Diod Tube question, can somebody help me out with this?

[mizzarrogh]

For a functional project, i need a cheap rectifier tube that can handle at least 3A and give out 5V continuously. (it is for another electric valve which need 3A DC and i want to try this for the eastetic reason so one can see the rectifier tube in operation was my plan). My budget for this is unfortunatly pretty low, so i looking for cheap but reliable tubes that are reasonably easy to obtain inside the EU or cheap to import.
Any suggestions?

[J. Wilhelm]

Just clarifying, any kind of rectifier (diode), tube or solid state will only give you the top half of an alternating waveform, so you will still need a current smoothing capacitor(s) to eventually get to a ripple-free DC voltage, yes?

Is this for a sound amplifier or radio circuit? There's a difference in desired behavior between the two general classes (tube/solid state). For guitar amplifiers, for example, voltages are above 300-400 V, and a voltage time lag in a tube diode is desired for tonal qualities.  For general power amplifiers, solid state diodes have many values starting with single digit voltage, and these have a better response (less time lag, no voltage drop, exponential voltage rise when crossing a voltage threshold).

Unfortunately haven't used Tube Rectifiers, ever, so I can't be of much help with designations. I've never seen tube amplifiers work at 5 V though.

For example, here's a discussion on the subject of low power rectifier tubes
https://www.diyaudio.com/community/threads/low-voltage-rectifiers.126541/

[von Corax]

Perhaps if you could post a circuit diagram, or a link to one, we could advise you better.

[mizzarrogh]

Nothing serious, i was just curious about if it could be done to DC feed a 5Ц4С from a tube rectifier as an experiment for a Hi Fi amplifier, but i did quickly run into other obvious problems with that particular tube... i stronlgy suspect in must hawe fully insulated ground on that one because of the strange construction whan i red the datasheets.

I know this can be done in a much, much easier way, but i just wanted to know if that would work. 

[mizzarrogh]

Honestly, i still really want to know this in theory how this exact question can be solved without using modern tecnology or silica.