Problems with Modmic 4.0

Some weeks ago I decided to get a new pair of headphones instead of my old siberia v2 because they were quite awful for listening to music. So I picked up a pair of AKG K701 and K612 Pro to test/compare them and a Modmic 4.0 as a microphone since a Solution with separate condenser mic with arm and everything is a bit pricey and may be too much for gaming voice. 

I always had problems with the mic sound on my internal sound cards (onboard realtek and creative x-fi xtreme audio are both very quiet on almost all mics, windows mic gain just makes quality awful), so I use a old logitec usb sound card just for the mic and the volume is much better like this.

But now to the main problem: on some mics I get a deep static hum using this setup wich isn't nice but its tolerable, but on the Modmic I get a very high hiss/hum and this is almost unbearable. It's not permanent, sometimes its louder sometimes its almost gone, it also gets worse when I put my hand around or near the mic tip. 

I tried switching usb ports (frontside different backside ports, usb hub) but almost no change.

Since I also watched the Tec Syndicate review on the Modmic and the was surprised by the quality I would be interested what they had the mic plugged in to.

Maybe someone could help me to fix this because it gets really frustrating buying a better mic and getting worse quality out of it.

 

EDIT: I also tried it with a creative X-Fi HD USB, was a little bit better but still not the quality I heard in most of the review videos.