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Advice needed on distortion

Discussion in 'Amps and Cabs [BG]' started by Larry Kaye, Dec 25, 2004.


  1. Larry Kaye

    Larry Kaye Retailer: Schroeder Cabinets

    Mar 23, 2000
    Cleveland, OH
    I have a very tight range to set my preamp volume (drive control I guess) on my Sunn 1200S head, no matter what bass I use, where I can't clip the preamp. I check this every time I plug in. If the "light" goes even slightly to "red" the speakers will distort. If I can find that extremely delicate balance where the light stays green no matter what, my speakers will not distort or fart out without me being way way too loud, so my question is thus:

    Is there a preamp tube, 12ax7 I believe is what is in there now, that is "better" at just warming up the tone but is more resistant to overdriving and clipping the preamp? I haven't replaced the preamp tubes in at least 3 years....does that have something to do with how much input they can handle before distortion and overdrive get through to the output stage of the amp?

    My ideal tone is totally clean with no overdrive unless I really dig in finger style extremely hard which there's only a couple of tunes we play that are even close to that intensity.

    Any suggestions? The basses I have are passive, active 9 volt, and active 18 volt preamps. They all have the same issue..it's almost impossible to dial in the preamp volume without clipping it....the "sweetspot" is just that...an extremely narrow range....like between 2 and 2.05.....2 is too weak a signal and 2.05 is too strong.

    Help?
     
  2. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
    Did you try pressing the pad button? That will reduce the signal level at the input and should allow you to turn up the gain a bit higher before clipping.

    If that doesn't work, there might be something wrong with the amp...
     
  3. Larry Kaye

    Larry Kaye Retailer: Schroeder Cabinets

    Mar 23, 2000
    Cleveland, OH
    Yeah....doing the pad thang helps slightly with the passive bass moreso than the active one....there's still, however, even with the pad button activated, what seems like such a small range where I can get the basses punchy and crisp sounding without clipping.

    This has always been an issue with this head for me. Also, something to contemplate, is that when we rent a PA and the bass goes through it for some extra ooomph, the signal is SOOOOO hot from the head that they can't use it at all, pre or post eq!!! I have to be mic'ed up rather than run it direct, even with a direct box.

    I do have a DOD 31 band eq in between my bass and the input stage of the amp. I'll try dropping the volume of the EQ and see if that helps but if I remember correctly, the amp really lost a significant amount of punch when I tried that before?

    Do you think the preamp tubes need to be replaced?

    L
     
  4. IvanMike

    IvanMike Player Characters fear me... Staff Member Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    woah.
    when you say you cant use a direct box, and you previously said you use a passive bass that had me wondering. then i saw that you're using this eq before your amp input which you failed to mention in your initial post. When you have tried to use a direct box, was it before or after the dod 31 band eq? I'm guessing that this eq of yours is the problem.
     
  5. Larry Kaye

    Larry Kaye Retailer: Schroeder Cabinets

    Mar 23, 2000
    Cleveland, OH
    will get back later on that. Good detective work guys!!!

    LK
     
  6. IvanMike

    IvanMike Player Characters fear me... Staff Member Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    i would try taking the eq out entirely 1st and see how it goes. and i'm still wondering. when your bass signal was too hot with a direct box, were you plugging the bass straight into the direct box? or were you going thru the eq and then to the direct box?