Bluetooth receiver powered by battery- annoying static and hiss

Thread Starter

dontknowwhatimdoing

Joined Apr 11, 2020
3
Hi! Very new here, please let me know if this is the wrong place for this question. I recently built a portable boombox that's powered by a 5s 18650 battery. I'm currently trying to add bluetooth because well, it's a boombox, so I bought one of these: https://www.amazon.com/Bluetooth-Adapter-Streaming-Wireless-Speakers/dp/B016NUTG5K/ref=sr_1_3?crid=3O755KDPJV41&dchild=1&keywords=bluetooth+receiver&qid=1586656171&sprefix=bluetooth+reciever,aps,551&sr=8-3 which runs on 5v. To step down my voltage from the battery, I bought one of these: https://www.amazon.com/gp/product/B00SY37S00/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 I tested the receiver with the power supply provided first, and it worked perfectly fine, no static or hissing or anything. Then, I snipped the power wires going into the receiver and connected it to the step down regulator, which was connected to my battery, after confirming with my multimeter that the regulator was outputting 5v. After powering everything on, I hear hissing and feedback. So what's going on here? I really have no idea what I'm doing when it comes to batteries and power supplies, this is my first 18650 battery build too, so any help would be appreciated. If it's relevant, I've noticed the hissing and static gets worse when I try to play anything through the system.
 

ericgibbs

Joined Jan 29, 2010
10,055
hi,
Welcome to AAC.
The specification states a Vout ripple of 200mV, this is most likely the cause of some of the electrical noise.
Try adding 100nF and 100uF capacitor across the output of the step down converter.
E
 

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Thread Starter

dontknowwhatimdoing

Joined Apr 11, 2020
3
hi,
Welcome to AAC.
The specification states a Vout ripple of 200mV, this is most likely the cause of some of the electrical noise.
Try adding 100nF and 100uF capacitor across the output of the step down converter.
E
Thank you, should that be across the positive and negative outputs? And two capacitors?
 
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