I know this is a sub for guitar pedals, but my problem applies to how I’ve been using with bass guitar. Hope that’s ok. After, a bass guitar is a guitar. 

First of all, please excuse my untidy cable management. 

Anyway, I recently picked up a bass guitar that I’ve been excited about for years, a Peavey T-40. The issue: it sounds like shit when I play it through drive/fuzz pedals. The only way I know how to describe it is that it sounds like it might be going in and out of phase. 

Depending on the pedal, there might be almost a slight vibrato effect happening (much like when I use a phaser pedal with subtle settings). Other times, it sounds like some of EQ settings drop in and out. I understand that the pedals I’ve been using aren’t designed for bass so there can be a loss of low end, but that’s not what’s happening here. 

Some pedals I’ve tried: Way Huge Red Llama, Drunk Beaver Seattle Driver, Walrus Iron Horse, and EHX Op Amp Big Muff (the latter two I played through my Tri Parallel Mixer to preserve the low end). To some extent, the issue exists with all the pedals I’ve tried. 

Does anyone know why this is happening? The bass sounds fantastic otherwise. It’s only using drive/fuzz pedals where this happens. 

Drive pedals causing phase issues?