Review on High-powered Bluetooth Amplifier Board with Treble and Bass Control - 100W+100W, DC 9-24V, BT and AUX Inputs, DIY Stereo AMP Board for Wireless Speakers by Jeff Prabhu

I bought this to get notifications from JBV1 on Android. Unfortunately, this device shuts down the amplifier if there is no sound for a few seconds. The amplifier will turn on automatically once Bluetooth resumes audio streaming, however there is a 1 second activation delay. That means you will miss app notification sounds and announcements. The exception would be someone who only plays music. Since the music is constantly playing, you will most likely never notice this audio-induced amplifier activation delay, and it can work great if music is playing all the time. Due to my circumstances, I cannot accept a device with such an activation delay. The Bluetooth connection was pretty reliable. It connected to my phone within seconds of turning it on. One thing to note is that the Bluetooth chip is constantly powered, even when the volume button has been turned off completely and the blue power indicator is no longer lit. This is something you cannot control. As long as the device has a wired connection to a DC power supply, the Bluetooth chip connects to the network and your devices can connect to it automatically. I've found that if I lay the phone horizontally and the amp is also horizontal, only 15 feet away, the Bluetooth connection becomes less reliable. Different device orientations helped improve connectivity. Output power was excellent even with 8 ohm speakers at 12v. I used a pair of Bose Lifestyle 301V bookshelf speakers with it and at 2/3 volume with a 12v power supply it was louder than I could speak or scream. Tip: If you only need to connect one speaker, you can get twice the power by bridging the speaker output. This is a common technique in the car stereo world. To connect the output, connect your single speaker to the plus of the left channel and the minus of the right channel; They don't use a negative left channel or positive right channel. If you've done everything correctly, the two external ports will be connected while the two internal will remain separate. Now you get the output intended for 2 channels but using only one speaker. Essentially, you mix the left and right channels for a "split stereo" output on a single speaker.