I tried guitar –> H9 –> amp with no other pedals. I used two different guitars. On both the bypassed signal was significantly louder than the effected signal for a wide range of settings and different presets. I tried it with the mix at 50/50 and the clean signal was much louder than the dirty signal.
My bass was a little harder to tell—levels seemed a little more comparable, and the EQ made a huge difference. I only tried one bass.