I am building a portable Bluetooth speaker. I have this Bluetooth module: Amazon.com : Bluetooth Audio Module MP3 WMA Player MP3 decoder with Board Module w/ SD Card Slot / USB 2.0 Port / FM / remote display : MP3 Players & Accessories and this amp: Mini Hi Fi High Power 2 1 DC10 18V Digital Amplifier Board 15W 2 30W Class D | eBay. When I connect them to separate power supply's it works perfectly and the sound is great. When I connected them to the same power supply there is this annoying buzz. I did some research and found that it was probably a ground loop problem. I then bought a ground loop isolator which got rid of the buzzing but diminished the volume and the bass of the speakers. I was wondering if there was any other way to get rid of this buzzing noise.
I use the same one for my boombox. http://www.diyaudio.com/forums/full-range/274036-fast-class-d-boombox-build.html
One solution you have discovered...use a supply that does not have the same GND.
An isolated DC-DC converter will work to break the GND loop.
This breaks the loop in the power path, not the audio path.
(this is not the only solution...just the one I use)
One solution you have discovered...use a supply that does not have the same GND.
An isolated DC-DC converter will work to break the GND loop.
This breaks the loop in the power path, not the audio path.
(this is not the only solution...just the one I use)
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Or you could use this New 3 5mm Car RCA Amplifier Ground Loop Isolator Audio Noise Filter Suppressor | eBay in the signal path. It has 2 trafos inside so ground is broken. If you take off the plastic shell the inside board is quite small 🙂 The isolated converter idea is better but sometimes more costly.
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