Amazon.com: 9V DC 1.7A 1700mA Center Negative Regulated Power Supply Adapter with Noise Reduction Filtering for 9 volt Guitar Effects Pedals + 5 Way Daisy Chain : Musical Instruments
Joyo JP-06 ZGP-W USB Guitar Effect Power Supply and Noise Filter - ETONE.SHOP
Fixing a Pedal with a Loud Hum or Buzz (Not Power Supply Related) - YouTube