Oops! Pardon the link blooper.
Shouldn't take nearly 500 hrs to tell the tale.
BTW: I am also using the Shuguang Treasure 6CA7-Z power
tubes in my Quicksilver amps. These bested one dozen sets
of NOS and new production tubes I've search through and used
over a number of years.
Like the CV181 the sound is solid, detailed, clean and clear
while maintaining very fine musicality. Honestly, except
for the 12AU7 in my system, I am off of old stock tubes.
Honestly, that is quite a relief.