Cornish's tube buffered effects?

[Cymbal Monkey]

So I was reading that somehow each effect is tube buffered in Gilmour's board, can someone explain how this works? Wouldn't that send the gain through the roof?

[CynicalMan]

Tube buffer would suggest that Gilmour is using common plate tube stages which have a gain of just under 1.

For example, the tube stage here is a common plate buffer: