I decided to buy a middling set of headphones, Beyerdynamic DT770 Pro 250, and a low end tube amp, the Little Bear P8. I had found a steal on a lot of tubes including 2C51 and 6AS7 types so it made sense at the time. Well, it died. One channel is dead. Is there a headphone amp design that might use this combo of tubes? I have accumulated a pile including some slotted column Bendix 6080, Tung Sol 5998, and Bendix, GE, and Western Electric 396A tubes and would like to use them. Even found some Tesla preamp tubes. Any suggestions? I do not want to mess with the P8 and I do not have the ability to design anything without a great deal of further education, time, and effort. A few searches yielded no easy answers. It did sound good while it lasted! Ideas?