DC elevated heaters and Fender 6.3 Jewel bulb

[goldstache]

I have a CF stage in a new build and I think the elevated heater supply is frying the Fender style 6.3v bulb. 

I have about 90VDC on the filaments and my CF stage cathode is at about 154VDC.  Seems legit.

Does anyone have any experience with bulbs frying from high float voltages?

Does anyone know the max DC these 6.3 bulbs can handle?

Thanks

[sluckey]

Elevated heater is not an issue with the indicator lamp if the lamp is wired correctly. Show us your schematic.

[goldstache]

Don't have it handy but it's the first in the string and the elevation point enters there at the jewel.

Elevation:
B+ > 180K > 47K (cap here to ground) >ground

second bulb is in and going strong after 30 minutes. 

[sluckey]

the elevation point enters there at the jewel.

If I understand this correctly, your lamp and all your tube filaments are at risk.

The elevation point should be the filament winding centertap. If there is no real centertap wire on PT filament winding, you should create an artificial centertap using two 100Ω resistors. The elevated voltage would connect to the junction of the two resistors.

[goldstache]

I'm sorry.  My filament CT is where the float is.  Then filament runs to the jewel on down the line. 

[PRR]

Bird on a wire. Neither leg of the jewel knows it is 150V up so it is fine.

[goldstache]

Thanks, second bulb is still glowing after many hours so me thinks it's fine.  False alarm.