sunn 2000s tone stack

Discussion in 'Amps and Cabs [BG]' started by ngh, Mar 3, 2014.

  1. ngh


    Feb 6, 2013
    brooklyn, ny
    hey there, I have a pre bass boost sunn 2000s which i love dearly. and I would like to know the specifics about how the tone stack functions. from messing with it I have deduced that it is some variation on a baxandall type tone stack (I get a mid bump with both treble and bass at 0 and a mid scoop with both at 10). what I want to know is what are the shelving frequencies for the bass and treble shelves respectively. and also what exactly is the contour knob doing, i know by using it, that it adds clarity or sparkle as you turn it up, it seems to react differently depending on how the EQ is set though, what exactly is achieving this effect?

    thanks in advance guys.

    (side note: I already know from playing it a lot how to get sounds I like, but I am just curious as to the specifics of this design.)
  2. Sunn was Fender type tone stack, as I recall. The contour knob I think is a mid knob.
  3. ngh


    Feb 6, 2013
    brooklyn, ny
    does not seem to act that way, i know that the later model T had the fender tone stack but these older ones seem to work differently.
  4. I recall some Sunns being like a Superbass tone stack with the Contour knob being a mids knob.

    But I just looked at a 2000s schematic and it seems slightly different. But it's still passive and still probably functions the same.
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  6. ngh


    Feb 6, 2013
    brooklyn, ny
    I'm not familiar with the superbass tone stack could you explain it for me?
  7. Steve Dallman

    Steve Dallman Supporting Member

    There were two tone stacks, both based on a Fender tone stack. One had bass, treble and contour/mid. The other had bass and treble with a treble boost and fixed mid. Both had a bass boost that simply added a larger coupling cap in parallel with a smaller coupling cap. That's all I found.
  8. The Superbass is a Marshall head with a tone stack similar to a fender but with different values. Less mid scoop, more bass, etc.

    It was modeled on the tone stack from the early Fender Bassman's that Marshall got their start cloning.
  9. D.M.N.

    D.M.N. Supporting Member

    Oct 6, 2008
    Friday Harbor, WA
    The contour knob is definitely a mid-controlling knob. I run both my 2000s and 1200s with the treble at 10, the contour at 20, and the bass at 2, giving a very mids aggressive tone. If I turn the contour to 0, all else constant, it very audibly alters the mid range. However, as it was explained to me, it's not so much a mid-boost or mid-cut, as it is a mid-shift, in that it changes the shape or focus of the mids. You notice a mid-boost when the treble and bass controls are turned down, because you are attenuating those frequencies relative to the mids. Turning them down means less of them, and you perceive more of the mids (which you seem to already get and have experienced). If you turn them down, then mess with the contour knob, you'll see what I mean about how it shapes the mids. If I had to hazard a guess, I'd say it's most likely a modified fender tone stack similar to how the Marshall amps were modified Fender stacks. This is not from scientific studying of the tone stack mind you, rather just from years of playing exclusively on these amps, aiming for a mid-powerful sound, and reading what others have previously discussed. Sorry I can't help you more with the actual numbers side of things though.
  10. vegedge


    Jul 14, 2012
    are all the "boost" switches this way? my 200s has the treble/bass boost obviously. i feel like if i have both on i am not boosting, just able to access a wider range. like a shift. sure wish the 200s had a mid contour :(