6.5v into 12au7 too high or within spec?

As I have been trying to isolating a different problem on my FPIII, I measured 6.5v for both of the 12au7s heater voltage.

Is it too high or within the safety range?  Will it shorten the tube life with the higher voltage?  Just like to double check.

Thanks,
Milton
 
Milton,
The spec for the 12AU7 heater filament voltage is 6.3V +/- 10%.  You are good to go at 6.5! That is well within normal range, given line voltage variations.

Cheers,
Geary
 
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