I built a microphone preamp for my computer (a kit preamp), and I've been powering it by USB. Because its output goes into the computer's mic socket, which shares the same ground as USB, a ground loop is created.
To rectify it I put a ground loop isolator between the output of the pre and the input of the computer. Alternatively I guess I could have used one of these instead if I wanted the signal to remain unaltered:
http://www.ebay.co.uk/itm/360860072660
Right, so let's say I wanted to power an amplifier with the PC's PSU, as well as receive its signal from the soundcard. There'd be a ground loop of course, so I'd either have to use a ground loop isolator (slightly degrading the signal), or find a way of isolating the power for the amp (like in the above link). The latter isn't really practical because of the power requirements.
SO this leads me to my main question! How do you design an amplifier, pre or normal, that won't be affected by ground loops? I know it's possible because I've salvaged a few small amps designed for Ericsson mobile phones that are both powered by and receive the signal from a common ground (the phone). Or maybe these little amplifiers have DC isolation ICs on them?
Thanks in advance - this is something I've wondered for a long time!
To rectify it I put a ground loop isolator between the output of the pre and the input of the computer. Alternatively I guess I could have used one of these instead if I wanted the signal to remain unaltered:
http://www.ebay.co.uk/itm/360860072660
Right, so let's say I wanted to power an amplifier with the PC's PSU, as well as receive its signal from the soundcard. There'd be a ground loop of course, so I'd either have to use a ground loop isolator (slightly degrading the signal), or find a way of isolating the power for the amp (like in the above link). The latter isn't really practical because of the power requirements.
SO this leads me to my main question! How do you design an amplifier, pre or normal, that won't be affected by ground loops? I know it's possible because I've salvaged a few small amps designed for Ericsson mobile phones that are both powered by and receive the signal from a common ground (the phone). Or maybe these little amplifiers have DC isolation ICs on them?
Thanks in advance - this is something I've wondered for a long time!