I just looked at the original brick I recieved with my Mk2. It's rated 15v@1amp. It's also suspiciously lite compared to the Netgear 12v@1.2A brick I have handy. The same Netgear brick will run my empeg but poorly, the led keeps ramping up and down in brightness.
Come to think about it most car batteries output something more like 14v.

FWIW my empeg's wart is labeled:

Sunpower
Model: WA15-150
INPUT: 100-150VAC A.0A / 47-63Hz
OUTPUT: +15VDC@1A

also
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