Valvestate 8080 way too bright

Discussion in 'The Workbench' started by gsgtrman, Feb 24, 2020.

  1. gsgtrman

    gsgtrman New Member

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    Hey, I have an 8080 combo that I have been using for pit work and other low-volume gigs since I bought it new in 1995. I play a Strat with Dimarzio Virtual Vintage 54's, not many effects. Maybe my ears are changing, but this amp suddenly seems very, very bright. I have the treble turned to zero on both channels, and it's still razor-sharp. Rather than add an eq pedal, can I change a cap and/or resistor on the board to tame the highs? The work I do calls for a lot of sound changes, quickly, so adding the need to change the tone control on the guitar is most times impossible. Being able to dial in a warmer base tone would be most helpful. Any suggestions are appreciated. Thanks!
     
  2. FracStrat

    FracStrat Well-Known Member

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    Have you replaced the PreAmp Tube ?
     
  3. gsgtrman

    gsgtrman New Member

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    Yes, a couple of years ago. I believe it's an EH.
     
  4. FracStrat

    FracStrat Well-Known Member

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    My suggestion is to start there ……I would change it out again
     
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  5. gsgtrman

    gsgtrman New Member

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    Yeah, easy enough to do. Thanks for your suggestion, will do that first.
     
  6. mickeydg5

    mickeydg5 Well-Known Member

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    That is the first step, acquire several 12AX7/ECC83 to test.
     
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  7. gsgtrman

    gsgtrman New Member

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    I will do that today. Is it possibly something else though? This is also going on in the clean channel which, from what I remember about this amp, doesn't incorporate the tube in the signal chain. I may be wrong about that though..

    Thanks for your replies guys, I appreciate you taking the time.
     
  8. mickeydg5

    mickeydg5 Well-Known Member

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    You are correct in that the tube is in the overdrive section.

    Lets start here.
    Where is the Effects Mix control set and what does it do as you rotate it from DRY to EFF?
     
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  9. jmp45

    jmp45 Well-Known Member

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  10. mickeydg5

    mickeydg5 Well-Known Member

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  11. jmp45

    jmp45 Well-Known Member

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    I know your sig says you have no clue but I know better ..;)
     
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  12. gsgtrman

    gsgtrman New Member

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    I didn't see this before I left for rehearsal. The amp is at the gig, it currently has a TC Triple delay in the loop and the blend control is functioning as it should as far as the effect is concerned. If I am not using any effects in the loop I turn it to fully dry.
    When I get back on the gig this week I'll check the control with norhing in the loop and let you know what's up. Thanks for your replies.
     
  13. mickeydg5

    mickeydg5 Well-Known Member

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    Please do check it out and tell us if it makes a difference with the bright/bass situation.
     
  14. gsgtrman

    gsgtrman New Member

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    Ok, unplugged everything from the loop and checked it out. No change in tone as the knob is rolled dry to effect, volume drops as it rolls from 12 o'clock to full effect, which I would expect. Same in both channels.
     
  15. mickeydg5

    mickeydg5 Well-Known Member

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    Ok, just to check one more thing about this VR11 22k Lin potentiometer, amplifier OFF, turn the control all the way to cut the effects loop signal and then measure resistance across the potentiometer. What do you read?
     
  16. gsgtrman

    gsgtrman New Member

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    Hey Mickey, I have to finish the show running through Saturday night. I'll pull it apart Sunday and get that measurement and let you know what I find. Thanks again
     
  17. mickeydg5

    mickeydg5 Well-Known Member

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    No rush. Do it when you get a chance. We can nip this in due time.
    I am watching the thread.
     
  18. gsgtrman

    gsgtrman New Member

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    Good afternoon! The reading across VR11 is 10.8k.
     
  19. gsgtrman

    gsgtrman New Member

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    Also, the top of C40, a 35v 1000 uf cap, is bulging slightly.
     
  20. mickeydg5

    mickeydg5 Well-Known Member

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    That is about 3K off but could it be off or something could be throwing it off that much.
     

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