Thanks much, Paul! I figured you would be the first to reply :-)
BTW, digging up an old "argument", the ifi IEMatch IEM attenuator is just resistors, but also some switching for balanced and unbalanced operation. You called it :-) It wasn't obvious until I actually had one iin my hands. If you're interested, the ifi site has a technical PDF that explains it -- I have terrible options for reading PDFs, so I never read this and have no idea what it really says.
I can tell you that there is one built into my iDSD Black Label DAC/Headphone amp, and it works really well -- quite transparent as well.
-- Jim
Jim Rebman -- recovering audiophile
Equitech balanced power; uRendu, USB processor -> Musette DAC -> 5670 tube buffer -> Finale Audio F138 FFX -> Cain and Cain Abbys near-field).
s.e.x. 2.1 under construction. Want list: Stereomour II
All ICs homemade (speaker and power next)