I've been reading about which power supply to get, and all the recommendations I've been seeing have suggested that one should get a cheap old HP power supply and not one of those cheap new Chinese ones. I am looking to get a cheap linear power supply that has a small ripple. My question is though are all of the old hp power supplies more or less the same? For example I've been looking at the HP 6200B and the 6286A, but I know so little about power supplies to know what the difference is between them. Is there a big difference? And can someone recommend a particular model for me?