I had a linear power supply custom made from individual parts.
All I really know is that I now have a two-box unit and that there are some relatively big transformers and new capacitors in the boxes.
Now that I know that it works great I will ask the technician:
1. to try and explain to me -exactly- what he did.
2. if he would do anything different if he had to do it over again.
3. is there anything more that could be done.