Cool! Being able to choose between an active and passive preamp suits me where I use the Mogwai SE for both headphones and speakers (with powered subwoofer).
I’ll keep you posted. In the past, I’ve preferred headphones without the MZ2, but that was primarily with the more highly revealing Verite Closed. The HD6XX is less sensitive even if not reflected in the specifications.
I’m a chronic optimizer and am aware! I’m not so lucky. Even if the noise went away, I prefer the more controlled presentation of the 32 and 8 ohm outs. The 300 ohm out is a candidate for instrumental and more mellow genres for me.
It’s nice that the Morpheus has a preamp and remote functionality. I used to have a Topping DAC with built-in preamp. I got better sonic results by deactivating the preamp and using it as a DAC only; you may have more success with the elevated Morpheus and Bigger Ben.
I’m generally a proponent for simplifying the audio chain and signal path, but have found that the Mogwai SE benefits from an active preamp with speakers (and most recently the HD6XX while running the lowest power/gain tube roll and DAC output voltage). The difference is subtle and we sometimes make a big deal of things. I trust Justin’s builds and am pretty sure that similar enough performance can be reached without a separate preamp by optimizing the tube roll and/or power supply management.