Nelson Pass inspired headphone amp

[mlackey]

Bump...

Seems this thread has been inactive for some time, but I stumbled across it, and it has piqued my interest.

@Fenris, @agdr, if you are around I'd appreciate any comments on the schematic. Others too.

 

[Fenris]

I don't think that will work. Your gain stage has what looks like two 2540s configured as constant current sources one on the source and one on the drain. Change Q5 to a resistor or LED string, something with LOW dynamic resistance rather than the very high impedance of a CCS.

 

[mlackey]

Thanks for the response. Is Q1 behaving as a current source? And the voltage drop across a resistor/led string determines the current? Or what determines the current?