The last more or less "official" report I heard was that there are NO TUBE MANUFACTURERES IN THE "WESTERN" WORLD. The last operating tube maker was somewhere in the Soviet region, producing a very limited selection of tubes.

That report may have slightly stretched the truth of the situation, but the simple truth is that it's almost impossible to buy a new tube, so to make a "tube type" radio you'll need to get friendly with those who salvage and sell them, or someone who collects them and might have come across some "spares."

Since nobody makes tubes any more, nobody makes tube sockets to plug them into. See above junk dealer.

Since the AM Broadcast Band is at a very low frequency (for radio) the variable capacitors need to be much larger than the things people are still using, so finding one in the right size range again will almost certainly take you deep into someone's junk bin. There is some AM broadcasting still at "Short Wave" frequencies, but at these higher frequencies having exactly the right components and assembly becomes much more critical.

Homebuilts that people made in the olden times could get by with an RF amplifier stage and a rectifier - basically two or sometimes 3 tubes; but with the amount of "noise" around now an AM radio is going to be virtually worthless unless it's a "superheterodyne" circuit. You're unlikely, with any simpler circuit to be able to "lock" onto any broadcast frequency other than strong local stations with sharp enough drop off on either side of the carrier frequency to avoid picking up more noise than signal.

IF you want to "go classic style" you'll need batteries of two or three different voltages. Since they don't make 'em any more in the voltages required, you'll need to hit Radio Shack or similar place for "battery holders" that you can use to wire piles of little ones into the appropriate big 'uns. (Common tubes used 37.5 V plate voltages, so you'll need 25 1.5V flashlight batteries in series. There are 15 V tubes, but they were less widely used, and only late in the "vacuum tube era" so they're likely to be hard(er) to find.)

An old ham radio handbook (called the ARRL Handbook in the US, for the Amateur Radio Relay League) might give you enough info to whip up a workable circuit, if you can find one that dates to the 1960s or before - preferably before.

The instructions that Skipy posted for a crystal set are fairly complete, although if a link had been posted you could see the pictures. (or maybe he scanned it from his old boy scout "merit badge book").

In crudest form, one doesn't even need a capacitor. One layer of B&S #28 wire wrapped around the cardboard tube from the center of a roll of toilet paper (US style at least) with the turns cemented in place with "Duco" cement painted on with a brush after winding very carefully and evenly will have enough "self capacitance" to tune, with the right number of turns, to the US AM Broadcast band. A wire wrapped around a piece of graphite pencil lead and twiddled against the sharp edge of an old carbon steel double-edge razor blade, with the blade connected to one lead of a high impedance earphone, will give (if you twiddle right) enough rectification to extract hearable audio from a reasonably strong station. I used one I built like that ca. 1948, with only a coathanger for an antenna, for a couple of years (in the bedroom after lights out) before it got trashed. Of course I probably just got lucky with the windings etc., and trying again might not work at all.

IFF you want to build anything with tubes in it, you'll want to search the junk sales for a copy of the "RCA Vacuum Tube Handbook." They quit publishing it in the 1960s¹, I think, but by then it had all the tube types that ever would be built, with the few "properties" you'll need to know to substitute what you can find for what think you want.

¹ The "Sylvania Transistor Handbook" came out only a little before the Tube book ceased being published. It was similarly "thorough," but was published for less than a decade because integrated circuits drove the "discrete transistors" pretty quickly out of widespread production. Now you buy a chip, connect it to your earphone, slap on a battery, and you're up and running. (only slightly kidding.)

John