Build Your Own Clone Message Board

I just got an 18v wall supply today. The case says Output: 18VAC 500Ma.

I have 3 pedals that each should handle this:
BYOC 5 knob compressor, GGG Marshall Bluesbreaker, and GGG BSIAB. The problem is, this power supply is giving a distinct buzzing noise through each pedal, either on the pedal board, or if the effect is taken off the board and used alone.

I can't understand this problem. Could I have a bad unit? Each pedal works fine at normal voltage BTW.

thanks

Those pedals (and most pedals) take DC not AC.

Knight is right on with this one.