I personally had a surprisingly improved signal to noise reduction from using Alan Maher's Power Enhancer products The idea is each device treats the power line in your home which feeds your equipment by removing AC power supply related artifacts.
I was shocked that this was indeed the case. Consider most equipment in your house has a power supply running on the line and its effects are relatively unknown till now.
Less money spent great bang for the buck and his new products now use Quantum treatment with Bybee technology.