the "Helpful Hints" section, it looks like this smp has a pretty typical solid state power amp section. But one would have to see the schematic to be sure.
     
  18. Heckxx

    Heckxx

    Nov 2, 2004
    Libertyville, IL
    did anyone mention that possibly power regulations are different in Singapore, thus that may be the cause of the problem? Maybe an electrical surge, voltage mismatch, soemthing like that?