In the RM20:
V1 is the closest to the input jack ( input - hardest one to change from the back). V2 (loop) is behind V1 and V3 (PI) is next to the EL84.
.....................v1
el84 el84 v3 v2
So if you were thinking of this as a regular amp V1 input stages (rm20), V2 gain stages (v1 in...