Your ability to play really great bass lines goes up not down when you understand a bit of music theory. This video shows you how to use scales, triads, arpeggios and chords on the bass guitar. Theory can be an impenetrable subject but I want to show you how you can use it to unlock your creativity and play awesome bass! There are more lessons here...
C Major Scale
C Major Triad
C Major Arpeggio
C Major Chord
Learning how these relate to each other is key in your ability to make up bass lines, hear music well and improvise. There are loads of different scales, chords, arpeggios, and triads but this is the real basics. You want to get that down and really understand this before moving on.