6SN7GTB replacement


Hello, friends, I have a canary audio M 600 fitted with the 6SN7GTB reissue TungSol can I replace them with just the 6SN7 GT 
128x128jasbirnandra
Thought the GT was rated as 300V (not 350V) maximum plate voltage.

Bigger difference than 350V.

There is an "old" production 6SN7 rated @ 450V, but I do not recall the "after" 6SN7 "letters".

Again, as mentioned, it depends upon the circuit design.

DeKay
If a modern 6SN7GT like the Chinese Shuguang, yes, you can as even though they are marked as GTs, they are spec'ed more like GTBs and we've been using them that way for over 20 years with no worries. Don't do that with any of the boutique Chinese tubes like the Psvane- they are actual GTs.
You should ask the manufacturer or a dealer. Typically, you can't substitute a 6SN7GT in a circuit designed for the 6SN7GTB. The plate voltage is higher in the GTB (450V) vs. 350V for a GT, so the biasing would be different.