New to TB and 1st post so hopefully this all makes sense. Having some sound issues with my rig and it is only happening when I'm playing passive basses. I play a TC Electronic RH450 through a RS 210 and RS 212. I normally play a Warwick Corvette $$ and first noticed the issue when a battery had died and I used the push / pull knob to run the bass passive. Lower notes started to make distorted "farting" noises at times. Fresh battery back in running active .....no issues. Ran the bass passive again ....same issue. Ran another bass with active electronics through it...no issues. Ran my American standard jazz bass (passive) through it...same issue. Thoughts or ideas? Thanks in advance for any insight.