Just to be clear, Mjolnir isn't a bridged amp. It's a circlotron--an inherently balanced, differential in, differential out stage that automatically converts single-ended inputs to differential, thanks to the magic of an input differential amplifier. Yes, lots of differential there.
Bottom line, Mjolnir doesn't have the "only one leg driven" problem of some amps you're discussing, nor does it have to
compromise by summing everything down to single-ended, then running through a volume pot, then applying the signal to two separate stages, like other amps you're discussing. It's really an elegant solution--the only catch being the complexity of the power supply.
I know I'm being pedantic, but people get strange ideas, especially when the thread title is "Schiit Mjolnir Headphone Amplifier." Just a little disambiguation among friends.