Audio FX Mini current draw?

[phawkins]

The various docs on the Audio FX Mini are a confused mix of documentation for the Mini and for the original Audio FX with amplifier. Every reference to power refers to the original board with amplifier. I would like to know how much current the Audio FX Mini uses when idle and when active to figure out what size battery I need for it.

[adafruit_support_mike]

I just measured one to be sure: at idle it uses 25mA, and when playing it uses 30mA.

[phawkins]

Thank you! That is a bit problematic, as I haven't got room for a 350 mA battery, and want it to last all day. I have a similar device from invitebyvoice that uses ~10 mA idle and active, but can only store 5 samples. (Also only 20KHz playback, but I don't think that matters with my dinky speakers and abysmal acoustics.)

Did you have it hooked up to a mini speaker (eg 30 ohms) while making your measurements? I have my device hooked up to a pre-amp and powered amplifier, which (I suppose?) might make it draw less current even while idle.

[adafruit_support_mike]

I didn't connect the output to a speaker, but that's a separate circuit.

Most power amps have high-impedance inputs, so the current necessary to get a signal from the source to the amp is negligible. The amp itself will use significantly more current than the FX Board to drive even a small speaker.

[phawkins]

Yes, true. In this case the amp is in a different physical location and has its own power supply. I could also run power lines to the Audio FX, but it is aesthetically undesirable.