Since I was forced to move to headphone listening, I have tried numerous headphones and amps none of which I enjoyed all that much with classical music until I found:
SparkoS Labs Gemini with vintage 12BH7 tube (mine is a Tung Sol 12BH7A black plate)
Grado Hemp with white stitching on headband (the so-called revised version) and the Grado brand G-Cushions and ddHiFi 1/4 inch adapter