Re: Routing a battery box in a finished guitar ??
I do know that some older pedals on a power pack whistle on cheap switch mode power packs and on transformer type give hum. I take a 12v pack, and put a regulator 7809 with caps, but often there is no space in the pack, and others are sealed. I built a power pack with 4 double output transformers, so it had 8 independent regulated 9v outputs with no noise. But new pedals all seem to use higher current and voltage, many cant run on battery.
With an AC adapter you might get more noise. I know sometimes pedals don't like being run from an AC adapter.
I do know that some older pedals on a power pack whistle on cheap switch mode power packs and on transformer type give hum. I take a 12v pack, and put a regulator 7809 with caps, but often there is no space in the pack, and others are sealed. I built a power pack with 4 double output transformers, so it had 8 independent regulated 9v outputs with no noise. But new pedals all seem to use higher current and voltage, many cant run on battery.