Question Regarding GK's "Boost" Feature

Discussion in 'Amps [BG]' started by matante, Dec 11, 2013.


  1. matante

    matante

    Joined:
    Nov 3, 2003
    Location:
    Los Angeles
    Is the "boost" feature essentially an overdrive knob? or is it simply a volume boost? I'm having trouble understanding the function of that knob.

    Also, does the boost feature kick in before or after the effects loop?

    I'm asking because I would want to put flanger, chorus, and delay effects in the effects loop, and I would not want any overdrive/distortion added later in the signal chain.

    Thanks in advance.
  2. Lonesomedave

    Lonesomedave Supporting Member

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    dude.....i think you inadvertently put this in the wrong forum

    i mean, i wish i knew the answer and could help you, but i think you'll get more answers over in amps

    [​IMG]
  3. matante

    matante

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    Sorry for the mistake. Hopefully someone will move it. :oops:
  4. Lonesomedave

    Lonesomedave Supporting Member

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    I have done the same thing once or twice (usually on a weekend)....when i saw what i had done, i pm'd MAJOR METAL, who was in forum at the time, i believe, and he has been gracious enough to move them promptly...

    [​IMG]
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  6. fdeck

    fdeck Supporting Member

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    I have three GK amps, and am somewhat of an electronics geek. Here's my understanding of the "boost" feature. It controls the level of signal going into a simple JFET stage, which exhibits a gradual onset of distortion as the level increases. I'd never dare to say that it sounds like a tube stage, but it is functionally similar.

    So it's like a volume knob feeding a stage that can be overdriven.

    Where it appears -- before or after the FX loop? GK does a pretty good job of showing block diagrams in their owners manuals which, if you don't have one, can be downloaded from their website. For the insanely complex MB150E combo, I have a copy of the block diagram taped to the back of the amp.
  7. matante

    matante

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    OK, thanks man. According to the MB500 owner's manual the boost section comes in after the "return" of the effects loop. So there's my answer. That amp has 2 channels so I could always just leave the "boost" channel off, but then I'm paying for 2 channels and only using one. :meh:
  8. eukatheude

    eukatheude

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    Report your own post, it'll make it easier to the mods.
  9. matante

    matante

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    It's okay. I found my answer. :)
  10. BassyBill

    BassyBill The smooth moderator... Supporting Member

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    Um - that's not really the point, is it? :D

    Moved to Amps.
  11. bassgod0dmw

    bassgod0dmw Supporting Member

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    That's kind of a silly way to look at it. You use what works for you. I'd venture to say that a lot of bassists only use one channel of a two channel amp. GK's boost feature has always been footswitchable.

    I would not put those pedal effects in the effects loop. The chorus and flanger will more than likely sound better out front. Delay may work well in the loop, but it depends on the signal level the loop is looking for. Most loops want a line level signal (from rack gear) rather than the instrument level signal a pedal (generally) puts out.

    To answer your original question, the Boost is a gain stage placed after the EQ section and the effects loop. I'd call it more of a volume boost than OD.
  12. matante

    matante

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    Nov 3, 2003
    Location:
    Los Angeles
    My effects run at line-level.

    The GK owners manual says that Boost is used "to add growl", so I'm getting conflicting information. I'll have to experiment with it.
  13. bassgod0dmw

    bassgod0dmw Supporting Member

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    White Plains
    GK is known for the GK growl. RB series amps can push their power sections to "ride the rails" which creates a wonderfully musical growl. One of the few SS heads that sound good sending the amp into OD. Justin Chancellor and Duff McKagan are nice examples of GK growl.

    The MB series heads don't have the same type of power section, so they don't quite have the same sound. The boost on those heads still sounds decent to my ears in a live environment.

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