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disable plugin power

Is there a way to disable the plugin power (PIP) for the external mic, eg. through the software or by removing the 1k1 resistor from the PIP RC circuit? Where can I find the resistor on the USB-Audiomoth? I would like to connect a hydrophone that is self powered and might get damaged from the PIP DC.

5 comments

5 Comments

Gerwin Meijer

Apr 17

Thank you Alex, I will give it a try and will report back on the forum. I was afraid of introducing a filter in the audio line, but, when I understand the circuit correctly, this configuration would result in a high pass filter of 5-10 Hz, which is no problem for me.

Alex Rogers

Apr 17

Replying to

Yep. The issue with un-powerd hydrophones is that they are typically just a bare piezo tranducer that has a very small capacitance (around 10nF) so when combined with the bias resistor of a few kilo-ohms you end up with a high-pass filter with a corner frequency of about 20kHz. You lose all the low frequency components. With your power-hydrophone and this configuration you end up with a high-pass filter again but the corner frequency is very low - around 20Hz - so you should get good sound quality.