after a long time of joy, my pedalboard suddenly sounds "squeaky". I turned on my MXR 5150/Morley Wah,Bogner pedals (not at once) and a loud feedback-ish high-frequency tone (weeeeeeeep!) was screaming through the speakers. But that was just the tip of the iceberg. My overall tone with pedals bypassed has also an ugly feedback-ish/HF-ish undertone...you don't hear the bleep, but it's there...everything sounds harsh and ugly I had that before, years ago, but I can't remember exactly what it was... the nature of the symptoms tells me, it could be the the power supply (cables) what do you think?