Chazzbo- The Sino 845 is fine as has been pointed out already. In a really tweaked system, there is really no comparison with good NOS 845 though. The Sino tubes sounds thin and harmonically lean compared to the United 845. In my system, there simply was no choice. I had to have NOS 845 once I tried them. As previously stated, you will likely pay 300 to 500 per tube. However, considering the fact that a pair of NOS 845 tubes will likely outlast your ownership of the amplifier, I'm not sure if I would consider the money unwisely spent. Just one man's opinion. Good luck.
