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400RB Boost/Master

Discussion in 'Amps and Cabs [BG]' started by chris h, Jul 8, 2002.

  1. chris h

    chris h Guest

    Jun 16, 2002
    Oxford, England
    What is the function of the Boost and Master pots on this amp? Is it two channel or something? there doesnt seem to be a footswitch. Im confused!

  2. The boost adds, essentially, another gain stage to the amp. It increases the grind and the available power. Older versions of the 400RB had a footswitch jack in the front to remotely switch the boost stage in or out. I use it occasionally to step out front, or when needed for gigs that have a wide variety of sounds required from very clean to grind (weddings, etc.). For most rock gigs, I set the boost for the sound I want and tweak it manually when necessary -- usually from 9-12 o'clock on the knob.

    Adding even a little boost adds substantially to the amp's volume.

  3. fourstr00


    Mar 21, 2002
    Chicago Area
    It so happens I have one of the GK 400's in question.

    The volume knob controls how much signal you send INTO your EQ, power amp, etc. It's like a pre-amp.

    The master knob controls your power amp, or the amount of juice sent into your speakers. Iffin' you want a clean sound, keep your volume below your master, and vice versa for a "dirty" sound.

    As for the Boost, it does add a little bit of volume and presence, but all it really does on my amp is make it overheat at an incredibly fast rate.

    Check out the GK web site for manuals.

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