The Fishman PRO-EQ Platinum Bass Preamp/EQ/DI
I personally use the the Fishman Pro-EQ Bass Preamp. I bought it originally to control feedback which I was experiencing when I turned up the volume. The preamp includes photo-optic compression, 5-band EQ, XLR direct out with ground lift, and a tuner/send output.
The Fishman Pro-EQ Bass Preamp can be used with both upright or electric bass. It helps control frequencies that may cause you trouble and has bass, treble as well as 3 midrange bands that you can tweek until your sound is perfect.
The preamp has a bass slider which has a range of 30-275Hz and this will be useful when working on your G-string’s tone.
The Depth and Phase switches help control feedback. The unit is solidly constructed and has non slip rubber feet.
For a great price on check it out – Fishman PRO-EQ Platinum Bass Preamp/EQ/DI