FYI, i am now listening to the pre exclusivly thru battery mode; i will never go back. since i am still breaking in the dart amps i do leave it in AC mode when i'm not in the room; but switch to battery mode when listening. I am using the remote without incident including muting; whatever 'gremlin' caused the initial battery mode issues has vanished. i do still need to power down to switch to battery mode (unplug the pre); the regular production run of dart pre's will automatically be in battery mode without the need to worry about it. i have not found a limit to the length of time i can be in battery mode or even the slightest clue that the batteries are running down; i am told that the pre will do 'at least 12 continuous hours' in battery mode and likely longer......i have done 7 continuous hours with no issue except my body's need for sleep.
there are so many amazing aspects to the performance of the pre in battery mode that it boggles the mind.......but i keep being startled by the effortlessness of everything. it's like the damn AC power was a chain around the sound......no matter how you try to make the chain 'pretty' or palatable......it limits what can be done in music reproduction; at least in terms of preamps.
however over-the-top this reads......it is my feelings at the moment.