Portable Bluetooth Speaker

Recently made several Bluetooth speakers, and only a little satisfaction this point, things used are: Bluetooth decoders, level indicator, step-up board, a pair of 5W speakers, 5000mAh lithium polymer battery, lithium battery display, two switches (respectively to disable the display and the lithium battery level indicator), rod antenna, 5.5x2.1 female charging, the lithium battery with protective charging module. 1A.

This decoder comes with Bluetooth 3W amplifier, so I do not need to add here amplifier board, Bluetooth decoder charging function, so without charging module can be, but it is unclear whether such a charge voltage too high undermine the batteries, so I a charging module is coupled with the protection, the additional decoder also supports Bluetooth card player and radio function. Level indicator need 7V ~ 12V DC voltage, it is necessary to step-up booster plate, the original 3.7v rise above 7V. Lithium battery display to show the percentage of power, and during normal use when charging can visually understand the power, accuracy can.

Overall, durable power, the sound is large enough, Bluetooth and radio okay.

47 amp

Recently welding two 47 amp plates, and later a board capacitance burst during use, but also for a new capacitance up, this type of amp board is cheaper, op amps are NE5532, I replaced the OPA2604, dual DC power supply and are generally at the beginning I of laminate battery powered dual 9v, 12v and later the output AC transformer double, double 12v DC output by rectifying the voltage regulator filters, such welding rectifier filter regulator I several not easy to use, after the internet to buy a ready-made kit, no problem, I do not know if the welding problem?

47 amp sound quality can have some modification, music has more levels and more full sound, headphones can drive greater Europe, there is that you can adjust the volume knob, this is very convenient. Since the components and circuit design are more general, to enhance the overall only a Diudiu, no qualitative improvement.