I just finished recording upright bass tracks with an LR Baggs Para Acoustic guitar pre/DI. The engineer at the studio had one and took my Full Circle pickup direct with it. I normally use a Fishman Pro Platinum Bass unit when playing live, and have been using the Fishman for many years because it sounds ok and works fine. The LR Baggs set flat sounds way better to my ears. More natural and clear without sounding thin. I couldn't hear any issues at all. I know it says acoustic guitar in the literature, but it works equally well for upright bass. I immediately ordered a Para Acoustic DI for myself, and will start using it on the jobs I do. I really like that it's phantom or battery, 10-meg input, has a notch filter, and versatile EQ. I read that it has a preset 35hz HPF; sounds great to my ears.