Hi Clive. We'll I have reconstituted someold pc power ssupply's that I use to run my 12v battery charger this give me around 20a. Good for a cheep bench 12v supply. They have the added advantage of having 5v and 3v if I need them. But that's as much as I have done. I know my way around a multimeter thow as I'm a heating breakdown engineer. I will have a look on YouTube and see if I can find a video on building a linear supply that will give me what I need. Thanks for all the input.