My absolute favorite PSU is the first one, the colourful one (no, it's not sparkling!). My father build it in the 1980s after a plan made by ELV - one of the few products designed by ELV that doesn't have ANY special ELV branded Item in it. Sadly, it broke down shortly after my father died because of my inhability to think clearly at that time. I will repair it in the future, but maybe I need some help from you there.
However, why do/did I love this thing?
- 19" Rackmount formfactor
- Two independant voltage sources, one can go slightly into the negative, the other one can be current limited
- nice feel, rigid build quality
- ground lift switch
- fixed output voltages
- 4 wire output at one channel
- remote controllable
- I love analog instruments!
- Dad build it
No cons at this one, for what it was designed, it seems perfect to me.
We used that thing in the basement lab, so when I was working in my teenagers room I needed something, too. I first build the big black 19" rackmount thing, which is basicaly a high voltage tube regulated power supply on the one channel, combined with a variac (is that the right word for a variable auto transformer?) and a 40V 25 amps power transformer at the second channel. This thing was very usefull when I started working with tubes, but it has some negative aspects...
pros:
- generates nice high voltage for most common tube experiments (up to 360V at 100mA short time)
- Output voltage is very stable because of a big output cap and good regulation of the EL34 tube
- 40V 25A AC output is more then enough for most experiments.
- I still love analog instruments...!
cons:
- DC voltage and current too low to use in advanced tube experiments
- DC path is dangerous and has a slow regulation due to big output capacity
- no low voltage high current DC output
- high voltage transformer is too small to handle 100 mA continuously. It should have been able to deliver up to 450V, but with any significant load attached it drops down to around 360V.
- nobody wanted to carry that beats up to the third floor when I moved into this apartment, so I had to carry it by myself
One of the biggest cons at this one, besides the immense weight, was that it didn't deliver any DC voltage with anything above 100 mA power (actually, it didn't deliver any DC voltage below 50V at all...). So I had to get another one. After some projects of building a variable switch mode power supply (which failed spectacular) I was frustrated and bought the third one, a noname Power Supply which is capable of delivering 2x 0-30V / 3A. This is what I use now on a regular base, mainly because I didn't repair Dads old PSU untill now. That thing is quite okay, it's one of those range switching PSUs that use relais to switch the secondary transformer windings. I found that under different brands all over the world, for example I saw one labled Mastech, one from Conrad Toolcraft and so on...
pros:
- Quite compact. No heavyweight!
- two independant channels with enough voltage/current capability to work with
- Channels can be combined in series or parallel.
- GND is floating but can be connected to earth via a bridge
- stays cold due to the switching-thingy
cons:
- switching-thingy produces some noise which can disturb sensible electronics.
- digital displays... meh. I don't like them. It's nice for fine adjusting the voltage, but for amps I definitely prefer the old fashioned analog meter.
- cheap build quality