freestompboxes.org

Hi.
I´m referencing the Abasi Pathos schematic from here: https://docs.pedalpcb.com/project/Pathogen-PedalPCB.pdf
I noticed every inverting opamp stage gets its own voltage divider + filter cap connected to the non-inverting input, and I´m asking myself if I could use a single voltage divider (instead of 6) like a plethora of other pedals, connect all Vrefs together and call it a day.
Does it mean anything to the sound or noise floor?
Is there any reason for dedicated voltage dividers at all?
I plan to route a PCB for this pedal and I can drop it here if anyone wants it too.
Thanks.

I can't see any justification for it. I think I'd set Vref with a couple of resistors (could be bigger than 10k if you want), add a cap to ground, run Vref into a unity-gain op amp and use the op amp output as a common stable Vref feed for all the other op amps. If you use those 4580's, each half draws a bias current of 500 nA max.

The theoretical goal is to improve performance (e.g. reduce noise) by providing better isolation between stages. I've seen this in many high-gain pedals. Likely they just did it in the original design as a preventative best-practice sort of thing, not to fix an actual issue they discovered during prototyping, so chances are good you wouldn't notice a difference if you simplified it so they all shared the same bias voltage (provided the layout is otherwise optimized with good grounding and signal routing).