Questions & Answers

closed Why is phantom power causing this sound?

+1 vote
asked Jun 4, 2017 in AudioBox USB by glendacraig1 (200 points)
closed Jun 7, 2017 by glendacraig1
This problem started recently. I have an Audiobox USB, MXL 990 Condenser Microphone, and an HP Notebook 15-x64 based PC. About a month ago, I started getting this high pitched whine in Audacity. After having to do noise reduction more and more and more I finally decided to fix it. I have tried:
1. Restarting my computer
2. Turning off the WiFi
3. Turning off every appliance that I could in the house
4. Using longer and shorter cords of all types
5. Changing locations
6. Changing mic stand
7. Uninstalling and reinstalling the driver
8. Using the Audiobox on my keyboard and it created the same sound
9. Changing the USB it was plugged into
10. Using a powered USB port
11. Experimenting with different levels between all five knobs
12. Testing with different audio programs, even PreSonus
If it helps, I am not using any other output devices. I am only connected to my microphone and my computer.
My current theories are either my laptop is causing excess electricity to be picked up, or the Audiobox has a hardware problem. However, I really don't want to buy a new interface if I don't have to; so any advice I can get is appreciated! I have also attached a recording of the sound. Thank you for the responses.
closed with the note: Discovered answer on my own

2 Answers

0 votes
answered Jun 6, 2017 by AlexTinsley (925,190 points)
Best answer
Just pull the power connector off the back of the laptop and run the laptop on the battery to isolate the computer ground from your power supply / wall supply.

If the noise goes away, then you'll need to acquire / invest in a UPS Power Strip (Furman Power Conditioner or APC 500 or similar) that isolates your wall power and provides a layer of noise protection from the power.
0 votes
answered Jun 7, 2017 by glendacraig1 (200 points)
Thank you for your answer, but I performed more tests and it is the Audiobox itself. I bought a new interface and I am not experiencing the same problem.