300 VDC supply for DIY tube project... where to start ?

Before I start collectings all the parts for the infamous McCurdy AU300 preamp project, I'm looking to get a power supply that will feed at least two channels in the same box.

I found this kit on ebay, any thoughts, suggestions ?

http://cgi.ebay.com/Tube-Power-Supply-for-DIY-Tube-Amplifier-MM-MC-Tested_W0QQitemZ5780776024QQcategoryZ73369QQssPageNameZWD1VQQrdZ1QQcmdZViewItem



Heres the Mccurdy AU300 schematic:

http://www.nashaudio.com/DIY/DIY/McCurdy/au300.jpg

Bah... It's overkill, just more shit to break. And if you're after a "vintage" sound--the usual reason for cloning a circuit like this--then you're barking up the wrong tree with a regulated supply. Regulation was expensive/complicated in the old days and only used when really necessary. A typical console power supply would provide well-filtered but unregulated plate voltage. A push-pull amp like this has good PSRR and would benefit from regulation even less.

Get a power transformer with a suitable heater winding for the configuration you wanna use, and a 250V plate winding rated about 50mA. For the plate voltage, use a full-wave bridge (four 1N4007 diodes are fine for this) followed by a 50uF/450V filter cap. Follow this with a 1K/5W wirewound resistor and another 50uF/450V cap, then decoupling filters of 3.3K/2W and 22uF or 50uF/450V feeding to each amp. That'll give you pretty well-filtered DC of about 250V at each of the two preamps.

thanx, this is the kind of advice I need... I wasn't really keen on buying/shipping this ebay product all the way from Hong Kong.

Hammond in CANADA (my part of the world) seems to have a good selection of power trannies for tube projects.

although, the McCurdy schematic is asking specifically 290 VDC, and not 250 VDC... that's a difference of -40VDC, does this matter ?

Oh, it's 290? I thought it said 250... it's hard to read on that scan. In that case, use 1K instead of the 3.3K I suggested earlier, and that should get you in the ballpark. As you probably know, supply voltages are not critical with most tube stuff anyway.

And yes, Hammond makes at least one model that's perfect for your needs. I don't recall the model number offhand.

That's right 290 VDC,
I have a much clearer photocopy of the AU300 schematic,
and the original specs call for 290VDC.
Somebody must have modified that online/linked schematic to lower voltages.
My schematic was a special order, straight from McCurdy Radio Industries in CANADA.