You need to get a filter. It will filter out the noise that comes from the alternator. Run the hot wire straight from the battery through the filter to the amp. I had the same problem and it fixed it. Let me know if it worked.
Has anyone seen this and most importantly, has anyone used enthanol in their tank. Very interesting read. Looks like NY is trying to make a change. I was trying to find out if there was anything negative on using an alternative to gasoline...