I am amazed as how many people are looking for Sunn Beta lead amps. I purchased a Beta lead guitar amp brand new in high school (many years ago). I still have the unit in my basement but never use it because of a terrible hiss that I get when the amp is turned up and over driven. Has anyone else experienced this? If so how can I fix it. It is difficult to find anyone to work on these things, most amp tech only work on tube amps. If I could get rid of the hiss I might use it instead of purchasing the Marshall I have been looking at. Thanks