About a year ago I decided to build an external power supply for my Foreplay. I just recently completed it. This modification is neither cheap nor easy, I had to source the parts from various vendors, but I think you can get all the parts you need from Angela Instruments and Mouser. The Power Supply is basically a modified Steve Bench design. It is based on his Power Supply One, in fact and you could build a stock PS1 and it could power a Foreplay. But I added extra capacitance and filtering, and the B+ voltage is closer to the specified 157VDC than a stock PS1. The filament power supply is the same as the PS1 except I used a 7805 regulator on a heatsink instead of a LM309 regulator. The 7805 is cheaper and easier to find so that's what I used (you can even buy em at Radio Shack).

Here are some pictures of the Power Supply

The parts to build the Power Supply will most likely cost more than the $99 Foreplay?!

I bought the choke, power transformer, and tube sockets from Angela (you can also buy the tubes from them). The rest of the parts I bought from Mouser and few from Fry's Electronics and Radio Shack. I didn't use any fancy parts to build the PS; I used Xicon 350V Caps, and NTE 25W resistors. You could use BlackGate caps if you have money to burn, or Poly caps if you want a to build a PS the size of a refrigerator. I am considering 4 (2x100uF) Elna Cerafines at $10 each for an upgrade(Note:these caps are discountinued). As for resistors I think 12W Mills' could be substited for the 25W NTEs. The values of the caps isn't critical(+/- 50%), but I would stick to 350V rated ones. You could also fudge the values of resistor a little bit if needed.

Click Here For A Printable Schematic

Parts not shown on the schematic: I used a IEC receptacle with a built-in filter for the power connector. I isolated it from the chassis and connected the ground the the chassis using "ying-yang" diodes. I also isloated the power transformer, using vinyl grommets from Radio Shack, and grounding it via ying-yang diodes. The connection betwen the Foreplay and the power supply is via a 4 pin Jones plug and receptacle, they require a square hole which I made with a drill and a Dremel.