I use a DI Box solely when playing live; I work in a club band. I used to use a Laney RB4 amplifier, which I'd use to monitor my bass on stage and also take the DI out from the amp into the Desk, so that a cleaner signal would come out front (I'm a fiend for having as clean a bass tone as possible).
I recently bought the Radial JDI box and it's completely transformed my sound, I've gotten rid of my amp, and have no intentions of going back, the convenience of the box is just superb. Maybe some nights I can't hear myself, but I just put up with it, and keep playing as I would, completely locked with the drummer.
Haven't had a complaint yet!
[quote name='Evil Undead' post='1200363' date='Apr 15 2011, 10:12 AM']I apologise if I sound a bit dumb, but what does earthing/grounding entail?
I'm wondering if it's possible for me to DI straight to the PA, without using an amp at all (I live on the top floor, without a lift, and have back problems!)[/quote]
The elimination of Ground Hum allows for the signal to be clearer, though I've never found it a problem on my bass guitar, and may just be something that entails with active bass guitars. It is very common for digital devices to have a great deal of ground hum though, due to the amount of electronics involved, i.e Laptops and Keyboards. The rule is to always use your ears, just push the Ground Lift, does your bass sound better than it did before? Keep it there then!