Simple 45/2A3 schematic error?

[Richard Ellis]

I was perusing thru the JE Labs schematic sourcing parts when I came across the 6SL7 filiment off the Hammond 272 DX.
Correct me if I'm wrong but isn't that set-up wrong? JE has the heater filiment grounded off one side...how is that going to define ground?
Reading MJ on page 330...Morgan is adament that grounding one side of an AC filiment will induce hum....think about it...one side of a waveform shunted directly to ground....just as JE Labs has it in their schemo!
Morgan has either a humdinger or precision matched resisitors or a center tap so define ground.......not merely grounding one side................Anyone caught this?
________________________________________Rick...... ......

[Miles Prower]

^^^^

It's strictly a case of yes, no, maybe. I did a design that has no noticeable hum at all with a floating AC heater supply (to avoid Vhk poofage problems). Usually, some sort of balanced AC is best, but each case may be different, and it's a case of try it and see what happens.