strange amp, questions

[fade]

i own this all-tube reel-to-reel tape recorder from the 50's,
and i use it to play guitar through, because it's tone hypnotizes me.

here's the schematic:
VM-700 schematic

when used simply as an instrument amplifier,
the signal simply goes through a 12AX7, then a 6V6,
single ended setup.
(there's a second 6V6, but it's simply used in a tape bias oscillator)

but here's what's weird,
Notice that it looks like they've got the Screen voltage set
Higher than the plate on the 6V6 (?)

what's up with That?
is this normal?

[Enzo]

It was done all the time on small inexpensive amps.

One could make a technical case against it, but the thing works, you like the sound, and the tape recorders did not have a reputation for eating up power tubes. So let it be.