DC heaters are nice. You can’t run directly heated tubes that way, but otherwise it’s a fine idea with definite benefits. I did get one DHT amp in once that had the 300B heaters run from a 40kHz oscillator and SS power amp through an interesting handmade toroidal transformer to give them a center tap ground. I guess if you really really don’t want any 60Hz in there, that’s one approach.
Meanwells are ok, but I have had some longevity issues. Nobody really builds switchers to last. They build them to be cheap and efficient. They are cost effective and readily available, though. If you’re only using half capacity except for turn on, they might keep going longer. Regardless, in ten years there will doubtless be something that would do the trick in a similar if not smaller package. Where I run into problems are manufacturers that have multiple output switchers go bad. If you’re using standard voltage single output units, there will always be something to replace it with.
