"A nit to pick: The EL34 tubes are not self-biasing nor can the user adjust the bias. That means a trip to the dealer or a technician when you want the tubes replaced, or just checked. Tube rolling (trying tubes from different manufacturers), a favorite pastime of tube enthusiasts, would therefore be expensive."
I found this in a review. I know nothing about tubes, but thought it might help.
https://www.soundstagenetwork.com/revequip/raysonic_sp100.htm