[JimJ]

So I've got a need for 145V-ish of B+...thinking about doing a choke-input supply with a 5Y3 or 5U4G rectifier. I've been playing around in PSUD2, but I think I need more help

What's the recommended way to "tune" the B+ if it doesn't exactly get to where you want it? A dropping resistor, or fiddling with cap values?

I was looking at a design from JE Labs, was 20H -> 100uF -> 12H -> 100uF, but even starting with a much lower voltage transformer, I couldn't get the B+ low enough. Or would getting within 30V be "close enough"...

Thanks in advance 

[Niteshade]

The peak voltage will be approximately 1.4 times the transformer's secondary (relative to center tap) voltage IF you place a filter capacitor directly after the rectifier. If you have a 145 volt transformer, place the choke in between the center tap and ground. This will reduce the peak voltage output under load. Choke size: Around 10h should do. It doesn't sound like you'll have much of a draw.

If this is for a preamp, you can try wiring the choke as I said and/or making a voltage divider from the 5U4's output (use pin 8 so 5AR4's can be subbed). Filter the output after the voltage divider. Use 10 watt resistors to make it and account for the wattage that both resistors in the network will have to absorb. I would NOT exceed 5 watts per resistor with 10 watt resistors.

[nullspace]

Do you already have the power transformers on hand? If not, you might think about getting custom power transformers made to your specs. I have been getting mine from Heyboer for a number of years now. I model the supply in PSUD2 and then get them to knock out a pair for me. Prices are reasonable, about what you'd pay for Hammond, and turnaround is quick -- usually a week or two. Results have been positive. I think ElectraPrint and Edcor will also do custom power transformers.

[JimJ]

Do you already have the power transformers on hand?

No, I was looking at the Hammond 300 series ones, EPs would be really nice though

Also wondering if it's worth it to go separate filament/HV transformers...I'm going to be running regulated DC for the heaters anyway.

[nullspace]

I've read good things about the Hammond 300 series, but from personal experience can absolutely recommend against the 700 series. I'm sure the ElectraPrint iron is first-rate, though I've never used Jack's wares. The stuff I've gotten from Heyboer has performed very well, but doesn't have the sex appeal of the trannies from EP or Magnequest.

No direct experience, but I've read that for a top-shelf amplifier separate HV and filament transformers help isolate the power supplies. Seems reasonable to me.