Transformer rectified power supplies are incredibly simple. You can use a single diode as a half-wave rectifier and filter it as well as possible. Or you can use a pair of diodes to form a full-wave rectifier.

With four diodes, you can form a bridge. That's what Douglas was doing with the tube dual diode and the pair of solid state rectifiers. He was making a bridge rectifier.

I'll probably just go with a dual diode full wave rectifier and a filter. I'll probably use a large choke instead of the constant current source too. Then I can always change the circuit later and do Douglas's design for a mod. That's kinda how I did my Paramours too - First as the original plans showed having no CCS, and then later I added them and compared the two.

• Tube Power Supplies

I did, however, get the Bottlhead SEX amp (BTW it is integrated and does not a pre) built. The voltage check was dead-on, but the smoke test was just that - SMOKIN' SEX. I toasted the PS transformer. Pulled it apart and found I missed one solder joint. I'm hoping that was the only problem. I should have a new transformer in 3-4 weeks.

I pulled out an old project that I set aside a couple of years ago. It's a chip headphone amp I saw on headwize. I'm should have this up and running in a day or two.

Back to the present. I have been playing around with PSU Designer (Duncan Amp Tools) for the power section. Pretty cool interactive tool for designing both tube and SS rectified PS - and it's FREE. I am still really leaning towards John's original idea. It's simple and there is a very done web site. Did anyone catch the Power Point presentation? One of the pictures is hot-linked.

John, you mentioned beefing up the PS. Haveyoulooked into upgrading the parts? You know, beeswax caps? Seriously, the part count is so low that it might be a worthwhile project for each of us to do a slightly different variation of the same theme just to see how the sounfd is affected. I would have no problem sending mine to you for a head to head. Maybe you could do an honest write-up, like you mentioned over at the Dungeon. I am still trying to resond to that post. I've got a few stories to tell about honest peer review......Colin

The PS cap I sugested is a 370VAC rated item, good for use at more than 600V( I have factory labeled 330VAC-rated ASC with 600VDC tags on them ). At ~$10 each, I suggest buying a few. They are quite good.

On the chassis, Lowe's has cut 1x4 hardwood for my last base quite cheaply. Glue, a Square and some weights( or proper clamps ) make asembly easy. Look at sheet metal shops for the plate. a 13.5 x 18 inch piece of .125 plate cost me $22. You should consider paying a bit extra for a clean, unscratched piece, or plan to spend extra time fixing some of the nicks...

ON parts, from Mouser:
switch, 633-S331T @ $6.60
IEC socket 161-3516 @$1.41
Filament DC capacitors 10,000 uF/16V Low ESR 647-UHE1C103MHD @$2.45 each. It would probably be best to use 25V-rated and go smaller in capacitance...
Filament diodes, 512-SB5100, 5A/100 PIV Schottky diodes
Filament TX, mouser has lots of Hammond.

If you want more than the cheapest, and simplest, the first and most important upgrade is the active loads. Use the cascode circuit. It is the easiest, most cost effective( additional gate stopper and $2 DN2540N5 mosfet ) improvement to this design. Don't plan on neglecting this one when you find out how good the simpler method works, rest assured, there is still some performance 'left on the table' and it is *EASY* to pick it up.

more later, and as requested...
regards,
Douglas
!

It may be better to divide up the voltage a bit diferently. The insulation will be better protected if we don't drag a lead across other turns.

I will contact Phil at Heyboer and see what he can do for us and how much it will cost. I will do the footwork on behalf of the group, as I have been dealing with them for a while.
regards,
Douglas