The WA8 is designed with simplicity in mind. Tube rolling on the WA8 is easy although it cannot compare to a full sized desktop amp.
The 6S31B power tube is a very unique tube. There is no direct substitude. It has a long lifespan so you won't need to worry about changing tubes once a while.
You can roll the 6021 which is a common tube.
At the end, the WA8 is for a minimal, user friendly setup.
We will offer tube kit for replacement. Right now, we just want you to...