There's this section on building a separate power supply....
Change over C8 and C9 to larger value, "known good" sounding electrolytics, I'd be tempted to specify at least 100uF/385V Nippon Chemi Con (radial leads) VX series, these will be a VERY "tight fit". Also find a way to bypass them with at least 0.47uF Wima MKP04 or better (tight fit again). You could use Black Gates again, or Elna Cerafine if you can find them, the Cerafines I quite like, the Black Gates I don't like that much.
If I'd build another unit from scratch I would use a pair of Ansar
Supersound 32uF + 32uF 400V, but these are 4" long and 2.5" in diameter, no way you get them inside the original EAR case. And they cost around 50 Bucks each too....
They are available from Cricklewood Electronics in London, you'll have to e-mail them for details.
http://www.cricklewoodelectronics.com/If you modify an existing unit retaining the on-board supply change D1 & D2 to soft switching, superfast types and place a 100 Ohm 2W Resistor between the transformer HT secondary and the Diodes.
In a scratch build unit I actually would/do use a 240-0-240V Mains transformer and a Valve Rectifier (6X4/EZ90 or 6CA4/EZ80/EZ81), and make two electrically independent supplies, with the HT Rail in the EAR split up between the channels, so that C8 and C9 doubled up, R13 doubled up but changed to 200/220K per channal and R14 doubled up and changed to 20/22k per Channel.
Transformers and rectifiers realy belong into a seperate chassis, so C10 and on are off board, I'd recommend per channel a filter chain using 3 pcs each of 510 Ohm Resistors and 3 each of Nippon Chemic Con 47uF/450V Axial Electrolytic Capacitors (Radioshack in the US sells them) or better for that. Of course such an external unit may be added to an original EAR and the HT MAY be split up there too as detailed above if the original supply is stripped out to make room.
To me such a supply sounds much better on pretty much all accounts compared to the original. I have tried both a completely split supply (two transformers and all seperate from there on) and "semi" Dual Mono Supplies that have a common Transformer and rectifier and split up after that.
I have found (not only for the EAR and other phonostages) that if only one main supply exists the arrangement originally used in the EAR is the better one. If you have two complete seperate supplies, bring the two grounds together near the Input, to signal ground and split the PSU Rail as discussed above, taking care to return the negative side of the second added capacitors directly to the same point where the original capacitor is connected.
What do you knowledgeable valve power supply people think of the above suggestions?
