Fulltone IPS-18 18-Volt Worldwide Power Supply 100-240VAC 800mA
These adapters have the USA-type NEMA 1-15P 2 pin configuration. (see photo below) You may need a $3-$5 pin-adapter your particular country. For example this one here.
ALL other switching type adapters hum! Believe me, engineering one that doesn't was a huge undertaking and headache, but I did it.
Many switching type also make a droning synth-like noise due to the use of a cheap, poorly designed regulator. I designed the Fulltone IPS-18 to be Noise-Free, and gave it plenty of available current; 800ma.
The Fulltone IPS-18 is a MUST-HAVE for all owners of older 18 volt powered MDV-1, MDV-2, and MDV-3 because of the massive amounts of current it offers. (800ma) The older Deja'Vibe models mentioned have internal 18 volt conversion, and we've recently discovered that they need the extra current to sound their best because there is a large amount of sag at a certain part of the oscillation cycle.