Accessories / Gadgets

A sound engineer said the DI box only brings a level down, and won't bring it up to produce a stronger signal. I thought what DI boxes do is increase a low signal to a high signal. Who's right?

I recently bought a large-diaphragm condenser mic which came with a foam wind shield (the kind that fits over the top of the mic). Will this do a good enough job of stopping plosive blasts?

I am having serious earthing problems which are making it difficult for me to record a clean guitar sound. All my leads are good, and I don't have this problem with any of my other equipment — just the guitar stuff. Could it be a problem with my domestic mains supply?