Originally Posted by Rob Watts View Post
1. The battery is capable of delivering 3A of current, and has very low impedance.
2. Mojo amplifier has a very high power supply rejection ratio.
3. The output is pure class A at 5v RMS into 300 ohm.
I just had an email today from a very experienced dealer that asked me this question:
"Chord Mojo should have single amplification which drive to both headphone output, but if I'm using any headphones (HD800 for example, very heavy to drive) to put on headphone output 1 and I connect another headphone to headphone output 2 (Beyer T1 for example), I hear no differences on sound quality. Normally if one amplification section used to drive 2 headphones output, then once we connect the second headphone will make overall sound quality degradation (as the case of Beyerdynamic A20 amp, Grace Design M903, etc). What is the logical explanation of this? As it seems Mojo has 2 separate amplification sections which drive independently for each headphone output."
Of course Mojo does not have two amplification stages. It can drive two headphones with ease because it has exceptional low output impedance, and it has exceptional current linearity. So loading it with more headphones has no effect, unlike other headphone amplifiers.
Indeed, when I initially started designing Hugo I was shocked how poor from a measurement point of view headphone amps were. Poor output impedance, huge levels of distortion, and poor current linearity seem to be typical. And these things matter, if your goal is transparency and musicality.
Rob