What sorts of noise margins can you tolerate? Digital stuff is pretty forgiving, but you seem to be use converters, etc. quite a bit. I try not to do that too often. I can't spare the hair.

When a guy hooks up a bipolar supply and wants it adjustable with a big pot, you've got to conclude he's wanting low noise because he's going to do something in the analog domain.

I've use lots of switchers, but I buy them off the shelf, often as simple-switcher based modules that just plug into a site. Sometimes they're big supplies that go into a rack with a half-dozen others, though.

The big ones, providing dozens of amperes at 5, 12, 24, or even 48 volts and going in the other direction from common as well, have always produced a fair amount of noise on their own. Then, of course, when I'm whacking on the supplies with relays, driven by mosfets, etc, that noise begins to look pretty insignificant, until the guy who is trying to keep his circuits accurate down into the microvolts tells me he has to have his own isolated supply. He generally wants a linear supply.

RE