One of the inputs on my Digidesign PRE preamp recently started producing a distorted sound with a lot of static. Are there some basic things I can do or check for to fix it before I send it in to get repaired?
This sounds like a broken circuit to me. If you still have a valid warranty on the machine (I don't know how digidesign does this), I would return it immediately for a proper repair. Otherwise, either send it to Digi, or to some radioshack (do find a good one though).
One advantage sending it to digidesign is that they replace the broken components with the same brand of material. This can be important because other brands of capacitors for instance could have a slight offset in real capacity resulting in a different sound or sensitivity on that particular channel, which is never good to work with.
If you are into electronics yourself, there is always the option to open the device and look what could be wrong. Make sure to check if you are not voiding warranties if you do so.