Pre-amp to boost signal info

[Ironderby]

I only briefly read about what pre-amps do, i think they increase the signal your bass puts out, does this mean they increase the power slightly? i have no idea what they're for

 

[will33]

The signal from your pickups is some millivolts. The preamp boosts that up to 1 - 1.5 volts or so.....enough to "feed" the poweramp what it needs to work to get loud.

Totally simplified answer there.