Thanks for everyone's help...
I eventually found another forum, and it turns out that the PSX to USB doesn't work with the Real Arcade stick because it's a universal arcade stick, for GC, Xbox, and PSX. BUT it appears that using an Xbox adapter would work just fine, as the general USB cords don't... do whatever the stupid PSX plug does.
So the solution is to buy another adapter, if anyone was wondering.
I eventually found another forum, and it turns out that the PSX to USB doesn't work with the Real Arcade stick because it's a universal arcade stick, for GC, Xbox, and PSX. BUT it appears that using an Xbox adapter would work just fine, as the general USB cords don't... do whatever the stupid PSX plug does.
So the solution is to buy another adapter, if anyone was wondering.