sudomod

Well it DOES adjust it technically, albeit very scarcely and barely even noticeable. I am using the original DMG volume wheel and it seems to work fine for headphones, but the change in volume is barely noticeable through the speaker. I am using this wiring layout: Another issue is that when plugging in/unplugging headphones it cuts power to the system. found that quite odd.

Any way of adjusting the volume levels either via software or wiring would be appreciated.

That schematic looks wrong to me, Try this wiring instead. Please double check the GB jack wiring as i don't have one to hand to verify the pinout

When you're in the main emulation station screen, if you click start and go down to sound options you can manually adjust the volume so you can enjoy your games til you get the wiring sorted out. I did this for a week before I could tear into mine again when I was having volume issues.

It's default at 100%. I find when I'm just on my own gaming in the bedroom or living room, 82-86 is about perfect depending on ambient noise.