dr z maz jr dead preamp tube, advice needed!

Discussion in 'Amps and Cabs' started by bmorelli, Apr 1, 2008.

  1. bmorelli

    bmorelli Member

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    i've got a max jr (212 nr) and i'm pretty sure i've got a dead preamp tube. no sound coming from the amp, i put new power tubes is, tried diff guitars, and cables too - still nothing. if i'm looking at the back of the combo the preamp tube just to the right of the power tubes isn't lighting up.

    two questions - 1. what position is that tube? (v1?,), 2. what do you suggest i put in its place? i pulled the suspect tube and it's a sovtek 12ax7lps. any advice is appreciated!
     
  2. joejazzguitar

    joejazzguitar Silver Supporting Member

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    Sovtek's 12AX7LPS doesn't show a filament glow in the same way many other 12AX7's do... many people think that working LPS's are dead because they don't readily see the filament...

    But if you think that it's dead, you could throw in any working 12AX7 or equivalent (12AT7, 5751, 12AY7, etc) in that slot to see if you get sound out of the amp....

    joe
     
  3. jumpnblues

    jumpnblues Member

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    Replace all tubes, including rectifier, one at a time. If that doesn't do it I'd send it to Mike Zaite (Dr. Z).

    Tom
     
  4. bmorelli

    bmorelli Member

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    ok joe, good to know thanks! i just checked the fuses and the 1/2 amp fuse is blown - maybe a bad rectifier?
     
  5. david eaton

    david eaton Member

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    That happened with mine, the power light stayed on, but I kept blowing 1/2 amp fuses. I swapped out the rectifier tube and it solved the problem.
     
  6. silencer eleven

    silencer eleven Member

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    that happened with mine and it was the PI slot. i changed it out to a ge 5751 and i like it alot more.

    Jordan
     
  7. bmorelli

    bmorelli Member

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    great advice guys, thanks!
     
  8. lakesider

    lakesider Member

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