I was poking around pricing some NOS tubes and what not and came across this concept - swapping a 274B (a big coke bottle shaped thing) rectifier for a 5AR4/GZ34. Apparently it will do wonders for tone. However, the application discussed turned out to be high end audio equipment. But I was wondering if anyone knew anything about this in a guitar amp circuit. Apparently the NOS 274B was made by Western Electric and there's a few modern production including a cheap Shuguang version. Valve gurus?