We’re initially confused by the AD-2.
It’s called a preamp but there are no EQ controls. Instead you get Ambience (reverb) and Acoustic Resonance (processing) controls with a notch filter.
The Resonance is similar to the Xvive Mike and TC Bodyrez in that it aims to add a natural acoustic character back into your sound. It certainly warms and rounds off higher end piezo tone for mellower solo players - if that’s what you want - and the reverb and notch are useful, along with dedicated TRS balanced out for going to a desk without a DI box, but the processing doesn’t feel quite as organic as the competition.