Where does the Arduino come into this?
yes sorry about that. its a project containing an arduino but this post doesnt mention it.
The 230kHz signal is the Class-D switching (a special kind of PWM). It should be filtered out!
ive just checked out the PAM8403 description here and it says it requires no external filters. what would be your opinion on this DVDdoug?
If you have a 2-channel 'scope check to see if it's out-of-phase on the other output (it may not be present differentially)
i am a mere hobbyist and my scope is of the most basic kind and lacks that functionality unfortunately.
Does the audible noise change? (Is the audible noise coming from the MP3 module?)
yes the noise does change. making me think that this is a power based waveform which can only be seen when the scope is sampling at a very high rate.
ok i posted something before but i was confusing myself.
i made a discovery. when i plugged my computers output into the amp it worked flawlessly when the setup was being powered by a battery but when powered over usb there was the noise again.
i think it might have something to do with grounding issues....