Nostr Web Client

I just wanted to circle back to say that of course you are correct. The AI version of events makes no sense. Even with the cathode physically connected to one side of the heaters, B+ does not flow through the series filament string as DC is unidirectional and grounded at the power supply.

AC does appear on the cathode, however, but is filtered by the 1st cap of the power supply.

ChipTuner 1w ago

Yeah thanks for following up. I definitely had a hunch something was off.

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micahcmiracle 1w ago

Let me know your thoughts on this:

In many old, transformerless, series filament (AA5) radio/amps, one side of the AC is indeed tied to the chassis, along with the ground for B+ ...

In such a case, is it possible then that the B+ on the heaters would be carried through the heaters?

This assumes that the cathode really is tied to one side of the heaters, which I havent fully verified, but seems likely.

micahcmiracle 1w ago

Oof. I'm in circles. ⭕️ ... 🤣

The tube in question (35W4) is not directly heated. The cathode and heater is not connected.

In fact it can hold its isolation up to 360v: https://www.amplifiedparts.com/sites/default/files/associated_files/35w4.pdf

So there's that. Such misinformation spread through AI. 🤷‍♂️

This is all moot now. Thank you for your attention to this matter.

ChipTuner 6d ago

XD Yeah thanks again for clearing that up. I use AI for software, every time I've tried for electronics I get spun in circles and always end up back in my college textbooks and notebooks lol.