GK MBFusion 800 Tube Rolling

Discussion in 'Amps and Cabs [BG]' started by 2string1, Nov 27, 2013.

  1. 2string1


    Apr 1, 2013
    Has anyone done any tube rolling in the Fusion 800. What where your results. I called GK,they didn't seem to know which tube did what...
  2. JonnyAngle

    JonnyAngle Dropping Acid Pedal Etching .com Supporting Member Commercial User

    Nov 24, 2008
    Maple Grove, MN
    I don't own one or have any experience with them, but here's what my memory produced from what I think I remember reading.

    You have to move a circuit board to access the tubes any your warranty will be void afterwards.

    I'm sure GK knows exactly what tube does what, but they're hoping you'll forget about it from their non-response and move on. I'm sure there are a lot of people "who know what they're doing," and mess things up. They will have a response like, "GK told me if I put tube X in my MB800 X will happen. I did exactly what they said and now my amp won't work."
  3. 2string1


    Apr 1, 2013
    No...the tubes are right under the cover very easy to get at. I did end up getting and email, this is what they said.

    "OK, I spoke with the engineer and he supplied the following information regarding what tubes drive which stages. The tubes are placed in the circuit left to right as you look at the front of the amp. Each tube has multiple stages stages so each tube may effect multiple functions".

    V1 – Input driver and Contour
    V2- High Mid
    V3- Low Mid/ Bass and Treble