sennheiser hd6xx

Looking for an AMP to power HD 6xx/HD650, what's a better option between Topping dx3 pro+ vs FIIO K7. Other suggestions also welcome.

I recently bought the Truthear Hexa to dive into the world of audiophile. I am considering purchasing another device to compare and contrast the two. My options are: Massdrop X Sennheiser HD 6XX Headphones - $229 7HZ Timeless AE - $259 I want to learn more about my preferences in music...