Can also try Class A, my preference.
Schiit Audio: Audio Products Designed and Built in Texas and California
Tired of compromise? Kinda crazy when it comes to sound? Then maybe you’re in the mood for Mjolnir 3, a real-deal, 100% Class-A, no-feedback, dual-mono, choke-input, fully-discrete, balanced-differential headphone amp and preamp. It’s by far the most extreme desktop product we’ve ever done.
This is better to my ears than the Schitt Freya+ (owned it before). The Mjolnir is not as good as my Benchmark LA4 and Holo Serene, but it is a really good 2-channel preamp.
I listen to the Mjolnir preamp and a Schitt Aegir amp each night with headphones, but in a 2-channel manner.