kolban wrote:Thank you Valen. What I hadn't appreciate was the apparent fact that the micro SD card needs to be powered at 3.3V while the sound module can be powered at 5V or 3.3V.
I don't know where you could have gotten that distinction from. The WTV020-SD datasheet says it's working voltage is up to 3.5 volt. So, 5 volt will likely damage it. In fact, on page 19 of the datasheet is suggests to use two diodes to reduce 5 volt to 3.3 volt. So, apparently 5 volt directly could kill the chip. But if you meant this Sparkfun board could be powered with 5 volt then you are correct, but only on the condition that this is connected to the battery connector/Vcc pin. As this would then be lowered by the onboard regulator.
So ... if I understand it correctly, if I am powering from external sources bypassing the input regulator, if I supply 3.3V I can connect that to both Vcc and 3.3V ... however, if I want to power at 5V bypassing the regulator, I still need to supply only 3.3V at the 3.3V connection.
No, you may have gotten my meaning of "bypassing" wrong. I did not mean to connect both the input and output together. I meant not using the voltage regulator if you have an external source of 3.3 volt. By leaving the Vcc/battery connector floating, and rather supply the external 3.3v source into the 3.3 pin directly. Eventhough this pin is also the output of the regulator, it remains non-operational if there isn't a higher supply going into it.
BUT!, since you have not said anything about what other controller or shield/board you are going to connect this to, it is impossible to judge from here if you have what it takes to supply this sound breakout board with 3.3 volt. Some 3.3 volt regulators on Arduino board may not be able to supply as much current as needed. So, I agree with Codlink. Apply 5 volt to Vcc if you have it , or at least .3 volt higher than 3.3v to Vcc for the regulator to operate correctly and provide a nice steady 3.3 volt. It will probably do the sound quality a lot of good as well.