Can I use Tung Sol EL34B tubes in my Origin 20H amplifier to replace the stock EL34 tubes ?

Hello everybody,

I just got the CODE50 amp and tryed to install the Gateway app in my Samsung A5 but due to compatibility  issues I cannt download it. 

I am very disappointed because I tried everything to get the app downloaded, and still not enjoying the amp as I wish. Please fix this problem.

Alejandro