mesa roadking 2 tube issues

Discussion in 'Amps and Cabs' started by beerawk, Feb 20, 2012.

  1. beerawk

    beerawk Member

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    Hi everyone, from what I've read here there are some quite knowledgeable people here. My issue is with my Mesa Boogie road king II, when I bought this amp (used) it sounded poor, very little gain and no high end on the 3rd and 4th channels. From what I gathered this is a preamp tube issue. So I started checking the tubes and when I removed the case the glass tip of the tube was broken and it ended up cracking when I attempted to remove it. Now im left with the plastic base of the tube plugged into the socket. Is it safe for me to try and remove it myself, I would prefer not to lug it to the shop seeing as how it's 100 lbs. Another question : is okay to operate this amplifier with the metal covers off the preamp tubes? I find it daunting to get it on the tube with the spring on there

    Many thanks!
     
  2. beerawk

    beerawk Member

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    Here's a shot of the broken tube in the socket (if that's what the plastic part is...)

    [​IMG]
     
  3. Blue Strat

    Blue Strat Member

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    That's not the base of the tube, 12AX7s don't have plastic bases...only power tubes (except for EL84s) do.

    What you see there is a mica spacer, part of the internals of the tube. If you take that off you'll likely have more broken glass and 9 tube pins, plugged into the socket, beneath it. You'd have to CAREFULLY remove all the pieces without shocking yourself. Amps can hold voltage for days after they're turned off. Unless you have a way to check the power supply for voltage I don't recommend doing this yourself.
     
  4. beerawk

    beerawk Member

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    I managed to get it out, pins intact! Now, can I replace my preamp tubes and run them with no covers? I mean in terms of physical danger to the amp being damaged, I assume I can pop in any 12ax7 into any slot?
     
  5. NortheastHick

    NortheastHick Supporting Member

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    Yes, the covers are not necessary. Any 12ax7 will work. If you're losing a lot of high-end i would guess you're power tubes are shot. High end is the first thing to go when power tubes get old.
     
  6. beerawk

    beerawk Member

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    Hmm, thats interesting, most times I have read that losing gain, high-end and having the lows go flabby and muddy is the pre amps. Maybe I ought to swap both the pre and power amp tubes....
     
  7. BoogieManSC

    BoogieManSC Supporting Member

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    Yes, I'd swap out the tubes if you can swing it. I also have the RK2 and if it's not giving your searing gain, it most likely is the tubes. Also, regarding the pre-amp tube covers...if I remember right, you kind of have to push them in, then twist them off...just so you're not tweaking them while removing/installing, etc.

    Also, putting a TungSol ( http://www.musiciansfriend.com//accessories/tungsol-12ax7-tube/212231000000000?src=3TEMORD ) in the V1 position makes it sound SWEET! I picked up that tip off the Boogie Board...worked like a charm. The rest of my tubes are stock Boogie....JJ's if I'm not mistaken?
     
  8. beerawk

    beerawk Member

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    Problem is that's going to run me about $250. I might have to do the pre amps first then the power amp later. Perhaps the crappy tone is a combo of both the sets, my hope is it makes the amp usable and not sound like muddy ass.
     

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