aint this been discontinued?
Anyway, i have one and using for guitar. Its not transparent. It add certain fatness to guitar. It suck tone when you set the compression to hi rate. At low to moderate setting, it compress nicely, adding a a certain fatness. At higher or max setting, it squeezed squashed a lot and add some hiss
imho
anyway, for bass, either get a parallel mixer like xotic x blender and pull the compressor in the loop to parallel blend with original bass signal to get the best of both world. If not, barber tonepress has that parallel mix konb that can do the same thing.
Fk-1 for bass, imho, theres better pedal for it