Please Help Me Fix My Dirty Channel

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by funkywrench, Jul 13, 2008.

  1. funkywrench

    funkywrench Member

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    Perth, Western Australia
    I've recently bought a used Hughes & Kettner Studio 84 (same as the older Tube 20) amp, see picture below:

    [​IMG]

    The amp has variable wattage (0-20 watts) and has two footswitchable channels. I really like the features and think it would be a great amp if I can just get a few things right.
    The clean channel sounds good, but the dirty channel sounds like the amp has a blanket over it. I've been using my p-90 equipped guitar and it still is very dark. I tried my Les Paul yesterday and it was pretty much un-usable.
    I've tried swapping both preamp and power amp tubes, as well as upgrading the speaker to a Hellatone 30 (G12H30).
    While all these helped the overall sound, I can't understand why the clean channel sounds clear and not muddy, while the dirty channel sounds like a blanket has been thrown on my amp.

    I have heard that H&K amps are normally bright and articulate, but the dirty channel definately isn't.

    I've also had EQ and OD pedals suggested to me but I'm beginning to suspect that something minor might actually be wrong with the amp that is causing this. Can anyone suggest what it could be, or direct me somewhere that I could get some more information?
     
    Last edited: Jul 14, 2008
  2. funkywrench

    funkywrench Member

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    Can anyone help or perhaps suggest where I could go to get help?
     
  3. SatelliteAmps

    SatelliteAmps Member

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    If you think something is wrong, then the best thing to do is probably take it to a tech to have them check it out. Trying to diagnose tonal issues is really difficult, because bright to one person is shrill to another.

    If you want to try a few things, you can try doing things like turning the volume up, and the treble up, and everything else down. How does it sound? Do the same thing with the volume and middle, and volume and bass. Is it isolated in those areas? Does it sound this way with other guitars? Are you running ANY pedals or effects that might be dragging anything down?
     
  4. funkywrench

    funkywrench Member

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    Thanks for the reply SA. I've tried both guitars I have (Les Paul and Double Cut Junior), I've tried EQ'ing, and I'm not using any pedals. Even with all that the inherent muddy blanket-over-the-amp quality remains.

    I've attached a link to a schematic I found on the net if that will help anyone.

    http://www.tomhoelle.com/Studio84Schematic.pdf

    Also, if anyone knows of a forum that would be better suited to answering this question (i.e a place where amp techs hang out) then please suggest one!
     
    Last edited: Jul 18, 2008
  5. SatelliteAmps

    SatelliteAmps Member

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    Techs hang out here. Myself and quite a few others.

    Having the schematic won't help without having the amp in front of any of us.

    The best thing to do is to take it to a tech at this point. With what you are descriubing, it's not something that can't be fixed through discussion, here or on any other forum.
     

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