and the trick is that you can connect the heaters in series instead of doing it all in parallel and pumping out a ton of amps at a very low voltage. Yes, this

and the trick is that you can connect the heaters in series instead of doing it all in parallel and pumping out a ton of amps at a very low voltage. Yes, this is what a lot of tube equipment did, as they are naturally high-voltage, low-current devices; here is one notable example: https://en.wikipedia.org/wiki/All_American_Five https://en.wikipedia.org/wiki/All_American_Five