I have had a very good headphone system for decades. I got serious about putting together a really great system fifteen or twenty years ago. I did a lot of experimenting with great headphones as well as amps and DACs. One conclusion was that Woo headphone amps should always be a top contender… for my tastes it is the brand. Extremely natural and powerful (typically the higher tier the more powerful.
I collected the top tier headphones of Focal, Sennheiser, Ultrasonde, Denon, Beyerdynamic, and a couple others. So I have Focal Utopia and Sennheiser 800s. It became very clear that these amazing headphones require outstanding input to reach their real potential. Anything less, they are just not going to be close to their potential. You can see my current headphone system under my virtual systems.
The difference between my end system here, and lessor amps that I had tried was simply astonishing. Powering this system with an incredibly high current head amp I imported from Germany, a Woo WA6SE, and a couple other very good head amp, did not prepare me, or suggest the switch to the Woo WA5. [The WA5 is a much better amp than the WA6… this can be confusing]. The WA5 is a two chassis 300b head amp… that is so powerful it can be used as an integrated amp for speakers. This took every set of my headphones and elevated them to a level I had no idea possible. If you read the reviews of different headphones sound characteristics, weaknesses. They just seem to go away and become such minor nuances as to be not worth noting. For instance the Sennheiser 800s are often criticized as being trebly… not even remotely with this kind of massive natural input. Some headphones are criticized for lack of bass… problem gone.
One must have a great streamer and DAC as well. I have an Aurender N100 and Ayre DAC… natural and detailed both.
So, my recommendation is Woo for amps. But also, for future consideration, you got some great headphones there and if you want your headphone system to provide an overwhelmingly magical experience, it will take something like what I have.
Unfortunately, headphones are by far are the least expensive component of a great headphone system.