Bottlehead Forum

Bottlehead Kits => Legacy Kit Products => Foreplay III => Topic started by: audiblesoundwave on October 08, 2014, 02:11:43 PM

Title: 6.5v into 12au7 too high or within spec?
Post by: audiblesoundwave on October 08, 2014, 02:11:43 PM

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

Title: Re: 6.5v into 12au7 too high or within spec?
Post by: galyons on October 08, 2014, 02:23:53 PM

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

Title: Re: 6.5v into 12au7 too high or within spec?
Post by: audiblesoundwave on October 09, 2014, 05:38:51 PM

Thanks Geary!

Have a wonderful weekend,
Milton