Basically this. In the most basic way I can describe it, I found the biggest changes in sound came from what tubes I rolled. Some sound like shit, some laid back, some no different than a good clean solid state. In the end, it was fun rolling but after blowing through a dozen or more tubes only to find out I liked tubes that were just a really good solid state sound... it was a huge waste of money, I could have just scooped up a really nice SS amp and have been done with it rather than the hundreds of dollars in tubes I wasted my money on including the amps.