I agree with Atmasphere and that speaker is not well suited for tubes. I have heard it driven well via a McIntosh MC275 but it was a pair that was bridged mono at 150w. Not sure 200w is required but it is very clear the 20-30w you will get out of a Raven is not going to be adequate.
There are not a lot of mid to high powered tube integrated amps and even fewer that can deliver decent power in Triode. Most are ultralinear. Something low risk like a Rogue Audio Cronus Magnum III might be an option for you as it will deliver 100w in ultralinear and will be in the same sort of price range.
Another option would be a hybrid integrated with a tube input stage. Something like a Rogue Pharaoh and find some killer NOS tubes like Mullard long plates to swap in. This won't be as good, but will give you more of a tube presentation than a SS amp and delivers plenty of power to drive those at 175w into 8ohms.
There are not a lot of mid to high powered tube integrated amps and even fewer that can deliver decent power in Triode. Most are ultralinear. Something low risk like a Rogue Audio Cronus Magnum III might be an option for you as it will deliver 100w in ultralinear and will be in the same sort of price range.
Another option would be a hybrid integrated with a tube input stage. Something like a Rogue Pharaoh and find some killer NOS tubes like Mullard long plates to swap in. This won't be as good, but will give you more of a tube presentation than a SS amp and delivers plenty of power to drive those at 175w into 8ohms.