Fred Sutter's original "QST-40" power supply is a nice study in empirical design. He used a choke-input supply for stability under varying loads and a fairly low-resistance bleeder resistor to keep the B+ from soaring between Morse elements. The power transformer is one a contemporary ham could have readily salvaged and the rest of the parts were pretty stock -- in 1938.
Today, we have fewer choices. Specs are more stringent, too; there's usually more safety margin for a given current rating and modern measurements of choke values are less optimistic. Hammond transformer has probably got the widest range and availability of any outfit still making tube-suitable iron, so I've worked from their catalog. It's good news and bad news; the plate transformer will run $80 to $100 and the filter choke is another $46 to $50, but you can get them;* the rest of the parts are quite reasonable.
Here's the untested, not-yet-built power supply so far:(Click on it for a large version) There are a couple of options for the transformer and different filter circuits for each one -- either a 279X (850VCT at 170 mA) using a choke-input filter (leave out the 8 uF filter condenser!) or a 273BX (700 VCT, 175 mA), with a pi-section filter. As I have noted on the drawing, you really don't want to try the pi-section filter with the higher-voltage transformer.
5U4 or 5Z3 is your choice; the former is an octal tube, the latter 4-pin but they're otherwise the same. 83V is another possibility.
I also detail two options for the bleeder resistor, which additionally supplies lower B+ voltage to the screen of the 6L6.
The biggest change is in how the B+ is turned on and off; the five and dime no longer sells nice ceramic-based knife switches (more's the pity) and even if they did, it's not a very user-friendly means to that end. So instead, I added separate filament transformers for the 5u4/5Z3 rectifier and 6L6. This results in two good things and one "gotcha:"
1. Now you can turn the B+ on and off by switching the primary voltage; you can even do fancy pilot lights for filament and plate voltage, just like the big rigs!
2. With no heater voltage being drawn, the plate transformer's got a little oomph to spare. (If it has too much, Hammond provides primary taps for 115 and 125V mains).
3. Mind that heater transformer for the rectifier! It's only providing 5V to the tube but it's got the full B+ voltage on the secondary. Hammond hi-pots them at 2kV and it uses "two-bobbin" construction, with primary and secondary on their own plastic spools, but
The output connector is notional at best; you can still find the old Amphenol plugs and sockets at places like Radio Daze and hamfests. A terminal strip would work as well -- just keep your pets and extremities clear!
I'll close by repeating that this circuit has not been built and tested. While I have done my best to predict how it might behave, I cannot verify its safety or suitability; proceed at your own risk. (On first power-up, I'd want a big old 100W or 60W incandescent in series with the hot side of the incoming power, and I'd use a GFI-switched outlet strip to turn it off and on. I'm not much for excitement.)
* Angela Instruments, listed under "Sources" in the sidebar, seems to have the best prices at this writing. Antique Electronic Supply, Radio Daze and Parts Express all stock Hammond transformers.