2 distortion pedals in a row - Volume Balance - How ?

  • I have a question I can not answer me.
    I place two distortion pedals series, eg take one rig - Fender Bassman - clean
    e.g.
    First Stomp C - Green screamer gain 0 Volume 0
    Second Stomp D - green screamer gain 3 - Volume + 2dB (for example, lead)


    Stomp A, B is not occupied
    Stomp activate C
    -> Output volume is much higher than without Stomp C - despite volume 0?
    -> Stomp D Enable (Stomp C) is still active
    -> Output volume is now lower than when only Stomp C active


    Cleane Sens stands at 5.5
    Distortion sense stands at 0.0


    Kind regards Micha