Microphone level decreasing after turning on Phantom Power


Windows 10
Tascam US-2x2
Audio Technica AT 2020 Condenser Mic

I have a track in Cubase that I have already put all the tracks on Drums( Used Midi), bass, and guitars. All the sound came through great and properly mixed

Problems started when i tried to record vocals and the mic level was very low
Gain only increased hissing white noise and very little actual vocal sound
Db levels seems to be correct, and I am getting some decent waves on my track , but audio is very faint
Weird thing is if i swtich to another window or open up chrome and go back to cubase, it is louder and then gradually decreases

Troubleshooting is as follows

  • Went through all of windows settings and sound properties of inputs and outs
  • Made sure the program was not allowed to take control of the levels
  • made sure windows does not interfere when I am recording ie making a call, skype so on
  • updated all drivers on cubase , tascam and windows
  • Swapped out to older Tascam US 122mkii and exact same problem occors

If it was my mic it would not sound great when i turned on the phantom power and gradually get lower

Please advise, this is driving me Bananas

If you use the direct monitor on the US (knob turned to input) do you hear the same thing happen with the mic?

I’m not sure I understand the sentence above?

However, if you’ve getting the same result with two different interfaces, it sounds to me like the mic or its lead is the problem. From a quick look it appears there are two versions of this mic, USB or XLR…I assume you have the XLR one?

I can only hear it through input very quitley
When it is set to the computer mix I cannot hear anything at all

Hey Planarchist,

Yes i am using the XLR

The thing is, the levels are all DB levels are good and I am getting good waves and reads on my mixing panel
When it is set to the input, volume is barley audible unless I crank the gain but then of course it is too much and it brakes up
When it set to the computer mix i hear nothing

Also the sentence about the mic

So when I first turn on the phantom power, the mic seems to be at a good level for me to hear and then gradually gets lower.
I can even record it getting lower as i am using the mic

Also to note, after i turn on the phatom power, and scratch the outside of the mic with my fingernail I can hear it perfectly and can do this for quite a long time, but as soon as i starting singing or speaking into it, it seems to adjust the volume quite low

OK…but when set to input, does it do the thing where it starts at good level and then gets quiet.
If it does then the problem must be the mic or the interface.

yes thats exaclty what it does on both interfaces

Guess i’ll try to swap the mic.
I just never heard of a mic decreasing in volume by itself

Any inserts on the audio track?

None, I have re created the issue on multiple projects and new projects
When I add effects or a compressor it makes it a bit louder but also severely peaks it

Guitar inputs work fine

It sounds like the mic or the mic cable (I have had Phantom powered mics behaving strangely with dodgy cables).

I’m still not clear on exactly where and when you’re hearing (and seeing?) this drop off. Does the recorded wave also drop off in amplitude or just what you’re hearing live?

Yea i’ll try cable as well, just sounded too much like a software / interface issue

Yes, the recorded also starts off at normal volume and then decreases… i have never heard or seen anything like this…

That Tascam US-2x2 has a 5V power supply connection. Do you have a power supply connected? Some sound devices have problems generating a decent and stable 48V phantom power when connected to the USB cable only. In that case an additional power supply is needed.

To me this problem sounds a bit like the 48V phantom power is there when switched on, but starts to drop as soon as there is a load (the microphone) connected and draws power. It’s just a wild idea, but it would not be the first interface that has problems keeping all stuff running on USB power only. This also happens a lot when you use a non-powered USB hub with a lot of stuff connected. In that case an USB hub with power supply is advised.

Excellent comment, sounds like a very probable explanation.

…and a quick look at the US 2x2 manual yields this, which tends to support JClosed’s theory:

"When using a US 2x2 that is connected to a computer, it will receive power from the computer’s USB port. Depending on the computer, the USB port might not be able to supply enough power to operate the unit.

USB 1& 2 ports are only rated at 500ma. Its why trying to fast-charge your smartphone off of your pc doesn’t work too well.

Other than getting a PSU for the interface or a powered hub, you could also try different USB sockets on the PC.

Although there’s a defined standard for maximum milliamps drawn from USB ports, the “always on power” yellow port (if fitted) is often rated higher. This is an unofficial “standard” so don’t be surprised if a. you don’t have a yellow port and b. the milliamp rating is identical to the rest. :laughing:

Thanks JClosed, Great idea. I will definitely try that.


Bought the Tascam 5V PSU. No difference.

It basically sounds like im singing out of an old school radio. No bass or mids and very quiet.

I also have isotopes nectar vocal processor, and if i add it on to the track, it doesnt show any input going into the processor. Going to try my mic and cable out at a local studio to see if they are the problem.

Also when the dial is set to the “Computer” Monitor Balance, nothing comes out. Which leads me to believe it is being stopped somewhere after windows or Cubase for I am hearing no effected sound or outputed sound

You need to enable input monitoring in Cubase when set to computer.
Also, are you 100 % sure, your are switching Phantom power “on”, not “off”?