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Phantom power + high pass filter

Member for

9 years 10 months
hello, couple of quick questions for any good samaritans out there

if i have a dual preamp and i turn phantom power on, then insert one mic that requires phantom power and one that doesnt. .will the mic that does not require phantom power have any problems? as in will its signal be overloaded by the extra volts or anything like that? the same question applies to phantom power mic combined with a straight line in.

second quick question, if i turn on the 80hz high pass filter on the preamp when recording, does that mean when mixing it in Cubase i dont have to cut out the low frequencies? (usually everything below 100hz ish)

many thanks,



Member for

15 years 7 months

Boswell Sun, 01/22/2012 - 05:37
There should be no problem, providing you are using a pro mic with a known good XLR-XLR cable. The two signal wires (pins 2 and 3 on the XLR) will be elevated to the 48V phantom potential, and the body of the mic remains at ground. It's the small difference in the voltage between pins 2 and 3 that is amplified and becomes the audio output of the mic.

You should always plug and unplug microphones with the phantom power turned off.

In any self-respecting pre-amp, the 48V does not get applied to the TRS line input jacks.

Using the HP filter on the pre-amp (or on the microphone, if fitted) makes it less likely that you will need to apply further high-cut in the mix. However, you should treat the HP-filtered mic channel as simply an audio channel in its own right, and if it needs further EQ to fit it into the mix, then apply it (in moderation) as you would for any other channel.