I'm in love with the sound of the Deep Switch on my Aguilar DB680. According to the manual: The deep switch controls a tube driven RLC resonant EQ, fixed at 30 Hz. Two positions are provided for flexibility. In the left setting (+) 30 Hz has a smaller amount of gain than in the right setting (++). The (+) setting is great for "fattening up" a bass sound, while the (++) setting adds loads of bottom. I'm moving out of the world of heavy, rack mounted gear. I'm curious if anyone has any ideas for duplicating this effect? Most boost pedals (I have an xotic bass rc booster) seem to be pegged higher (i.e. 90hz on my xotic). Any ideas?