Just guessing here but the 1 to 4 splitter is designed to be a distribution amp and not a point amplifier. That and the fact that You cascaded the amps means that the TV is not only being overdriven, but they also amplify noise as well as signal. If you have a picture problem notify the cable company.......unless it's an illegal tap. In that case put the amp at the feed side not the TV side, and try to find an amp that has a variable gain that you can fine adjust.