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  • Bye Bye Tubes?

    I use Marshall stereo amp (model 9200; 2 mono blocks 100W each) in my rig with Mesa Boogie Tri-Axis pre-amp and Rocktron processor. I have been experiencing problems in recent times with distortion bleeding through the clean set up of TriAxis pre-amp (green mode) and popping sounds. I suspect that the problem is in Marshall, as I have not serviced it or changed any of the 8 power and few driver tubes for the last 11 years, since I bought this set up. However, before I go and spend the money in buying 8 power (EL034) tubes and/or driver tubes, it would be nice to be reasonably certain that this is where the problem is.

    The problem could also be with TriAxis pre-amp tubes (12-AX7), however, less likely. Pre-amp tubes usually last lot longer than power output tubes. Any comments or suggestions would help me in deciding what to do, before I spend the money on the tubes.
    <div class="signaturecontainer"><b>&quot;So Jimi Hendrix, Nicolo Paganini, Chet Atkins, Wolfgang Amadeus Mozart and Shawn Lane walk into this bar... &quot;</b><br />
    <br />
    <i>&quot;Versatility and originality are your friends.&quot;</i></div>

  • #2
    find someone with a tube tester...good luck, though. They used to have them in every 5 and dime store, but those days are long gone.
    First, observe the tubes and see if any look different (Color, glow intensity) under power, if not, you could try swapping in one known good new tube at each position until you find the one that needs replacing...
    _"We are currently experiencing some technical difficulties due to reality fluctuations. The elves are working tirelessly to patch the correct version of reality. Activities here have been temporarily disabled since the fundamentals of mathematics, physics and reason may be incomprehensible during this indeterminant period of instability. Normal service will be restored once we are certain as to what 'normal' is."

    Comment


    • #3
      I'd swap out the pre amp tubes first and see what happens. Too, if you can just monitor the output of the preamp and try to hear anything weird, that may be a clue as well. If all is well, it most likely is the Marshall. You can lightly tap on each tube and see if that causes any popping or noise.... to try and isolate the prob.
      IN any case, I think you are due for tubes. You should be able to run just two power tubes per side on that power amp if you don't need the full 100w .... just adjust your impedence accordingly.

      Comment


      • #4
        Hook your Triaxis up to another Amp,

        Bypass the Marshall

        Just Go Into The Front
        <div class="signaturecontainer">My HC Classified Thread<br />
        <br />
        <a href="http://acapella.harmony-central.com/showthread.php?2482854-Gibson-Fender-PRS-Jackson-Marshalls-More" target="_blank">http://acapella.harmony-central.com/...Marshalls-More</a></div>

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        • #5
          Hook another amp into your Marshall

          Bypass the Triaxis

          Go Out of the Send, Effects Loop

          Into The Marshall
          <div class="signaturecontainer">My HC Classified Thread<br />
          <br />
          <a href="http://acapella.harmony-central.com/showthread.php?2482854-Gibson-Fender-PRS-Jackson-Marshalls-More" target="_blank">http://acapella.harmony-central.com/...Marshalls-More</a></div>

          Comment


          • #6
            Slam the Marshall on the ground really hard a few times and then if you slammed it hard enough, you'll be pretty sure the problem is with that amp.

            Comment


            • #7
              ^ The Joe Bean Method!
              _"We are currently experiencing some technical difficulties due to reality fluctuations. The elves are working tirelessly to patch the correct version of reality. Activities here have been temporarily disabled since the fundamentals of mathematics, physics and reason may be incomprehensible during this indeterminant period of instability. Normal service will be restored once we are certain as to what 'normal' is."

              Comment


              • #8
                Usually with bad Power tubes

                you have high's and lows with the Volume


                You first turn the amp on and its ok,

                then within minutes the volume drops

                ( goes low )


                Then you start blowing fuses


                As We All Know
                <div class="signaturecontainer">My HC Classified Thread<br />
                <br />
                <a href="http://acapella.harmony-central.com/showthread.php?2482854-Gibson-Fender-PRS-Jackson-Marshalls-More" target="_blank">http://acapella.harmony-central.com/...Marshalls-More</a></div>

                Comment


                • #9
                  I'd swap out the pre amp tubes first and see what happens. Too, if you can just monitor the output of the preamp and try to hear anything weird, that may be a clue as well. If all is well, it most likely is the Marshall. You can lightly tap on each tube and see if that causes any popping or noise.... to try and isolate the prob.
                  IN any case, I think you are due for tubes. You should be able to run just two power tubes per side on that power amp if you don't need the full 100w .... just adjust your impedence accordingly.



                  Both Good

                  Recommendations
                  <div class="signaturecontainer">My HC Classified Thread<br />
                  <br />
                  <a href="http://acapella.harmony-central.com/showthread.php?2482854-Gibson-Fender-PRS-Jackson-Marshalls-More" target="_blank">http://acapella.harmony-central.com/...Marshalls-More</a></div>

                  Comment


                  • #10
                    Thanks for the responses guys, I'll try some of these test methods. The money isn't an issue to replace them, but more of a time issue if it's not the tubes causing the problem. I can get them a lot cheaper from overseas. They are due for a replacement regardless I guess as well. Oh well, for now I am playing on the Vox, haha.

                    Thanks again.
                    <div class="signaturecontainer"><b>&quot;So Jimi Hendrix, Nicolo Paganini, Chet Atkins, Wolfgang Amadeus Mozart and Shawn Lane walk into this bar... &quot;</b><br />
                    <br />
                    <i>&quot;Versatility and originality are your friends.&quot;</i></div>

                    Comment


                    • #11
                      btw, if you are going with Tweedies' 'tap teh tube' method...do not use your finger...use a pencil with a rubber eraser...
                      _"We are currently experiencing some technical difficulties due to reality fluctuations. The elves are working tirelessly to patch the correct version of reality. Activities here have been temporarily disabled since the fundamentals of mathematics, physics and reason may be incomprehensible during this indeterminant period of instability. Normal service will be restored once we are certain as to what 'normal' is."

                      Comment



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