Help with an SVT

[Buddha's Guitar Tech]

Discovered something which had me scratching my head, then chuckling.

Replacing that 4k7 with an 8k2 was the right thing to do. After that, all the voltages checked out except for the preamp section. Supposedly 300v at the final node, but i'm getting 330.

So i replaced another 8k2 (2W this time) thinking maybe it was drifting when under load. But no joy. Working back, all the voltages are fine.

Well... if you look at the 6550 power amp schematic, Power Supply Node B has 485 volts on it.

Looking at the preamp schematic, that 485 has magically turned into 430. At least i know it's not me!

If i have to, i can just replace that 8k2 2w with something a little higher and close the book.