For bass I know the DI is used to match the impedance. a high instrument singal to low mic singal, so the low and high frequency of the bass guitar can't lose and we can adjust the gain or volume with the DI. And the preamp? make the level up? Colour the sound? Can anyone tell me? I decide to buy a DI + preamp to record bass. I consider: 1, Radial JDI + D-tar solotice(or another preamp) 2, Avalon U5 3, Demeter VTBP-201S Thanks!