I’m really enjoying the Pendant SE tube headphone amp made by Amps and Sound and available from Zach and Bevin at ZMF. It pairs very well with my ZMF Vérité’s and contouring the sound is possible by rolling different tubes. It has a lifetime warranty, also. The original Pendant OG had some noise issues but the new pendant is very quiet. It’s worth considering. Here is the thread for the Pendant.
Have fun and good luck!