Bench top power supply.

I was looking at the following DIY power supply
Laurier's Handy Dandy Little Circuits: Supply Project.html and had a few questions.

I will be using a 24VDC 1.25A Wall Wart supply in to eliminate the transformer. This one uses 2 - 2000uf 50v capacitors. I was told by the author if I used anything else that I would get hum in the circuit testing or if I wanted to get up to 4amp service I needed a mouser $50 transformer.

I've noticed most DIY lab power supplies are using 4700uf 50v Capacitors.

The 2000uf 50v caps are close to $24/ea while the 4700uf 50v are $5 or less.

Getting just the parts he has listed would put the cost higher than some adjustable lab power supply that it kind of takes the fun/lower expense of doing it your self.

I need to get as near as possible to 19VDC 4amp or 12VDC 4amp (This is what some LCD monitors are using), and as low as 5volts for circuit testing. I thought of buying a couple of LCD power supplies to have around but they are still close to $10/each.

I have several Wallwarts, but that's starting to get kind of crazy to think of having many different ones laying around.

Thanks in advance for your help.

Thanks

YES, you can have a single 4700uF/50V. A set of parts would always be costly compared to bulk manufactured end product, let it be a psu. Many times, you get a laptop power supply at 19V and few amps , much cheaper.

Generally for LCD and test bench supplies for digital circuits,
you can have switch mode supplies, instead of Linear PSU. the rectified output of wallwart con be handled by a switching regulator rather than LM317
and wallwart has isolation, a inductor based noon isolated arrangement can be foreseen.

also, IMO, it would be better to have independent suppies for LCD and bench PSU.
we need not have combined one .

So this power supply I'm looking to build will not be that great of one?

Do you have any you recomend to build that do not use the LM317?

I was thinking to find one that uses the 7805 etc.. but have not had much luck.

The idea was to get away from all the wallwarts if possible.

I would like to try and build one that has at least 3.3, 5v, 9v, 12v - I using an ATX power supply for this but it didn't do so
well keeping steady voltage output.