Power supply phenomenon:Can't go beyond a certain voltage even when knob turned

Lets put it this way, you don't need current limiting on properly designed circuits, they have there own current limiting build into themselves based on there rated voltage, they only pull what they need based on ohms law.

That current limiter is for test circuits, and troubleshooting repairs to prevent accidentally frying the device your powering when unsure of expected current pull.

If you fried your Bluetooth then either it was defective, over volted, or wired wrong to name the most likely causes.