fizz in amps is the result from having their volume too low, you have to get the thing cranked high enough to get rid of the fizz for the amount of distortion that you want. Having the bias set correctly helps if the fizz is the result of crossover distortion. Only other advice I can give is that if you are recording, Low Pass filter to help if you need it, make sure you are not picking too hard/your action isn't too low (string-fret buzz), and make sure your gain isn't too high.