Fender Hot Rod Deluxe Crackling

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by kkendog21, Feb 26, 2012.

  1. kkendog21

    kkendog21 Member

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    I just put some JJ 6L6GC power tubes in my hot rod after noticing one of the two GrooveTubes had burned out. Sounded great after replacing them, but just a few minutes later I had noticed that there was a more than noticeable crackling noise behind my guitar sound. It goes on and off frequently, like one second its off, then the next few seconds it is crackling, and so on. Any suggestions or diagnostics?
     
  2. WaltC

    WaltC Member

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    time for a trip to the amp doctor. Search this forum for "hot rod deluxe" and read the numerous posts on problems, fixes, etc.
     
  3. LarryN

    LarryN Member

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    Burnt or open resistors in the power amp are common the Hot Rod series. Carbon films don't have as high a voltage capacity as the carbon comps in older designs.
     
  4. Stonecutter

    Stonecutter Member

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    When I hear crackling I first think tube sockets, since in my experience that's the most common cause. Try to wiggle the power tubes around really carefully while it's doing it and see if you can affect it, don't get burned.

    Check ALL those tubes as well, you need to get that out of the way if you want to continue troubleshooting. It's not uncommon for a preamp tube to go bad like this. But, also since those new tubes are the only thing that have changed, they are highly suspect as well.

    After that, and checking all the other obligatory checks, (guitar, chord, speaker) you would might want to take it to a pro (who probably has A LOT of experience with Fender PCB amps).
     
  5. Ronsonic

    Ronsonic Member

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    As Walt says, this is a well-known, well-documented problem with those amps.

    For the quick fix, try running a short cable in the FX loop.
     
  6. Zerksies

    Zerksies Member

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    Did you happen to clean the tube sockets before you put them in
     
  7. Stonecutter

    Stonecutter Member

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    Ah yes! The first thing that should be done on those amps anyways. Totally slipped my mind.
     
  8. Don A

    Don A Silver Supporting Member

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    Could be a screen resistor.

    I just went though this with my Ampeg Jet. There was crackling that would come and go. It was worse on bass notes. I thought it was a speaker or a bad tube. One power tube was barely getting warm. The screen resistor looked fine but read completely open on my meter.

    I replaced them both and the problem is gone.

    A blown power tube can take a screen resistor with it.
     
  9. kkendog21

    kkendog21 Member

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    Its getting progressively worse now. When I turn it on it pops really loud, crackles, and pops really loud as I am playing. This is the 3rd used Hot Rod I bought from Guitar Center, and Im getting pissed
     
  10. Ronsonic

    Ronsonic Member

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    Take it to a tech, have it gone over and don't worry about it again.

    These have regular problems from poor solders. Get it fixed and stop getting pissed.
     
  11. kkendog21

    kkendog21 Member

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    Will do. Thanks everybody
     
  12. mageerc

    mageerc Member

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    It could very well be the plate load resistors on the PI tube or bad solder joints where the tube sockets connect to the circuit board...
     
  13. Zingeroo

    Zingeroo Member

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    Those amps always have bad solder joints.
     
  14. Ronsonic

    Ronsonic Member

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    I'm almost ready to start lobbying for a sticky thread on every amp forum. It seems I'm explaining this weekly.
     

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