I'm interested in upgrading my setup and trying to understand the preamp options. The only preamp I've had is the one currently on my active Corvette. Prior to that my basses were passive. So what are the advantages and what would be the effect in sound/tone having and onboard preamp, an outboard preamp (e.g., Sadowsky) with a passive bass or a rack mount preamp (e.g., Aguilar DB659) with a passive bass? (For the purpose of this question, these brands are strickly referencing the different preamp packaging). Cheers.