Peavey 5150 heater design?

[Cannibal]

Hello everybody, I was looking at the original peavey 5150 schematics that you can find here:

https://www.thetubestore.com/lib/the...-Schematic.pdf

And I've found the heater design to be very strange: there's the usual artificial center tap (2x100 ohm resistor between heater and ground) but also it also looks like that R69 connects a small positive voltage (+24v) to one of the heater 's tap, granting some kind of heater elevation.
To me it looks like the heater elevation is made useless by putting the artificial center tap to ground, it just loads the transformer and doesn't contribute in any way in reducing noise (which is substantial in this amp).
Am I missing something?

[Helmholtz]

To me it looks like the heater elevation is made useless by putting the artificial center tap to ground, it just loads the transformer and doesn't contribute in any way in reducing noise

This would be true if the artificial center tap would connect to DC ground/chassis. But R201/R200 are connected to ground via an ecap. This means an AC ground only. So no DC current possible and elevation works fine.
As the 6.3VAC are sitting on +24VDC a cheaper polarized ecap can be used.