mrvco,
I too considered the W4S products mPre and the STP-SE, especially during their recent sale. However, I got the impression from a dealer that the headphone amp is only decent on the mPre and that’s important to me. I also, looked at the Pass Labs HPA-1, but pricey.
Will look again at the Tortuga.
What are your thoughts of the mPre with the J2, especially the DAC section?