Hello, first of all let me just apologize if this thread is in the wrong section, i didn't know where to put it because of it's nature...
So, i have a problem with the speakers that i'm building, if anyone could help me i would appreciated so much because i really don't know what to do know....
the problem is: i custom made portable speakers, these consist of an sta540 2.1 amplifier from ebay (all links in end of post), a sure electronics bluetooth module, 2 winmax 11.1v 5200mah batteries and respective pcm boards, and some speakers i had laying around..
these speakers had never had any Hiss or noise in the music, they had a surprising and superior sound quality but that was before i installed the bluetooth module last night, i made the board just like the schematics in the bt module's pdf, i tested it outside the speakers using an ATX power supply and it was just awesome quality and volume (without any external amplifier, just the module), then when i put it inside the speakers connected to the same power source as the amplifier, and connected the audio to the same input on the amplifier's board as the rca's it started making a horrible VERY LOUD hiss, so by then i didn't know what to do.. and later besides the hiss, the sound from the bt's module just turned awful, very distorted even at very low volume, sorry for the long explanation, has anybody have any idea ? :S
ps: i tried a 10uF cap. in parallel with the tweeter's output, and also tried decoupling the power source (the output of pcm board, for protection against battery over-discharge) with a 10nF capacitor.
Bluetooth module: http://www.sure-electronics.net/mcu,display/MB-CM15113/MB-CM15113%20Manual.pdf
STA540 2.1 Amplifier:sta540 2.1 | eBay
My pcb layout of the bluetooth module:
NOTE: the three pins on the farthest left are the lm317 regulated to 3.42V
Thank you in advance for your help
DD
So, i have a problem with the speakers that i'm building, if anyone could help me i would appreciated so much because i really don't know what to do know....
the problem is: i custom made portable speakers, these consist of an sta540 2.1 amplifier from ebay (all links in end of post), a sure electronics bluetooth module, 2 winmax 11.1v 5200mah batteries and respective pcm boards, and some speakers i had laying around..
these speakers had never had any Hiss or noise in the music, they had a surprising and superior sound quality but that was before i installed the bluetooth module last night, i made the board just like the schematics in the bt module's pdf, i tested it outside the speakers using an ATX power supply and it was just awesome quality and volume (without any external amplifier, just the module), then when i put it inside the speakers connected to the same power source as the amplifier, and connected the audio to the same input on the amplifier's board as the rca's it started making a horrible VERY LOUD hiss, so by then i didn't know what to do.. and later besides the hiss, the sound from the bt's module just turned awful, very distorted even at very low volume, sorry for the long explanation, has anybody have any idea ? :S
ps: i tried a 10uF cap. in parallel with the tweeter's output, and also tried decoupling the power source (the output of pcm board, for protection against battery over-discharge) with a 10nF capacitor.
Bluetooth module: http://www.sure-electronics.net/mcu,display/MB-CM15113/MB-CM15113%20Manual.pdf
STA540 2.1 Amplifier:sta540 2.1 | eBay
My pcb layout of the bluetooth module:
NOTE: the three pins on the farthest left are the lm317 regulated to 3.42V
Thank you in advance for your help
DD