i had a thread awhile back on this
i was using a 6v sla to power my m1
i thought it was ok to run it on 6v, but i hear otherwise
we tested the wall wart to find out is is like 5v...
all i hear is that alot of people are frying thier m1s with 6vs, so i will never again use a 6v with mine, but yes it did work when i tryed it.
i have use regular aa's, the supplied 1300mah aa's that came with the m1, and i now use 1800mah aa's.
with the 1300 i taped phish at bonner springs and played back most of first set on the one set of aa's
the 1800 mah's i used for the first time, after cycling them 5-6 full times, on friday i got 2 hours recording, one hour playback, all with the lighted disply on, and the battery meter still said full....