Low Heater Voltage

kanderson70 · Post by **kanderson70** » Wed Oct 31, 2018 1:19 pm

I'm measuring 5.8V on my heaters of all my tubes in my latest Liverpool build. Sounds great and it's within a 10% variance, but I was wondering, since it's not the full 6.3V, should I be concerned about it? Will it affect the tube life longevity in a negative manner?

Reeltarded · Post by **Reeltarded** » Wed Oct 31, 2018 1:55 pm

Nope, but yank all the tubes and measure unloaded just for a test. Everything else seems right?

kanderson70 · Post by **kanderson70** » Wed Oct 31, 2018 2:08 pm

Reeltarded wrote: ↑Wed Oct 31, 2018 1:55 pm Nope, but yank all the tubes and measure unloaded just for a test. Everything else seems right?

Cool. Thanks!
Yes all other voltages are lining up close to what others have measured. I'm getting about 340V of B+, but my wall voltage is around 122.

Post by **pompeiisneaks** » Wed Oct 31, 2018 3:02 pm

There will be a definite impact on tube longevity. They'll last longer being ridden less.

~Phil

kanderson70 · Post by **kanderson70** » Wed Oct 31, 2018 3:05 pm

pompeiisneaks wrote: ↑Wed Oct 31, 2018 3:02 pm There will be a definite impact on tube longevity. They'll last longer being ridden less.

~Phil

That's what I wanted to hear!

Post by **pompeiisneaks** » Wed Oct 31, 2018 4:07 pm

I doubt it is significant, but it also means the tubes can have less free electrons to flow for current delivery. Also probably nominal, but that's what the heater's do, boil off electrons that can be avaialable for the tube to operate.

~Phil

Reeltarded · Post by **Reeltarded** » Wed Oct 31, 2018 5:21 pm

If it was an itch in the middle of your back, you'd go back to sleep and scratch it in the morning... and wake up having forgotten about it.

About what?

pdf64 · Post by **pdf64** » Wed Oct 31, 2018 5:22 pm

My understanding is that as long as the heater voltage is within spec, the electron cloud generated will be massively in excess of what is required for the max intended cathode current.
That's because if the electron cloud becomes depleted, for the types of cathode coatings used in receiving tubes, damage might be caused to the cathode.

kanderson70 · Post by **kanderson70** » Wed Oct 31, 2018 5:35 pm

Reeltarded wrote: ↑Wed Oct 31, 2018 5:21 pm If it was an itch in the middle of your back, you'd go back to sleep and scratch it in the morning... and wake up having forgotten about it.

About what?

LOL... well good. I have only built three amps now and the other two were both 6.3V. Just wasn't sure if this was a common thing with brand new Pacific transformers.

I guess now I'll start worrying about CC vs. Carbon Film resistors.... or cloth wire vs. PVC coated wire.... or VVR vs. PPIMV... "SIGH"

Reeltarded · Post by **Reeltarded** » Wed Oct 31, 2018 6:28 pm

oh no.. because none of that is a problem unless you have worried about it!

JINX! Happy Halloween! May all your eccentric behaviors add a nominal 10% mojo to your future builds!

(Call Pacific and tell them you tried turning it off and on already)

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