The sound example is marked as private, so nobody can listen to it.

For such troubleshooting, you should always provide some information about the operating system and the hardware. So that it is clear
- whether ASIO drivers are in use here,
- whether the system has the required performance and
- to be able to check whether there are other USB3 controllers on the mainboard in addition to chipset drivers, which could perhaps have something to do with the audio dropouts.

In this case, it is not clear to me whether there really is a problem with the microphone or microphone input or whether it could be due to something else, perhaps settings.

Have you ever worked with the microphones on the UFX III before? Did the issues suddenly occur? How does it behave in other use cases such as audio playback, are there also audio dropouts?

In terms of preamplification, the UFX III should definitely be superior to your Focusrite. Because the Focusrite does not have a 75 dB gain range.

How did you set the microphone input in TotalMix FX? Please send a screenshot.
Don't forget to click on the tool symbol so that you can also see the settings for phantom power and gain.
It would be useful to select the HW output for monitoring to see if the fader for the microphone is also set to 0 dB. Otherwise, it would be no wonder if the volume is low if you turned its volume down for the selected submix (HW Output). Remember, each HW Output has its individual submix.

Have you ever tried audio playback? Because if you also had the audio dropouts during playback, then they would at least not be due to the microphone. It could also be that you have several problems here, partly USB3, partly incorrect settings.

Open ports have noise, mute them, thats normal.

> I've tried unplugging the USB cable, and the issue persists when monitoring the microphone

Ok, by using stand-alone mode, you eliminated any potential USB issues.

But did you also validate, that the internal clock is being used?
In stand-alone and normal operation mode?
Check at the UFX III: Options -> Clock -> Clock Source: "INT"

When you validate that
—  there are still clicks and pops even in stand-alone mode and
— even if the clock source is set to "internal"

Then please contact RME support by mail, if RME doesn't respond in this thread.
Maybe there is a defect with the analog session.

Model 125?

There is no valid link anymore at sE Electronics web server for the mentioned S5 mic.
The product picture of this legacy product leads to the wrong webpage for the S8.

But if you look at Music store or other online stores, you see that this is a condenser mic which needs phantom power:

https://www.musicstore.com/de_LU/EUR/sE … 011174-000

@MC, one of the (optional) components seems to be a phantom-powered mixer

https://helpinstill.com/helpinstill-pha … mixer.html

On the UFX III, the sE5 should work flawlessly of course. And yes, they need phantom power. I have several similar mics including sE1A and sE8 combined with my two RME interfaces as well as with other preamps - all fine.
So let’s hope it’s this caps forming thing which is new to me - thanks @MC, I just learned something new!

Then Google it. And no, this can not be done during production as it would delay production and in the end cost the costumer a lot of money. Also this is no obvious issue unless you have the OP's situation - he seems to use a brand new unit with a very low volume source, unusually high gain and phantom power on.

Apart from that it is not even clear if this is really the cause of the issues.

The system requires phantom power indeed. It was especially made for my custom Una Corda piano.

"This playlist does not contain any tracks."

Sounds like electrostatic discharging and I think this is inside of this phantompowered mixer.
This issue appears on every mic input in the interface, right ?

So the issue disappeared ?
Glad you can work

Do you have another microphone for testing the inputs of the interface ?

Then where are the test results with those mics on the UFX inputs ?