Fender Dual Showman bias setting

[MarkusBass]

I'm looking for advice on bias setting in Fender Dual Showman ab763 (4x6L6GC). Power supply is 458V. I measured the quiescent current (one valve) - it's 21mA. Shouldn't it be something like 40-50mA? I have -53V on the grid. I cannot see the voltage on the schematic - it something like -52V.

Mark

[dodona]

Tube amp bias calculator

[MarkusBass]

Great tool. It looks like 29mA is recommended in this case.

Mark