Does anyone else have any thoughts on the el-cheapo isolation transformers  I put at the top of the thread?

WM - Thinking in terms of which parts of a HiFi put noise out onto the mains, in some places I've read that power amps are the biggest source, and in other the digital components.  If it were the power amp it would make sense to put an analoge pre-amp with the digital stuff, but if the digital components were the problem then putting the pre with the power amp would make more sense.  Should I ever get round to having two isolation transformers, then I guess it will be just be a question of trying things out.  Much as I'm going to do with HenryT's PowerKord which arrived this morning   .