he did not go with replacing process, the amp was mine and he sent it back
he claimed 4 hours under high gain 25%vol drive philips x2
i did another test, charged for around 5 hours then fed from sony x lineout drive v-moda m80,low gain, 50% vol(almost too loud for normal listen-as some one mentioned above even lcd2 only needs low gain) and it lasted for more than 12 hours before completely turned off
Not sure is it normal to have such huge difference between high vs low gain battery life
Sound right, at high gain it 3x louder than low gain so it make sense that it only last three time less.