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My amp is acting grumpy....

Discussion in 'Glowing Bottle Tube Amp Forum' started by jddub440, Jan 25, 2021.

  1. jddub440

    jddub440 Tele-Holic

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    I have a Carvin Vintage 16 that was always super reliable but now periodically acts up with loud noise issues, usually while warming up. I should note that it also most frequently happens when my guitar and/or pedalboard are not plugged into the input jack of the amp.

    It will feedback like nuts when I turn the amp on and nothing is plugged into the amp. If I then try to plug something in while the amp is starting to feedback the amp takes off like crazy with a louder much more piercing pitch.
    Then I'll turn it off.... unplug and re-plug in my pedalboard (which is powered during all of this everytime I've experienced this) and turn the amp switch back on and everything goes smooth for the rest of the night.

    Is this a situation where I might my power tubes not properly biased or one of the tubes is starting to die??
    I've used this amp for at least 10 years now, I've had the tubes changed a amp technician a time or two and then me and my bandmate started to do it ourselves in the last two years, mostly just the preamp tubes tho.

    Thank you in advance for any advice or knowledge you might be able to throw my way. I love this amps character and tones, I do wish the spring reverb was bouncier however lol.
     
  2. dogmeat

    dogmeat Friend of Leo's

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    I'd start with the jack. it's supposed to ground out when there isn't anything plugged in. maybe just replace it if it's not too hard. I've had bad noises come from a bad jack, though not as you describe. I have had squeals like that from a bad "negative feedback" loop. I found the diagram on Hoffman's site. looks like Carvin is calling it the "FB output".

    https://el34world.com/charts/Schematics/files/Carvin/Carvin_vintage16.pdf
     
    tonejam and jddub440 like this.
  3. jddub440

    jddub440 Tele-Holic

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    Thank you for that advice , I'll try snooping around the input jack tomorrow and see if anything looks suspicious!
     
  4. jddub440

    jddub440 Tele-Holic

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    I tried inspecting the input jack of my amp but it is all covered by a metal plate/shield and I dont feel confident nor comfortable trying to open it up and poke around in there myself.
    My guitar did shock me the other day when I was playing, walked away for a moment and came back to pick it back up and play. I hope that was just a coincidence of some static buildup or something along those lines.
    Overall I'm going to try to take a video of what is happening, capture that awful sound that happens upon warming up and if I can get that I will most likely post it here. But overall I think I just gotta save up and take it to an amp technician because I want to live and I need/love this amplifier!
     
  5. Burning Fingers

    Burning Fingers Tele-Meister

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    Yes..take it to a tech rather than play Russian roulette trying to figure it out yourself.
     
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  6. Don Rich Rules

    Don Rich Rules Tele-Meister

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    You say you're amp is acting grumpy?
    Come by and meet my mother in law then
    you'll really know what grumpy is all about!
     
    jddub440 likes this.
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