Headphones

It's potentially tricky because of the voltage and gain requirements. For example, some report even the Bliss with 12 Watts at 32 Ohms and Spring 3 (5.8 vrms) sounds soft and lacks headroom partially due to insufficient gain (amp lacks a high gain mode), which my ears tend to agree with.

Luckily though, my dac has a pre-amp putting out a max 11.6 vrms, which the Bliss hungrily accepts, providing a much different experience - greater dynamics, better low end etc. A number of Tungsten owners report wildy varying impressions listening to the same amps (Oor, CA3, Mjolnir 3). I'm guessing this is likely due to differences in the input voltage received from their dacs.