Xavier, a plate load dropping 20v would allow about 10vRMS swing, allowing 6v minimum compliance. That's about 0.020 watts in a 5K load ... That said, I do have some plans for a C4S loaded 45 using the Paramount power transformer; the problem is finding a reliable current source device at such high voltages. It's on my list. :^)
You can drop the plate current for a 5K load; I'd go with 30mA at 250-275v. It leaves more current for the shunt reg which is a little starved due to the PT-2 limitations. (That's another reason I want to switch to the PT-7 eventually.)
For those who bought PT-2s with the intention of resurrecting this 5-yr-old design, I'll see if we can send a paper copy of the original notes. For those who want a replacement for the original C4S board, which is no longer available, I recommend the Paramount soft-start kit and I'll throw in a paper copy of the modified circuit diagram showing the connections to that board. That should bring the project to about the level it was originally - it was never a real kit with a real manual, after all!
