At the risk of being:
b: stating the obvious
c: all of the above
bear with me........
an average stereo SE headphone amp with have two amps, one for the left channel, a second for the right channel
The Mo also uses only two amplifiers
one for the left channel and one for the right.
The difference is, each amp in the Mojo has a balanced input and a balanced output, so it is a balanced amp, input to output. It uses a circuit topology called the Circlotron.
more than you probably want to know about the Circlotron topology here
Another example of a single amp with a balanced input and a balanced output:
Matrix sells an amp called the Quatro, it uses 2 amps per channel to create a "fake" balanced amp.
I'm not trying to dump on Matrix Electronics, I own a Matrix M Stage.
Anyway, by now someone thinks I'm