Electrical noise — hiss, buzz and hum — is something that plagues every electric guitarist to some degree, but noise comes in a variety of forms and it is important to establish exactly which kind(s) you are experiencing in order to devise an appropriate solution.
I bought a Boss guitar effects processor the other day and noticed that the guitar sounds a lot better through it than it does just straight into my mixer. Also, could the sound from my mic be similarly improved by getting a stand-alone voice channel for it, rather than just putting it through the mixer?
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?