Ah well that makes a lot more sense.
So I just designed a regular non-split PSU for this, I take it I will have to redesign it? Or is there a way to convert it to split supply on the amps board?
https://sound-au.com/project15.htmAnd if I do have to redesign it, lets use the link above for reference(Figure 3 - Complete Dual Capacitance Multiplier (Darlington Pair)), my PSU does not have a transformer, I am just rectifying 120V AC, then going to a buck converter, which ends in the capacitance multiplier(thanks Dave, I had thought I had finished my PSU, and then your 5 year old video pops up in my feed, creating more work for me!).
Where would my common ground point be? Could the earth pin on the AC connector be used as a common ground, or is that just for grounding things like the case?
This is my first time working with AC, so a lot of this PSU design is new to me.
Edit: I'll just post my PSU schematic, so where would the common ground point be? My guess is I'll have to add an inverted buck controller for the minus voltage, but everywhere I see they are using a transformer for common ground.

As for capacitor, with minimum specs of 470uf, rated at 50V, (which I can't seem to find), a Film Capacitor is about $60 CAD, or is there a better type cap for the job?
I did read the heat sink requirements, well, I started to, was going to wait until I started routing, but yes I'll read more.
Started this as a side project to add to my PCB order, so I've kinda been rushing it, I really want to order the boards for my main project.