/diy/ - Do It Yourself

Anyone here knows his stuff about power sources?
Im thinking about building my own tube amp that's able to play music through network (RPi, Esp32, or whatever I come up with). I'm not an audiophile, but the tube technology always interested me.
For that, I need two power sources, one ~5-24V for the platine, and one ~250-480V for the amplifier side.
There are a few online sources selling transformers like that, but they're super expensive, and all cost more than 70 bucks.

>The actual question(s)
-Do you know where to get cheap, ready to use multi source power supplies?
-Can I just use two ready-to-use power supplies? I'm a bit sceptical if they would like having their ground on the output side connected

- if that's possible: modern power sources are way more efficient than transformers, but I'm not sure if the chopping frequency will have an effect on my sound. Would that be safe to use

Oh, and if anyone had problems with signal interference, be it power supplies, WiFi boards or grounding, please let me know!

(And pic unrelated, I know that the EL34 are better suited for guitars then HiFi systems)