DC heater supply bypass caps?

[HighFidelityGuy]

I'm upgrading a few resistors and capacitors etc in my KEL84 and while looking at how the DC heater supply for the input tubes is designed the thought occurred to me that it might be beneficial to add an extra smallish cap across the DC heater supply right next to each input tube. My thinking behind this was that it would add a small but very close energy supply for the tubes and also provide a little extra ripple smoothing.

Is there any actual electronics engineering sense behind this? I seem to remember reading that putting bypass caps close to the current demand is a good thing. :confused: If so, what value of cap would you recommend? I was thinking of maybe using a film cap of some kind. Is that a good choice?

If it helps the heater supply will be from a 3.15V-0V-3.15V centre tapped tx with a Schottky bridge followed by a 4700uF smoothing cap, then a 1R resistor in series followed by another 4700uF smoothing cap. This will provide a Pi filter to reduce the output from the Schottkies by approx 1V to bring it to 6.3V. This is the setup recommended my WD.

Thanks. :cool:

[lurcher]

I think the idea is good, but it would possibly be better to have a small ceramic (say 100nf) cap from each heater pin to ground to dump any noise to ground.

[HighFidelityGuy]

I think the idea is good, but it would possibly be better to have a small ceramic (say 100nf) cap from each heater pin to ground to dump any noise to ground.

That seems like a good idea. I've heard ceramic caps can be microphonic. Would a silver mica cap be any better or is ceramic definitely the best choice in this application? Cheers. :)

[lurcher]

Its on the heater, the valve will be far more microphonic than any cap on its heater. Best in my opinion to only pick fights where winning will make a difference (if you see what I mean).

[HighFidelityGuy]

That's fair enough. I might give this a try.

Cheers.