CTC5 Pickup!

[Yamamaya42]

OK, something is not making sense here, you put in a NOS 6CG7 and it blew right away?
You say it shorted? How, H-K?
If this is indeed the case, then you have had something critical fail in the area to cause it to push the tube way beyond it's max ratings if it shorted that fast, like an open resistor or shorted capacitor.
You should be extra vigilant in looking at every related part and finding the cause before destroying another way WAY overpriced tube, thank you audiophiles very much!