Bluetooth Receiver Causing a High Pitched Tone

Discussion in 'General Electronics Chat' started by woodondrums, Dec 7, 2014.

  1. woodondrums

    Thread Starter New Member

    Dec 7, 2014
    hi there!

    i'm building a portable stereo system and am having some unwanted noise from the bluetooth receiver. the noise is typically a high pitched tone.

    please see the attachment for my chicken scratch schematic.

    the general setup is an amp connected to a 12V battery. there is also a step-down converter, connected parallel to the same battery, that goes to USB, which then connects to a bluetooth receiver that sends audio to the amp via an 1/8" cable.

    i've tried adding a capacitor at 200µF to the battery terminals with no luck of eliminating the noise.

    the high pitched tone goes away only when i power the bluetooth receiver from a separate power source.

    i've ordered a ground-loop isolator, but haven't received it yet, so i figured if anybody can suggest something, that'd be most excellent.

    also, i've tried subbing in alternate bluetooth converters, batteries, amps, and step-down converters, with no luck.

    thanks so much for the help!!!!!