I've run into a problem with my Powercab+ . When I plug it into my laptop via USB, usually for playing along with songs, it will develop a loud, harsh, hissing buzz.
I've tried multiple USB cables and ports and tried moving the power cords to prevent ground loops. The noise is present even when running laptop on battery power.
A few odd things:
If I have some audio playing at the time I plug in, the Powercab will play the audio without the noise, but once the audio is done playing the noise develops after a short period of no audio output. Starting the audio again after the noise starts does not stop the noise after it has started.
I was able to narrow it down to what seems like a specific set of circumstances. The noise appears when the USB is in use and a 1/4 guitar cable is plugged into input 1. It doesn't matter if the guitar cable is connected to anything. In a twist, plugging into input 2 does not cause the noise when Input 2 is set to Monitor mode. If input 2 is set to normal mode... the noise comes back!
Another peculiarity: the buzzing results in a super distorted, nasty, sound if guitar is played through it, but the USB audio is completely distortion free at the same time.
Anyone have any ideas about what may be causing this or how to fix it? Anyone run into similar issues?
Thanks in advance!