Using the example of a Acoustic electric Bass. With the built in preamp at the output is it a line level signal or instrument signal? Outboard preamps are all line level. What type cable should you use and what input. Do you plug into instrument level input on a preamp/combo amp or to line level input such as 'preamp input' or any line input? Use a line level cable or Instrument Cable? If plugging into Instrument input your Bass signal now goes through another set of Volume controls, Eq, and preamp circuitry. The more electronics a signal passes through, the more chance of distortion from original Bass Tone and frequency imbalance. [I come from a High End Audio Background that preaches virtues of 'Straight Wire With Gain'] In my 25 year experience with High End Stereo Equipment although something may work with various type cables a cable is not just a cable, the type and quality are critical. I am guessing whether an AEB or ACTIVE Bass converts preamp line signal to instrument just before output. Can anyone teach me on this?