I recently went to C4 for a re-tube and biasing. What Chuck didn't tell me then is that he gets his tubes directly from the Russian factory so they cost about 50% more than what you'll find elsewhere. Are they worth it? It's debatable. If you're a working musician on a budget like me, probably not. Chuck told me that, "most people have better things to do than write reviews." I disagree. If you're taking the time to read this, you probably value reviews as much as I do.