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Alessandro making a funny popping noise

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Sam Evans, Jun 5, 2003.

  1. Sam Evans

    Sam Evans Compliance Officer Gold Supporting Member

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    After tube swaps (pre and power), I'm still getting an odd popping/sputtering sound when I play. The amp does not do this when I'm not playing. It kinda reminds me of the sputtering of the Fuzz Factory. I'll ask George in the a.m., but I figured I'd run it by here first to save myself some potential frieght charges.

    Sam
     
  2. Braciola

    Braciola Silver Supporting Member

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    With the amp on, gently wiggle each tube and see if you get the noise you described. It may be something as simple an a dirty tube socket. If you find by wiggling one of the tubes you get the noise, unplug the amp, then try pulling the tube in and out a few times to help clean the connections, a good spray cleaner would'nt hurt in the process.
     
  3. Leonc

    Leonc Wild Gear Hearder Gold Supporting Member

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    I had the same problem with my Bloodhound when I was using all 12AX7s and EL34s. I switched to 12AX7, 12AU7 and 12AT7, as I recall (it was what George recommended to me). Problem solved.
     
  4. In that case, I suspect its blocking distortion. You're probably driving the grid positive. Its a pretty hot circuit, so cutting it back a it should help.

    Does the problem occur when you turn down to pretty low levels?

    DS
     
  5. Sam Evans

    Sam Evans Compliance Officer Gold Supporting Member

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    I swapped out 2 of the AX7s for an AT7 and a 5751. Still does it, but not as much. It also does it a lower volumes.

    Sam
     
  6. johngalt

    johngalt Guest

    Is it tube rectified? I have experienced something like that when a cheap Chinese rectifier was near death.
     
  7. Sam Evans

    Sam Evans Compliance Officer Gold Supporting Member

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  8. VaughnC

    VaughnC Supporting Member

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    It sounds like to me that the amp is just on the brink of breaking into oscillation. Sometimes just rearranging the routing of the internal wiring can correct this condition.
     
  9. Sam Evans

    Sam Evans Compliance Officer Gold Supporting Member

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    Sorry Leon,

    I know I've asked you this before, but is the AX7 in V1, next the AU7, then the AT7?

    The problem seems directly related to how hot the guitar is. With a s/c, the problem is gone with lower gain preamp tubes.

    I just got the amp back from George. He repalced a scratchy pot, and when the amp was first fired-up it sounded great as usual. That's why this funkiness has me puzzled.
     
  10. Leonc

    Leonc Wild Gear Hearder Gold Supporting Member

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    Sam - man, sorry but I can't remember... :(
     
  11. Sam Evans

    Sam Evans Compliance Officer Gold Supporting Member

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    No big deal, Leon. I'll run it by George on Monday.

    Thanks to everyone for your help!

    Sam
     

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