Hi, my new mic doesn’t come with a switch on it to kill the low hum noise.
So I’m going to turn on PRE and set the low cut to 75Hz in order to compensate for the lack of physical switch.
I’d like to know if the proper way to enable the PRE on the INPUT channel (with the red fader on the mixer), or on the AUDIO track (white-ish fader on the mixer)?
Well, if I remember the cubase-routing correctly:
If you do it on the INPUT-Channel the printed Audio (recording) on the audio-track will already be free of the humming.
If you do it on the AUDIOTRACK-Channel the printed Audio will contain the humming (but you will not hear it upon playback because it passes the filter then).
Cheers, Ernst
Plus: A valid question might be why your microphone is humming at all. Do you have issues with the cables?
Cheers, Ernst
To elaborate a little more: if you do it on the input channel, the RECORDING will be WITH the 75Hz low cut. It’s gone, it’s not there, never was.
If you do it on the audio channel, you record the 75Hz low cut and then basically use a ‘plugin’ to do the cut. The original audio is still there.
Conclusion: the outcome is absolutely the same, but on the input track you change the audio signal. On the audio track you merely mask it… (if that makes sense).
Hmm, these are very good replies! 
I’m not detecting any hum. Its just that I was used to working with a mic that had the pad switch on it and I always used it as preventative measure from capturing any low frequency ambient noise. Is there a recommended best practice as to whether I should cut it from the signal or simply mask it? I should mention this is a vocal mic - used only for singing.
Personally, I always record as ‘clean’ as possible. Which means I don’t use cuts when I record.
When it’s gone, it’s gone forever and you can’t get it back. When you mask it… you still can use it 
Hi, same here: I always record what Comes in without modifications in the Input channel.
If you are not sure how you prefer it, you can as well do both at the same time. Simply use the same physical Audio port for two different Input channels. One with the “filter” on, the other “dry”. Then set up two Audio channels and use the two Inputs simultanuousy for eather of the Audio channels. If you place them in a Folder you can even simultanuously record-enable them.
Cheers, Ernst
If you have the filter on the Input track, you’ll find it adds a bit of latency. If you filter on the channel track after recording, you won’t have that issue