Noisy electronics are usually a symptom of a grounding issue or interference coming from outside of the guitar. Try plugging your amp into a different outlet or move the amp to a different room. You can test the outlet with an inexpensive plug tester to make sure it's wired correctly. Ground loops can also create unwanted hum. If you're using more than one piece of AC powered gear in your signal chain, you have the potential for a ground loop. To troubleshoot, plug the guitar directly into the amp with nothing else connected. Bypass all effects and disconnect any auxiliary audio connections such as a direct out on the amp.