Reducing the feedback inna Sup Reverb

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by dick wiewy, Nov 16, 2005.


  1. dick wiewy

    dick wiewy Member

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    Does anyone have a recomendation for reducing the feedback squeal in a silverfaced Super Reverb? I'm using it onstage for harp playing so it's proximity to the mic is pretty close as a rule. I'm thinking in terms of preamp tube substitution or sumpin'.:confused:
     
  2. dave s

    dave s Member

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    1st, plug in a guitar to the amp and turn it up really loud. Is it still feeding back?

    My guess would be that you are cupping a microphone in addition to being too close to a guitar amp with a microphone which is the true cause of the feedback situation and not the amp itself.

    dave
     
  3. bob-i

    bob-i Member

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    Use a 1/3rd octave eq in line with the mike. Once you're setup "ring out" the eq, meaning get yourself in playing position and turn it up slowly until it just starts to ring (squeel). Find the slider that controls that note and reduce it until the ring just goes away, turn up and look for the next slider. By the time you get done ringing it out you'll have a half dozen or so sliders reduced a few DB.

    Since a 1/3 octave eq only takes away a small portion of the tone, you'll most likely not hear a difference.
     
  4. Blue Strat

    Blue Strat Member

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    A lot of harp players use lower gain preamp tubes in (at least) the first stage of their amps. I recommend trying a 12AY7.
     
  5. AL30

    AL30 Member

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    Changing the pre-amps is a good suggestion as are the other suggetions.

    Check this page for some gain factors of different pre-amp tubes

    http://www.thetubestore.com/gainfactor.html

    I'm certainly no harp player but that amp is a MONSTER for a harp player. Have you considered something smaller? The few harp players I've seen use much smaller amps - old Gibsons etc.

    AL
     
  6. dick wiewy

    dick wiewy Member

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    So the gain reduction of a 12AY7 won't sound wimpy in the final signal? Does this squash the snot outta my headroom? I'm asking rather than trying this 'cause I'm not near my gear if you know what I mean. Thankyou folks for the responses!
     
  7. tonezoneonline

    tonezoneonline Member

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    There are a lot of things you can do or have done.The lower gain preamp tube being the easiest and less invasive.You can have a tech lower the plate voltage on the first preamp tube with the dropping resistor or you can change a resistor on the in put jack to pad the input some.3.3M works well in place of the 1M.
     

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