Why am I getting these high-pitched feedback-y sounds?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Jason Calieri, Apr 28, 2016.

  1. Jason Calieri

    Jason Calieri Silver Supporting Member

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    VHT Fifty Twelve 1x12 combo, all new tubes, re-biased. New Scumback speaker.

    As these chords trail off, you can hear (hopefully) a high-pitched oscillating feedback type sound. It changes depending on the notes. Any idea what could be causing it?

     
  2. Rod

    Rod Tone is Paramount Silver Supporting Member

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    Preamp tubes?
     
  3. Jason Calieri

    Jason Calieri Silver Supporting Member

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    I don't think so - I swapped out the preamp tubes one at a time, and pulled pairs of power amp tubes, and the sound was still there. Also happens with a different guitar.
     
  4. Rod

    Rod Tone is Paramount Silver Supporting Member

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    Ok, it's not the tubes.. Did you try the amp with a different speaker.?. Sometimes that can the the cause
     
  5. TimmyP

    TimmyP Member

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    I think the first one is about 1785Hz. I could not isolate the second one.
     
  6. darkfenriz

    darkfenriz Member

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    Reverb spring interactions with the speaker?
     
  7. Jason Calieri

    Jason Calieri Silver Supporting Member

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    I was getting some loud buzzing when I turned up the reverb sometimes, so it seemed like there was a bad contact or something. I think that's fixed now, though. And this sound happens even with the reverb tank unplugged and reverb knob turned off.

    I emailed Fryette, too, so hopefully they have some ideas.
     
  8. Seth L

    Seth L Silver Supporting Member

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    Is your reverb tube driven? If so, what kind of tube.
     
  9. Jason Calieri

    Jason Calieri Silver Supporting Member

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  10. Jason Calieri

    Jason Calieri Silver Supporting Member

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    The amp is from 1994, and I don't think it's had any components replaced. Any chance old caps could result in sounds like this?
     
  11. zenas

    zenas Member

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    If it was me on a 1994 amp. Yeah it'd get all new electrolytics. 22 years on 90's electrolytics is a long time. Just maintenance at this point.
     
  12. Chris Pile

    Chris Pile Member

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    It's not the amp. It's the guitar. Get it intonated.
     
  13. Jason Calieri

    Jason Calieri Silver Supporting Member

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    Bummer. Just bought it used and wasn't expecting that! I'll have a decent tech check it out.
     
  14. Jason Calieri

    Jason Calieri Silver Supporting Member

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    It happens with multiple guitars that are intonated well.
     

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