How to design power supply for tubes?

[Realeigo]

I am trying to design a SLO 50 with a different clean channel, from a plexi.
But i can't figure out what i need for the powersupply..
Becaus it's changed i't should become somewhat different.
Wich caps, and wich resistors should i use?

Edit: I am going tu use Mercury magnetics JTM 45 trannies. The PT is the 500v B+ one.

Here's a pic of the slo lead channel with the plexi channel

WIth maybe some errors too.

Please help me design this into a working good preamp!

[carlg]

You want to take that 10K/1watt resistor that's hanging above v2 in the plexi part and connect it to some part of the power supply rail from the the other schematic, which isn't shown in this schematic. Shortly downstream of the phase inverter would probably be fine. Exact resistor or cap values in this part of the power supply aren't needed to make it work, they fall under fine tuning/experimentation. Those resistors in the power supply rail drop the voltage down as you move downstream from the power amp. There's a very wide range of voltages that will "work". Higher voltages will allow the stage to pass a larger signal, which may or may not be what you need. To be "plexi correct" you'd want to tweak the resistor to give the same voltages as a stock plexi, I don't have those but if you connect this to around 300Vdc you should be fine.

I think you'll need to spend some more time on the switching or mixing of these two channels too. That 470k/500pf you've got in the plexi channel was half of the mixing point in a plexi, you don't need it the way you have it laid out now. I'd use the tone stack from the plexi in that channel if I were you and after that you're going to need something to mix or switch the channels. Very doable project though, good luck with it.

[Old Tele man]

..."how to design" a power supply? Work backwards from the preamp to the power stage...determining both (a) desired VOTLAGE levels (remember preamp tubes are down around 100-250Vdc) and CURRENT levels (rule-of-thumb: ~1mA per triode, unless a driver tube like REVERB circuit).

...Preamp tubes need the most well-filtered but LOWEST DC voltages, while intermediate voltage amp tube(s) (like post-tonestack, PI, etc.) need MEDIUM level DC voltage but less critical filtering, while the power tubes need the HIGHEST DC voltages but can tolerate LOTS of ripple, due to cancelling action of push-pull OT, and so have lowest filtering requirements.

...look at the [A] [B] [C] and [D] voltage taps along the power supply "chain" shown on older Fender amps and notice how the voltage gets lower as taps get further away from the power supply...with the highest voltage / lowest filtered voltage going directly to the OT-center tap.