Bluetooth receiver question

Discussion in 'General Electronics Chat' started by BWBW, Mar 29, 2015.

  1. BWBW

    Thread Starter New Member

    May 17, 2013

    I'm assembling the bluetooth receiver + Pam8304 board recipe. The components:
    - 2 pam8403 boards (
    - 1 3.7 battery
    - 1 step-up to 5V board
    - 1 mini usb charge board
    - 1 usb bluetooth receiver (car audio type with stereo jack)
    - 4 3w speakers

    The issue:
    The BT reciever (yet-m1) "stutters" when powered on - "b b b b blue b b b b blue". It keeps trying, but won't truly connect/turn on. When only one PAM board is connected to the circuit, BT powers on correctly, it speaks "bluetooth". When I solder the 2nd board to speakers, once the BT is working, it continues to work. When I power system off and turn back on (all 4 speakers/both boards connected) it stutters. The issue appears to be related to having both PAM boards connected to speakers and turning power on. (I've taken the step up, battery, various parts out of the circuit, and used 5v directly into the BT, and the only way to create the issue is as mentioned above.)

    I didn't have this issue in previous builds, although I previously used a Red PAM board and whatever version of BT receiver via DX (they appear the same). That BT receiver didn't require a step up board. This YET-M1 receiver needed to see 5v, even with the 4.2v the battery shows.

    The circuit connects components to a strip board. The PAM and BT are on their own power and ground strip. The charger and battery are on their own power and ground strip. The step up "power in" connects to the battery line. The step up 5v power and ground lines connect to the PAM/BT lines. The circuit is turned on via connecting both ground strips via a switch. The BT signal goes through a 133hz passive high pass, the boards share the BT's signal to R and L channels.

    Any experience or thoughts about the stuttering BT?