Thanks for your opinion! The tube rolling is also one of the main reasons that I'm considering the Valhalla over the Asgard.  

I'm interested in an amp for the Beyerdynamic DT880s (600 Ohms).  I have heard these cans when paired with the Bifrost and Lyr and it was amazing! However, that rig is out of my budget.  I'm looking to spend between $500 and $650 on a rig including the cost of the DT880s.     The Lyr sounded...