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EVH keeps burning tubes

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  • EVH keeps burning tubes

    A few weeks ago I started getting screech noises from my EVH 100w. Around the same time, one of the power tubes started glowing like mad, leaving a burn mark on the inside of the glass.

    Took the amp home, chopstick tested it. Sure enough, one of the preamp tubes had gone microphonic. Replaced that one and also replaced the burnt power tube as well as its pairing tube.

    Played it maybe three times since then, everything seemed fine. Then after maybe 15 minutes of playing today, I start getting weird noises. Peek into the amp and sure enough, same power tube as before is glowing like a house on fire. Quickly shut off the amp. JJ logo printed on the tube looks burnt out, cant tell yet if anything on the inside got scorched as well.

    Have two gigs abroad in five days, so I need to fix this ASAP.

    Any clues where I should start looking? Will try to find a tech that can get it done pronto but figured it can't hurt to know what to look for from the get-go.
    --------------------------------------------------------
    1973 Aria 551
    1984 Larrivee RS-4 w/ EMG SA/SA/89
    1989 Charvel 750 XL w/ DMZ Tone Zone & Air Norton
    1990's noname crap-o-caster plywood P/J Bass
    1991 Heartfield Elan III w/ DMZ mystery pups
    1995 Aria Pro II TA-65
    2001 Gibson Les Paul Gothic w/ PG-1 & SH-8

  • #2
    Re: EVH keeps burning tubes

    Screen grid resistor maybe ?
    Are you blowing fuses ?
    Get rid of the JJ tubes.
    Last edited by JMP/HBE; 05-12-2019, 12:45 PM.

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    • #3
      Re: EVH keeps burning tubes

      Originally posted by JMP/HBE View Post
      Screen grid resistor maybe ?
      Are you blowing fuses ?
      Get rid of the JJ tubes.
      Get rid of the JJs as in "you need new tubes" or as in "that particular brand is not to my liking"?

      Haven't opened up the amp yet, so no idea if any fuse is blown.
      --------------------------------------------------------
      1973 Aria 551
      1984 Larrivee RS-4 w/ EMG SA/SA/89
      1989 Charvel 750 XL w/ DMZ Tone Zone & Air Norton
      1990's noname crap-o-caster plywood P/J Bass
      1991 Heartfield Elan III w/ DMZ mystery pups
      1995 Aria Pro II TA-65
      2001 Gibson Les Paul Gothic w/ PG-1 & SH-8

      Comment


      • #4
        Re: EVH keeps burning tubes

        For a moment I had a flashback about reading how Edward would supposedly crank his variac to 150V and melt tubes...
        Lefty Lounge Lizard's Guitars & Amps Extravaganza

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        • #5
          Re: EVH keeps burning tubes

          Edward never did that, he lowered the voltage to ~80, he said that in the interviews though because A) it sounded cooler and B) he never gave away secrets in those days.

          Back to the OP, I would have it on a tech's bench ASAP if you have big gigs coming up, definitely sounds like something in the bias circuit is toast. JJ tubes aren't always the best sounding tubes, but I've never heard of them not being pretty sturdy.

          Comment


          • #6
            Re: EVH keeps burning tubes

            Had the same kinda issues with a deluxe reverb once
            Took it to a tech and got new screen grid resistors!
            Sounds like what you need

            Sent from my SM-G930U using Tapatalk

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            • #7
              Re: EVH keeps burning tubes

              Originally posted by Coma View Post
              Get rid of the JJs as in "you need new tubes" or as in "that particular brand is not to my liking"?

              Haven't opened up the amp yet, so no idea if any fuse is blown.
              Both. Put it on the bench with a qualified tech.

              Comment


              • #8
                Re: EVH keeps burning tubes

                Tech sorted it out. Turns out there was one right across the street from where we rehears. One tube was short-circuited across all pins. Another one was overheating so hard it had burnt a bunch of components around it. Screen grid resistor was shot. One big resistor rated for 5W had flat out exploded. Should've just handed it in when it first started acting up - the new pair of tubes I put in two weeks ago went straight in the bin.

                Still, seems to be working now. Techie replaced all busted components and put in a new quad of power tubes (yes, JJs. They sound fine in that amp).

                Asked me how I liked it biased. I had no idea how it was set before, so I just told him to set it to what he thought was best. But it seems to have lost a lot of headroom now, might ask him to adjust it for me when I'm back in the country.
                --------------------------------------------------------
                1973 Aria 551
                1984 Larrivee RS-4 w/ EMG SA/SA/89
                1989 Charvel 750 XL w/ DMZ Tone Zone & Air Norton
                1990's noname crap-o-caster plywood P/J Bass
                1991 Heartfield Elan III w/ DMZ mystery pups
                1995 Aria Pro II TA-65
                2001 Gibson Les Paul Gothic w/ PG-1 & SH-8

                Comment

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